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Radiation truth: there is no threshold below which risk is zero

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Anti-nuclear demonstrators from Bosnia hold a banner with text 'We do not want another Chernobyl on Balkans' during a protest marking the 25th anniversary of the nuclear accident in Chernobyl in western town of Banja Luka 240 kms northwest of the Bosnian capital of Sarajevo, on Tuesday, April 26, 2011. Bottom text reads "better to be active today then radioactive tomorow". Photo: AP/Radivoje Pavicic

The Bulletin of the Atomic Scientists has published an article titled ‘Radiation exposure and the power of zero’. This talks breifly about the history of medical work with radiation, and the fallacy – alas not challenged enough – that there is no such thing as “safe” levels below which one is not harmed.

In 1895, the article recounts, Wilhelm Röntgen discovered x-rays and used them to take a picture of the bones inside his wife’s hand. A year later, Henri Becquerel realized that invisible emanations from uranium salts would expose photographic plates. Marie Curie and her husband Pierre carried this work further, leading to the use of mobile x-ray machines in World War I.

Madame Curie, it is said, enjoyed the glow from radioactive test tubes that she kept in her desk. She died at age 66 from aplastic anemia thought to be caused by her work with radiation. Were she alive today, she would undoubtedly follow the precautions that modern scientists take when dealing with radiation, and would not be carrying around radioactive material unprotected. Likewise, radiologists began taking steps to protect themselves from the damaging effects of radiation after noticing that people in this profession were dying at earlier ages than their colleagues who were not exposed to radiation.

[You can go to earlier coverage of the Fukushima nuclear emergency on this page. It contains excerpts, news reports, photos, graphics and links during the first weeks of the crisis.]

South Korean mothers stage an anti-nuclear energy rally to protect their children from radioactive exposure in Seoul, South Korea, Tuesday, April 19, 2011. Fears over possible radiation contamination are growing in South Korea, the country closest to Japan, after Japanese nuclear power plants were damaged by earthquakes last month. Photo: AP/Ahn Young-joon

Yet even in the 1970s it was common medical practice to x-ray pregnant women during labor to see if the pelvis was “adequate” — a procedure, incidentally, that was absolutely worthless. Sentinel work by Alice Stewart, a physician and epidemiologist who studied the effects of radiation on health, revealed that even one x-ray before birth could increase a child’s chances of getting leukaemia. Despite criticism of Stewart’s work by the nuclear industry, doctors no longer perform x-rays on pregnant women unless absolutely necessary. The trend throughout the nuclear age has been a growing recognition that there is no “safe” or “harmless” dose of radiation.

In 2006 the National Academies’ National Research Council published a comprehensive report, “Health Risks from Exposure to Low Levels of Ionizing Radiation (BEIR VII – Phase 2)” stating that radiation exposure has a linear relationship to the development of cancer. The report concluded that even low doses of ionizing radiation are likely to pose some health risks; there is no threshold of exposure below which the risk drops to zero.

Scientific arguments regarding the effects of particular doses of radiation will and should continue. However, to make this the focus of any discussion of nuclear safety obscures the real issue, thus missing the forest for the trees. The real issue is that the use of nuclear power and nuclear weapons is forcing humankind, and indeed the whole ecosystem, to participate in a particularly cruel and totally uncontrolled experiment. Given the scientific evidence that there is no safe dose of radiation, this is an experiment that has already gone awry. Indeed, if this were a true scientific experiment, it would have been halted a long time ago.

The Bulletin’s article, ‘Radiation exposure and the power of zero’, concludes by saying:

The real question is whether we, as a human race, can afford in good conscience to risk annihilation with our continued reliance on nuclear technology. Can we continue to despoil our environment with long-lived radioactive materials that are scattered to the wind and embedded in our precious soil, randomly exposing large populations, and foisting health impacts on unsuspecting future generations who have no choice in this matter?

We may choose to do so. But if we do, I am quite sure that our children and grandchildren will roundly condemn us for our lack of foresight and our selfishness. As they struggle to deal with a poisonous environment and waste that must be safeguarded for thousands of years, they will certainly wonder what possessed us to do this.

Around 900 demonstrators gather to protest against nuclear power in Helsinki on Tuesday, 26th April, 2011. The day marks the 25th anniversary of the Chernobyl nuclear disaster in 1986. Banner reads: Finland get rid of nuclear power. Photo: AP/Lehtikuva, Antti Aimo-Koivisto

One question in particular demands attention: Why was the actual event in Japan, an earthquake and tsunami, so different from the “credible” event that was expected?

