While today’s answer was informative and did answer the question posed, I found its conclusion to be overly optimistic for one of the worst atrocities of the 20th century.
The column in question: If nuclear fallout lasts thousands of years, how did Hiroshima and Nagasaki recover so quickly?
That’s a slippery slope you’re attempting to climb, epicac. For every person that says Hiroshima and Nagasaki were uncalled for atrocities, you’re going to find someone who says it was justified because of the potential deaths of countless U.S. soldiers. Even I, liberal pinko tree-hugger stereotype extraordinare, straddle the fence on this one.
On a different note: one thing that sprang to mind during the reading of Cecil’s article is the possiblity of the sophistication (or lack there of) of the A-bombs playing a role in the rapid dissipation of the fallout. Would anyone who is better versed in this issue offer some possible insight?
–greenphan
Nothing really positive about it, epicac, but as far as nuclear bombing goes, it could have been a lot worse.
greenphan, while I am by no means an expert in this area, important to consider is the relative youth of the technology employed to create the a-bomb. The study of atomic warfare and consequent tests/endeavours were in their infancy and its entirely possible that the engineers weren’t aware that mid-air detonation wouldn’t produce optimum damage or lingering residual radiation. Or perhaps that’s what they were doing: aiming for a more humane approach.
I don’t think they had much of a clue what they were unleashing. The mid-air detonation was clearly for optimum damage, the fact that it would reduce the radiation was not known.
It is possible, I would imagine, that during the bomb tests in New Mexico, they did mid-air detonations and were able to study the effects such a detonation would have on the radiation.
Actually, they only did one test before they dropped the bomb on Hiroshima - the bomb was placed on a steel tower a couple hundred feet high, IIRC.
I’m not sure what about the conclusion would be called over-optimistic. The lack of long term contamination is, in retrospect, a natural result of higher elevation nuclear detonations. The lack of long term genetic effects is also in line with what is known about radiation damage to genetic material (it tends to make subjects sterile or results in non-viable mutations - resulting in the genetic defect not being passed on). Wars and bombing are not desirable things, just like militaristic dictatorships that enslave and murder people are also not. Somehow you have to reach a balance.
To clear up something from Cecil’s article re: “initial” and “residual” radiation.
When a nuclear bomb goes off, there is an initial burst of ionizing radiation from the explosion itself. This burst is strictly line-of-sight and dissipates literally instantly. This is where much of the “local” radiation poisoning comes from in a nuclear blast. A 1 MT blast will deliver about 500 REM at about 3 km. 500 REM is the LD50 for ionizing radiation. Serious illness and disability can occur at doses as low as 100 REM.
Fallout or “residual” radiation is another thing entirely. This is caused primarily by dust and debris mixing with the fireball itself. When the bomb goes off, the bomb itself is, of course, vaporized. That vapor, however, is highly radioactive, not only because of the “unexploded” uranium or plutonium used to make it, but because the explosion creates lots of unstable isotopes of various elements, one of the most dangerous being a radioactive isotope of iodine. If the fireball is high enough and doesn’t reach the ground, the relatively small amount of material, though highly radioactive, rises fairly high in the atmosphere (remember, it’s really hot) and blows away relatively harmlessly. Well, only relatively because the bomb debris can still produce dangerous fallout, often hundreds of miles away. However, if the fireball is close enough to the ground (especially if it actually touches the ground), hundreds of tons of dirt and debris get sucked in with the bomb debri and much of it is deposited near the blast site. This stuff can be very concentrated and very dangerous. Having several metric tons of plutonium laden dust spread around your town will, indeed, make it permanently uninhabitable.
A friend of mine who recently retuned from Japan on a one-year teaching contract told me that Hiroshima and Nagasaki are still showing a much greater than average rate of radiation-related diseases. I’m not sure who to believe. Does anyone know of any other studies since the 1981 study that Cecil mentioned? (Always good to have multiple sources…)
When my Mum lived in Dublin, Ireland in the 60’s she shared accomodation with a girl whose parents were in one of the two cities bombed and she had been left with birth defects, her chest was distorted somehow. Seems strange that my Dad met a Holocaust survivor only when he actually visited Poland and saw one of the concentration camps, Mum met someone from such an event the other side of the world simply by chance.
(Note, I’m only comparing the Holocaust and the A-bombs as historical events, not morally, thats for another thread)
I’d recommend the Radiation Effects Research Foundation website; RERF has been studying the Hiroshima/Nagasaki survivors (and children born of them) for over fifty years now.
Do Hiroshima and Nagasaki show a “much greater than average rate of radiation-related diseases”? Depends on what spin you put on that. The average rate of disease that can be attributed to radiation exposure is zero, even in populations living in areas of higher-than-average radiation exposure. So, if you can detect it, it is, by definition, much greater than average.
Detectable radiation-related disease is essentially cancer (RERF indicates that there may be other diseases, but the evidence doesn’t fit well with the standard linear zero-threshold model, so no one quite knows what to make of it). And cancer generally takes years or even decades to develop (the dirty little secret, which Cecil hints at but doesn’t really emphasize, is that if you’re close enough to the hypocenter (ground zero) of the blast to die of acute radiation exposure, you’re probably close enough to be killed by the blast wave or the thermal pulse first). There’s no detectable difference in cancer rates between those survivors who’ve stayed in the cities and those who’ve moved away, and those persons never exposed and who’ve moved to Hiroshima and Nagasaki later.
