Reference Material: Radiation Exposure Data for Nuclear Industry Workers (2022)
By Tanimura Nobuko (CNIC)
CNIC has compiled nuclear power facility radiation management data based on data published by the Nuclear Regulation Authority. *
If we discount the harsh conditions of the decommissioning work at Fukushima Daiichi NPS, the high numbers of exposed workers exceeded an annual 4,000 persons at Kashiwazaki-Kariwa, Onagawa, and Takahama nuclear power plants. Of these, since Kashiwazaki-Kariwa and Onagawa have not been restarted, it is thought that large numbers of workers are engaged in work related to safety measures. Fukushima Daiichi Nuclear Power Station accounts for nearly 80% of the total collective effective dose. This is followed by Takahama, Ohi, and Genkai NPPs, which are operating and where dose rates are high. In maximum effective doses, subcontracted workers tend to be high, but the characteristic of Fukushima Daiichi NPS is that the difference between power company workers and subcontracted workers is small.
At Fugen, currently being decommissioned, FY2018 to 2023 has been termed “The Period for Demolition and Removal of Facilities in the Vicinity of the Nuclear Reactor.” In FY2021, the highest collective exposure dose since FY2009 (0.23 person Sv) was recorded, but this was reduced in FY2022. In order to change to a more conservative decommissioning method, it was announced in November that the start of demolition of the nuclear reactor itself would be changed to sometime between FY2023 and FY2030, and decommissioning operations would be completed at sometime between FY2033 and FY2040.
* www.nra.go.jp/disclosure/law_new/genshiryoku_index.html (in Japanese)