Also in the Bulletin, the first of a contribution to a roundtable on ‘Fukushima: What don’t we know?’ starts to provide an answer. From our perspective as geoscientists, the article has said, this is the most important question because the definition of the credible event provides the basis against which a nuclear power plant is designed. In the case of the Fukushima Daiichi power station, the magnitude of the earthquake (9.0 on the Richter scale, or M9) and subsequent tsunami (with a reported wave height of 14 meters) exceeded the credible event on which the nuclear power plant’s design was based. The site has six nuclear reactors; three of them were operating at the time of the quake and successfully shut down in response to the ground shaking. Nevertheless, the power station and its spent fuel storage pools were overwhelmed by an event that had not been planned for — a “larger-than-expected” tsunami wave, leading to a sequence of catastrophic failures.

Some experts have since described the tsunami as a “rare” or “exceptional” event that was entirely out of the range of reasonable or credible expectation. But shallow, offshore earthquakes can cause tsunamis, and the height of the tsunami at Daiichi was certainly not unexpected for a 9.0 magnitude earthquake. In addition, there have been three 9.0 magnitude earthquakes during the past decade: Indonesia in 2004, Chile in 2010, and now Japan in 2011. The fact that such earthquakes occur infrequently over historical periods does not explain why the Fukushima nuclear power plant was not designed to withstand this type of geologic event.

From a geologic perspective, the earthquake and its great magnitude should not have been a surprise. Ten years ago, Japanese earth scientists, led by Koji Minoura at Tohoku University in Sendai, described a major earthquake and tsunami that happened in July 869 and was recorded in an historical document. This event, which is also clearly recorded in the coastal sediment of the Sendai plain, extended inland about four kilometers from the coast. Based on even older tsunami deposits that go back some 3,000 years, Minoura and his colleagues suggested a 1,000-year recurrence interval for large-scale earthquakes and tsunamis in Japan and presciently published their results in the Journal of Natural Disaster Science.

Their results and conclusions did not go unnoticed. Based on the Minoura et al. paper, Yukinobu Okamura, the director of Japan’s Active Fault and Earthquake Research Center, raised the possibility that a large tsunami could damage the Fukushima Daiichi plant. The plant operator, Tokyo Electric Power Company, dismissed these warnings.

Written by makanaka

May 5, 2011 at 00:15

Fukushima nuclear emergency, Japan

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08 February 2017: A month short of six years after the 11 March Fukushima disaster began unfolding, the situation at the nuclear power plant has entered a new phase of danger, one which modern industrial civilisation has no experience with and very little knowledge about.

The highest radiation level at Fukushima is now much higher than the highest ever measured at Chernobyl, which was 300 sieverts per hour, an inconceivably high dose which can kill a person almost instantly. Radiation is usually measured in thousandths of a sievert, called millisieverts. For example, most people receive around 2.4 millisieverts per year from background radiation, or only 0.0002739726 per hour.

But a radiation level of 530 sieverts per hour has just been measured at Fukushima’s number 2 reactor. This new record at Fukushima is 70% higher than that of Chernobyl. (The highest level previously measured at Fukushima was 73 sieverts per hour, in March 2012.) The leakage of highly radioactive water has been continuing every day, a daily flow of radioactively contaminated groundwater into the ocean. The estimates are of about 300,000 litres per day of relatively low-level radioactive waste water. But there are storage tanks with 800,000 tons of highly radioactive water, as every day about 100 tons of water are poured on the three melted down cores.

18 December 2011: You will find the Updates archive, info links, video clips and pictures on the Japan emergency page.

Street lights shine in the abandoned town of Iitate, outside the 20 kilometre exclusion zone around the Fukushima No. 1 Nuclear Power Plant, in northeast Japan. Residents were forced to evacuate the town after radiation levels from the leaking plant exceeded those inside the exclusion zone. Nov. 20, 2011. Photo: Mainichi Daily News / AP Photo / Greg Baker

More than nine months have passed since the 11 March earthquake and tsunami that devastated northeastern Japan and triggered a still-unresolved disaster at the Fukushima No. 1 Nuclear Power Plant. This set of news reports, news features and editorial in the Mainichi Daily News reveals the chronic deception and criminal corporate irresponsibility that continue to hinder all meaningful effort to mitigate the meltdown, and to obstruct at all costs the truth.

