By Tanimura Nobuko (CNIC)
CNIC has compiled nuclear power facility radiation management data based on data published by the Nuclear Regulation Authority.*
The number of workers engaged in the decommissioning work at Fukushima Daiichi Nuclear Power Station has increased in recent years. The number of workers increased from 10,137 in FY2021 to 11,945 in FY2023. Regular employees account for 12% of workers. The removal of nuclear fuel debris, scheduled to begin by 2021, started on August 22, 2024, almost three years late. Immediately after that, however, work was suspended due to work errors. The Nuclear Damage Compensation and Decommissioning Facilitation Corporation, which monitors the decommissioning of nuclear reactors, pointed out that the background to this problem was the “multi-level subcontracting structure.” Problems have continued to occur.
The ratio of subcontractors among workers also exceeds 80% at other nuclear power plants. Large numbers of workers were present in FY2023 at Onagawa and Kashiwazaki-Kariwa plants, which have not yet been restarted, with many of these workers believed to be engaged in safety measure construction. At the Takahama plant, the total exposure dose was high, 13 workers having been exposed to radiation exceeding 10 millisieverts.
As a result of the dose evaluation regarding two persons who were exposed to X-rays at Nippon Steel’s Setouchi Works (Himeji City, Hyogo Prefecture) in May 2021, one person was reported to have received 400-500 milligrays and the other person was reported to have received less than 100 milligrays.
*The dose distribution of radiation workers for one year is described in the materials related to “Received Radiation Management Reports from XX Power Plant of YY Electric Power Co., Ltd. for the Latter Half of 2023,” located under “Documents Related to Regulatory Laws and Notices by Nuclear Facility” on the Nuclear Regulation Authority website.