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Since a magnitude 9.0 earthquake rocked Japan and set loose a massive tsunami March 11, the Tokyo Electric Power Co. (TEPCO) has been scrambling to avert a nuclear disaster at its hardest hit plant. The Fukushima Daiichi nuclear power station, home to six nuclear reactors, has witnessed explosions at three reactors and a fire in a spent-fuel pool at a fourth. At two reactors, unit Nos. 2 and 3, the vessels containing the nuclear material are suspected to be compromised.
A handful of plant workers remain on the site, implementing emergency cooling measures at the stricken, overheating reactors. Radiation levels have fluctuated wildly during the crisis, and the extent to which the workers' health has been endangered may not become apparent for years. But so far, the radiation releases have been limited compared with the 1986 Chernobyl disaster in Ukraine, an explosive event that caused dozens of cases of fatal radiation poisoning among plant workers and that has been implicated in thousands of thyroid cancer diagnoses in the years that followed. (Nuclear fission of uranium fuel produces radioactive iodine, which gathers in the thyroid gland.) As many nuclear experts have noted, the Fukushima reactors are better designed than the failed Chernobyl reactor.
Below are some facts and figures about the radiation hazard posed by the Fukushima breakdown and how it compares with other nuclear accidents in history. Many of the figures are measured in millisieverts, an international unit of radiation dosage. (One sievert is equal to 100 rems, which is a dosage unit of x-ray and gamma-ray radiation exposure; one millisievert is 0.1 rem.)
Radiation dose at the boundary of the Fukushima Daiichi nuclear power station on March 16: 1.9 millisieverts (mSv) per hour
Peak radiation dose measured inside Fukushima Daiichi on March 15: 400 mSv per hour
Maximum allowable exposure for U.S. radiation workers: 50 mSv per year
Average exposure of U.S. residents from natural and man-made radiation sources: 6.2 mSv per year
Estimated total exposure at the boundary of the Three Mile Island site in Pennsylvania during the 1979 accident there: one mSv or less
Average total radiation dose to the 114,500 individuals evacuated during the 1986 Chernobyl disaster: 31 mSv
Half-life of iodine 131, a dangerous radioactive isotope released in nuclear accidents: eight days
Half-life of cesium 137, another major radionuclide released in nuclear accidents: 30 years
Decay products of iodine 131 and cesium 137: both emit gamma rays and beta particles (electrons or positrons)
Amount of nuclear fuel in Chernobyl reactor No. 4 that exploded in 1986: 190 metric tons
Amount of nuclear fuel and fission by-products released into the atmosphere during Chernobyl disaster: 25 to 57 metric tons
Approximate amount of nuclear fuel in each crippled Fukushima Daiichi reactor: 70 to 100 metric tons
Sources: Japan Atomic Industrial Forum, International Atomic Energy Agency, U.S. Nuclear Regulatory Commission, National Council on Radiation Protection and Measurements, U.S. Environmental Protection Agency, United Nations Scientific Committee on the Effects of Atomic Radiation, National Institute of Standards and Technology, Nuclear Energy Institute
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17 Comments
Add CommentThanks for the great, clear article. One troubling stat: if peak radiation in Japan was 400 mSv per hour (vs. the 50 allowed per year in the U.S.), how can this incident not surpass by far Three Mile Island? -- to my knowledge, it was ranked less grave yesterday.
Reply | Report Abuse | Link to thisLuca Semprini
www.poweringanation.org
Good question -- France has stated that the Japan accident should be classified a 6, not a 4, on the 7-point International Nuclear and Radiological Event Scale, or INES. (Three Mile Island is classified as a 5.) Perhaps the INES figure for Fukushima will be revised upward.
Reply | Report Abuse | Link to thisI am happy to that someone is trying to put the facts out for everyone to see, but the information about cesium and iodine is incorrect. Cesium-137 decays to Barium-137, so the "decay product" is Barium-137, not gamma rays or beta particle. Gamma rays and positrons are emitted when the cesium-137 decays, but radiation is not the same as decay products. The same applies to iodine-131, which decays to xenon-131 by positron emission.
Reply | Report Abuse | Link to thisA major problem with nuclear power is that the public does not understand it (and especially its risks) well. I would hope that Scientific American would help to solve this problem by providing accurate information in its future articles.
Now that they are on the verge of a meltdown we will see whether or not THIS hypothesis holds water .. ?
Reply | Report Abuse | Link to this"The China Syndrome is a term to describe one possible result of a severe nuclear meltdown in which molten reactor core components penetrate their containment vessel and building. The term is misleading, since molten material from such an event could not melt through the crust of the Earth and reach China."
