News Watch
Onagawa Unit 2 Shut Down During Restart Due to Problems
The Unit 2 reactor of Tohoku Electric Power Co.’s Onagawa Nuclear Power Station (BWR, 825 MW) was restarted on October 29 to resume operations. It was scheduled to begin transmitting electricity a few days later, on November 3, but a calibration device for a detector to monitor neutrons inside the reactor stopped working sometime after it was inserted into the reactor. On November 4, the reactor was shut down. An investigation report released by Tohoku Electric Power Co. on the 11th revealed that the incident occurred due to failure to tighten a nut connecting the measuring device. The nut loosened due to the vibrations at startup, leading to a loss of connection. The company will take action to prevent recurrences, such as by reviewing work procedures. Regardless, as of that time, plans to resume commercial operation in December were not affected.
The reactor was halted for periodic inspections in November 2010 and automatically shut down again during its restart early the next year in response to the Tohoku Earthquake on 11 March 2011, during which it was damaged. It is the same type of boiling water reactor (BWR) that experienced serious accidents at the Fukushima Daiichi Nuclear Power Station and has been unable to resume operations since then. See “CNIC Statement: Safety problems at Onagawa Power Plant Unit 2” (cnic.jp/english/?p=7879) for more on the problems with this restart.
Experimental Debris Retrieval from Fukushima Daiichi Unit 2 Reactor
Tokyo Electric Power Co. (TEPCO) announced on November 7 that it had recovered debris for the first time from the meltdown of Fukushima Daiichi Unit 2 (BWR, 784 MW). Though this is doubtlessly an achievement, in terms of scale, it is like taking a sample with an earpick. This operation finally got underway on August 22 this year, three years later than originally planned, but faced continuing troubles resulting in further delays (see the previous News Watch). The sample will be transported in the future to the Fuels Monitoring Facility (FMF) at the Japan Atomic Energy Agency (JAEA) Oarai Research and Development Institute in Ibaraki Prefecture. It is scheduled to undergo analysis at that facility and JAEA’s Back-end Fuel Cycle Key Elements Research Facility (BECKY), and also by Japan Nuclear Fuel Development Co. (NFD) and MHI Nuclear Development Corp. (NDC). Initially, the plan was to divide the sample into portions of about 0.2 grams per facility for analysis, but they were unable to retrieve any more than 0.7 grams so they will have to consider how they are going to distribute it. See “CNIC Statement: Is there any point in the fuel debris sample collection at Fukushima Daiichi Nuclear Power Station Unit 2?” (cnic.jp/english/?p=7722) for more on the significance (or lack thereof) of this experimental sample collection.
Takahama Unit 1 Operation to Exceed 50 Years
The Unit 1 reactor (PWR, 826 MW) of the Takahama Nuclear Power Station has been in operation for 50 years as of November this year. On October 16, it became Japan’s first nuclear reactor to be approved for operation past 50 years under the current system. This will allow it to continue operating until June 2025, when the new system is inaugurated. Regarding operation beyond that time, an application was made on October 24 to the Nuclear Regulation Authority (NRA) for approval under the new regulatory system.
Mutsu Spent Fuel Storage Facility Begins Operations
Recyclable-Fuel Storage Co. (RFS) in Mutsu City, Aomori Prefecture obtained a pre-use confirmation certificate from the NRA on November 6 and announced the start of operations of the Recyclable-Fuel Storage Center as an interim spent fuel storage facility. The company, jointly funded by TEPCO and Japan Atomic Power (JAPC), can store spent fuel at the scale of 5,000 tons uranium (tU) equivalent, until it can be shipped to a reprocessing plant. Operations are starting from a storage building with a capacity of 3,000 tU.
The “interim storage” period has been set at 50 years, as stipulated by the safety agreement concluded on August 9 between Aomori Prefecture, Mutsu City and RFS, whose parent companies, TEPCO and JAPC signed the agreement as witnesses. At issue is the destination of the spent fuel after storage. Originally, it was supposed to be transferred after storage to a “second reprocessing plant,” which was to follow on from the Rokkasho Reprocessing Plant. There is neither hide nor hair of that facility. The Rokkasho Reprocessing Plant is supposed to operate for 40 years and be gone 50 years from now. Thus in an attempt to form an agreement to extend the operating period of that plant, the Agency of Natural Resources and Energy proposed to the Subcommittee on Atomic Energy to “assume the Rokkasho Reprocessing Plant as the destination” at the General Meeting of the Advisory Committee for Natural Resources and Energy on October 16.
Note that the 27th delay in completing the Rokkasho Reprocessing Plant was announced on August 28.
Equivalent Exchange Proposed for Low-level Waste Returned from France
The Federation of Electric Power Companies petitioned Rokkasho Village in Aomori Prefecture on October 10 to exchange about 1,800 containers of miscellaneous solid waste generated in the course of reprocessing in France, that are to be returned to Japan by the end of 2033, with about 20 canisters of high-level vitrified waste that would be “equivalent in radiation effects.” Governor Miyashita Soichiro of Aomori Prefecture rejected the proposal, saying, “As things stand, I am not in a position to consider that.
