In this fifth and final part, I’m going to discuss the nuclear capabilities of North Korea, and dispel some of the myths behind their nuclear program, as well as the myths surrounding their leader, Kim Jong-un.

On April 5^th, 2009, North Korea launched a satellite known as Bright Star-2 into space. Their only previous attempt at a space launch had taken place in 1998 with the failed attempt to put Bright Star-1 into orbit. By most accounts, the launch of Bright Star-2 was a failure, with the three-stage rocket failing to achieve orbit, and the satellite package crashing into the Pacific Ocean. North Korea, however, disagreed and claimed that it had indeed placed a satellite into orbit, and that it was a complete success.

Whether or not they actually achieved a stable orbit with the satellite, (spoiler alert – they didn’t) North Korea’s announcement that the launch had been a complete success was probably not hyperbole. If their intent was actually to test a rocket capable of entering space at low-earth orbit altitudes, such as the type of rocket that would be capable of delivering a nuclear weapon – the type otherwise known as an ICBM, it was indeed a success. And that is what many in the intelligence community believed it to have actually been.

At the time of the launch, North Korea was involved in what was known as the Six-party talks, a gathering of six countries whose goal was to find a peaceful resolution to concerns over the DPRK nuclear weapons program. The talks were originally in response to North Korea’s advancements in creating a nuclear program since they withdrew from the nuclear non-proliferation treaty in 2003. During the talks, North Korea had made concessions such as dismantling their lone nuclear reactor, and allowing international weapons inspectors access to their processing facilities, in exchange for international aid and an easing of sanctions put in place against them after their withdrawal from the treaty.

When the remaining countries of the six-party talks, particularly South Korea, Japan, and the United States (China and Russia being the other two) strongly condemned the Bright Star-2 missile launch, claiming it was nothing more than a test of ICBM technology, North Korea angrily removed themselves from the talks, expelled international weapons inspectors from the country, and reassembled the nuclear reactor, announcing they would resume full operation of their nuclear program.

On May 25, 2009, less than two months after the presumed ICBM test, North Korea conducted its first (successful) detonation of a nuclear device. The device was probably a fission-only bomb utilizing uranium-235 as the fissile material, and it resulted in a blast yield that was likely between 2 and 5 kilotons. Not a large explosion with regard to nuclear blast yields, but a clear message to the world that North Korea was now a nuclear power.

On February 11, 2013, North Korea conducted another successful nuclear test, this one with a blast yield in the 6-9 kiloton range, and on January 6, 2016, they conducted a fourth test (third successful test) resulting in a similar yield of 6-9 kilotons. They claimed that this one was actually a hydrogen bomb, however there is nothing to confirm that, and the low yield makes that claim dubious. There is ample evidence (the bomb was detonated much further underground than previous tests) that the DPRK expected this blast to be much larger than it actually was, making it likely they failed in an improvement they’d implemented. It seems possible, with their claim that it was an h-bomb, they’d attempted unsuccessfully to detonate a boosted fission device, and it had achieved a fission-only yield.

A fourth successful detonation was made on September 9, 2016, and this was the largest yet, with a yield estimated to be somewhere between 10 and 20 kilotons.

In order to launch a nuclear strike, North Korea (which I’ll often refer to as the DPRK – the Democratic People’s Republic of Korea) needs two things: a functional and reliable nuclear bomb, and a reliable means of delivering it to its target. I use the word “reliable” in both of those things because reliability is one of the most difficult aspects of the very technical process of building both nuclear weapons and ICBMs.

As you saw in part two of this paper, a nuclear weapon is fairly simple to build if you have the necessary amounts of a fissionable metal such as uranium-235 or plutonium-239. Uranium-235 is present in very small percentages in naturally occurring deposits of uranium-238, of which North Korea has plenty. There are several ways to separate the two isotopes, but the most common and effective method is through the use of a gas centrifuge.

Centrifuges are actually collective farms of thousands of cylindrical centrifuges, all working to enrich uranium, either to a high enough percentage of uranium-235 to be weapons grade uranium, or to the lower percentage to be reactor grade uranium. Remember, natural uranium is about .7% U-235 and 99.3% U-238. For reactor grade uranium, you need to enrich the content to between 3-7% U-235, known as low-enriched uranium, or LEU, a process that is a relatively simple undertaking. In order to create weapons grade uranium, or HEU (high-enriched uranium) however, the U-235 content has to be a minimum of 90%, ideally closer to 95%. This is a much more laborious, time consuming, and complex undertaking.

We know the DPRK has one centrifuge collective for sure, and that it contains around 2000 individual centrifuges of a type modeled from an Iranian design. A group of non-government experts were allowed to tour it in 2010 and that gave us a lot of insight into just what type of centrifuges they have and what they’re capable of.

Here’s a screen grab I took from Google Earth that shows the centrifuge building (blue roof) and a truck I pointed out just for scale.

This is the only centrifuge building we know of, however, it is highly suspected, particularly with their allowing the group to tour the building in 2010, that the DPRK may have another, secret centrifuge, and we don’t know where that is, how big it is, or what it’s capable of.

It takes time to enrich uranium, and then it takes time for that uranium to be converted to plutonium in a nuclear reactor. North Korea has two nuclear reactors. One is an old model they got from Russia in the 1960s. It has the ability to create plutonium, but we know from infrared satellite imagery that it runs infrequently and probably not to the power level required for plutonium production. The other reactor they have is what’s known as an Experimental Light-Water Reactor, or ELWR. A light-water reactor is designed to produce electrical power, and isn’t as efficient at producing plutonium as a heavy-water reactor would be, (light water is just regular water, heavy water is deuterium, or 2H₂O, hydrogen that has two neutrons) however, the spent fuel from the ELWR can be processed to extract plutonium, something we know the DPRK has been doing under the guise of a radiochemical laboratory. I pulled a screen grab from Google Earth of the DPRK radiochemical lab that is actually used to process plutonium from the spent fuel.

All of these buildings and processing facilities are located at a place called Yongbyon, in the north part of North Korea, known officially as the Yongbyon Nuclear Scientific Research Center. Satellite images show modernization and construction of many new buildings all over that area in the last few years, easily identifiable by the new, blue roofs that show up well on the images.

So, what does all this mean? Well, North Korea likely has a stockpile of both HEU, and plutonium-239, enough to build a number of weapons. In this paper published in February, 2015 by physicist David Albright, he gives low-end, medium, and high-end projections on the number of nuclear weapons North Korea will have by the year 2020. He bases the projections on all the known and suspected factors,in addition to the unknown but possible factors, such as whether or not they have a second, secret centrifuge plant, and whether or not their ELWR is capable of running consistently and continuously. He then uses standard deviations to predict manufacturing numbers. For his medium projection, he estimates North Korea will have approximately 50 working nuclear weapons by the end of 2020.

Google Earth image of North Korea’s two nuclear reactors

The fact that they have nuclear weapons is undeniable, and the fact that they’ve been able to achieve miniaturization of those weapons is extremely likely, though there’s no actual proof of that. These weapons are almost certainly entirely fission weapons, with boosted fission hydrogen bomb technology still years away, and true two-stage thermonuclear devices even further. But still, fission weapons in the 10-20 kiloton yield size can be devastating enough to a city or military target. What matters now is, can they deliver them?

There are a number of ways of delivering nuclear weapons to their targets, but few of them are valid options for North Korea. They have no bombers to speak of, and certainly none capable of reaching any U.S. targets. The ones they do have are 70-year-old models from Russia that are slow and ponderous, and don’t have the range to even come close to Guam, let alone the U.S. mainland. In fact, they can’t even reach all of Japan with the bombers and expect to get back home. Plus, they’re fitted with old technology and would be easy to intercept or shoot down. So that’s not a real option.

They could possibly have the ability to detonate a weapon from one of the two satellites they’ve managed to put into orbit over the United States. This would result in an EMP, or electro-magnetic pulse. This would have a devastating impact on the United States power grid, and would result in serious loss of life and inability to function as a country, and many experts believe this is the most likely scenario of a North Korea nuclear attack.

From what I’ve read, and the research I’ve done, this is a definite concern, and the U.S. needs to take steps to harden our electrical grid against such an attack. However, this type of attack implies that North Korea has installed a nuclear weapon on one of its two satellites, and that seems very doubtful. They attempted to launch satellites several times unsuccessfully prior to the two recent successes, so the likelihood they risked one of their precious nukes in a package that was doubtful to achieve a successful orbit, is unlikely. I would be much more concerned about future satellite launches containing nuclear weapons than the two current satellites.

Ignoring the more extreme and unlikely methods of delivering a nuke, such as floating one over in a balloon, and launching a missile from a freighter that sails in close to the U.S. coastline, the only option left for North Korea is to develop an ICBM.

This is the most likely scenario, and the one they’ve spent the most effort achieving. It seems that the world is constantly underestimating the drive and determination of Kim Jong-un, including even the experts at my favorite website, 38north.org. If you go back through their archive of documents and articles, all the way back to 2009 as I did, you find numerous instances where they underestimated how quickly North Korea would achieve both nuclear, and missile (particularly ICBM) technology and success. There are several articles that project North Korea will not have a true and functional long-range ICBM until 2020, 2025, and even later. Yet, it seems that they’ve developed one already here in 2017, and you can read the surprise in the voices of the analysts each time Kim Jong-un achieves a stepping stone they didn’t think would be possible for many years.

If you spend enough time studying North Korea’s advancement in missile technology, you can see the incredible leaps they’ve been able to take, starting with their medium range ballistic missiles, up to their intermediate range ballistic missiles, and right up to the July 4^th, 2017 launch of their first ever long-range ICBM, known as the Hwasong-14. Take a look at the state footage of that launch:

https://www.youtube.com/watch?v=tD9styRiuYQ

Note a couple of things: First is that Kim Jong-un is present during the unloading of the missile onto the launch platform, which shows the extent of his direct involvement in the evolution of their nuclear program. You can find pictures and video of him at all major stages of development, watching the tests closely, and consulting with the scientists directly involved. The next thing to note is that, despite the DPRK claims that this was a mobile missile launch, it was clearly not launched from the transport truck, but rather from a platform that was set up in advance. This is important because the ability to launch from a transport truck would mean that North Korea was able to forego much of the preparation time necessary to launch a nuclear warhead – preparation time that gives the United States time to notice the preparations and monitor them so as to not be taken by surprise.

Now, granted, the platform that launched the missile was some type of temporary and mobile platform; not as efficient as launching directly from the mobile truck, but still as step up from the requirement to launch from one of their two permanent launch facilities, one of which is pictured below, grabbed from Google earth.

This Hwasong-14 missile also appears to be liquid-fueled, and that’s extremely important. Liquid fuel takes a lot of time to prepare, and it can only be loaded into the missile just prior to launch. Liquid fuels need to be kept at a constant extremely low temperature, and the fuel bleeds off as it warms. Liquid fuels are also extremely volatile. Notice how slowly the truck was driving in the video? Large bumps can cause the liquid fuel to explode. If North Korea is able to convert the Hwasong-14 ICBM to a solid-fuel missile, it will become a much bigger concern, and they have proven the ability to create solid-fuel rocket motors, as evidenced by this video from last year:

https://www.youtube.com/watch?v=lsxOg2fXQMc

Analysis of the Hwasong-14 launch of July 4^th, 2017, showed that it was capable of delivering a payload of up to about 1000 – 1200 pounds all the way to the west coast of the United States. Remember, an ICBM goes into space and then has to come back into the earth’s atmosphere on its ballistic trajectory, which means that it needs a reentry vehicle to survive the extremely high temperatures when reentering the atmosphere. This reentry vehicle is going to take up much of that weight, and North Korea did test reentry vehicle technology as seen in this picture from KCTV/Reuters, modified by 38north.org:

The weight of the reentry vehicle is part of the payload, but leaves just enough for the type of nuclear device North Korea is thought to possess. And that’s a bad thing. The good thing is that the reentry capabilities of this particular missile hasn’t been tested, nor has its ability to successfully carry a nuclear payload at the extremely high speeds achieved during the ballistic portion of the missile’s flight. One little shimmy as it reenters the atmosphere, and the reentry vehicle will tumble and burn up. It typically takes years for countries to make new missiles reliable and safe, and despite the rather rapid pace of North Korea’s advancements, they can’t guarantee the success of untested and unproven missiles.

