CNIC has compiled a list of accidents and breakdowns occurring at nuclear power plants and nuclear fuel-related facilities in FY2017 (April 1, 2017 to March 31, 2018) from the following four sources.
(1) Reports based on the Nuclear Regulation Act and Radiation Hazard Prevention Act (FY2017)www.nsr.go.jp/activity/bousai/trouble/houkoku/h29.html
(2) Records of Nuclear Regulation Authority meetings with nuclear power operatorswww2.nsr.go.jp/disclosure/meeting/index.html
(3) Reports of problems in the NUClear Information Archives (NUCIA) (Japanese nuclear power plants and nuclear cycle facilities)nucia.jp/nucia/kn/KnTop.do
(4) Power company and nuclear power operators’ press releases.
Seven accidents are listed in (1). Of these, two accidents were at facilities handling radioactive isotopes (Shionogi & Co., Ltd. and Tokyo Institute of Technology). Persons interested in these accidents should please refer to the website given in (1) (Japanese only).
Looking at the database in (3), it can be seen that large and small accidents, breakdowns and defects occurring in FY2017 number 139 (132 in NPPs, 7 in nuclear fuel-related facilities). We have included in the list only accidents from the “T class” (trouble) and “M class” (maintenance quality).
Circles○ in the ‘Classification’ column are accidents published on the website in (1) and are the same as accidents classified under “T class” in (3).
A wide variety of accidents and breakdowns are reported, from plutonium exposure and leakages of radioactive materials to fires, smoke emissions and diesel fuel leaks. Several problems occurred due to differences between design drawings and the situation onsite. The dust collector filter fire at Hamaoka NPP Unit 5 could possibly have led to a dust explosion accident. The accident at Genkai NPP Unit 3, where the reactor was not shut down after damage to the secondary system in the pressurized water reactor, is reminiscent of the accident response at Mihama NPP Unit 3 in 2004, when a burst pipe accident occurred.
<Chihiro Kamisawa, CNIC>