Mainichi Daily News has said that the government has declared a stable “cold shutdown” at the plant, representing a major milestone in its handling of the disaster. The public has keenly waited for the nuclear reactors to be brought under stable control, but Japan is still standing on thin ice and is miles away from a situation where it can really declare that the crisis is under control.

In the meantime, rebuilding the lives of residents near the crippled plants has been an urgent critical challenge. On the occasion of its latest political declaration, the government needs to renew its resolve to settle the crisis and achieve regional recovery. The disaster-hit reactors are certainly now in a more stable condition. However, the phrase “cold shutdown” usually refers to suspension of a sound reactor. The fact that the government is attempting to apply this term in a severe accident in which three reactors have suffered core meltdowns should be called into question. The government should rather explain in detail the possibility of any additional explosions and whether a recriticality accident has been ruled out.

Police on duty at a roadblock at the edge of the 20 kilometre exclusion zone around the crippled Fukushima No. 1 Nuclear Power Plant, at Namie, in northeast Japan. Nov. 20, 2011. Photo: Mainichi Daily News / AP Photo / Greg Baker

Simulations suggest that nuclear fuel has melted inside the reactor containment vessels, eroding their concrete floors. Although Tokyo Electric Power Co. (TEPCO), the operator of the stricken nuclear plant, has indicated that melted fuel has also been cooled down by water, this is nothing but speculation. We urge the utility and the government to find a way to ascertain the precise condition of the fuel.

Mainichi Daily News has reported that conditions at the Fukushima No. 1 nuclear plant are far worse than its operator or the government has admitted, according to freelance journalist Tomohiko Suzuki, who spent more than a month working undercover at the power station. “Absolutely no progress is being made” towards the final resolution of the crisis, Suzuki told reporters at a Foreign Correspondents’ Club of Japan news conference on Dec. 15. Suzuki, 55, worked for a Toshiba Corp. subsidiary as a general laborer there from July 13 to Aug. 22, documenting sloppy repair work, companies including plant operator Tokyo Electric Power Co. (TEPCO) playing fast and loose with their workers’ radiation doses, and a marked concern for appearances over the safety of employees or the public.

An earthquake-damaged grave is seen at a cemetery in the abandoned town of Katsurao, outside the 20 kilometre exclusion zone around the Fukushima No. 1 Nuclear Power Plant, in northeast Japan. The town was abandoned when radiation levels became unsafe for long term exposure. Nov. 20, 2011. Photo: Mainichi Daily News / AP Photo / Greg Baker

For example, the no-entry zones around the plant – the 20-kilometer radius exclusion zone and the extension covering most of the village of Iitate and other municipalities – have more to do with convenience that actual safety, Suzuki says. The situation at the plant itself is no better, where he says much of the work is simply “for show,” fraught with corporate jealousies and secretiveness and “completely different” from the “all-Japan” cooperative effort being presented by the government.

“Reactor makers Toshiba and Hitachi (brought in to help resolve the crisis) each have their own technology, and they don’t talk to each other. Toshiba doesn’t tell Hitachi what it’s doing, and Hitachi doesn’t tell Toshiba what it’s doing.” Meanwhile, despite there being no concrete data on the state of the reactor cores, claims by the government and TEPCO that the disaster is under control and that the reactors are on-schedule for a cold shutdown by the year’s end have promoted a breakneck work schedule, leading to shoddy repairs and habitual disregard for worker safety, he said. “Working at Fukushima is equivalent to being given an order to die,” Suzuki quoted one nuclear-related company source as saying.

At a Tokyo market, a smartphone shows radiation test results by the grower of a package of Maitake mushrooms, showing them as free of radioactive contamination. Many consumers worry about the safety of food from Fukushima and surrounding prefectures, although produce and fish found to be above government-set limits for contamination are barred from the market. Mushrooms, for example, harvested in and around Fukushima are frequently found to be contaminated and barred from the market. Sept. 12, 2011. Photo: Mainichi Daily News / AP Photo / Shizuo Kambayashi

Kenichi Oshima is currently a professor at Ritsumeikan University. After long years of nuclear power research, he had learned that the actual cost of maintaining nuclear power in Japan was twice as high as what government and electric power companies had publicly announced, the Mainichi Daily News has reported. In March 2010, published his findings in a book, but found himself under fire at a time when pro-nuclear energy was becoming even stronger. In September the same year, during a meeting of the Japan Atomic Energy Commission, his comments were rejected and even mocked. “Do you call this research?” he was told and few even cared to look at his findings.