Here’s an excerpt from an article written last month by John Schilling on 38north.org, about the future capabilities of the Hwasong-14.

Thus, we expect there will eventually be more than just a single warhead under the shroud. But it probably won’t be multiple warheads, at least not for a decade or more. Multiple warheads of the size North Korea has displayed and can plausibly build today, along with reentry vehicles to carry them, simply wouldn’t fit. To put multiple warheads inside that fairing, at a weight that would still allow intercontinental reach, North Korea would have to develop a lightweight nuclear warhead comparable to the W-68 warhead of the US Poseidon missile. It took the United States almost 15 years to go from building the sort of nuclear weapons North Korea has today to the W-68. And while the North Korean missile program has been conducting tests at an accelerated pace, they have conducted only two nuclear tests in the past four years. So perhaps in 2030 we will see a multiple-warhead Hwasong-14, but probably not before then.

Keep in mind, as I mentioned earlier, 38north has been wrong about the capabilities of North Korea and their advancement abilities before, but it seems that at the very least, we don’t have to worry about multiple warheads (MIRVs) on a North Korean ICBM anytime soon.

The difficulties of designing a vehicle that can survive the heat and friction of reentry was shown in the next test. On July 28^th, 2017, North Korea launched another missile, thought to again be the Hwasong-14, but this time with a larger second stage, powered by a higher thrust-producing engine. This missile flew for 45 minutes, and reached an altitude of more than 2000 miles. Now, this is WAY up into space. As a comparison, the International Space Station orbits earth at an altitude of about 250 miles, so this missile flew well past what would be considered low-earth orbit. Based on that high apogee, the range of the missile was calculated to be somewhere north of 6000 miles, which caused great consternation in the media as they reported that North Korea now had a missile that could reach Chicago, and possibly as far as New York. This is somewhat accurate, but, as President Trump might say, actually “fake news.” Yes, it’s true that in a perfect simulation, with a perfect ballistic arc, the missile could have flown that far. However, it didn’t have the weight of a warhead, and it didn’t survive reentry into the atmosphere.

Video taken from a Japanese television station weather camera which looks west into the Sea of Japan, catches the missile as it reenters the atmosphere. This was a night test, and so the reentry vehicle is clearly seen glowing as it begins to heat up from the reentry friction. Here’s the footage:

https://www.youtube.com/watch?v=AEh9–yJQPs

Although it’s grainy, analysis of the footage clearly shows that the reentry vehicle is breaking up as it falls through the atmosphere, which means that if it had contained a nuclear weapon, the weapon would not have survived the reentry and would not have exploded. North Korea clearly has more work to do to actually produce a reliable nuclear delivery system that can target the United States mainland.

That doesn’t mean that they can’t target other U.S. assets though. Guam is clearly within reach, and they have numerous ways to target U.S. allies such as South Korea and Japan. And, North Korea is certainly capable of making threats to do just that. Preemptive strike threats are nothing new to them, in 2010 alone they threatened preemptive nuclear strikes twenty times.

So, missile technologies aside, why shouldn’t we fear them?

Mostly because, despite what the media loves to report, North Korea is not a “hermit nation,” and Kim Jong-un is not an “unpredictable madman.” North Korea watchers are mostly in agreement that Kim Jong-un acts in unpredictable ways, but with a predictable path. He’s very aware of the capabilities of the United States, and he’s very aware of what a nuclear strike against U.S. interests and U.S. allies would mean. Above all else, he’s extremely motivated toward self-preservation, both for him and for his regime, much like his father was before him, and his grandfather was before his father.

If Kim Jong-un ever feels that the United States is about to make a strike against him in a decapitation attempt where he feels he has nothing to lose, he will likely launch whatever weapons he can. But that is again due to his self-preservation instincts. Other than that scenario, he knows the consequences of an actual strike. He also knows he can rattle his sabers and make all the threats he wants, safe in the knowledge that the American people, and the world in general, would never tolerate a first strike against him or his country, despite his verbal grandstanding and blow-hard announcements. In short, he’s no different from the teenage bully who struggles to get away from his friends who are, “holding him back,” while he shouts insults. All bluster, secure in the knowledge that as long as he toes the line without crossing it, he’s safe.

Last week, Kim Jong-un threatened to launch two ICBMs into the waters off Guam, and Donald Trump responded by threatening to shoot down the missiles. Trump also made threats against the country itself: From CNBC

“North Korea best not make any more threats to the United States,” Trump told reporters, speaking slowly and deliberately with his arms crossed in front of him. “They will be met with fire and fury like the world has never seen. He has been very threatening … and as I said they will be met with fire, fury and frankly power, the likes of which this world has never seen before.”

He later doubled down on that statement, saying that against the likes of the Kim regime, it might possibly not have been a strong enough stand, following that up with vague statements about what he meant, saying, “You’ll see,” when asked for clarification.

The left-media had a field day with these statements of course, stating that Trump had “threatened nuclear war,” and that he had escalated the situation to unacceptably high levels of danger. However, as we’ve seen, North Korea does not have the capability to launch any real attack. Yes, they could possibly launch a nuclear missile at Guam, but that would be the end of Kim Jong-un, if not of North Korea itself.

Not only would that mean a massive retaliation, it’s unlikely the missile would be a success anyway. The United States has a pretty good missile defense network, which I’ll discuss in a bit, and Kim Jong-un is very aware of that fact.

So what was Kim’s response to Trump’s statements? Did he launch his missiles toward Guam? Did he escalate the situation and bring the Korean peninsula to the brink of nuclear war as the alarmists and sensationalists predicted with their outraged shouts? No. He backed down, away from the edge of the cliff, which came as no surprise to those outside the north who watch him and know him best. A quote from 38north’s Robert Carlin on August 15^th.

The North Korean report that Kim Jong Un has said he will wait and see what the United States does before deciding whether or not to order execution of a plan to envelope Guam with four Hwasong-12 missiles signals a decisive break in the action. This is no mixed message. It is exactly how the North moves back from the edge of the cliff. It’s classic, and anyone paying attention could have seen it coming.

This is not a question of parsing the precise language Kim used. It’s the act itself that speaks volumes. Put that together with the fact that the regime hadn’t been mobilizing the population for imminent crisis over the preceding four or five days, and you get a familiar North Korean dance move. Didn’t Kim say he was just giving the Americans a little more time? Of course! He’s not going to say “I surrender” or “I’ve decided that launching missiles would be a bad idea.” This way he can project the aura of the one still in control of the situation, of the one who scored the victory, of the one who kept the region from descending into war. He can be seen as the one who has the whip hand.

Not to turn this into a blog where I support Trump and his moves, because I don’t; most of them have been complete disasters. However, these statements by him were spoken in a language that Kim Jong-un was able to understand. Neither Trump nor Kim have any experience in diplomatic speech and carefully crafted statements. His regime doesn’t speak “diplomatese.” Remember, they made 20 preemptive nuclear strike threats in 2010 alone!! Kim Jong-un only understands the language of force, and Trump delivered that message to him very convincingly, in a way that caused him to step back while still attempting to save face. Accidentally or intentionally, Donald Trump spoke to Kim Jong-un in a way that he’s not used to being spoken to, and in language that he understood and feared. Trump is much more unpredictable than Kim Jong-un is, and no doubt his advisors warned him that he wasn’t dealing with a pushover in the White House, and Kim is the one who chose deescalation.

Now, let’s discuss some of the United States defenses against a missile strike. Obviously, we have enough nuclear weapons with high enough yields to turn the entire country into a smoking pothole and make South Korea an island nation, so retaliation for a nuclear strike is our biggest deterrent, but not only that, we have actual defensive capabilities against any initial strike Kim Jong-un may make.

THAAD – Terminal High Altitude Area Defense

This missile defense system is designed to shoot down ballistic missiles while they’re on their way down, during what’s known as their terminal phase, hence the “Terminal” in THAAD. The missile is capable of mach 8 speeds, and can intercept missiles nearly 100 miles above the earth’s surface. Now, these missiles shoot down the short and medium range ballistic missiles that might be fired at South Korea and Guam, but do not shoot down intercontinental ICBMs with their significantly higher speeds. Their deployment in Guam and South Korea however, does allow early warning radar of any ICBM fired toward the continental U.S., which allows our other missile defense assets more time to track the incoming warheads.

Patriot system – In particular, PAC-3

This system is designed to shoot down ICBMs, and has incredible ability to determine which warheads are armed in the event of a final stage that deploys decoys along with the actual warhead carrying ordnance, or in a multi-rocket launch where some are pure decoys. These systems are deployed at military bases along the west coast, as well as Guam, Hawaii, and other potential target areas. It’s an incredible defensive weapon, and you can read more about it HERE.

Aegis Ballistic Missile Defense System

The United States has 30 of these Aegis systems on cruisers and destroyers split between the Atlantic Ocean and the Pacific Ocean. These have some of the most advanced radar and tracking capabilities today, and are capable of shooting down a ballistic missile prior to it beginning its reentry stage. It even has the ability to shoot down a satellite from low-earth orbit, mitigating fears that North Korea might deploy a satellite containing a nuclear weapon meant to cause an EMP. This ability was proven in February 2008 when an Aegis-equipped ship in the Pacific destroyed a U.S. satellite that was failing and in a degrading orbit, over fears its radioactive payload may contaminate land areas when it reentered the atmosphere. Pretty amazing technology that could come in handy if North Korea launches more satellites.

Ground-Based Midcourse Defense (GMD) System

This system, our best defense against long-range ICBMs, is currently deployed at Vandenberg Air Force Base in California, and at Fort Greely in Alaska. It has the ability to shoot down ICBMs while they’re in the space portion of their flight, outside of the atmosphere. These interceptor missiles are three-stage, solid fuel rockets that sit in underground silos. They’re 55 feet long, and can intercept even the fastest long-range ICBMs. Here’s a picture of one being loaded into a silo at Fort Greely.

These defensive systems, along with a few others I’m leaving out, and near-future technologies that will likely consist of space-based platforms which will be able to target, track, and shoot down missiles entirely out of the atmosphere, make it difficult for nations like North Korea to actually convincingly threaten the United States and our allies.

If North Korea decided to fire a long-range ICBM toward the mainland of the United States, a lot of things would have to go right for them to be successful. First, the missile would have to launch correctly, something they’ve thus far only been able to achieve at a rate of about 50%. Next, the missile would have to be able to hit a target, something that even with the “close is good enough” theory of nuclear explosions, is not easy to accomplish. For example, it’s thought that many of their successful missile launches have landed as much as 10-50 miles from the intended landing area. Next, the missile would have to survive reentry, something they’ve not yet accomplished with any of their long-range ICBM tests. Next, the warhead would have to work. This is something I didn’t discuss, but the forces that act on a missile and reentry vehicle during the flight portion are extreme, and nuclear devices have to be built to withstand those forces, something that requires an enormous amount of testing to accomplish — testing North Korea hasn’t yet done.

Next, the U.S. would have to miss with every attempt to shoot the missile down. We can intercept ballistic missiles with a success rate of well over 50%. Now, if North Korea fires ten or fifteen missiles at a time at the U.S., some containing actual warheads, and some as decoys, we’re going to miss a few, guaranteed. But let’s be clear, the U.S. is going to certainly fire all 40-some GMD interceptors, along with a bunch of Patriots and THAAD missiles at these things, so it would take a lot of ICBMs at the same time to get one through, something North Korea is not capable of doing as of yet.

