The Tohoku Earthquake that struck this year on March 11th was a massive earthquake of magnitude 9 and saw the largest ever tsunami, which reached between 14-15 meters, descend on the coast of Fukushima Prefecture. These facts have led some people to also associate the accident at the nuclear power plant with these natural disasters. Certainly, the reactors in operation at Fukushima Daiichi Nuclear Power Plant automatically stopped immediately. However, right from the beginning, I held strong misgivings about the simultaneous loss of the cooling capabilities in all the emergency diesel power generators, caused by the onslaught of the tsunami. First of all there was the simple and engineering issue of "What has happened to the multi-faceted protection?" related to nuclear reactor safety.
In fact, during my seven years (1997-2004) on the Nuclear Safety Commission (NSC), there were two occasions when I had a strong desire to inspect Fukushima Nuclear Power Plant and see the older generation nuclear reactors (Mark 1) that I too was familiar with. Nevertheless, despite this desire, it was not possible to hold an inspection even once at this nuclear power plant. To this day, I still regret that I wasn’t stricter in my questioning of the officials in charge as to the reasons why an inspection was not possible.
I have learned the following facts from newspaper articles related to the the current accident. Fukushima Daiichi Nuclear Power Plant was constructed in the 1960s and 1970s by Toshiba in accordance with the plans of the American company GE and commercial operations started in 1971. The important safety emergency power generators used for cooling the nuclear reactor core were not housed in the secure nuclear reactor building, but instead were placed in the turbine building. On the other hand, at Fukushima Daini Nuclear Power Plant, which went into commercial operations from 1982, the emergency power generators are housed in the nuclear reactor building. These were not damaged by the recent tsunami. Still today, only approximately half of reactors have their emergency power generators installed in nuclear reactor buildings. I hope that the management at other reactors will take note of this lesson. This design concept was changed in the wake of the Three Mile Island nuclear power plant accident that occurred in the U.S. in 1979.
People had scientifically predicted the risk of accidents
Once a nuclear reactor has been constructed it is not that easy to completely shut it down, repair all of it or scrap it. However, intentionally dismissing technical opinions concerned with the risks and hazards from the field and engineers involved in planning has led to a huge error in safety for organizations and society. A former GE engineer, Dale Bridenbaugh, pointed out flaws in the Mark 1 nuclear reactor and then resigned in protest when these concerns were ignored by those around him. In the same way, this led me to recall some of the points mentioned and papers of Dr. Katsuhiko Ishibashi, professor at Kobe University (at that time, currently professor emeritus) who was an NSC advisory committee several years before when I was on the NSC, sincerely asserted that "Is it not strange that this is the case even though Japan is a country where an earthquake could strike anywhere?" Later, I heard that he had resigned as Technical Adviser to the Safety Committee.
In the organization, minority opinions are left behind, but there are occasions when before one becomes aware of it, commonsense opinions persist that are formed without questioning or discussion. This is also the case with the safety of nuclear reactors where the phrase ’multi-faceted protection’ has become commonsense, but consequently these words have put everyone at ease. This has meant that both specialists and the general public have failed to skeptically question the reality and feasibility of this multi-faceted protection.
Lessons learned from the Chernobyl Disaster
I have held an interest for a long time in the Chernobyl Disaster that occurred in the former Soviet Union and I have published several papers on the subject. Nevertheless, I never considered the possibility that an accident might occur in Japan that would be at a level that could be compared to this disaster where there was an enormous release of 14 exa (10 to the power of 18 (1018)) becquerels of radioactive material. On this occasion, the aggregate amount of materials, such as radioactive iodine and radioactive cesium released from Fukushima Daiichi Nuclear Power Plant, is nearly one twentieth of this. Once, I paid a visit to Chernobyl after over 10 years had passed since the accident as a member of the NSC and at the riverside in the town of Kiev I thought of the hopeful words of a young Japanese engineer who said "I wanted to construct a safe nuclear reactor here."
There are people that identify the organizational management doctrine as the cause of the Chernobyl Disaster, but it is clear that the enforcement of an unreasonable schedule and human error played a role here. Even though the cause of the accident at Fukushima Daiichi Nuclear Power Plant was different, these two incidents share in common the consequences of the release of radioactive materials. If we summarize the World Health Organization (WHO) report into the effects on health after the Chernobyl Disaster we can see that so far, the deaths of around 50 nuclear reactor workers have been attributed to radiation. We can also see that although it hasn’t been confirmed yet, there is, for example, an increase in leukemia among the general population that have been exposed to radioactive materials in the polluted area (in 20 years, an aggregate amount of an average of around 50 mSv). Its striking characteristic was that over 4,800 children have developed thyroid cancer, despite the fact it doesn’t usually occur in those so young. This has occurred because thyroid glands are an internal organ that secretes growth hormones composed of iodine and this iodine is especially important in growing infants, so they absorb larger quantities of radioactive iodine than adults. There has been a great deal of dispute over the future increase of carciogenesis among the residents of the polluted area and so the WHO report does not record these numbers.
