On April 11, Tokyo Power Electric Co. (TEPCO) submitted its plan to construct an interim storage facility for spent nuclear fuels in Mutsu City, Aomori Prefecture. Upon receiving TEPCO's request, Mutsu set up a discussion meeting to investigate the project. TEPCO had already finished its feasibility test for the proposed site last March, beginning the test in November 2000.

On May 26, the governor of Mutsu city, Masashi Sugiyama, formally announced that the city would invite the establishment of storage facility to the city. One study estimates that Mutsu city could receive a subsidy of approximately 12.9 billion yen in exchange for accepting nuclear fuel for next 60 years.

This is the first time a power company has sought to build an interim storage facility. However, the construction of such a facility has raised the concern of the local residents, and the Mutsu citizens oppose the plan.

Mutsu city is located in the northern part of Aomori Prefecture. The Rokkasho Reprocessing Plant is 40 km south from the city. Mutsu is known for the mass resistance movement against the mother port of the nuclear ship named "Mutsu", which was later modified into a weather ship - the nuclear reactor being removed out of the hull - after some hundred hours of experimental cruises. The reactor itself can be seen at the exhibition facility near the Mutsu port. Spent fuel from the Mutsu nuclear ship had been kept at the same place, but was later transported to the Japan Atomic Energy Research Institute (JAERI) in Tokaimura, Ibaraki Prefecture. The proposed site for the interim storage facility partly overlaps the spent fuel storage facility for the reactor ship.

According to TEPCO's press release, the storage capacity of the facility is around 5,000 to 6,000 metric tons of uranium (tU) and there will be two buildings, each accommodating 3,000tU. TEPCO expects to store the fuels for up to 50 years, and it plans to begin full operation from 2010. The spent fuel is stored in a cask, which will never open in the interim storage facility. The casks are to be shipped by the long route to the reprocessing plant. The storage facility will share the port of the "Mutsu" weather ship. The spent nuclear fuel is stored in metal casks, using a dry storage method. The casks will be shipped directly from TEPCO's reactor sites to the port of Mutsu.

TEPCO had told the city that several other electric companies, such as Tohoku Electric Power Co. and Japan Atomic Power Co., would jointly use the storage facility, and then it received a preliminary agreement from the city authority to go ahead with the project. (Officially, however, the Tohoku Electric Power has denied plans to use the facility.) The project also includes a plan to set up a joint venture company to manage the storage facility. The revision of the law was made in June 2000 to allow private companies to conduct business by storing spent nuclear fuels.

Shortly after TEPCO's announcement, on February 21 2003, it was revealed that Kansai Electric Power Co. also considered building an interim storage facility in Gobo city, Wakayama Prefecture, where the company has planned to construct a thermal power plant (Gobo No.1) on reclaimed land. (Contrary to the claim, the Kansai Electric Power says that it has not made any approaches.) However, the company had to extend its plan every year due to declining demand for electricity - thus the power company has investigated an alteration of the plan to construct the storage facility. With regard to the city's proposal, Wakayama prefectural governor expressed his opposition to Kansai Electric's plan, saying that he would stick to the construction of a thermal power plant. Assuming that a storage facility will be build at Gobo city, spent nuclear fuels from reactors, which are typically located along the Japan Sea coast - e.g. Tsuruga, Mihama, and Takahama - would need to take a long journey from the Japan Sea to the Pacific Coast, which almost equals the length of Japan Island. This is not a logical strategy for transporting highly radioactive materials. Another source indicates that Kansai Electric is also targeting Obama city in Fukui Prefecture as a candidate site for the interim storage facility, and it is more certain that this will be the case.

Other electric companies have not produced any initiatives for siting an "interim" storage facility; however, every company will have to face the issue of disposing of spent fuel sooner or later. In this regard, Kashiwazaki-city (Niigata Prefecture) and Sendai-city (Kagoshima Prefecture) set up municipal laws to levy nuclear fuels that are stored at the reactor site. TEPCO and Kyushu Electric Power Co. both had to accept such an imposition from the local government. It is also possible that more on-site storage facilities would be built, because it will cost less than constructing an interim storage site. The reason behind recent movements concerning the interim storage facility is that many of the existing storage facilities (all of which are located within the site of nuclear reactors) are reaching their storage capacity, and some of them will not be able to maintain operation unless a new storage site is built. Fukushima No. 2 reactor and Mihama nuclear power plant (owned by Kansai Electric Power Co.) have already exceeded 90 per cent of their spent fuel storage space.

In the Japanese context, "interim storage" for spent fuels means the temporary storage space used before the fuel reprocessing to extract plutonium. In this perspective, the meaning of the term is different from the one used overseas, where the facility's name is given as "recycled fuel storage center." Japan maintains nuclear fuel reprocessing as a pillar of its nuclear policy. The construction of the Rokkasho Reprocessing Plant has been plagued with delays and the permission for adding the second reprocessing plant will not be given in the foreseeable future. The total amount of spent fuels produced from Japan's 52 nuclear reactors reaches 1,000tU to 1,200tU annually. The Rokkasho Reprocessing Plant could handle 800tU per year at best, meaning that the plant could not reprocess all the spent fuels. Therefore, the government says that the storage facility will be constructed to store the spent fuels for several tens of years (40 to 50 years) until they are ready to be reprocessed. However, the actual operation of the Rokkasho Reprocessing Plant is still uncertain. It is possible that the plant will not be able to begin its operation. Therefore, the interim storage facility could become a permanent disposal site. In such a case, the agreement with local government to remove the stored spent fuels could easily be neglected. Local residents are particularly fearful about this. The radioactive materials could be left forever, no matter what the electric power company and the government say. This seems most likely, since research has only been conducted on the disposal of vitrified high-level radioactive waste in Japan, and no study has been done on the direct disposal of spent fuel option in this country.

Picture 1. Some spent fuels are stored in nuclear power plants (Tokai Daini power plants), 
Source: Ministry of Economy, Trade and Industry

By Hideyuki Ban (CNIC, Co-director)