So, what happens if they somehow manage to beat the odds and successfully land and detonate a nuclear warhead on a U.S. city? Well, if you happen to live there, it’s going to suck for you. The nukes they have, in the 10-20 kiloton range, will have a destruction radius of around one mile. If you live within that one mile radius of the detonation point, you’ll likely die instantly. Outside of that, as long as you’re somewhat protected, such as being indoors, you’ll probably survive. Depending on the altitude at which it explodes, there may be some radioactive fallout, so you’ll want to not be downwind of the explosion point.

However, all of these difficulties combined makes a scenario so unlikely that I’m much more concerned with things like the advancement of artificial intelligence that I feel is a real threat to all of mankind. Nuclear war with North Korea might be a concern in the distant future, when their capabilities improve dramatically, but as for now and the foreseeable near future, dying in a nuclear attack from North Korea is not something we should be spending much time worrying about.

If you want to read more about nuclear weapons and just how they work, be sure to check out parts 1-4 of this article.

Bibliography and sources:

Many of my sources are actual links in the article. The ones I didn’t specifically link to are listed below.

Geneticist James Crow study: http://www.rerf.jp/news/pdf/residualrad_ps_e.pdf

Radiation effects of Hiroshima and Nagasaki: http://www.atomicarchive.com/Docs/MED/med_chp22.shtml

Radiation effects on humans: http://www.atomicarchive.com/Effects/effects15.shtml

The British Mission: https://archive.org/stream/TheEffectsOfTheAtomicBombsAtHiroshimaAndNagasaki-ReportOfThe/british-mission-to-japan_djvu.txt

Halifax Explosion: wikipedia.com/halifax_explosion

Firestorms from nuclear explosions: http://www.atomicarchive.com/Effects/effects11.shtml

Dead Hand: https://en.wikipedia.org/wiki/Dead_Hand_(nuclear_war)

National Nuclear Security Administration: https://nnsa.energy.gov/aboutus

Yield to weight ratios: http://blog.nuclearsecrecy.com/wp-content/uploads/2013/12/yield-to-weight-trends.png

Design of Fat Man and Little Boy: https://web.stanford.edu/class/e297c/war_peace/atomic/hfatman.html

Alex Wellerstein – Asst professor of STS Stevens Institue of Technology: http://blog.nuclearsecrecy.com/about-me/

Nuclear physics of atomic bombs and thermonuclear devices http://www.barryrudolph.com/pages/atomic.html

Hydrogen bombs lecture: http://work.atomlandonmars.com/h-bomb-lecture/Wellerstein-HydrogenBombLecture-Slides.pdf

Harvard PhD dissertation of Alex Wellerstein on secret patents for the atomic bomb: http://alexwellerstein.com/atomic_patents/

A guide to nuclear weapons from the nuclear weapons archive: http://nuclearweaponarchive.org/

History of the atomic bomb in WWII: http://nsarchive.gwu.edu/nukevault/ebb525-The-Atomic-Bomb-and-the-End-of-World-War-II/

DPRK missiles: http://www.armscontrolwonk.com/archive/1203680/the-more-you-kn-0w-about-north-korean-missiles/

Nuclear proliferation article: https://www.nobelprize.org/educational/peace/nuclear_weapons/readmore.html

Discovery Channel – Ultimate explosions – Tsar Bomba https://youtu.be/aMYYEsKvHvk

http://nuclearweaponarchive.org/Usa/Weapons/B83.html

http://www.atomicheritage.org/history/soviet-atomic-program-1946

Declassified CIA Soviet Atomic Energy program report: https://www.cia.gov/library/readingroom/docs/DOC_0000843187.pdf

Project Crossroads atomic testing: https://www.osti.gov/opennet/manhattan-project-history/Events/1945-present/crossroads.htm

https://www.physicsforums.com/threads/touching-weps-grade-uranium-plutonium.76051/

Lots of technical nuclear information – used extensively: http://nuclearweaponarchive.org/Nwfaq/Nfaq4-1.html#Nfaq4.1

Analysis of North Korea – weapon design and rocketry analysis http://www.38north.org/

Institute for science and international security report on North Korea’s lithium-6 production http://isis-online.org/isis-reports/detail/north-koreas-lithium-6-production-for-nuclear-weapons

Command and Control – Nuclear weapons, the Damascus Accident, and the Illusion of Safety – book by Eric Schlosser

Defusing Armageddon: Inside NEST, America’s secret nuclear bomb squad – book by Jeffrey T. Richelson

hppt://wikipedia.org/ numerous pages dealing with nuclear weapon design, production, and testing, as well as nuclear physics.

Hydronuclear testing – http://www.globalsecurity.org/wmd/intro/hydronuclear.htm

Future Directions in the DPRK’s Nuclear Weapons Program – Feb. 2015 paper by David Albright http://www.38north.org/wp-content/uploads/2015/09/NKNF_Future-Directions-2020.pdf

Hundreds of blog posts about North Korea, their nuclear program, and their missile technologies, along with related analysis and projections were used estensively, and can be found by visiting www.38north.org/

In part three, I talked about just how inefficient the early nuclear weapons were, and how the discovery of adding fusionable hydrogen isotopes to the equation resulted in boosted fission weapons that were many times more powerful than the fission weapons alone. Well, scientists weren’t finished improving on the destructive power contained in those little atoms.

In the early 1950’s, a nuclear physicist by the name of Edward Teller had been working on an idea he’d discussed a decade earlier with famed Italian physicist Enrico Fermi, the same physicist who proposed The Fermi Paradox. If you’ve never heard of the Fermi Paradox, it’s a fascinating subject that has nothing at all to do with nuclear weapons, but rather with the question of where the hell are all the alien civilizations. The most incredible article I’ve seen dealing with that can be found at one of my favorite websites HERE.

Now, if you clicked on that link and just got stuck in a Fermi Paradox internet black hole for the last few hours, I can’t blame you, and welcome back. Enrico Fermi was much better known as one of the preeminent nuclear physicists of his day, and he had the idea of developing a fusion weapon that was triggered by a fission reaction. When Edward Teller realized that actually seemed to be able to work with the boosted fission weapons they’d developed and tested, he went to work developing a multi-stage nuclear weapon where the first stage would be a standard fission chain reaction, and the second, completely separate stage would contain a fusion reaction, ready to be touched off by the fission reaction. His work was aided by Stanislaw Ulam who came up with the idea of separating the two stages of the bomb, and the Teller-Ulam configuration that is still the design used in today’s thermonuclear weapons, was born.

The key to making the two stages work was X-rays.

X-rays had been studied for many years prior to the discovery of nuclear fission, and it was no surprise to anybody that the fissioning of a heavy atom produced extremely powerful X-rays. Teller and Ulam knew that if they could harness the power of those X-rays, they would provide enough pressure to implode the secondary device which contained the hydrogen-based fuel. Compressing the secondary would cause the hydrogen fuel to undergo fusion, which would release tremendous amounts of energy.

Before I go into the details of exactly how this works, I want to discuss something I found interesting and fascinating. First of all, the exact processes and designs of nuclear weapons are top-secret in every country that has them. Nobody wants the information getting out to rogue states or terrorist cells that may use the info to create their own nuclear weapons, something that most can agree would be a disaster. Some would consider that to have already happened, what with North Korea having successfully detonated several nuclear bombs, and Iran having shown they were well on their way to developing them, if they aren’t secretly still working on it.

What’s interesting about the top-secret nature of nuclear weapons though, is that nuclear information in the United States is what’s known as “born secret.” That means it’s so top-secret, that even if you come up with information about how they work all on your own, it automatically falls under the top-secret classification. There’s a lot of information out there about exactly how nuclear weapons work, but a lot of the intricate design detail that’s published is speculation. If I was to speculate about non-published information regarding nuclear weapon design, and I was correct, I could actually be arrested and charged with Treason for spilling the secrets in this blog.

Now, I’m not so vain and arrogant as to think that I could actually succeed in spilling top-secret information about nuclear weapon design through speculation about the unknown aspects of it, so don’t think I’m saying that. Nuclear scientists have done plenty of that, and I’ll simply report on what the leading nuclear physicists who are not directly involved in the manufacture of nuclear weapons think about exactly how they work. They’ve already done the spilling of the secrets, so I don’t have to be the first. Even though I just may have some ideas that I’ve never seen published…

So here’s exactly how (hypothetically of course) the Teller-Ulam configuration works.

1. We’ll start with the primary, a boosted fission device. Into a hollowed-out sphere of plutonium-239 (and some plutonium-240) is fitted a neutron generator and a mixture of tritium and deuterium gases. Around the plutonium is a sheet of beryllium designed to reflect neutrons back into the reaction, and surrounding that is a tamper made from aluminum or some other light metal, possibly beryllium itself in some designs. High explosive lenses, exactingly milled into shapes very similar to the hexagons and pentagons that make up a soccer ball, tightly surround the plutonium package.
2. The explosive lenses are triggered in an exacting and carefully calculated pattern to create a perfectly shaped blast wave. If this blast wave isn’t perfect, critical chain-reaction fissions will not be achieved and the weapon will “fizzle” and be a dud. The mighty blast wave compresses the tamper, which compresses the plutonium-239 to between 1/3 and 1/5 its original diameter. At the same time, the neutron generator inside is activated and begins shooting free neutrons into the tritium and deuterium (hydrogen isotope gases), which are condensed and heated by the compression of the cavity.
3. The hydrogen gases undergo fusion from the pressure, heat, and free neutron bombardment, generating an even larger amount of free neutrons as the hydrogen isotopes are converted to helium-4, a free neutron, and energy. In the meantime, the plutonium has begun to undergo fission and a chain reaction of fissions has begun which is aided by the free neutrons from the boosted hydrogen isotopes which are now undergoing fusion.
4. As this begins, X-rays are produced from the atomic nucleus of the fissioning plutonium. These X-rays shoot out at near the speed of light, which is about 100 times faster than the explosion that is brewing in the now critically fissioning plutonium, and plenty fast enough to reach the secondary before the explosion itself does. (We’re talking in terms of nanoseconds and milliseconds here. Billionths of a second and millionths of a second, with a total time of the entire device in the thousandths of a second, or microseconds.)
5. The secondary device is both a fusion and fission bomb and it nests in a cavity, known as a hohlraum, which is a cavity that is in perfect equilibrium with regard to radiation. This is actually the most closely guarded secret of thermonuclear weapon design because the secondary has to be compressed perfectly symmetrically without the use of the exacting conventional explosive lenses, and through only the use of X-rays. What happens is, the bomb casing is lined with a metal meant to channel (without absorbing) the X-rays directly to the secondary housing. This housing is encapsulated in a polystyrene foam that fills the entire bomb compartment encasing the secondary, and when the X-rays hit the foam, the tremendous energy they carry converts the polystyrene into a plasma nearly instantaneously.
6. I found a lot of information that stated the pressure of the plasma itself compresses the secondary device, but that’s not actually true, and seems to be a common misconception. Incredibly, and nearly inconceivably, it’s the ablation of the plasma that compresses the secondary. Ablation means that the polystyrene foam is heated so quickly by the X-rays, that as it converts to plasma, it vaporizes away from the casing that houses the secondary with such force that the vaporizing mechanism itself causes the secondary to implode. This secondary housing is either a cylinder or a sphere, and the ablation process causes it to implode to about 1/10^th of its original diameter, (if it’s a sphere; 1/30^th the original diameter in the case of a cylinder design) making it 1000 times denser than it previously was. And the container is made from uranium that’s about 1 inch thick! Just to be clear, X-rays and ablation alone cause this tremendous implosion of the secondary housing, nothing else. Incredible.
7. Inside the secondary is the fusion fuel, along with a plutonium-239 “spark plug.” Much like the spark plug in a car, the plutonium-239 rod is designed to spark the fusion process of the secondary, and to aid in free neutron generation, which assists the fusion of the hydrogen isotopes inside.
8. For the fusion fuel of the secondary, a solid (powder) called lithium-deuteride is used. This is a mixture of lithium and deuterium, which, since lithium is a solid, allows the mixture itself to be a solid instead of a gas or liquid, which makes it much easier to maintain than when it’s a mixture of deuterium and tritium like you find in the primary. Lithium is number 3 on the periodic table, with an atomic weight of 7, which means it contains 3 protons and 4 neutrons. For the lithium-deuteride, it’s actually the lithium isotope called lithium-6 that’s used, and when it undergoes fusion, the lithium-deuteride converts to tritium and deuterium, which, as we know from our discussion of primaries, converts to helium-4 and a free neutron, and, of course, copious amounts of energy.
9. The spark plug, which as mentioned, is plutonium-239, also undergoes fission while the lithium-deuteride is undergoing fusion, and that adds to the yield of the secondary. As it goes critical, the expanding explosion from the primary boosted fission stage reaches the secondary, and they combine to form a big boom.

