Nations all around the globe had a collective freak out this week when North Korea detonated a nuclear bomb in a test and declared that they have a hydrogen bomb. Oh crap! The most unstable leader in the world has the most powerful bomb on the planet! Well, maybe not.
What is a Hydrogen Bomb?
Before talking about what a hydrogen bomb is, let’s talk the old fashioned fission bomb first. Nuclear fission takes place when the nucleus of an atom is split into atoms of less mass. The ‘lost’ mass is converted into energy – a bunch of it. If you do this to a lot of mass, and do it quickly enough, then you get a big explosion. That is an atomic bomb. A hydrogen bomb – also known as a thermonuclear bomb or fusion bomb – does things a little differently. It uses fusion, not fission, to create the big boom. Fusion is much more powerful so the boom is much larger. But fusion isn’t easy. Fusion takes place in the middle of the Sun. For that to happen, there needs to be massive temperatures and pressures to support the reaction. Since that’s not easy to do on Earth, fusion bombs need some help to get that fusion reaction to happen. How can you get a bunch of heat and pressure quickly? How about a fission bomb? Yep, a fusion bomb uses a fission bomb to create the conditions necessary to allow fusion to occur – and then you get that even bigger boom. It allows you to make smaller weapons that can more easily be delivered. So if North Korea were to have a hydrogen (fusion) bomb, it would really be a big deal.
Why I Don’t Think North Korea has the H-Bomb
The bombs dropped on Hiroshima and Nagasaki at the end of World War II were fission bombs equivalent to about 16,000 and 20,000 tons of TNT respectively. Hydrogen bomb yields are typically measured in millions of tons (megatons). North Korea has performed four nuclear tests, including this latest one. The yields were 1000, 4000, 7000, and 10000 tons. If the last test was a hydrogen bomb, why did it fall well short of the first nuclear bomb ever developed? It is not in the class of a hydrogen bomb. The only thing telling us this was a hydrogen bomb is the North Korean leader. Remember that this is the same leader that said they’d successfully tested a submarine-launched missile – the same one that traveled about 100 yards before plopping into the sea. I guess by North Korean standards, that’s a success.
Hydrogen (fusion) bombs are far more complex than fission ones. First, they use tritium, a form of hydrogen that does not occur naturally. It is very difficult to produce, requiring hugely expensive and complex production facilities. Then you need to have a working fission bomb to set off the fusion reaction. Considering that North Korea still hasn’t perfected fission weapons, I find it hard to believe they suddenly took the big leap to fusion.
The “Hydrogen Bomb” That Really Isn’t a Hydrogen Bomb
Some people are postulating that what North Korea meant by a “hydrogen bomb” was a boosted fission weapon. Fission bombs don’t use all their fissile material (e.g. uranium) when they explode. The explosion blows it apart before it can be part of the reaction. The Hiroshima bomb used only 1.4% of its uranium in the detonation. The remaining material was blown into little bits and became that nasty stuff known as fallout. If you can include more uranium in the reaction, then you get a bigger boom. A boosted weapon uses small amounts of deuterium and tritium to create a small fusion reaction that then creates neutrons to help the fission reaction along, allowing it to consume more material before it blows apart. A boosted weapon can use as much as 25% of the fissile material, significantly increasing the destructive force.
So, potentially North Korea has a boosted weapon and is calling it a hydrogen bomb. I still find that very hard to believe. The size of the explosion was just too small.
What Does it All Mean?
The fact that North Korea is testing nuclear weapons is no joke. Any time a madman has that kind of destructive power at his disposal, you have to take notice. Still, the country is a long way from an operational weapon, much less a hydrogen bomb, and, while the results from this latest test are surely moving them forward, they aren’t going to be threatening their neighbors, much less the rest of the world, with the threat of nuclear annihilation any time soon.