HOLDING TANKS: Tanks hold some of the radioactive water overflowing from cooling efforts at the stricken Fukushima Daiichi nuclear power plant in Japan.
Image: Courtesy of TEPCO
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More than three months after a powerful earthquake and 14-meter-high tsunami struck Japan, the Fukushima Daiichi nuclear power plant remains flooded with a salty mix of ocean and fresh water that is contaminated with the radioactive residue of three reactors and four spent fuel pools' worth of nuclear fuel. Every day an additional 500 metric tons of seawater is poured onto the still hot nuclear fuel in the stricken reactors and fuel pools. More than 100,000 metric tons of such water now sits in the basement and trenches of the reactors—or evaporates inside the hot reactor buildings, making for a radioactive onsen (hot bath).
Thus far, neither the nation's 75 aftershocks of magnitude 6.0 or greater—the latest of which struck on June 23—nor inclement weather has halted ongoing efforts to cool the stricken nuclear power plant. With the start of any decommissioning process still at least year away, cooling the fuel with water remains the focus—as well as a potential source of additional problems as contaminated water threatens to overwhelm the plant and its environs.
In early June Tokyo Electric Power Co. (TEPCO) installed a series of devices—from nuclear equipment manufacturers Kurion and Areva Group—meant to filter radioactive material from the contaminated cooling water and enable it to be reused on the hot nuclear fuel rods. Without such filtration, radiation levels in the reactor buildings can climb too high to permit workers to advance their efforts to control and clean up the damaged power plant. But a trial run of the new filtration system was halted on June 18 in less than five hours when it captured as much radioactive cesium 137 in that span as was expected to be filtered in a month.
Massive tanks have been delivered to store some of the excess radioactive water, given that spraying must continue due to leaks in the reactors themselves that prevent restoration of the normal cooling system. "The most important thing is to keep the reactor fuel cool. If the only alternative is to use saltwater then that's the best thing to do," said Bill Borchardt, executive director for operations at the U.S. Nuclear Regulatory Commission (NRC) at a talk in May. "Given the situation that existed and that there were very few options available, I think injection of saltwater was clearly the appropriate thing to do," although TEPCO has switched to using fresh water more recently.
With just centimeters remaining before the radioactive water overtops its storage, however, another release of contaminated water into the ocean looks ever more likely. Already, pools of this water burned at least two workers at the plant when they stepped in the puddles, and TEPCO was forced to dump more than 11,000 metric tons of such contaminated water in early April.
"The reactors weren't designed to have water poured in the top, pour out the bottom and pool in the basement," says nuclear energy advisor Arnie Gundersen of Fairewinds Associates consultants. "What TEPCO should be doing is building a trench around the reactors down to bedrock, 20 meters deep and 1.5 meters wide, and fill that trench with zeolite." Zeolite minerals capture radioactive particles, and are used in the reprocessing of spent nuclear fuel.
The normal equipment for such cooling is inoperable thanks to the complete meltdown and corrosion from seawater, so spraying new water on the hot nuclear fuel remains the only option. Debris and detritus—radioactive and inert, alike—continue to impair human and robot workers' attempts to achieve so-called "cold shutdown," which would allow the real work of tearing down and cleaning up the contaminated site to begin.
"It's going to be very complicated to decommission this thing," physicist Arjun Makhijani, president of the Institute for Energy and Environmental Research notes. "The handling equipment has been destroyed, it was a complete meltdown, it's a highly radioactive environment and there's radioactive water."
The rising level of used cooling water is just one of the challenges at the plant, more than three months after the crisis started. Radiation levels continue to spike at times as high as 4,000 millisieverts an hour, impairing repair efforts, even with robots. (A sievert is a unit of ionizing radiation equal to 100 rems; a rem is a dosage unit of x-ray and gamma-ray radiation exposure.) Despite the restoration of electric power in April, cooling systems remain inoperable. And radioactive material—cesium 134, cesium 137 and some 50 other longer-lived radioactive isotopes—continue to be found farther and farther afield from the site itself, concentrating in hot spots as far as 225 kilometers from the stricken complex. For its part, Japan's Nuclear and Industrial Safety Agency now estimates Fukushima has released some 770,000 terabecquerels worth of radiation—or roughly 15 percent of the amount released by the catastrophic 1986 fire at Chernobyl in Ukraine. (One becquerel represents the rate of radioactive decay—or radiation emitted by a substance—as one disintegration, or count, per second.)
