Shika-2 Verdict Demands Suspension of Operations

TOKYOMay/June 2006 NUKECitizens' Nuclear INFO Information Center No. 112 3F Kotobuki Bldg., 1-58-15, Higashi-nakano, Nakano-ku, Tokyo 164-0003, JAPAN URL: http://cnic.jp/english/ e-mail : [email protected] Shika-2 Verdict Demands Suspension of Operations Reactor Cannot Withstand an Earthquake as an individual and my environmental right, in order to prevent this harm, I demand that operations be suspended." There is a history behind this case. In 1988, 100 plaintiffs lodged a case against the Shika-1 reactor (540 MW BWR). Their case was rejected by the District Court in 1994. They appealed and the High Court rejected their demands in 1998. However, although they lost their case, they extracted an acknowledgement that nuclear power plants are a negative legacy for future generations. They appealed to the Supreme Court, but their case was The ritual victory banner photo rejected in 2000. The Shika-2 victory therefore n March 24th the Kanazawa District came 18 years after they first lodged a case against Court handed down a verdict demanding the Shika nuclear power plant. that operation of Hokuriku Electric Major features of the verdict OPower Company's Shika-2 reactor (1,358 MW Reading the verdict one notices that it has ABWR) be suspended. There are currently 55 several features. commercial reactors operating in Japan, but this First, the plaintiffs' claims about issues such is the first time that citizens have won a court case as the following were all rejected: the problems against one of these reactors on the grounds that of stress corrosion cracking and pipe thinning, the it is unsafe to operate. As such it was a ground- intrinsic dangers of ABWRs, the hollowness of the breaking victory. History of the case Contents Construction of Shika-2 began on 27 August 1999 and four days later, on August 31st, 135 Shika-2 verdict demands suspension of 1-3 plaintiffs from 17 prefectures lodged a case, operations demanding as follows: FBR Feasibility Study Report 4,5 "If this reactor were to be operated, during Rokkasho Active Tests: Baku's View 6 regular operations, or under extraordinary Rokkasho Active Tests: first leak 7 conditions, exposure to the radiation and 2006 Electric Power Plan & Nuke Industry 8 radioactive material released into the Chernobyl 20th Anniversary Symposium 9 environment would cause me grievous harm. Group Intro: Kansai Relief for Chernobyl It would do irreparable damage to my life and Hibakusha 10 person." For this reason, "based on my rights News Watch 11,12 2 May/June 2006 No. 112 Nuke Info Tokyo system for preventing the emergence and escalation several smaller faults, but the Headquarters for of problems in nuclear reactors, the defects of the Earthquake Research Promotion recognized the system for preventing the release of radioactive possibility that all these faults could move together materials, and the dangers associated with the use as a single fault zone. of MOX fuel. However, it should be noted that (3) The largest predicted earthquake has until the court showed considerable sympathy for the now been estimated using the Osaki Method. plaintiffs' claims. For example, it held that in the However, the Osaki method is not appropriate, case where a pipe burst due to thinning, it could not because the results obtained using this method be said that there was a possibility that this alone do not match the results obtained from empirical would result in radiation exposure in excess of the observation. The court referred to the Southern permitted limit. However, it acknowledged that it Hyogo Earthquake and the earthquake off the coast would be a different matter if a thin section of pipe of Miyagi Prefecture in August 2005 as examples burst as a result of an earthquake, and multiple of earthquakes where the movement greatly other failures occurred at the same time. exceeded the movement predicted by the Osaki Second, with reference to the Three Mile Method. Therefore, it cannot be said that the safety Island (1979) and Chernobyl (1986) accidents, has been assured of reactors designed to withstand the court rejected any presumption that such earthquakes predicted using this method. accidents could happen at the Shika-2 reactor. It Specific danger to all plaintiffs held that it was not possible to claim that there is CNIC's Masako Sawai gave evidence at the a specific possibility that an accident could occur 27th oral hearing held on 18 March 2005. As part which would cause the plaintiffs to be exposed to of her evidence she presented the results of CNIC's radiation in excess of the permitted limit. calculations of the impact of an accident involving However, the third feature of this verdict was a core melt down at the Shika-2 reactor followed its decisive departure from verdicts by other courts by a steam explosion and a