I have a fast suggestion for cooling of reactor in Fukushima. It's hard to find email address where people can post their ideas to help in this difficult situation.
Reply | Report Abuse | Link to thisAnyway...
Air balloon(s) over reactor for water supply.
This solution can be fastly accomplished without any need of people
presence for a long time.
1. Place water pump close to reactor - can be done shortly, militaries
probably have one.
2. Fix a light water supply tube from pump to air balloon (balloon
should lift up water supply over reactor)
3. Fix balloon over reactor using ropes on a ground to resist wind.
4. Supply water (better hard water with bohr) - diesel power station etc.
It should work. No people on air balloon necessary.
I have sent it already to news agencies and ministries but maybe we can discuss it here. Now, every minute counts.
Reply | Report Abuse | Link to thisDoes anyone know how much radiation releases an average nuclear bomb test during last century?
Reply | Report Abuse | Link to thisThey're probably not doing this because you'd need somewhere around 11 million liters of helium to lift a 2.5in diameter 100ft long hose. Water is heavier than you think. 100ft of two and a half, a standard fire fighting hose with a high flow rate, weighs almost 5,000 pounds when full of water. You're not lifting that with anything short of a blimp.
Reply | Report Abuse | Link to thisLets calculate for one balloon.
Reply | Report Abuse | Link to this2.5in tube is quite a big tube and maybe not required wen using a good diffusor and having inmind that it will be constant water supply. It will be about 11 kilo for one meter. If we take 1,25In tube then 1m will be about < 3kg. 1km will weight 3ton. To lift it up you will need about 3000 cubic meters balloon. Its about 10 radius balloon. Can be done also with several balloons.
10 radius = 10m radius
Reply | Report Abuse | Link to thisI am forwarding a suggestion made by Alberto Vorano at a Google website. I'm not a nuclear scientist, but I thought the boron nitride idea makes sense. But how can it be delivered to these highly reactive and inaccessible sites?
Reply | Report Abuse | Link to thishttp://groups.google.com/group/alt.gossip.celebrities/browse_thread/thread/10342ac96c12d7c6
"As now they are dealing with high temperature and high reactivities on fuel rods I think the ultimate way to have reaction slowing down is to cover the fuel rods pool with BN that is a very temperature resisting material and has a very high neutron capture section"
I was wondering if the people looking after this disaster are looking at zeolite?
Reply | Report Abuse | Link to thisIt can be used ground, like sand, to entomb these reactors; you can also use it in cement to encapsulate them; as well using it in food as they did at Chernobyl will absorb radiation in people!
Three Mile Island also used zeolite, in particular it absorbs the very dangerous cesium 137 and strontium 90.
Perhaps, someone can get the word out if they aren't already considering this as they have good zeolite and close, in the North!
How about the radiation from the MOX fuel? How bad is this stuff? Do we know the original use of the recycled materials? How bad is that Plutonium likely to be? I'm wondering here the half-life we're looking at.
The difference between Chernobyl and Fukushima now is that the reactors I assume can't now explode? Or, if they go into meltdown what about explosions when the core contacts ground water? How bad could this be? We don't have any experience with this do we? Purely hypothetical I suppose. At the end of the day does anyone have an estimate of world-wide coverage and what about that amount of radiation going into the ocean? Won't the ocean circulate this?
Lots of questions!
Everything around the Daiichi plant in the English-language media is a Goebbels "big lie". Take into account the amounts of background radiation from various parts of the world--all the time:
Reply | Report Abuse | Link to thisUS natural background radiation exposure is an average of 3.6 mSv/yr; Australia 2.4mSv, Ramsar (Iran) 260mSv.
More here: http://truenorthreports.com/facts-and-information-about-radiation-exposure
Also: http://mitnse.com/
But, people should know that the insane "greenie" ideology has imposed a false "zero tolerance" measure for radiation which is used to scare people. Its a political thing to get people to go back to lower levels of technology, and thus reduce the ability of people to develop. Secondly, it is important to really understand these measures (http://www.godlikeproductions.com/forum1/message1394413/pg1)
Relevant portion: Where beta-gamma radiation is concerned:
1 Gray (Gy) = 1 Sievert (Sv)
1 Sievert (SV) = 100 Rem
therefore, 1 Gy = 100 Rem
The highest reported beta-gamma radiation thus far is 0.3817 millirem per hour.
WW2 Japanese survivors got 50 Rems of radiation...they survived.
Фукусима-1. Проблемы были предсказуемы.
Reply | Report Abuse | Link to thisFukushima-1. Les problèmes étaient prévisibles.
