News Watch
Second Experimental Retrieval of Debris
Following up on the first experimental retrieval of debris at the Fukushima Daiichi Nuclear Power Station Unit 2 reactor in November 2024 (see the News Watch articles in Nuke Info Tokyo No. 223) a second test retrieval of debris was carried out at the same unit in April 2025.The work commenced on April 15 using the same fishing-rod-type of extraction device as the first time. With a goal of retrieving debris containing different components from the previous time, the device’s wire was lowered through an opening closer to the center of the containment vessel. A claw-like device attached to the end of the wire was used to pick up a tiny amount of the debris on April 17, and the retrieval was completed on the 23rd.
The amount of debris retrieved this time amounted to about 0.2 grams in several small pieces, but it is not clear whether several tiny chunks were picked up to begin with, or whether the debris was divided after its retrieval. On the 25th, this sample was sent off to the Japan Atomic Energy Agency (JAEA) Oarai Nuclear Engineering Institute, similarly to the first sample.
This is expected to have been the final test operation of the fishing-rod-type retrieval equipment. Retrieval work is scheduled to continue within FY2025 using a robot arm developed in collaboration with the UK.
National System to Support Construction of Safety Measures at Three NPPs
The Organization for Cross-regional Coordination of Transmission Operators (OCCTO) announced on April 28 that it would support Japan’s Long-term Decarbonization Power Supply Auctions, a system created by Japan’s national government for supporting the establishment and renewal of electric power sources toward decarbonization. A second auction has been held, with safety measures for existing nuclear power plants (NPPs) also newly targeted this time. Unit 6 of Tokyo Electric Power Co.’s (TEPCO’s) Kashiwazaki-Kariwa Nuclear Power Station, Unit 3 of Hokkaido Electric Power Co.’s Tomari Nuclear Power Station, and Japan Atomic Power Co.’s (JAPC’s) Tokai Daini Nuclear Power Plant each won a bid for safety measure construction costs. In the auction held the year before, which was limited to new construction, Chugoku Electric Power Co. won its bid for construction costs for its Shimane Unit 3 reactor. The system was launched in 2024 for soliciting bids to boost investment in electric power. It has significance in securing power sources for a stable supply of electricity over the long term and promoting decarbonization of those power sources. It provides a mechanism for calculating the fixed cost per kilowatt of power generation capacity, based on the construction and labor costs for the power plant being supported. The winning power plants are determined in the order of lowest price. Under this system, the companies bidding at the auction are responsible for supplying electric power, and in principle, for 20 years from the start of their power generation they are able to obtain revenue to cover the fixed costs of their necessary capital investments from the money collected via electricity bills.
The contract prices are not known, but regarding the case of Shimane Unit 3 in the previous auction, Secretary General Matsukubo of CNIC has said that the cumulative total for 20 years will come to about 1 trillion yen.
Disappointing Verdict in Trial to Revoke NPP Operating Life Extension
In the lawsuit filed by residents of Aichi and Fukui prefectures to revoke the extension of the operating lives of aging NPPs, the Nagoya District Court dismissed the plaintiffs’ appeal on March 14, saying that there had been nothing unreasonable about the Nuclear Regulation Authority’s (NRA’s) examination and judgement. Kansai Electric Power Co.’s (Kanden’s) Takahama Units 1 and 2 began operating in 1974 and 1975, respectively, and its Mihama Unit 3 reactor began operating in 1976, so all of them are classified as aging NPPs that have been in operation for more than 40 years. Takahama Unit 1 passed the 50-year mark in November of last year, Unit 2 will reach that milestone in November of this year, and Mihama Unit 3 will pass 50 years in operation in December of next year.
Following the nuclear catastrophe at TEPCO’s Fukushima Daiichi NPS, a rule was established that the operating period of NPPs would be 40 years in principle. If, however, an aging nuke passes an examination by the NRA, its operating life could be extended once for a maximum of 20 years. Such extensions were approved for Takahama Units 1 and 2 in June 2016. In anticipation of that, the residents filed an injunction against the extension in April 2016. When an extension for Mihama Unit 3 was approved in November of that year, they immediately filed for an injunction. Their case brought up embrittlement of reactor pressure vessels due to neutron irradiation, deterioration of aging electric cables, evaluation of seismic motion in active faults near the NPP, effects of large eruptions of Mt. Daisen to the west in the past, and other scientific evidence, turning the trial into a full-scale scientific debate. Nonetheless, the Nagoya District Court dismissed the appeal, saying it was insufficient for denying the NRA’s current judgement methods.
This must be considered in the context of Japan’s shift toward higher reliance on nuclear power, fading memories of the Fukushima disaster, a more pro-nuke stance by the Supreme Court of Japan and other factors, but in the future, the number of aging NPPs in Japan will only increase. The plaintiffs appealed to the Nagoya High Court on March 28.