breach of containment. in regard to earthquakes. It took into account The results, based on the WASH 1400 probabilistic progress in seismology since the Southern Hyogo risk assessment, showed that the annual radiation Earthquake of 1995. Thus, the third feature took exposure for people within a 728 km radius would precedence over the other two features and the exceed the limit for a single year for radiation plaintiffs' case succeeded. workers of 50 mSv (limit over 5 years of 100mSv). Earthquake design deficiencies Since the permitted dose for members of the There are three main areas where the court general public is 1 mSv/year, if the worst possible found the reactor's earthquake design to be accident were to occur as a result of an earthquake, deficient. there is a danger that this dose would be greatly (1) It found the current magnitude 6.5 earthquake exceeded for even the most distant plaintiff, who standard for earthquakes focused directly beneath lives in Kumamoto Prefecture. The court accepted the reactor to be inadequate. A magnitude CNIC's evidence and conlcuded that there is a 7.3 earthquake occurred in the west of Tottori specific danger for all the plaintiffs. Prefecture in October 2000 in an area where no Other court cases active fault had been discovered. Based on current Among the verdicts for court cases involving seismic knowledge, it should be assumed that an nuclear power plants during the 1990s, there were earthquake of magnitude 7.2 - 7.3 could occur a few which expressed some understanding of the directly beneath the reactor, even if no fault has plaintiffs' claims. The Shika-1 verdict (September been discovered in the area. 1998) recognized that nuclear power plants are a (2) In March 2005 the government's Headquarters negative legacy for future generations. The Tomari for Earthquake Research Promotion announced NPP verdict (February 1999) acknowledged that that a 7.6 magnitude earthquake could occur if the the suspension of nuclear power plants is an whole Ochigata Fault Zone were to move at once. option. The Onagawa NPP verdict (March 1999) Hokuriku Electric did not take this possibility recognized that an even greater degree of safety into account. The Ochigata fault is near the Shika is desirable. Then in January 2003 there was the reactor. It had previously been thought of as verdict by the Nagoya High Court (subsequently Nuke Info Tokyo No. 112 May/June 2006 overturned by the Supreme Court), which found design earthquake” (S2). The most important that the license for the Monju fast breeder reactor equipment for safety purposes, such as the reactor was invalid. The Shika-2 verdict seems to have and the spent fuel pool, must be able to retain their taken these previous verdicts into account. safety functions under an “S2” Basic Earthquake Shika-2 still operating Ground Motion. In the draft guidelines these Hokuriku Electric has appealed, so the case indicators have been replaced by a single indicator, will now go to the High Court. As long as there “Ss”. No numerical value for “Ss” is specified and are still avenues for appeal it is possible to continue it is quite unclear whether the value arrived at will operating the reactor. However, there is no doubt be higher, the same as, or perhaps even lower than that the spirit of the "precautionary principle", “S2” in some cases. which this verdict upholds, will become more and Under the existing guidelines faults which have more important. been active within the last 50,000 years must be Review of Earthquake Design Guidelines taken into account. The draft guidelines extend The ground beneath the government's this period to around 130,000 years. However, earthquake safety design guidelines was shaken they do not address the possibility acknowledged by this verdict. This is because the first and third in the Shika-2 verdict that several smaller faults design deficiencies identified above apply to all could move together as one. In this regard, they nuclear power plants in Japan. It seemed that are already behind the times. the Nuclear Safety Commission's Subcommittee Perhaps it could be said that the draft on Earthquake Resisting Design was in a rush to guidelines are honest in acknowledging that a respond when, on April 28th, it released the results "residual risk" remains that a larger than predicted of a five-year review of the guidelines (see also earthquake might strike and cause serious exposure News Watch section on page 12). However, it is to radiation. However, no probabilistic method quite unclear whether the new draft guidelines of assessing this risk has been determined. Until represent an improvement on the existing such a method is developed, it seems that if a huge guidelines. There was significant division within earthquake strikes, that is just too bad.

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