Following the nuclear disaster at the Fukushima No. 1 power plant, triggered by the March 11 earthquake and tsunami, Oshima’s situation drastically changed. He was selected as a member of two expert governmental committees to serve as a critical analyst of Japan’s current nuclear power stance. The group will openly release all internal debates and documents, Oshima says. He is now more optimistic than ever that the time to destroy the “cheap and safe” nuclear power myth will eventually come.

Workers in protective suits and masks wait to enter the emergency operation center at the crippled Fukushima No. 1 Nuclear Power Plant in Okuma, Japan. Nov. 12, 2011. Photo: Mainichi Daily News / AP Photo / David Guttenfelder, Pool

A sober and critical editorial in the Mainichi Daily News has said that Britain has already abandoned developing fast-breeder nuclear reactors, and is set to give up nuclear fuel reprocessing as well. Moreover, its planned construction of a facility to dispose of radioactive waste including plutonium is likely to materialize even though it is still at a planning phase.

In contrast, there are no prospects that Japan can build a disposal facility. However, for Japan to call for operations at the Monju prototype fast-breeder nuclear reactor in Fukui Prefecture and the nuclear fuel reprocessing plant in the Aomori Prefecture village of Rokkasho to be carried out as planned, would be like putting the cart before the horse as it appears the country is incapable of building a disposal facility.

Plutonium is directly related to security issues. The U.K. possesses nuclear weapons but Japan does not. One may wonder whether Japan’s independence will be threatened if it abandons nuclear fuel recycling and loses its ability to produce plutonium. Even though it is an important point of contention the issue should not be used as a reason to underestimate the harm of plutonium.

Economy, Trade and Industry Minister Yukio Edano who is in charge of energy policy, Goshi Hosono, state minister for handling the nuclear crisis, and Yoshito Sengoku, second-in-command in the ruling Democratic Party of Japan’s Policy Research Committee, have been hearing the views of experts on the issue. It is not enough for the government to talk only about the dream of “prosperity” built on dependence on nuclear power. Japan’s ability to overcome the mess that follows such prosperity is now being tested.

More updates, info links, video clips and pictures on the Japan emergency page.

Written by makanaka

March 17, 2011 at 22:20

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Japan quake tsunami links and notes

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Japan's quake more powerful than first estimate

New estimates by the US Geological Survey suggest that the earthquake that struck Japan on 2011 March 11 was magnitude 9.0. Grpahic from New Scientist.

The Mainichi Daily News has reported that the strongest recorded earthquake to hit Japan rocked the northeastern coast Friday, triggering a series of tsunami including a 10-meter wall of water that submerged residential areas and farms with muddy streams and washed away scores of people, vehicles, boats and a storage tank on fields and ports in northeastern Japan.

The 10-meter tsunami was observed at Sendai port in Sendai, Miyagi Prefecture at around 3:55 p.m. after the quake with a magnitude of 8.8 rocked the region, local police said. A tsunami expert at the government-affiliated Port and Airport Research Institute described the tsunami following the 2:46 p.m. quake as “one of the highest and widest in terms of areas of devastation in the nation’s history.” Shigeo Takahashi, senior researcher at the institute, said, “It’s a tsunami of a once-in-a-century scale.”

The New Scientist noted that the Japanese earthquake has triggered a series of tsunami waves that are now moving east across the Pacific. How will the countries they hit be affected? The shape of each landmass is a major factor determining how the tsunami behaves. Tsunamis are most dangerous when they run over a large area of shallow water. This causes the first wavefront to slow down, so successive waves pile up to form one tremendous wave.

As a result small Pacific islands, especially ones that lie in otherwise deep water, should be largely unaffected. Wave height here might reach 30 centimetres at most. “A little atoll presents a pencil in the water, and the wave just goes right past,” says Robert Cessaro, a senior geophysicist at the Pacific Tsunami Warning Center (PTWC) in Hawaii. Because most of the islands in the tsunami’s path are fairly small, they should see waves 10 to 30 centimetres high at most.

Written by makanaka

March 11, 2011 at 23:33