How big? The first bomb created with the Teller-Ulam design was known as Ivy Mike. It was detonated on November 1^st, 1952 at Enewetak Atoll in the Pacific Ocean. It had a blast yield of 10.4 megatons. That’s 20 times bigger than the previous largest bomb ever detonated.

Here’s a video of it.

Up to now, we’ve been discussing weapons with blast yields in the kilotons, or thousands of tons of TNT. The prefix mega means million. So, Ivy Mike had a blast yield of 10.4 million metric tons of TNT. For anybody struggling with the math, that’s almost 23 billion pounds of TNT.

As unfathomable as that amount of blast power is, the Teller-Ulam configuration allows for much bigger blast yields. By simply adding more secondary devices symmetrically around the casing, you can harness the X-rays from the primary through an arbitrary number of secondary devices, each contributing to the blast yield. It also has the theoretical potential to use X-rays from the secondary to ignite a tertiary stage which would be another fission stage, for a fission-fusion-fission bomb. Theoretical bomb yields of 100 megatons are deemed possible, though testing that large a bomb comes with enormous complications.

The Teller-Ulam configuration developed in 1951 is basically the same design used in today’s weapons. The hydrogen isotopes of the primary and the secondary devices give these bombs the names hydrogen bomb and thermonuclear weapon as opposed to atom bomb and nuclear weapon that describe single stage configurations.

Here’s a good but simple representation of what the Teller-Ulam design looks like.

Teller-Ulam design

Incidentally, the largest thermonuclear device ever detonated was by the Soviet Union on October 30^th, 1961 over the island of Novaya Zemlya near the arctic circle. The bomb was known as Tsar Bomba, and it was a monster. The blast yield was somewhere between 50 and 58 megatons, depending on which source you check. This Discovery Channel video has a few errors, but does a good job of showing the destructive power of Tsar Bomba. It had a total destruction radius of 15-20 miles. That’s a circle with a total destruction diameter of 30-40 miles. Plenty to completely annihilate most major cities with a single bomb. Of course, the bomb was so large that only one could fit on the bomber, and only then by making special modifications that had the Tsar hanging out of the bomb bay doors for the duration of the flight. The drag and lack of maneuverability of that plane would have made it effectively useless against the air defenses of the United States, then or now.

Which brings us to what really matters when it comes to nuclear weapons, and that is delivering them to the target. It doesn’t make much sense to build a nuclear weapon so big that you have to modify a bomber with the weapon hanging out the bomb bay doors, creating a radar cross section the size of Manhattan. What matters is making weapons as powerful as possible while still being able to mount them on Intercontinental Ballistic Missiles, or ICBMs. That required a miniaturization program, keeping all of the design components of the Teller-Ulam configuration and keeping the yield to a satisfactory level.

To give an idea of how difficult this was, the first deployable United States hydrogen bombs, tested again at Bikini Atoll in what was called Operation Castle, were getting yields of around 15 megatons, and were considered extremely compact for their time. Yet they still weighed upwards of 23,000 pounds and were about twelve-feet long. The lithium-deuteride fusion fuel in the secondary device itself weighed 880 pounds. That’s a huge secondary, and difficult to maintain and deploy. Not to mention the yield of 15 megatons was unnecessarily large. Cities are only so big, right?

So weapons had to be made small enough to fit onto missiles, and that was accomplished very quickly. Both the U.S. and the U.S.S.R. were throwing enough money into the nuclear arms race to ensure the scientists had everything they needed to make it happen, and it took just a few years before we began to see deployable nuclear weapons with yields in the megaton range.

It would take another 3 parts to this blog to discuss all the aspects and designs of ICBMs, so I’m not going to do it. However, North Korea now has ICBMs capable of delivering a nuclear weapon, and North Korea’s capabilities are actually the subject of this blog, so we need to talk just a little about them. Here are the basics:

1. The IC in ICBM stands for Intercontinental, which means the missile is capable of spanning the long distances between continents to deliver its payload. This is accomplished by launching the missile out of the atmosphere and into sub-orbital flight where it doesn’t have to deal with atmospheric pressures that would cause enormous fuel burn.
2. The B stands for Ballistic, and that basically means that the missile is thrust upwards into an arc and then allowed to enter an unpowered and unguided trajectory back to the target established during guidance of the initial portion of the flight. Much of the flight of the missile occurs out of the atmosphere in a sub-orbital flight trajectory in space. The M in ICBM stands for missile which means… well, if you don’t know what a missile is, ask the person reading this to you.
3. An ICBM can have a range upwards of 8000 miles in the case of the only current United States ICBM, the LGM-30 Minuteman III. North Korea’s only true ICBM is known as the Hwasong-14, and it’s thought to have a range of approximately 5000-6000 miles.
4. The incredibly fast speed attained by a ballistic missile (up to mach 23 for the Minuteman III), due to its travel through space with no atmospheric drag to slow it, makes it difficult to intercept. It’s short travel time, around 30 minutes for its maximum range, means decisions on what to do if one is launched need to come quickly from command and control units.
5. ICBMs can be stored and launched from missile silos, from submarines (where they’re actually known as SLBMs, submarine-launched ballistic missiles, usually with a much shorter range), from mobile rail launchers on trains, or from heavy trucks, such as this one.

Russian mobile missile truck – Vitaly V. Kuzmin

6. Each ICBM can carry multiple warheads known as MIRVs, or Multiple Independently targetable Reentry Vehicles. These are independent thermonuclear devices that all ride together into the sub-orbital flight portion of the ICBM, and then are released to reenter the atmosphere, each on its own trajectory toward a unique target. The United States doesn’t use MIRVs on its Minuteman III missiles due to requirements from the START II nuclear treaty with Russia, but its SLBM, the Trident II does carry up to 14 independent nuclear warheads on each missile.

Trident II SLBM launch from a submarine

Nine MIRVs mounted on an ICBM platform.

MIRV testing with tracers following the individual flight paths of the inert warheads.

Note: North Korea does not deploy any MIRVs on any of its ICBMs or SLBMs. Their SLBMs have failed numerous launch tests and are not thought to be ready for action at this time. We’ll talk a lot more about that in part five.

One of the greatest fears of the cold war was ICBM launched nuclear weapons. Not only had miniaturization of the Teller-Ulam design made it possible to launch nuclear warheads over the great distance from the Soviet Union to the United States, but both America and the USSR had developed enough warheads and missiles to completely annihilate one another. This is not the case with North Korea, and we’ll soon discuss exactly what they’re currently capable of.

The current thermonuclear warheads mounted on the ICBMs of the United States are known as the W87. They were originally designed in 1982 and mounted on Peacekeeper ICBMs, each of which could hold 12 W87s as MIRVs. They’re now mounted singly on the much smaller Minuteman III, and they’ve been upgraded with all the modern safety features that keep them from detonating accidentally. The yield of each warhead is 475 kilotons, making them significantly smaller with regard to yield than the megaton weapons that have to be delivered via bomber, such as the B83 which, at a maximum yield of 1.2 megatons is the largest yield weapon currently in the U.S. arsenal.

A W88 warhead, very similar in configuration and yield to the W87, By Dan Stober and Ian Hoffman, adapted by User:HowardMorland [CC BY-SA 2.5 (http://creativecommons.org/licenses/by-sa/2.5)%5D, via Wikimedia Commons

The B83, like most modern nuclear gravity bombs, has what’s known as dial-a-yield, which lets the operator choose the blast yield they want to achieve. This allows the bombs to be used for numerous different options. The yield is controlled by a simple dial on the outside, which, on the inside is effected by a few different options such as limiting the amount of boosted fission fuel enters the chamber, or by shutting down the secondary completely, making the device a primary fission bomb only. For the B83, the yield at the low end of the dial is classified but is reported to be in the “low kiloton range” whatever that means.

The United States has created nuclear bombs with very small yields. The Davy Crockett was developed in the late 1950s as a troop weapon, meant to accompany ground troops into battle. It was a tactical nuclear recoilless gun that was mounted on a tripod and had a range of between 1.2 miles and 2.5 miles. They could be mounted on an armored personnel carrier, or even a Jeep, and though it doesn’t seem that you’d want to be less than two miles from a nuclear explosion, that distance was perfectly safe for the yield of these nuclear weapons. They had variable yields of between 10 and 20 tons of TNT. Not kilotons…tons. The yields of the Davy Crockett were comparable to yields of several large conventional bombs of the day, but in a package that weighed only around 50 pounds.

Not only are low-yield nuclear weapons like the Davy Crockett able to be safely deployed from a short distance, but they are often safe even when they are detonated directly above a person. And, even when the blast yield is much greater than the 20 ton yield of the Davy Crockett. To show just how safe these weapons are, in 1954 the Air Force got five volunteers to stand directly under a 2-kiloton nuclear blast from an air-to-air nuclear rocket. Keep in mind, this blast yield is 100 times that of the Davy Crockett weapon, and it detonates only two miles from the officers, directly above them. Check out this video of these clearly low IQ volunteers.

https://www.youtube.com/watch?v=BlE1BdOAfVc

The point of these last two examples is to indicate that while nuclear weapons can be absolutely devastating, and are designed primarily for that purpose, there are some that could absolutely be used in place of, and more effectively than, conventional bombs. Let me give an example.

On April 13, 2017, the United States conducted an airstrike on Nangarhar Province in eastern Afghanistan. The target of the airstrike was a network of underground tunnels being used by ISIS in Afghanistan, tunnels that were originally constructed for the Mujahedeen during the Russian war in Afghanistan.

Multiple attempts had been made to destroy the tunnel network through bombing runs and drone strikes, and they’d been unsuccessful. That’s when the military made the decision to deploy the GBU-43/B Massive Ordnance Air Blast, commonly known as the MOAB, with the nickname, Mother Of All Bombs.

The MOAB has an explosive yield of 11 tons of TNT, which puts it on par with the yield of the Davy Crockett nuclear weapon. Except the Davy Crockett weighed 51 pounds, and could be fired from a Jeep. The MOAB weighs over 21,000 pounds and needs to be delivered by a heavy bomber.

Russia has a conventional bomb much larger even than MOAB. Known as FOAB, the Father Of All Bombs, it’s a thermobaric weapon, meaning it pulls in oxygen from the surrounding air to generate an intense, high temperature explosion. Its blast yield is 44 tons, four times larger than MOAB, and the total weight of the bomb is just under 16,000 pounds.

There are of course, many critics of the use of weapons such as MOAB and FOAB that can cause indiscriminate and unintentional killing of civilians due to their large blast radii. But, when used cautiously, they can also be very effective weapons, succeeding where other bombs had failed. MOAB destroyed the tunnel system and killed a reported 94 ISIS fighters, including 4 commanders. There were some reports that two civilians may have also been killed, but overall, it was considered a very successful deployment. So, what would have been the difference if we’d used a low-yield tactical nuke such as the Davy Crockett in its place?

