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Impact of Fukushima Daiichi Accident on Japan's Nuclear Fuel Cycle and Spent Fuel Management

Joonhong Ahn

Abstract This chapter briefly summarizes the current status of spent nuclear fuel and historical development of nuclear fuel cycles in Japan, and problems that Japan faces after the Fukushima Daiichi nuclear accident for spent fuel management. (1) Aomori Prefecture's refusal to store HLW and spent fuel in Rokkasho without a plan for them to be taken out to a permanent geological repository, (2) drainage of national wealth for purchasing additional oil and gas, (3) international pressure on Japan not to have an unnecessary Pu stockpile, and (4) perpetual safeguards inspection and higher potential radiological risk to be imposed on a final repository for spent fuel and separated Pu and U, are coupled to each other, creating a deadlocked situation after the accident.

Keywords Spent fuel management Nuclear fuel cycle Pu stockpile Phase-out

Post fukushima

Status Quo

Nuclear fuel before usage in a contemporary light-water reactor (LWR) is made of uranium oxide (UOX) consisting of the fissile U-235 isotope comprising 4.5 % of total uranium (U) atoms. After producing 45,000 mega-watt-days of heat per metric ton (MWd/MT), the fuel is discharged from the reactor. This spent fuel still contains around 0.8 % of U-235 and 0.9 % of plutonium (Pu) (approximately 9 kg), of which about 0.5 % (5 kg) is fissile. If one metric ton (MT) of spent fuel is reprocessed, 9 kg of Pu and approximately 960 kg of U are recovered separately,

Table 6.1 Japan's spent fuel balance (02/2013)

Table 6.2 Japanese plutonium stockpile (kg) (as of the end of 2011) [1]

and the rest becomes vitrified high-level waste (HLW), including fission-product isotopes and minor actinide isotopes, such as neptunium, americium, and curium. The HLW is solidified with borosilicate glass in a stainless steel canister.

In the past 50 years of nuclear power utilization in Japan, 25,640 MT of spent nuclear fuel has been generated. Of this amount, 7,100 MT was reprocessed in France and U.K., and the plant in Tokai-mura currently owned by Japan Atomic Energy Agency (JAEA) reprocessed 1,020 MT (Table 6.1). As a result, Japan possesses approximately 44 MT of plutonium (Pu) (Table 6.2) and about 8,000 canisters of HLW. The un-reprocessed spent fuel (25,640 − 1,020 − 7,100 = 17,52 0 MT) is stored either at each nuclear power plant in Japan (total 14,170 MT) or in the storage facility attached to the Rokkasho reprocessing plant (3,350 MT). 14,170 MT occupies approximately 70 % of total storage capacity (20,000 MT) in all existing nuclear power plant sites. 3,350 MT is already 97 % of the spent fuel storage capacity at the Rokkasho reprocessing plant.

How Has This Status Quo Been Generated?

In 1955, 10 years after the end of World War II, Japan established the Atomic Energy Basic Law, and launched its nuclear development program. The Japanese national policy for nuclear fuel cycle was established during the 1970s and 1980s to achieve “energy independence” by decreasing dependence on oil, motivated by the experience of the oil crises in 1973 and 1979. The establishment of the nuclear fuel cycle, consisting of U enrichment, reprocessing of spent nuclear fuel to recover Pu and U, and a fast breeder reactor (FBR), became the national policy with the highest priority. In 1988, Japan successfully reached a comprehensive Nuclear Cooperation Agreement (NCA) with the United States that allowed Japan to develop and own the nuclear fuel cycle. It was a remarkable diplomatic achievement in the international environment after the nuclear test by India in 1974, upon which the U.S. strengthened its anti-nuclear fuel cycle policy. Indeed, Japan is the only non nuclear weapons country[1] that has industrial-scale capability of U enrichment, PUREX reprocessing, and FBRs, acknowledged by the international community, particularly by the U.S.

After reaching the U.S.—Japan NCA in 1988, Japan made steady progress toward construction of nuclear fuel cycle facilities. In 1992 the Japan Nuclear Fuel Industry (JNFI), a private company established by the utilities companies, started commercial operation of the first commercial U enrichment plant in Rokkasho, with the capacity of 150 MT Separative Work Unit/year. In 1989, the Japan Nuclear Fuel Services (JNFS), yet another company established by the utilities, submitted a license application for the first commercial reprocessing plant in Rokkasho, and in 1993, its construction began.[2] JNFI and JNFS were later merged into Japan Nuclear Fuel Limited (JNFL). In 1995, an experimental FBR, Monju, started electricity supply to the grid.[3]

After the 1997 Kyoto Protocol ratified at the United Nations Framework Convention on Climate Change (UNFCCC), reduction of greenhouse-gas emissions was added as the main objective of nuclear power utilization. In other words, the 1997 Kyoto Protocol solidified the raison d'etre of Japan's nuclear energy industry, and this was the mindset in place until the Fukushima Daiichi accident on March 11, 2011. Prior to it, the nuclear community firmly believed that the fleet of nuclear reactors supported by the nuclear fuel cycle would grow and expand, that capacities for U enrichment and spent fuel reprocessing should be established, that Pu should be bred by FBRs, and so forth. The Japanese nuclear community had never conceived of “sudden braking” scenario as the situation currently observed in Japan that all reactors halted operation after the Fukushima Daiichi accident. The sudden braking clearly revealed that there was a serious oversight, or lack of plan B, in the national policy for development of the nuclear fuel cycle and for spent fuel management.

  • [1] EURATOM consisting of EU countries has similar NCA with the U.S.
  • [2] But as of 2014 the plant has not started its operation due to a series of technical troubles.
  • [3] But soon after that it had the sodium leak accident, and stopped its operation since then until now.
 
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