The net appears to be: there’s a greater rate of cancer morbidity and mortality in Hiroshima and Nagasaki than elsewhere. That appears to be because there’s a greater concentration of atomic bomb survivors in Hiroshima and Nagasaki than elsewhere; if they’d all been relocated to San Francisco, the increased cancer rate would have been seen there instead.
Epicac, when someone says “worst atrocities of the 20th Century,” here are some of the events that come to my mind: The Nanking Massacre (300,000 Chinese civilians murdered, 20,000 women raped,) the Bataan death march, the Comfort Women (conscripted/kidnapped Japanese, Korean, Chinese, Phillipino (and others) sex slaves,) the torture and vivisection of prisoners for “medical research” (try Googling for ‘unit 741’ or ‘Maruta’,) and others. These atrocities were committed by soldiers of the Japanese Empire.
In fact, during their rampage through Asia, the Japanese murdered millions of civilians in China, Korea, the Phillipines and elsewhere. Unlike the Germans, the Japanese have made tremendous efforts to cover-up their conduct. They even have the audacity to portray themselves as the ultimate victims of that time.
Many thousands of American soldiers died putting an end to this affront to humanity. I personally can find no way to blame our leaders for doing whatever they could to put a prompt end to this terrible era.
http://www.cnd.org/njmassacre/
http://yarchive.net/mil/japanese_atrocities.html
http://www.everything2.com/index.pl?node=Japanese%20Atrocities%20in%20World%20War%20II
I was looking for an answer that addresses what happens in today’s world.
Are nuclear weapons designed to be detonated in the air above their targets? If so, does that mean that further use of nuclear weapons wouldn’t cause cities to be nuclear wastelands?
Excellent first post, arlin. Right on.
There’s so many different types and delivery methods that it’s impossible to say. Check www.fas.org for info.
Two points. First several metric tons of plutonium laden dust from unfissioned material is kind of far fetched. The Nagasaki plutonium bomb had only about 6 kg of plutonium. Some designs today have considerably more but not huge amounts.
Plutonium is not something to stay up nights about in spite of all the sensationalist press about it. It has an extremely long half life (24,000 years) and gives off primarily alpha rays, which cannot penetrate the skin. Therefore, it is only of concern if taken into the body. In reality,it is only a concern when inhaled since if ingested, it just passes through the body. Due to the heavy weight of the isotope, inhalation is not much of a long term concern since it does not stay airborne.
Although there is a theoretical long term (20 to 30 years) increased risk of cancer such as lung cancer with inhalation, there are other fission products which are probably more hazardous.
See this web page http://www.bikiniatoll.com/home.html for information on Bikini Atoll which saw far higher yield bombs then the two Japanese cities (including the largest ever detonated by the US). Although not livable it is aparenly safe enough to be a scuba driving attraction.
Actually, this was fairly well understood and the targeting decisions appear to have sought to minimise fallout. There had been part of the theory group at Los Alamos who had been tasked in November 1944 to estimate the damage effects in as much detail as possible. Part of this involved understanding the physics of the explosion after detonation. The group knew that a fireball would form, but that this would be relatively small compared to the total area of destruction. Fallout is most severe when this fireball touches the ground, because some of that surface is vapourised and becomes contaminated in the blast column. Detonating the weapons at 1850 feet maximised the blast damage, but also reduced the chances of the fireball touching the ground. Writing in a report after the fact, one of those involved in the study, William Penney, concluded:
Hans Bethe’s description of their understanding was that they’d had “a fairly complete picture.” (Both quoted in Critical Assembly, Cambridge, 1993, by Hoddeson et al; the issue is discussed in detail on p343-4.)
The Trinity test was signficantly different in that the tower wasn’t that tall and so the ground was significantly irradiated. Realising that this was going to happen, the initial approaches to the site after the explosion were conducted in specially shielded tanks. Eventually, people took samples of Trinitite, the fused surface remnent, as souvenirs, but they’ve been known to cause minor radiation burns. Even today, while the site is open to the public at times, it remains slightly abnormally radioactive. Still, while I don’t know exactly when it was taken, the famous photo of Oppenheimer and Groves standing next to the twisted stump of one of the tower’s legs must have been taken within a day or two of the test.
Because of the difference, the major input into the calculation of the detonation height from Trinity was actually the refinement of the yield estimates. Penney then briefed the Los Alamos staff on the expected effects on the target. By all accounts, his seminar did fully bring home that the result would be horrific.
What wasn’t well understood were the medical effects of the exposure.
**
Not a bit. Unlike in an ordinary explosion, the plutonium in a nuclear explosion is vaporized – it’s essentially plutonium gas. If lots of cool dust gets sucked into the hot fireball, the dust ends up being contaminated with plutonium as the gas reverse sublimates.
As you point out, inhaling is much more dangerous than ingestion. Dust particles impregnated with tiny amounts of plutonium are, therefore much more dangerous than good-sized particlcles of pure plutonium that can’t get airborne.
Just how dangerous? Well, 20mg of plutonium inhaled will kill you outright in a month. As little as .1 mg inhaled (well, really .08mg but who’s counting) carries a 100% probability of eventually developing a fatal cancer. In other words, 6kg of plutonium “optimally” distributed is enough to cause 60,000,000 fatal cancers or to kill “only” 300,000 people outright in a month.
That’s what makes it so dangerous when the fireball touches the ground. Rather than being widely disbursed and diluted as bits of pure plutonium. most of the debris are deposited near the blast site as fine dust with a light “coating” of plutonium. Since, as you say, plutonium has a half-life of 24,000 years, the blast site can exhibit dangerous levels of contamination effectively forever.