As far as yield, number of deaths, and probably even radioactive fall-out, next to nothing. The difference would have been the fact that it was a nuclear weapon, and that would have resulted in catastrophic consequences for the United States, numerous treaty violations, and an international incident on a scale previously unprecedented. But why? For what? Using MOAB is effectively the same thing as using a low-yield tactical nuke with one exception—MOAB uses conventional explosives instead of nuclear explosives.

The purpose of this paper thus far has been to show how nuclear weapons were developed and how they work today, and to show that the fears surrounding them are vastly overrated, and to do that, we need to talk about peaceful uses of nuclear weapons.

Nuclear weapons themselves are not inherently bad. They are inherently neutral, and can be used for both evil purposes and for good purposes. A nuclear explosion might be necessary someday to move an asteroid or comet out of its flight path to keep it from striking the earth. Nuclear pulse propulsion is a hypothetical method of using nuclear explosions to power the thrust of a spacecraft. Operation Plowshare in the 1960s and 70s detonated 27 nuclear devices for peaceful purposes. Most were experimental, and results were mixed. The ground explosions caused large amounts of radioactive fallout and contaminated water supplies which caused protesting and eventually brought the program to a halt.

The Comprehensive Nuclear-Test-Ban Treaty of 1996 prohibits all nuclear explosions, regardless of their purpose, and that brought a halt to all potential “good” uses of the explosive power. But should it have? At the time, I would say yes. The radioactive fallout of these ground bursts, even the peaceful ones, were causing environmental damages that will last for decades or longer. But, just as the treaty was being signed, scientists were making great strides toward clean nuclear weapons.

Clean nuclear weapons make use of the explosive power of the fusion stage of the weapon, and attempt to get rid of the radioactive metals of the fission stage. In theory, a complete fusion bomb would be potentially more powerful than the fission/fusion bombs of today, with complete control over the desired yield, and no radioactive fallout at all, which would allow clean surface and subsurface detonations.

In the 1970s, the Soviet Union attempted to create a canal joining two rivers. It was called the Pechora-Kama Canal, and they detonated three 15-kiloton weapons, each of which was reported to be 98% fusion and only 2% fission. This still wasn’t enough to avoid radioactive fallout though, as there is still some evidence today of radiation from the blasts. The danger is small, and people visit and live in the area without problem, but to ever have a peaceful nuclear program again would require 100% clean fusion bombs.

We’ll never be able to develop a pure fusion weapon with the current test ban treaties though, because development advances are only theory if the weapon can’t be tested and studied. And the Comprehensive Nuclear-Test-Ban Treaty prohibits all explosions of any type of nuclear device, fission or fusion, clean or dirty. That needs to be changed if we want to be able to ever harness the power of a clean nuclear detonation and use it for good.

On the flip side of the good of nuclear weapons, there have been some bad as well. Cobalt bombs, or salted bombs could be used for radiological warfare, designed to intentionally contaminate an explosion site with radiation, the sole purpose being to not allow humans to wait out the fallout in a bomb shelter. With a half-life of 5.27 years, the fallout of cobalt-60 would be dangerous for more than five decades using the 10 half-lives rule. This fear is what has driven many apocalyptic movies where you see radioactive wastelands. A nice plot for a movie, though there’s no evidence that any countries have actually produced and ever planned to use such weapons, although there is speculation that Russia did indeed have plans for similar devices, and may have even built some.

Another type of “bad” nuclear device, as I mentioned earlier, is the neutron bomb. A neutron bomb does the opposite of what most thermonuclear devices do; instead of trying to harvest the free neutrons and direct them back into the critical mass, the neutron bomb encourages their release out of the bomb. The casing of the bomb is made from depleted uranium, lead, or steel, all of which are translucent to neutrons. The explosion itself, without the addition of the free neutrons, is usually quite small, a fizzle compared to the explosions of today, but free neutrons are deadly to living beings. The massive neutron burst, which races ahead of the explosion, kills any humans or animals around. This type of bomb could be exploded above the heads of enemy troops, killing every person within a mile radius, but leaving the area fairly untouched by explosion. The neutrons are absorbed quickly into the atmosphere, and friendly troops could move right in.

With a neutron’s ability to pass right through steel and armor, even troops inside tanks or other armored vehicles would be killed immediately by the neutron bursts. An extremely effective but controversial bomb. If you’re interested in reading more about it, Wikipedia actually has a very informative page regarding the neutron bomb.

The radioactive fallout of conventional nuclear weapons is what led to their downfall, and rightfully so, considering the apparent complete lack of empathy employed by the superpowers during their production and testing in the 50s and 60s. The Nevada Test Site, which oversaw the detonations of 100 atmospheric thermonuclear devices (and an additional 828 underground detonations) often failed to completely consider fallout, or didn’t care to warn residents who were downwind of the explosions. This caused numerous and marked increases in cancers such as leukemia, bone cancer, brain tumors, and thyroid cancer in residents of St. George, Utah from the mid-50s into the 1980s, and caused a “significant excess of leukemia deaths” in children under 14 years of age. To date, nearly $2 billion has been paid out in compensation claims.

It is the combination of the real fears of nuclear annihilation from the Soviet Union during the cold war, in addition to the radioactive fallout experienced in the 100 above-ground tests at the Nevada Test Site and the atmospheric and ground tests at various atolls in the Pacific that have given nuclear weapons the chilling and almost universally feared name they have today. But, in my opinion, they don’t need to be so chilling. Conventional bombs are big enough today that they can compete with some of the smaller yield devices, and, clean nuclear bombs are a real possibility, with many, many uses that would greatly enhance the efficiency of any operation involving earth moving, mining, and tunnel drilling, as well as opening up possible space travel improvements. In order for this to ever happen, humankind needs to adjust its fears of the word, “nuclear.”

In part five of this paper, I’ll discuss North Korea’s specific nuclear program, what kinds of bombs they have, what types of delivery vehicles they have for those bombs, and how much fear Americans (and the rest of the world) should have about those bombs. I’ll also post the full bibliography and sourcing for this article.

Just to recap, in part one, I discussed the premise for this series of posts: that most Americans have an unmerited fear of nuclear weapons, in particular the type being developed by North Korea. I also stated that I felt that fear was grounded in two things, the first being the unknown — most Americans have no idea what a nuclear weapon actually does, or how it works, and the second being most American’s only experience with nuclear weapons — the Cold War.

In part two, I discussed The Manhattan Project and The Trinity Experiment, as well as the two different types of bombs that we dropped on Japan during World War II, including how they were made, how they worked, their blast yield, and the effects they had, both during the actual explosion and afterwards.

Here in part three, I’m going to go over the types of weapons that were built after World War II, and how they led to the types of nuclear devices we have today. I’m going to explain how they work, what they do, and how they are delivered to their targets. I’m also going to discuss how fission and fusion actually work in nuclear devices, and how different elements and designs can be used to increase the yield of the bombs.

It didn’t take long after World War II for America to continue testing nuclear weapons, this time at Bikini Atoll in the western Pacific. They used the same type of bombs there as Fat Man and The Gadget; plutonium implosion bombs. Let’s talk a bit about just what exactly plutonium is. This is important because, since the early 1960s, plutonium, not uranium, has been the standard fission material used in nuclear weapons.

Plutonium is a radioactive element that’s capable of decaying into other elements. The most stable version of plutonium that’s found in nature is the one on the periodic table, plutonium-244, and it’s only found in trace quantities – thought to be remnants of the formation of galaxy. This form of plutonium is completely irrelevant to nuclear weapons.

The plutonium isotopes we’re concerned with are plutonium-239, plutonium-240, and plutonium-241. These are the ones that capable of fission and they’re created in nuclear reactors, not in nature. Nuclear reactors produce plutonium-239 as the uranium-238 that powers the reactors decays and the neutrons it gives off are captured. Capturing a neutron changes uranium-238 to uranium-239. Uranium-239 rapidly decays into neptunium-239, which then decays once more to plutonium-239. This isotope is the one we want to capture to build a nuclear weapon.

Interestingly, plutonium-239 eventually decays into uranium-235, which is enriched uranium and what we try to process out of the mostly uranium-238 we mine from the ground so that we can make a nuclear bomb, which gives all of these isotopes an incestual relationship reminiscent of the Targaryens and the Lannisters.

All of this decaying of atoms and capturing of the isotopes is a complicated and technical process, and it’s not that important. What is important is that when the plutonium-239 is captured, it always contains some percentage of plutonium-240. Plutonium-240 is spontaneously fissile, so it’s unstable and unusable in nuclear weapons if the percentage present in the plutonium-239 is too high. If the plutonium-239 isn’t captured quickly, the 240 isotope builds up and it becomes only suitable as a reactor fuel. It isn’t feasible to separate the plutonium-240 from the plutonium-239, so the mixed plutonium product must be removed frequently from the reactors, which means that it requires very specialized nuclear reactors to make.

Why is this important? It’s one of the ways we’re able to monitor non-nuclear countries for adherence to the nuclear non-proliferation treaty. These countries who want to develop nuclear power, can create power reactors that are incapable of producing pure enough plutonium-239 to make a bomb. 98% of the world’s nuclear reactors are not capable of making weapons-grade plutonium.

Although plutonium radiation is extremely dangerous to humans, it’s very difficult to actually get infected. That’s because plutonium-239 decays with Alpha radiation. Alpha radiation is weak and can’t penetrate the skin; in fact, it can only barely penetrate the air, and only then just a few inches. That means you can actually pick-up a lump of plutonium-239 with your bare hands without negative effects from the radiation.

The largest danger from plutonium (other than being present when it goes super-critical of course), is from inhaling it. This can happen if it catches fire, such as when a plane carrying nuclear weapons crashes and burns, or in lab accidents, or potentially from breathing radioactive fallout in a ground burst. Although inhalation is thought to be the most likely way for plutonium to kill or cause cancer, there were about 25 workers at Los Alamos in the 1940s who inhaled a large amount of plutonium dust, which was thought would give them each a 99.5% chance of contracting lung cancer. None did.

Interestingly, Wikipedia has a footnote that states that plutonium has a metallic taste. First, duh, it’s a metal. Second, who tried it??

Apparently, although inhaling it is likely to have long-term and serious health effects, the Los Alamos workers notwithstanding, you actually can safely eat a small amount of plutonium, as the body tends to simply expel it without actually processing it.

Back to the Bikini Atoll tests, known as Operation Crossroads. The first test was an air drop that was unremarkable and quite similar to the previous two implosion devices that had been detonated. The main lesson learned from it was that the initial beta and gamma radiation from an airburst, while strong enough to kill any human or animal exposed to it, was short-lived and the long-term effects of the radiation on the ships in the harbor was negligible. While the first test was considered unimpressive, the second test was quite remarkable, and it showed the dangers of radioactive fallout in a ground burst.

The purpose of the second test was to determine the effect a submerged nuclear weapon would have on naval ships, and for this test, the navy assembled a fleet of 95 U.S. and Japanese ships in the bay at Bikini Atoll. Then, they detonated a plutonium implosion device under the water at a depth of about 90 feet. This was the result.

What you’re looking at there, is hundreds of millions of gallons of instantly radioactive seawater. If you look closely at the bottom right of the water column, you see a vertical battleship. A 27,000 ton battleship. Amazing amount of force.

The ships that survived the explosion were painted with radioactive seawater when the wave passed over them. Despite numerous efforts to scrub many of them clean, the Navy was unable to make them non-radioactive. The seawater had settled into the microscopic cracks and seams in the metal of every ship it touched, contaminating them permanently. Of the total of 95 ships in the harbor that day, only 9 were able to be salvaged. The remainder either sank from the bomb and the water column, or were scuttled by the Navy because of their radioactivity.

