Should we Worry about Radioactive Fallout from North Korea?
The latest push by the Democratic People’s Republic of Korea (previously referred to as North Korea) to develop a ballistic missile capable of reaching California with an atomic warhead on it, has caused some real consternation. In America and in the world.
Like their hydrogen bomb test that wasn’t a hydrogen bomb, this particular missile test wasn’t for a long-range missile as the DPRK tried to say. But it was an intermediate-range that could reach its neighbors easily.
From successful atomic bomb tests, to putting satellites into orbit and launching missiles from a submarine, in the words of one U.S. official, DPRK’s modern weaponry has gone from a joke to something very serious. They have sufficient plutonium for between six and ten atomic weapons similar in type to the one we dropped on Nagasaki.
It will be some time before the DPRK can threaten the United States. But our allies surrounding them are quite worried. If our nuclear umbrella reacts as designed, to an attack on South Korea or Japan from the DPRK, there will be more than just a few atomic and nuclear detonations that would follow as the political, industrial and military centers of the DPRK were obliterated.
I’ve been getting a lot of questions about what would happen after that. Even though the immediate destruction dwarfs any subsequent effects, most people’s minds go directly to the images from science fiction they’ve read or seen – that those areas would be uninhabitable for thousands of years, dead zones from radioactive fallout.
However, that’s not exactly true. Radioactive fallout is not a common result from using nuclear weapons.
In the decades following WWII, we spent lots of time and money researching the characteristics and effects of nuclear detonations, particularly fallout, especially when we did above-ground weapons testing before 1961. We know how to generate more fallout, or less fallout, or no fallout at all, by detonating the weapon at various heights above the ground.
But the generation of fallout is inversely proportional to destructive power, which means that if you want the biggest bang with the most destruction, which is the whole point of using such weapons, you won’t generate much fallout.
In the over 200 above-ground atomic and nuclear bomb tests in the 15 years following WWII, fallout was minor in 99% of them. Residual dose rates at almost all of these test sites are very low.
On the other hand, the Castle Bravo test in the Pacific was probably the largest generator of fallout as it was detonated close to the ground and the yield was larger than we expected. At 15 megatons, that hydrogen bomb was the largest detonation ever by the United States and was one of the events that led to banning above-ground nuclear tests precisely because of the fallout.
As a result of Castle Bravo, nearby islands had to be evacuated and a Japanese fishing vessel was contaminated with enough fallout to sicken the crew and cause one death. The long struggle of the people of the Marshall Islands in response to this fallout has been horrible and unnecessary.
Fortunately, the DPRK does not have hydrogen bombs and won’t for some time.
Therefore, if an enemy wants to care about contaminating the future more than winning the present conflict, there could be areas that will be contaminated for a long time, although not thousands of years as geological and biological processes spread out and dilute contamination relatively quickly.
A good way to understand this problem is to look at the only two atomic weapon attacks in history. Little Boy, the Hiroshima U-bomb, was about 15 kilotons (15,000 tons of TNT equivalent), and Nagasaki, a Pu-bomb somewhat similar to DPRK’s bombs, was about 25 kilotons. There are no areas in either city, or anywhere else, that are still radioactive above background levels as a result of those detonations. They are certainly not dead zones.
This comparative unit of kilotons is not hyperbole. It means if you could have put 15,000 tons of TNT in one spot in Hiroshima, and ignited it all at the same moment, the effect would have been almost exactly the same as Little Boy. The same mushroom cloud, the same destruction, almost the same deaths.
It’s the pressure and the heat that do the real damage, not radiation. The blast and the fireball. The difference is that in an atomic blast, a large gamma and neutron radiation burst goes a little beyond the blast zone. The effects of that burst are relatively immediate and don’t last more than a microsecond.
200,000-plus deaths occurred at Hiroshima and Nagasaki in the initial seconds of the blast and in the months following as the effects of the initial burst manifested themselves. But only about 500 deaths came later from radiation-induced cancer and other long-term effects. None have been found to be from fallout.
It is critical to understand that the destruction from these two atomic blasts during WWII did not come close to the conventional destruction that lead up to them. In just the months between February and August 1945, the United States dropped 100,000 tons of high explosives and incendiaries on Japanese cities, including Tokyo, Nagoya, Osaka and Kobe, killing over 500,000 people and leveling hundreds of square miles, much more than the two atomics did together.
The real horror about using atomic or nuclear weapons is that conventional destruction takes an entire military to deliver over some length of time. So there is a chance to counter it. But delivery of nuclear weapons is quick and the effects are immediate, with little possibility to counter them.
The mess this world might be heading towards is much more complicated than science fiction, but radioactive fallout is one of the least of our worries.
This article was written by James Conca from Forbes and was legally licensed through the NewsCred publisher network.