"When you have an accident for months and certain patterns of rainfall, you get hot spots," Makhijani says. As a result, entire towns, such as Date, Iitate and Iwaki City, may have to be permanently abandoned and roughly 80,000 people have lost their homes to radioactive contamination.
In addition to the failed water filtration system, TEPCO has proposed enshrouding in plastic the reactor buildings torn apart by hydrogen explosions to prevent further releases from that source of radioactive material. The good news is that the heat from the melted down nuclear fuel and still intact fresh fuel rods continues to decline. "As time goes on, the decay heat gets less and less," the NRC's Borchardt noted. "Around 90 to 100 days the problem becomes much less severe"—a time period Fukushima Daiichi has now entered.
More than 3,700 workers continue to attempt to control and contain the crisis. Nine of those workers have already reached the legal "emergency limit" of 250 millisieverts of cumulative radiation exposure, and 124 have received more than 100 millisieverts, the prior limit. In the U.S. annual exposure for nuclear power plant workers is limited to 50 millisieverts per year, and it is estimated by some that their risk of cancer increases by 4 percent per sievert. (This risk figure remains controversial as either too high or too low, by scientists who study the impact of radiation on health, primarily based on data collected after the 1945 detonation of the atomic bombs over Hiroshima and Nagasaki during World War II.)
In the end TEPCO plans call for a cold shutdown of the stricken reactors by April 2012—more than a year after the crisis began—and that means some kind of treatment plan for hundreds of thousands of metric tons of radioactive cooling water will be needed as soon as possible. Beyond that lies the challenge of hundreds of thousands of metric tons of soil contaminated with radioactive isotopes across at least 600 square kilometers of northeastern Japan.
The challenge is not insurmountable, just costly. "You can clean up almost anything if you're prepared to spend enough money on it," adds Peter Bradford, a former member of the NRC.
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19 Comments
Add CommentDamm! These things are monsters. And who wanted to build more of them in the USA?
Reply | Report Abuse | Link to thisFukushima is estimated to have released just 15 percent of the radiation at Chernobyl?”
Reply | Report Abuse | Link to thisI contacted the Nuclear Information and Resource Service who replied;
“We believe that is incorrect. Using actual radiation data collected by the Comprehensive Nuclear-Test-Ban Treaty Organization–which has the largest and most reliable data collection available–the Austrian government calculated on March 23 that releases at that time were about 20% of the amount of iodine as Chernobyl and 50% or so of Cesium. And, of course, the releases have continued since then, though at a slower pace. Our colleague Bob Alvarez at the Institute for Policy Studies believes now that the total number of curies released to air and water is about 60 million; Chernobyl release is estimated at 50 million curies.”
Please confirm the Japanese Government estimates with other sources, or correct this error.
Thanks.:)
Usual Big Oil propaganda from SciAm chief climate denier Biello.
Reply | Report Abuse | Link to thisGunderson is a completely discredited high school math teacher with almost no qualifications in the field other than a 40 year old masters degree.
Makhijani a notorious nuclear and climate denier has been caught lying so many times that Biello shames himself even mentioning the name.
There are no sites outside the main plant that come anywhere close to the natural radiation levels at Ramsdar, Iran where folks have a very low rate of cancer.
Chernobyl was a Soviet nuke weapons plant destroyed in a failed weapons production experiment - nothing to do with nuke power. It released many different radiation emitters like plutonium unlike Fukishima.
Even Chernobyl's releases where nothing compared to all the radioactive debris emitted in the many other atmospheric weapons tests to 1970.
I always get a kick out of the you Deniers with the junk science bringing up problems with a 1950's design Model T reactor that was damaged by corruption caused technical problems and hurt nobody. Crippled by the same corrupt practices, the event caused no damage to seventies designed reactors just down the beach.
The entire quake tsunami disaster would have been a non event to a modern nuke].
How about criticizing something Makhijani or Gunderson ACTUALLY said? I don't think they said anything controversial or nonscientific. If you don't think that decommissioning and cleaning up the Fukushima site when this disaster is all over will be difficult, then you're smoking some powerful nuclear crack, my friend.