What we learned from that bomb was that radioactive fallout is pretty dangerous when a nuclear weapon explodes on the ground, (or under the sea as in this case) and that such an effect can have a devastating impact for a long time. How long? Well, let’s discuss radioactivity and exactly what it means.

When we speak about how radioactive a substance is, we usually talk about its half-life. In nuclear physics, a half-life is the amount of time it takes for a substance to lose half of its atoms through radioactive decay. Some substances have a half-life in the billions, or even trillions of years, and others a half-life of only fractions of a second. Many of the radioactive isotopes that are present in a nuclear explosion have these very short half-lives, which is why they are only deadly during the explosion itself, and not afterwards.

What about the elements in a nuclear weapon? Well, in a nuclear reactor, uranium-238 is bombarded with neutrons. When it captures one, it becomes uranium-239. Uranium-239 has a half-life of 23.5 minutes. It decays into neptunium-239 which has a half-life of just over two days. Neptunium-239 decays into plutonium-239 which has a half-life of 24,100 years. Plutonium-239 decays into uranium-235 which has a half-life of just over 700 million years.

The longer the half-life, the less radioactive and dangerous the substance is. Radioactivity is inversely proportional to half-life, which is why the two main fissionable fuels of a nuclear bomb are so safe to handle. Both Plutonium-239, with it’s half-life of 24,100 years, and uranium-235 with its half-life of 700 million years can be safely picked up with your bare hands. (The mostly alpha-decay of these metals is the other reason they’re safe – alpha particles are incapable of penetrating even the dead layer of the outside of your skin.)

A lot of radioactive elements are produced in a nuclear explosion, and some of them have half-lives that extend beyond the initial effects of the explosion, but are short enough to be dangerous. Strontium-90, for example, has a half-life of 28 years, Iodine-131 has a half-life of 8 days, and cesium-137 has a half-life of 30 years. All of these substances can cause cancer in the human body, all live long enough to survive the nuclear explosion, and all have short enough half-lifes to be dangerous with regard to the inverse proportion rule.

Now, half-life doesn’t mean that the element is safe at the conclusion of that time. Far from it. Take iodine-131. It has a half-life of 8.1 days, but that doesn’t mean that after 8.1 days it’s safe to be around. What it means is that after 8.1 days, half of its molecules have decayed, which means that half of them remain. After another 8.1 days, it still contains one quarter of its original molecules, and so on. Typically with this halving, a radioactive element is considered safe after 10 half-lives, which is when it becomes undetectable to most instruments. So, for iodine-131, that would be about 81 days. For cesium-137, that would be about 300 years. Detectable amounts of plutonium-239 then, would stick around for the next 241,000 years.

While that sounds horrible, it really isn’t. Remember, radioactivity is inversely proportional to half-life, which means that the longer an element sticks around, the less radioactive danger it typically poses. (With a few exceptions)

Shortly after the underwater explosion at Bikini Atoll, nuclear scientists began experimenting with trying to make the reaction in the explosion a lot more effective. Remember, in the first detonations, less than 2% of the uranium in Little Boy, and only about 15% of the plutonium in Fat Man went critical and contributed to the blast yield. Scientists realized that there was something missing in the equation, and there had to be a way to harness more of the power of all that uranium and plutonium that went to waste.

The problem was that when a mass of plutonium goes critical and begins the fission chain reaction, it expels neutrons. Neutrons, along with protons, are what gives an atom its mass. You can see the number of neutrons in an element by looking at the periodic table and subtracting the atomic number from the weight. For example, plutonium-239 has an atomic number of 94, which means that it contains 94 protons and therefore, 145 neutrons. (239-94)

So, as the fission process begins (with the explosive compression and a small neutron generator in a plutonium bomb) some of those neutrons are thrown out of the reaction. They become what’s known as free neutrons, and some of them get absorbed by the other plutonium atoms. Free neutrons are the key to a good nuclear chain reaction. When they get captured by other plutonium atoms, it creates another fission event, which releases more neutrons, which get absorbed by other atoms, and so forth. This is the nuclear chain reaction, and in a nuclear power plant, it’s carefully controlled so that only small amounts of energy are produced and the mass of fuel can never reach a super-critical state.

In a nuclear bomb though, that chain reaction isn’t dampened, and it quickly reaches the super-critical state where it gives off so much energy so quickly, that we get the nuclear explosion. It happens so quickly though, that all that other plutonium gets wasted. The idea the scientists came up with, was to harness some of the free neutrons that were escaping, and redirect them back into the critical mass so that more fissions would occur before it went super-critical.

What they found was that covering the entire thing with a thin sheet of beryllium would reflect the free neutrons and cause them to re-engage the chain reaction, causing more fissions to start before the mass goes super-critical, and increasing the efficiency of the weapon, which also increases the blast yield.

(Later we’ll discuss how neutron bombs do the exact opposite, encouraging the free neutrons to actually escape the critical mass rather than joining it, and why that would be desirable with regards to killing humans.)

Beryllium also acts nicely as a tamper, helping to compress the plutonium when the explosive spheres surrounding it are detonated. Not only that, but it also produces some of its own free neutrons during the process, all of which help make the entire detonation more efficient and more powerful.

The other discovery nuclear scientists made shortly after the end of the war would prove to be even more significant, as it would lead to the ability to begin the miniaturization process of nuclear weapons, which would eventually allow them to get small enough to be mounted on missiles as warheads. This discovery involved hollowing out the center of the mass of plutonium and filling it with a gas. The gas used is a mixture of both tritium and deuterium.

Tritium and deuterium are both isotopes of hydrogen (think, hydrogen bomb), which simply means they are hydrogen atoms with additional neutrons. Everybody is familiar with hydrogen – it’s the most common element in the universe by a long shot. It’s also the simplest, with the nucleus of the atom containing just one single proton. When a single neutron is added, this hydrogen atom becomes deuterium (also known as hydrogen-2) and it’s a non-radioactive, stable isotope that can be found in small amounts in nature. When you add the second neutron though, that’s when it becomes radioactive, and we call that tritium (or more rarely, hydrogen-3).

Most people are familiar with tritium, at least having seen it if not knowing what it was. Tritium is used for night sites on guns, luminescent numbers on watches, altimeters, and clocks. The radioactive decay of tritium is what causes it to glow with a greenish hue. Tritium has a half-life of just over 12.3 years, which means it’s quite unstable. What makes it safe around humans is that it decays to a helium gas, helium-3, and though it decays through beta emissions which are typically less safe than alpha emissions, the beta particles are slow moving and can’t penetrate more than an inch of air, nor can they penetrate the human skin.

Because of tritium’s short-ish half-life, it is a bit of a problem. In the civilian world, for example, your gun sites and watch faces lose half of their brightness every 12.3 years, which means a 25-year-old watch that uses tritium to glow in the dark will be at one-fourth of its original strength. In nuclear weapons, this is a much worse problem as the helium-3 it decays into can cause problems during the nuclear reaction. Helium-3 has a large cross-section and the greatest ability of any isotope to grab the free neutrons in a nuclear explosion. We don’t want the free neutrons being grabbed by all the helium as that would be counter-productive toward the effort to create them in the first place. Therefore, not only does the tritium need to be replaced fairly frequently in the entire nuclear arsenal because of its short half-life, the helium-3 needs to be drained from the pit even more frequently, which is one of the reasons regular maintenance of the arsenal is so extensive.

So, what happens when deuterium and tritium are added to a hollowed-out pit in the plutonium core? Fusion occurs during the compression process, and fusion reacts with fission to vastly improve the efficiency of the weapon. This is known as a boosted fission weapon, and it was the first step toward the weapons of today, the two-stage thermonuclear warheads. It turns out that fusion is even more efficient than fission when it comes to nuclear weapon yields, though these early boosted fission weapons did not make use of the fusion as a yield increaser, but rather they used it to harvest more free neutrons to add to the critical chain reaction and increase its efficiency.

When I first learned of fission and fusion, way back in grammar school, it was explained to me quite simply. Fission is the splitting of the atom, and fusion is the joining together of two atoms. Very simple. I had an image of a scientist with a tiny knife cutting an atom in half and creating a huge explosion in a lab. Not quite accurate, obviously.

Fission doesn’t occur by means of a knife, or a laser, or any other type of weapon, but rather by bombardment. Throwing heavy atoms (like uranium and plutonium) into each other causes the neutrons in the nucleus to split off, which is what fission actually is. And, throwing lighter atoms (like hydrogen and helium) into each other causes the nucleus to bind together, creating heavier atoms and dispersing enormous amounts of energy. Fusion is the energy that powers most stars, including our sun, where it’s known as stellar nucleosynthesis.

When deuterium and tritium are compressed during the initial conventional explosion and compression of the plutonium core, they fuse together, and that causes those hydrogen isotopes to form helium and free neutrons instead of the energy that might be released were hydrogen-1 used instead of its heavier isotopes. The helium is simply consumed in the fireball which adds a small, but mostly negligible increase to its yield. The free neutrons however, contribute greatly to the chain reaction, vastly increasing the yield.

By hollowing out the pit of the plutonium to add the fusion gases, it not only increases the yield, it also decreases the weight of the bomb, not just through the lost weight of the plutonium, but through the smaller explosives needed to compress the core. It’s significantly easier to compress a hollow sphere than a solid one, and far less explosives are needed. There were almost 3000 pounds of conventional explosives in Fat Man, for example, which shows just how much explosive power was needed to compress the heavy plutonium. (Just to be perfectly clear, there was a small hollow pit in the Fat Man plutonium design – about 2.5 centimeters, into which was inserted a neutron generator which was found to be insignificant to the chain reaction and unnecessary to the design.)

Once boosted fission devices were perfected and tested, nuclear scientists had reached the limit of blast yield for a single stage weapon. They were eventually able to harvest some of the energy of the fusion reaction in the core, but the maximum amount theoretically possible was about 20% of the total yield. So, 80% of the nuclear blast yield still had to come from the fission of the plutonium. By playing around with highly enriched uranium-235, and surrounding it with lithium-deuterium fusion atoms, and other various configurations, they were able to achieve some impressive blast yields.

How impressive?

The United States produced a bomb known as the Mark 18 or the Super Oralloy Bomb (Oralloy is super-enriched uranium). The Mark 18 was tested one time at Enewetak Atoll in the Pacific. It had a blast yield of 500 kilotons, a 25x increase in yield over Fat Man.

Great Britain created a boosted fission weapon known as Orange Herald, which had a blast yield of 750 kilotons. Fifty times the blast yield of Little Boy over Hiroshima, and an incredibly destructive fireball.

This was nothing however, compared to the yield achieved when two-stage thermonuclear weapons were invented in the early 1950s.

In the next part, I’ll discuss the concepts of multi-stage weapons and the blast yields achieved, including talking about the largest ever nuclear detonation, and the advances in miniaturization and delivery vehicles that were achieved in the heart of the cold war. This will lead us to a discussion of the types of nuclear weapons that North Korea has, and to my thesis of why we shouldn’t fear them or their weapons, and why we shouldn’t fear nuclear weapons in general today.

Before I begin this discussion, I’m going to start with a statement that I should have made in part one. That is, I’m not a nuclear engineer. I’m not a scientist, or a national security expert, and I have no security clearance or access to top-secret information. What I do have is a very special set of skills…no, wait, that’s not it. What I do have is a lot of time. A lot of time in the last 12-14 months in which I have spent an inordinate amount of that time studying nuclear weapons.

Now, when I say that, I’m sure it conjures up images of me Googling “How does a nuclear bomb work?” then reading the Wikipedia page and spouting off as if I’m an expert.

I will say this, just so we’re clear: I’m not an expert in nuclear weapons. I’ve never touched one, or even seen one in real life for that matter. My knowledge comes from more than 300 hours spent studying nuclear weapons, on the internet, in books, and in scientific journals. I link to many of my sources in this blog with the highlighted words, which are clickable links. After the last article in this series, I’ll attach a bibliography with all of the sources I used.