Fukushima-1. The problems were predictable.
Fukushima-1. Die Probleme waren vorhersehbar.
Fukushima-1. I problemi erano prevedibili.
Fukushima-1. Los problemas eran previsibles.
Fukushima-1. Os problemas eram previsíveis.
福岛-1。可以预见的问题
福島-1。問題は予測可能であった。
En français:
Chers!
Pourquoi avez-vous pas remarqué la chose la plus importante?
Objet dangereux - la centrale nucléaire "Fukushima-1" (en japonais - 福岛 第一 原子 力 発 电 所) - a été construit au mauvais endroit.
Les conséquences possibles de la construction centrale atomique dans ce domaine pourrait avoir été prévue avant la construction d'une centrale nucléaire "Fukushima-1".
La centrale nucléaire "Fukushima-1" est situé sur le côté extérieur de l'île de Honshu (Honshū). Côté extérieur de l'île de Honshu (Honshū) est plus sensible à la menace de tremblements de terre et les tsunamis, que le côté intérieur de l'île, qui se penche sur le continent. Par ailleurs, parmi les 6852 îles de l'archipel japonais est un lieu qui est le plus sûr pour la construction ces objets dangereux. Avant l'accident dans une centrale nucléaire "Fukushima-1" 54 réacteurs nucléaires au Japon généré jusqu'à 30% de l'électricité du pays. Au Japon à ce moment produire de l'énergie environ 12 réacteurs nucléaires parmi 54.
En outre, il s'agit d'un projet fourniture d'électricité au Japon sans le risque d'une catastrophe mondiale et plus écologique. Parce que le séisme et le tsunami au Japon peut être répété. Comme le gouvernement japonais envisage de résoudre le problème?
English:
Reply | Report Abuse | Link to thisDears!
Why did not you notice the most important thing?
Dangerous object - the atomic power station "Fukushima-1" (in Japanese - 福岛 第一 原子 力 発 电 所) - was built in the wrong place.
Possible consequences of the nuclear power plant construction in this area could have been foreseen before the construction of a nuclear power plant "Fukushima-1".
NPP "Fukushima-1" is located on the outer side of the island of Honshu. Outer side of the island of Honshu is more susceptible to the threat of earthquakes and tsunamis, than the inner side of the island, which is directed towards the mainland. Furthermore, among the 6852 islands the Japanese archipelago is a place that is more safer for the construction of such dangerous objects. Prior to the accident at the nuclear power plant "Fukushima-1" 54 nuclear reactors in Japan generated up to 30% of the country's electricity. Now in Japan works about 12 nuclear reactors of the existing 54.
In addition, Japan may have a variant of the supply of electricity without the risk of global catastrophe and more environmentally acceptable. Because the earthquake and tsunami in Japan can be repeated.
What thinks about this occasion the Japanese government?
Фукусима-1. Проблемы были предсказуемы.
Reply | Report Abuse | Link to thisFukushima-1. Les problèmes étaient prévisibles.
Fukushima-1. The problems were predictable.
Fukushima-1. Die Probleme waren vorhersehbar.
Fukushima-1. I problemi erano prevedibili.
Fukushima-1. Los problemas eran previsibles.
Fukushima-1. Os problemas eram previsíveis.
福岛-1。可以预见的问题
福島-1。問題は予測可能であった。
По-русски:
Уважаемые!
Почему Вы не замечаете самого главного?
Опасный объект - атомная электрическая станция "Фукусима-1" (по-японски - 福島第一原子力発電所) - был построен в ошибочно выбранном месте.
Возможные последствия строительства атомной станции в этом месте можно было предвидеть еще до начала строительства атомной электрической станции "Фукусима-1".
АЭС "Фукусима-1" расположена с наружной стороны острова Хонсю. Наружная сторона острова Хонсю более подвержена угрозе землетрясений и цунами, чем внутренняя сторона острова, которая направлена в сторону материка. Кроме того, среди 6 852 островов Японского архипелага есть место, которое более безопасное для строительства таких опасных объектов. До аварии на АЭС "Фукусима" 54 атомных реактора Японии обеспечивали до 30 % потребностей страны в электрической энергии. Сейчас в Японии работают около 12 атомных реакторов из имеющихся 54.
Кроме того, у Японии есть вариант снабжения электричеством без риска глобальных катастроф и более экологически приемлемый. Ведь землетрясения и цунами в Японии могут повториться.
Что думает по этому поводу правительство Японии?
In Japan, as in other countries, there is a logical chain of "cause - result". There is an analysis of the causes and consequences (results) for different countries. Portions of analysts are published online in blogs of konsyltacii.
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