Reply | Report Abuse | Link to thisWhen you say this earthquake/tsunami disaster wouldn't be a threat to a "modern" nuke, do you mean the Gen III+ reactors that have had so many cost and schedule overruns that utilities across the developed world are cancelling orders or having serious trouble finding financing? Or do you mean the illusive LFTRs that could singlehandedly save the world even though we have NO idea what kind of cost and long-term safety metrics they'll have as commercial reactors? Sure, we should get a research LFTR up and running and fund it by cutting all the pork we throw at the established nuclear industry. But you have to realize all the boasting about how light water reactors would usher in an era when energy was "too cheap to meter" was absolutely wrong. All the idealistic banter about how good LFTRs or other reactor designs are could be just as misled.
The Nuclear Information and Resource Service is an anti-nuclear energy group. Be careful when considering their information. Their objectivity is in question, given their overarching agenda. Not that their info isn't potentially of value...just a big heads-up to all SA readers. I would respect them much more if the called themselves "The Anti-Nuclear Energy Information and Resource Service" which is a more accurate name, conveying their underlying misssion.
Reply | Report Abuse | Link to thisYou are so right.
Reply | Report Abuse | Link to thisWhen I read some of the comments (3,4,5 &6) I ask myself if I should join a group of idiots and give this conversation any credibility? (I am assuming I am not an idiot & have some credibility) When I read comment 2, I think, perhaps yes, just disregard the irrational wannabe Einstein egomaniacs (here I know I am not one, just see the name I use).
Reply | Report Abuse | Link to thisThe meltdown is a done deed and cannot be reversed. Thousands of people are going to suffer irreversible damage, especially babies and infants currently occupying the resulting radioactive regions worldwide. Does not matter if it is worse than Chernobyl or not.
The common people always suffer the consequences of executive greed. It was so during the global financial crises, it continued in Iceland, it is now happening in Greece. Not one single rich fraudster has been punished for destroying the savings and livelihoods of millions. The Icelandic and Greek people will live meager lives while the product of their toil is paid out to super rich billionaires for generations to come.
At the end of the day all the radioactive water will be released (and is currently discretely being released) to the biosphere. The iodine and cesium etc are of little consequence in the medium term. The U235 is a problem, it has a half life of 704 million years or its effects will last for 7.04 billion years. No man will be on this planet then, its highly probable there wont be any human around in 300 years; not a result of nuclear contamination, but the result of the sixth extinction brought on by man's destruction of the biosphere by overpopulating it with his species at the expense of all others, which are vital to maintain a stable environment for all life.
Well so you and I we don't have to worry about a thing. We shall all be dead soon.
scientific earthling: Your sincere and ardent pursuit of the truth is laudable and nourishing to us all. That said, I believe you are overestimating the lethality and toxicity of U-235. From my understanding, the fact that the decay rate of U-235 is so very drawn out is a GOOD thing, because this means it emits its radiation VERY slowly over glacial periods of time. U-235 is a bit less than one percent of the Earth's crust. Thus, U-235 has been in our midst in large quantities, always. Nothing new. If you want more info, here's one source: http://www.tass-survey.org/richmond/answers/uranium.html
Reply | Report Abuse | Link to thisI think you really have it right. All we have to do is bury our heads in the sand and all the bad things will just go away!
Reply | Report Abuse | Link to thisBesides, all this 'radiation' stuff is just plain silly. We can end the problem of radiation easily by simply going back to calling it 'sunshine units' again!
The only deformities from the Hiroshima and Nagasaki bombs were those who were fetuses at the time of detonation.
Reply | Report Abuse | Link to thisThis is recorded by the Japanese .
They know more about problems from exposure to high levels of radiation than the rest of us.
Just a thought, 24,000 at least dead from the quake and tsunami , and NO deaths or exposure over 25 milli Sieverts from the Nuclear Power Plant.
Check on the Interim Report by the IAEA ,if you want confirmation.
Sorry not 25 but 250 mSv.
Reply | Report Abuse | Link to this2121xxx: If you had posted your comment as a reply to mine I would have been notified by an email. I accidentally returned to the article to check data stated here and found 2 comments neither of which were posted as replies. Folk if you expect a response from the commenter please respond as a reply.
Reply | Report Abuse | Link to thisWe have U235 ores on our planet since it formed, it exists in very very small quantities dispersed in U238 ores and other minerals. Most of the U235 that existed has decayed into other lower atomic number elements. Generally 10 half lives reduce the remaining quantity to an insignificant level. (try dividing a very large number by 2 ten times) All the Uranium 235 that exists in the universe comes from supernovas. Suns as we know them can create elements up to Iron atomic no 26.