Now, 300 hours is a lot of time, but it doesn’t make me a nuclear scientist. In fact, it likely took me that much time only because getting my brain to absorb and comprehend this material is rather difficult for me. I think the level of research I’ve done only just barely qualifies me to convey entry-level information about nuclear weapons, and to try to clear up what I think are widespread inaccuracies in the perception of what nuclear war with North Korea would look like.

So, here we go!

In my first post, I began with a premise that I feel many people have an unhealthy fear of nuclear weapons, and that that fear is grounded in a lack of knowledge as to exactly what they are and what they do. I also stated that I thought people certainly had an unhealthy fear of the nuclear weapons that North Korea – the DPRK – has likely managed to build.

Now, just to be crystal clear, I don’t expect people to have no fear of nuclear weapons. I just think that most of the population has an unhealthy fear of them, and that fear comes from a lack of understanding as to just what they are, how they work, and what they do. I think of it as a monster under the bed sort of thing…we inordinately fear them because we don’t understand them. That premise is based on the fact that there is a vast difference in the types of nuclear weapons that the DPRK has, and the type currently owned by other nations such as the United States, Russia, and China.

When we created the first atomic weapons, nobody outside the scientists and engineers and a few people in the government and the military knew what they were. Although tens of thousands of people were involved, only a handful of them knew all the details. It was top-secret code word stuff. Most people today are familiar with the Manhattan Project and the story behind the effort to create the first atomic weapon thanks to movies and a lot of great documentaries. We all know that it was the British who really made the first strides toward creating the bomb, and the combination of the efforts between the U.S. and Great Britain that eventually led to Trinity, the first ever testing of an atomic bomb.

I’ll spare you the details of the problems that were encountered just in the isolating of the correct isotopes, first of uranium, and later of plutonium, not to mention the engineering difficulties that were encountered with 1940s technology, but let’s just say, they were extensive. Naturally occurring uranium is mostly uranium-238, and within that mined uranium ore exists a very small percentage of uranium-235, less than three-quarters of one percent to be exact. And uranium-235, known as highly enriched uranium, is what is needed to create fission, the catalyst behind the destructive power of a nuclear bomb. Separating it in the quantities needed to produce just one atomic weapon was a vast undertaking.

The other weapons-grade fissile material that could be used at the time was plutonium. Plutonium — both plutonium-239 and plutonium-240, could only be created in nuclear power plants, and, it turned out that plutonium-240 was too highly spontaneously fissile to be used in the original atomic bomb design. Like I said, lots of problems. Luckily, we had some of the world’s smartest scientists and engineers working on the problem.

Like J. Robert Oppenheimer, and nuclear fission was achieved. The first bomb created was tested in what became known as the Trinity Test.

The bomb detonated in the Trinity Test was nicknamed The Gadget, and it was detonated in New Mexico at Alamogordo (now part of the White Sands Missile Range.) It was an implosion-type plutonium bomb, of the same design as the bomb which was eventually dropped on Nagasaki, and completely different than the originally planned device which was a projectile fired design like the type dropped on Hiroshima. More on these types later.

The test was conducted at 5:29am on July 16, 1945. The first ever detonation of an atomic bomb was on U.S. soil, and it was an unequivocal success.

Here’s a picture of the explosion taken by Berlyn Brixner at sixteen thousandths of a second after the explosion.

The top of that spherical shockwave reaches about 500 feet high. Sixteen thousandths of a second after detonation. Incredible.

Before we discuss the blast yield of The Gadget, let’s talk about what blast yield actually means.

Blast yield for explosions is usually measured in the equivalent amount of TNT that would generate the same explosive force. TNT is short for trinitrotoluene, and it’s created from a mixture of various chemical compounds. It’s slightly less powerful, and NOT the same thing as dynamite, despite what I was led to believe from early childhood.

When we’re talking about nuclear-quality explosions, blast yield is measured in metric tons of TNT. A metric ton is 1000 kilograms, or about 2200 pounds. So, a blast yield of one ton would be the same as the blast that would be created by 2200 pounds of TNT.

A kiloton is 1000 metric tons. 1000 tons multiplied by 2200 pounds per ton means that an explosion measured at one kiloton of blast yield would be the equivalent of blowing up 2.2 million pounds of TNT. That’s a lot.

A megaton would be one million metric tons of TNT. Expressed in pounds, that’s the equivalent of…well, a ton. Lots of tons actually. I don’t want to get into these kind of ridiculous numbers yet, but we will later.

So, anyway, one kiloton would be a massive explosion. At the time of the Trinity test, the largest man-made explosion had been the maritime accident known as the Halifax Explosion on December 6, 1917. If you’ve never heard of it, it’s an incredible story. We know the blast yield of the Halifax Explosion because we know exactly what blew up – 2900 tons of TNT, making the blast yield around 2.9 kilotons. It resulted in approximately 2000 deaths and 9000 injuries.

If you were alive at the time and thought the Halifax Explosion was the mother of all explosions, the scientists at the Trinity test were about to ask you to hold their beers.

The Gadget detonated with a yield of approximately 20 kilotons. Seven times the Halifax Explosion. The equivalent of 20,000 metric tons of TNT, or 44 million pounds.

Eventually, we’re going to discuss the radiation exposure and fallout from this test, as well as the long-term effects it had on the test area, including what you can expect to find if you go right to ground zero today, but first, I want to talk about exactly how this bomb worked.

I mentioned earlier that it was an implosion-type plutonium bomb, and it was different from the original conceived model which was a gun-type fission uranium bomb. Since it was so difficult to extract uranium-235 from the natural uranium-238, and since they’d managed to enrich only enough uranium for one bomb at that time, they’d reverted to the plutonium bomb for the test.

As I mentioned earlier, plutonium is created in nuclear reactors. The plutonium for The Gadget, and the other bombs of that time, was all created at Hanford in Washington State.

The main difference between the gun-type bomb and the implosion-type bomb, other than the fissile material used, is the way in which the fission reaction is instigated. Uranium-235, plutonium-239, and plutonium-240 all have the ability to go super-critical under the right conditions: generally meaning when they are compressed or when they are slammed together at high speeds. This gives us the two earliest types of atomic bombs.

A gun-type fission bomb is about the simplest type of atomic bomb out there. It’s also the type of bomb we dropped on Hiroshima, the one known as Little Boy. It’s regarded as one of the highest risks for proliferation and terrorism because it’s so simple in design. If one has enough quantity of uranium-235, they can create a gun-type bomb with little manufacturing or fine engineering.

A gun-type bomb takes one slug of uranium-235 and fires it, using conventional explosives or propellants, into a target spike of the same material. The slamming together of the two chunks of uranium causes a critical mass, which results in nuclear fission, the splitting of the nucleus of an atom, which results in enormous releases of energy. And that’s it. That’s all it takes to make a nuclear explosion.

The science behind nuclear fission is too complex for my brain, despite the fact that I’ve spent dozens of hours trying to comprehend it, but the important part is, it causes a really big explosion as the fission works its way through the critical mass of the enriched uranium. All-in-all, the gun-type design is a very simple design, and quite dangerous as there are a number of ways the two chunks of enriched uranium could accidentally slam into each other (i.e., a crash of the airplane or vehicle hauling the bomb, or the striking of the ground in an accidental drop, or even the acceleration of a missile were you to try to mount this type of weapon on a missile) which could result in a nuclear explosion.

The other type, using explosive compression, is more complex, but necessary for both stability and safety, and for the use of plutonium as the fissile material. Because plutonium-239, when it’s created in a nuclear reactor, contains large amounts of plutonium-240, and because plutonium-240 is dangerously unstable and ready to go super-critical just from early triggering of the gun reaction, it can’t be used in a gun-type fission bomb. This is what led to the development of the implosion-type fission device, which is the type of bomb The Gadget, and Fat Man, the atomic bomb dropped on Nagasaki were.

In an implosion-type device, the fissile material is surrounded by carefully manufactured explosives in a sort of cocoon. (In modern designs, we use lenses, which we’ll discuss later.) Those explosives fire simultaneously, compressing the uranium or plutonium to two or three times its original density, which causes it to go supercritical and explode.

This type of device was the basis for all future nuclear weapons due to its versatility. The basic design of the implosion bomb is used for thermonuclear weapons, both single stage, and in the Teller-Ulam design, both of which we’ll discuss in great detail later on.

Approximately three weeks after the Trinity test, on August 6^th, 1945, the Enola Gay, piloted by Colonel Paul Tibbets, dropped Little Boy, the first gun-type atomic bomb created, on the Japanese city of Hiroshima. The device had never been tested because the U.S. hadn’t produced enough enriched uranium to create more than one device, and because it was such a simple design, the scientists were convinced there was nothing that could really go wrong. And they were right. Little Boy detonated at an altitude of almost 2000 feet above the ground, and it was a tremendous success (depending on your perspective), creating an explosive yield of approximately 15 kilotons, only 75% of the yield of The Gadget, but enough to immediately kill an estimated 66,000 people, including 20,000 members of the Japanese Imperial Army.

The interesting thing about the yield is that it was very nearly a dud. In fact, there was 141 pounds of uranium-235 in the fused pit of the bomb, and only 2 pounds of that actually underwent fission and contributed to the yield. That’s less than 1.5% of the fissile material that actually went critical and exploded, and it created a 15-kiloton yield. The remaining 98.5% of the highly enriched uranium contributed nothing.

A couple of notes about Little Boy:

1. The entire bomb weighed 9700 pounds, the majority of which was the weight of the casing.
2. The blast detonation is spherical, thus the desire to detonate it at an altitude of 2000 feet — by doing that, you’re able to utilize the full effect of the spherical blast wave.
3. It was determined that although the yield was the equivalent of 15,000 tons of TNT, the same destruction could have been realized by dropping just 2100 tons of conventional weapons, due to much of the spherical blast wave being wasted into the atmosphere and surrounding, sparsely populated areas.
4. It would have taken 220 B-29 bombing runs consisting of various types of conventional bombs to achieve that 2100 tons and achieve the same effect as the one Little Boy weapon.

So, 66,000 people were killed right away. In fact, the total number of deaths in the first few months following the explosion is estimated in the 90,000 to 140,000 range. In order to take a look at exactly what killed all those people, we have to look at how a nuclear device of this type and era actually kills.

The initial causes of death are from the fireball, the over-pressure/blast wave, and from the radiation. In Hiroshima, almost everything in a three-quarter mile radius under the point of the explosion was immediately destroyed by the pressure wave and fireball. There were some reinforced concrete structures that remained standing, and interestingly, in one of them, just 560 feet from ground zero, a man survived the blast, as well as the aftereffects, living for decades after.

Other than that guy and a few other exceptions though, nearly all of the people within that three-quarter mile radius of ground zero were killed immediately. Later testing determined that an over-pressure blast wave of just 5 PSI will kill 100% of people in its path.

In Hiroshima, this blast wave destroyed nearly every building, most of which were made of wood or paper products. The explosive fireball touched off a massive firestorm which caused even more destruction, killing thousands more people, and destroying nearly all the homes and buildings in an area of nearly five square miles.

Let’s talk about radiation. Much of the lethal radiation produced by a nuclear explosion survives only for as long as the fireball – mere seconds. It’s known as initial radiation, and it’s mostly gamma and neutron radiation. This is bad radiation. The kind that kills you very quickly. However, for most people exposed to it, they’re being killed by the fireball and the over-pressure wave anyway, so it’s mostly irrelevant and redundant. Anybody lucky enough to survive the fireball and over-pressure though, will usually die from this lethal dose of radiation. In Hiroshima, the lethal dose radius was close to one mile, and many people were able to survive the blast wave in that radius. Most of those inside that one-mile radius who received that lethal dose died immediately after the blast in the firestorm that followed, unable to escape the flimsy wooden structures, and so the effects of the radiation were not actually realized. The firestorm was so powerful that it cremated the bodies and destroyed all evidence of their existence, (birth and residence records were destroyed as well) which makes accurate death figures impossible to determine.