The area within 30 km around Chernobyl is a controlled region and so even now the general public doesn’t live there. This means that there has been an increase in the wild flora and fauna in the vicinity. Out of the approximately 100 species of plants in the surrounding area, three species have become extinct. Japanese people eat seafood on a daily basis, such as kombu (edible kelp), which contains a large amount of iodine, and so although it is difficult to think about the similarities with Chernobyl, this will act as a reference in the future.
Failure to learn and discuss with people in different fields
If we look back at the history of our planet which has undergone many changes, it is only logical that we should turn our eyes toward natural disasters. We overestimate the importance of civilizations and don’t show enough awareness of natural disasters. Originally the nuclear reactor was an engineering device that contained vast amounts of radioactive materials of approximately 10 to the power of 18 (1018) becquerels. The amount of radioactive materials contained in the nuclear reactor has not been discussed from a position of honesty and instead the focus has been on the non-existence of a containment vessel in the Soviet Union model. On the other side, we can find experts that have correctly recognized the reality of nuclear safety, that is, radiation safety.
However, the sense of these numbers that engineers posses is different to the pragmatic sense of biologists that deal with radioactive material of less than a millicurie. On the other hand, there is the case of Mr. Toshisou Kosako, a professor at the University of Tokyo, who resigned as an advisor to the cabinet over the issue of the impact of soil pollution in the schoolyards of elementary schools that were contaminated by this accident. He emphasized, from the standpoint of radiation safety, the recommended values of the International Commission on Radiological Protection (ICRP). This has made evident the discrepancies in opinions among specialists that understand the reality of the impact of radiation. I felt the need to clearly explain to the general public about the implications of strict regulatory values from the standpoint of radiation protection and the divergence with the level of radiation that brings about a real impact on living bodies.
In order to provide radiation protection, radiation is considered under the assumption that it has a harmful effect on everything, no matter how low the dose. This is based on the As Low As Reasonably Achievable (ALARA) principle that radiation exposure should be kept as low as possible. On the other hand, when we carry out medical investigations into the effects of radiation on the human body, it would appear this assumption that even a low dose of radiation has a carcinogenic effect, has no basis in reality. We can see this from the fact that it is not possible to grasp the acute effects if a dose is not above a certain level, from the fact that in animal experiments there is no proof that less than 100 mSv has a carcinogenic effect and also from the presence of a biological defense. This can also be understood by looking at real long-term implementation of management toward radiation exposure and also results from epidemiologic surveys, such as morbidity and mortality.
In the current administrative system, the Nuclear and Industrial Safety Agency of the Ministry of Economy, Trade and Industry is concerned with nuclear safety and it is the Ministry of Education, Culture, Sports, Science and Technology that is concerned with radiation safety. The separation of these organizations means that despite the importance of the issue of radiation safety in nuclear safety it is difficult in this system to voice opinions. I wonder if the late publication of results from the System for Prediction of Environmental Emergency Dose Information (SPEEDI), which everyone was keen to learn after the recent disaster, was really simply a case of loss of power to the system due to the earthquake.
Furthermore, while institutionally broad powers are given to the Atomic Energy Commission (AEC) and the NSC, none of each of their five committee members possesses substantial resources and so they are forced to rely on information from government offices. It is regrettable that this time the NSC has not come out in front, but in the future I hope they are assigned responsibility and proactive personnel similar to the Nuclear Regulatory Commission in the U.S. which has over 3,000 people and which possesses an independent sense of duty.
How to deal with uncertainty
In the world of medicine that protects human life, the unexpected is unacceptable. While we accept a certain degree of risk, in order to obtain certain benefits we are under pressure to take action. In those circumstances, whether you take into consideration the potential risks or not, can result in very different outcomes, both physically and mentally. After the recent earthquake, Fujinomiya in Shizuoka Prefecture also suffered epicentral aftershocks at level 6 on the Japanese earthquake scale (level 1: weak to level 7: devastation). However, in this region, preparations in readiness for a large expected earthquake mean that from a habitual basis residents have a high level of awareness and so I heard that these aftershocks passed off with little impact on houses there.
It is not simple to science the concept of risks that possess uncertainty but in order for us to judge things calmly, we mustn’t reject quantitative notions. In addition, it is also necessary to listen carefully to the opinions of people that aren’t influenced by majority opinion and who don’t just jump on the latest populist bandwagon. I hope by learning from past mistakes, understanding the importance of observing the facts and looking at things calmly that we can use developing science to reduce the risks to our lives.
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