Uranium 235 has little effect on account of its dilution. Its like using a pesticide (most effective are neurotoxins), the pesticide has exactly the same impact on your nervous system as it has on the insect you target. However since your body contains billions of neurons the effect is not as radical as it is on the insect with thousands of times less neurons. Generally the lethal dose is measured in grams per kilogram.
The same is true of radiation. But first we must define what we mean by radiation. Photons (light) that we need to see are radiation, So are emissions from all sorts of objects at temperatures above 0 Kelvin. The nuclear industry dilutes its radiations effects by including all the natural radiations into the equation, which are in fact necessary for life. Here is a reference for the nuclear industry:
www.world-nuclear.org/info/inf05.html
When they say 1 Kg of Uranium ore emits just 25 becquerel they don't tell you the typical ores contain 0.01% to 0.25% and most of that is U238 in oxide form. U235 is 0.711% of the total pure Uranium (not uranium oxide).
Here are references: 1. wikipedia.org/wiki/Uranium
2. wikipedia.org/wiki/Enriched_uranium
The radiation we are concerned with, emitted by U235 have lethal and extremely harmful effects. Marie Curie who discovered radiation died from radiation poisoning. So did Rosalind Franklin who discovered the double helix nature of DNA through xray spectrography.
Business (essentially greed) corrupts our best attempts to remain honest and perpetually seeks to distort the truth. This small flaw in human character has led to the destruction of the biosphere and extinctions.
Elderlybloke: See my response to 2121xxx. It answers your comments too.
Reply | Report Abuse | Link to thisHumans always fail acknowledging their own weaknesses and mistakes in understanding life. Despite of fact that agree majorly with what scientific earthling says in terms of exploitation and modern slavery, we shell not loose faith in our future, and the future of our kids. The other important notion to consider is I and Cs dumping into ocean that would cause much life extinction.The ion exchange french technology for water cleaning won't really work efficiently because of properties of two elements/ions (way to strong on each side of spectra). The largest illusion of humans/scientists is believing that we have no space on earth due overpopulation. That is silly propaganda and misconception and calculation. I say we have no sense of sustainability, consensus and creativity how to coexist with other species and consequences are terrible. Most people like you, say , who cares , we are going to die anyway. What a pity WORLD. So, yes, keep billionaires money in banks is just going to make things worse.
Reply | Report Abuse | Link to thisTHANK YOU SO MUCH FOR THIS POST!! If I read the misleading information about radiation release from Fukushima relative to Chernobyl reported in this piece one more time on the internet...I just don't think I could take it!
Reply | Report Abuse | Link to thisvendicar,
Reply | Report Abuse | Link to thisI assume you mean 15 Billion. Will never happen. Catastrophes galore, of all manner & severity, will prevent it if we don’t prevent it consciously.
Greetings,
Reply | Report Abuse | Link to thisYes Marie Curie died from the terrific amount of radiation she absorbed , but it took over 30 years from when she and Pierre started on Pitchblende .
Her Cook Book and other possessions are still regarded as very radioactive.
Go onto Wikipedia , and it shows what a hard life she had. The hard slog and poor conditions probably contributed to her early death.
Although not all that early for that era.
Elderlybloke: First you say Marie Curie died from a terrific amount of radiation absorbed, then you point out she had a hard life and that contributed to her early death.
Reply | Report Abuse | Link to thisI am sure her life was just as hard as any other person in her socioeconomic position at the time. So was the median age of death for the whole group equivalent to her age at death?
One thing I like about your comment, her death was not early for the era. Yes, science has increased our life expectancy, as a first born I would not be around in nature, having fulfilled my function of dilating the female delivery tract, I would have died in the process as did most first born children in eras gone by.
However facing extinction due to overpopulation and loss of environment, don't you think we should revert to these earlier lifespans? If you are one of those who believes in fairies, well that was the lifespan given by the fairies.
As a former Quality Control Nuclear Inspector, I have seen things during construction of these plants that NEVER should have been allowed. They were ok ed by the NRC to go online with structural defects and improper materials used. These plants have continual accidents that are never reported outside the industry. If the public knew of the frequency of these accident, fires, structural failures then there would be more unease within the general public. That is why the public is left in the dark. The nuclear industry should be shut down and the NRC disassembled. However, an agency the size of the NRC has to justify itself to stay open but not enough to alarm.
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