After initial radiation, the next concern is residual radiation. One of the benefits to the high-altitude air-burst of the bomb, was the lack of nuclear fallout. Most of the fallout from a nuclear explosion is due to the contamination of particles from the ground soil. After the initial fireball expands, it then has to contract, and that causes a suction effect that sweeps everything up into it and pulls it into the air — becoming the iconic nuclear mushroom cloud.

When that happens near the ground, particles of soil are pulled into the soup and become irradiated. They’re lofted into the air where wind currents take them along for a while before dropping them again, causing the radiation to spread far and wide. Some mushroom clouds actually reach into the stratosphere where particles can remain sometimes for years, circling the planet before falling to earth. This actually ends up being a good thing as it spreads the radiation far and wide, depositing it in non-lethal doses around the globe.

The higher the air-blast, the less particles of soil that will be pulled into the radiation, and the less fallout there is. In the case of Hiroshima, with the air-blast at nearly 2000 feet of elevation, nuclear fallout was quite small. There was still that ~140 pounds of subcritical uranium, plus the ~9600 pounds of bomb casing material, plus particles that were in the air already, and so forth, but the amount of nuclear fallout was minor due to the absence of soil particles.

One of the most common misconceptions surrounding a nuclear explosion deals with the level of residual radiation at the blast site. Most people believe that blast sites are uninhabitable for decades or even centuries. In Hiroshima, it’s been shown that the only radiation deaths that occurred were people who were directly exposed to the bomb detonation itself. None of the aid workers, doctors, firefighters, or anybody else who entered the blast area after the bombing were killed or even injured by residual radiation. Don’t get me wrong, there was some measurable increased radiation in the bomb area, particularly in the first day or two after the explosion, but it dissipated rapidly and wasn’t significant enough to kill or injure anybody.

There weren’t any standing houses left within one mile of the bomb epicenter, but had there been, residents of Hiroshima could have moved back into their homes directly under the blast area just days after the firestorm subsided, and they would have lived without a dangerous increase in radiation exposure. In fact, many people today live in Hiroshima and in Nagasaki, and they have the same level of exposure to radiation as the rest of the general population.

This is not meant to trivialize the effects of the radiation. For those exposed to the bomb blast who didn’t die from the blast itself, the radiation levels were often deadly, killing many within the first 30 days after the explosion. Others died years later from various cancers, leukemia being the most prevalent. However, all of those who died from radiation illnesses were exposed to the bomb blast itself, and all were close to the epicenter of the blast.

The British Mission, which went to the sites of Hiroshima and Nagasaki to study the effects found that at three-quarters of a mile from the blast epicenter, the radiation survival rate was greater than 50%. At one mile and beyond it was more than 75%, and at two miles distance, there were some reports of radiation sickness, but no reported deaths, and the residual cancer rates were statistically the same as the rest of the world.

There were no higher incidents of cancers or other mortalities from any person not exposed to the actual bomb, nor from any person outside of two miles from the epicenter, nor from any person who entered the actual bomb area immediately after the explosion.

For many years, even decades, reports of birth defects from pregnant survivors were reported. They were all shown to be false. In 1985, Johns Hopkins University human geneticist and professor of genetics from the University of Wisconsin, James Crow, completed a study that confirmed the number of birth defects from survivors of both Hiroshima and Nagasaki was not significantly higher than those of the general population. A pregnant woman could have moved into a house directly under the epicenter of the bomb, a week after the explosion, and both her and the baby would have been fine.

I mention this because of the common misconception that nuclear bomb sites are uninhabitable for generations. I grew up with the misinformed teachings that nuclear sites are graveyards, with images of zombie children with three arms living in the green glow of Hiroshima for years after the bombing.

It’s just simply not true. Now, there are ways to use nukes to make a place uninhabitable, and we’ll discuss those later, but other than intentionally irradiating an area, simply detonated a nuclear weapon on a city does not leave lasting long-term radiation effects.

Three days after the Hiroshima bombing, with the Japanese still refusing to surrender, the U.S. dropped Fat Man onto the city of Nagasaki. Fat Man was a plutonium compression bomb, similar to The Gadget detonated in the Trinity test. The blast yield was also similar to The Gadget, at an estimated 20 kilotons of TNT. Because the bomb was dropped slightly off-target, and because hills confined the blast to one narrow valley the death toll was less than at Hiroshima, even though Fat Man was more powerful than Little Boy. Estimates for the death toll seem to vary widely due to poor record keeping, but it’s likely they were somewhere between 35,000 and 80,000 total deaths.

The Nagasaki bomb was the final straw for the Japanese, who quickly realized that more of their cities would be destroyed by this awesome technology in the coming days and weeks. Emperor Hirohito unofficially surrendered on August 14th, just a few days before the next bomb was due to be dropped.

Debates have raged for decades as to whether or not the bombs were necessary, and that argument is well beyond the scope of this blog, however, it’s important to note that the Japanese were not going to surrender anytime soon, and that, as mentioned above, it would have taken 220 successful B-29 bombing missions to equal the destruction and death achieved with one atomic bomb. Who knows how many unsuccessful missions it would have taken to achieve 220 successes, and how many Americans, Japanese, and other nationalities fighting would have died in the other Pacific theaters during that time, or if that drawn-out destruction would have even been an encouragement for Japan to surrender. It seems unlikely to me that it would have.

In the next blog in this series, I’ll briefly discuss atomic testing after the war, as well as the Cold War and the arms race, all in a lead-up to present-day thermonuclear weapons and the types of bombs that North Korea has likely achieved, as well as the effect of a nuclear attack by the DPRK on America, and the likely result of an American nuclear counter-attack.

Well, it would be over really quickly. You can insert your own joke here about just how quickly. Most people, including Kim Jong-un understand that North Korea could never hope to emerge victorious from a nuclear conflict. So why does he continually bluster and threaten the United States? Why does he take the chance that his words and actions will escalate an already tense situation to a potential disaster?

Kim Jong-un, http://jbpress.ismedia.jp

Most likely it’s because he can’t win that he continues to crow in the face of his impending annihilation. He knows that he never has to worry about a preemptive first strike from the United States because we have a great fear of nuclear weapons, and all weapons of mass destruction. So if he makes us think he can reach out from his throne in his little impoverished country and strike at our homeland at will, he feels it will garner him a level of respect, driven by fear, and that his actions and words will have no ultimate consequence.

Which brings us to the question – why do Americans fear nuclear weapons so much? Why do most of us just want to continue to allow the little man to spout off about our destruction and allow him to continue to develop his nuclear weapons program with no consequence?

I think we fear nukes with something akin to the fear we get when we stand in front of a mirror in a dark bathroom, or when we see a clown in the woods. The same fear that caused my mother to tell us kids not to play with Ouija boards. The same fear that makes us hurry to our car at night in a deserted parking garage. It’s a combination of fears, including fear of the unknown, and, even more prevalent, anecdotal fears from our childhood.

Some of us grew up during the Cold War. If you didn’t grow up during the Cold War, then your parents did. There were many times during this conflict between the United States and the now defunct Union of Soviet Socialist Republics, when the possibility of nuclear war was more than prevalent. There were moments when it could have actually been considered imminent. And that would have been a war that nobody would have won.

War Games, https://www.pinterest.co.uk/pin/190628996699276787

The United States and the Soviet Union each has thousands of warheads, many mounted on intercontinental ballistic missiles with multiple independently targetable reentry vehicles (MIRVs), which gives each missile the capability to hit multiple different cities with a nuclear tipped warhead. (As many as 14 warheads on the submarine-mounted Trident system) Many of them are mobile and can be driven around to different locations, making targeting them with a first-strike difficult or impossible.

Russian mobile missile truck – Vitaly V. Kuzmin

The truly terrifying part of this was in that any single launch from one country, intentional or accidental, would have likely triggered an all-out response of the launch of every warhead from the other country. The entire planet would have been altered or even destroyed as a result. In the Soviet Union, they even had a program known as Dead Hand or Perimeter that would have triggered a comprehensive nuclear retaliatory launch in response to any launch from the U.S., regardless of whether or not anybody in the leadership was still alive or capable of giving the actual order. (BTW, this program is probably still active and operational in Russia today, and the U.S. has a similar, though safer one.)

And we all either grew up with those fears, or our parents did, and they passed those fears on to us.

But this is not what a nuclear war with North Korea would look like. They don’t have the technology the Soviets had, they don’t have the ability to destroy our country. A single city? Maybe. We’ll get into that. But our country? Nope.

So why do I see posts from people who seem to think that any nuclear attack would be the end of the world as we know it? Why are people so fearful of nuclear weapons, as evidenced by memes such as this:

And by the outcry to President Trump when, during his campaign, he wouldn’t say that nuclear weapon usage was never an option?

TRUMP: Well, I don’t want to take cards off the table. I would never do that. The last person to press that button would be me. Hey, I’m the one that didn’t want to go into Iraq from the beginning. The last person that wants to play the nuclear card believe me is me. But you can never take cards off the table either from a moral stand — from any standpoint and certainly from a negotiating standpoint.

The left had a field day with this one. A person running for President of the United States publicly stated that he wouldn’t take the nuclear card off the table.

Well of course he wouldn’t. No president has ever, or will ever (honestly) state that nuclear weapons are never an option. Now, what got so many people up in arms was the implication that nuclear weapons could be used as a first strike, as opposed to as a defensive retaliatory strike. And, as Americans, for some reason that thought is appalling to us. Even though we’re the only country who ever has used a nuclear weapon on an enemy, the thought of doing it again leaves us aghast.

But should it?

I believe one of the reasons we fear nuclear weapons so much is that most of us don’t actually understand what they are and how they work. We know they’re super powerful and they create great destruction, but most of us don’t know how they do that and what makes them so different from any other super-powerful bomb. I know people don’t understand what a nuclear weapon is when I hear comments like, “You won’t be able to visit Korea for the next ten thousand years.”

Our fear of nuclear weapons, much like our fear of dark parking garages, mirrors in dark bathrooms, and Ouija boards, comes partly from our natural and biological fear of the unknown and that which we don’t understand, along with our lingering fears from the Cold War, either through personal memories, or through history class lectures and anecdotes.

And that’s why, in this series of blog posts, I’m going to explain exactly what nuclear bombs are and how they work. I’m going to talk a little bit about the history of nuclear weapons, and what the weapons of today look like and are capable of. I’m going to discuss the types of weapons North Korea has, and what the launch of those weapons would mean to us and to the DPRK.

I’m going to attempt to alleviate some of the fears of the unknown; to put to rest some myths about what launching a nuclear weapon would mean, both as a first-strike option, and as a retaliatory option. I’m going to compare a nuclear blast to a blast from some of the powerful conventional weapons of today and weapons through history, including the original atomic bomb attacks on Hiroshima and Nagasaki. I’m going to explain the difference between those WWII bombs, which were atomic bombs, and the hydrogen bombs of today. I’m also going to explain why people live happily and free of radiation exposure in Hiroshima and Nagasaki right now.

This is going to be a long series of blog posts with a ton of information. If you don’t have any interest in nuclear weapons and how they work, and you don’t have any fears of a nuclear war with North Korea, and you understand perfectly why Donald Trump has made the comments and threats he has with regard to nuclear weapons in general, and North Korea in particular, then you don’t need to read them.

Otherwise, buckle in. Because nuclear weapons are fascinating, and the science and technology behind what makes them work, and what makes them so terrifying, is engrossing. I’m going to do my best to bring it to you in a way that will make you understand them a little better, and maybe even fear them a little less.