One of the earliest countries to participate in Atoms for Peace, Japan has utilized research reactors and critical assemblies powered by uranium enriched to 90 or 93 percent since the 1960s. Tokyo, however, became an early active participant in civil HEU minimization efforts. Tokyo's 1978 long-term plan concerning the research, development, and usage of nuclear power stated that "Japan has already positively participated in the International Fuel Cycle Evaluation and wishes to make a positive contribution to establishing a new international order for promoting the peaceful use of nuclear energy in the future." [1]

That year also marked the first meeting of the special "Five Agency Committee on HEU," comprised of representatives of the Ministry of Education, Ministry of Science and Technology, Ministry of Foreign Affairs as well as the Japan Atomic Energy Agency (JAEA, until 2005 called the Japan Atomic Energy Research Institute, JAERI), and Kyoto University. [2]

Japan's two largest owners of facilities powered by HEU, Kyoto University and JAERI, began to work with the Reduced Enrichment for Research and Test Reactors (RERTR) program in 1978 and 1979, respectively. [3] The Five Agency Committee directed the Reduced Enrichment for Research and Test Reactors (RERTR) program in Japan. The committee was active until 2000, but has not met since 2001 because the LEU conversion activities of the reactors under the RERTR program in Japan are in their closing phase. [4] Tokyo is nearing completion of the three-decades-long process to convert and shut down its HEU-powered facilities. Repatriation of spent fuel elements from these facilities to storage sites in the United States began in 1997, and continues today under the auspices of the Global Threat Reduction Initiative (GTRI).

OVERVIEW

Unlike several other states, Japan does not voluntarily declare its HEU holdings as part of its annual INFCIRC 549 plutonium report to the IAEA. The HEU materials at Japanese research facilities were supplied by the United States and the United Kingdom. [5] Approximately 500 kg of HEU at Japan's FCA critical assembly, which was started up in 1967, are of UK origin. [6]

Under the Atoms for Peace framework, the United States exported HEU fuel to Japan for research applications. Between 1957 and 1994, Washington sent 1,000 kg of U-235 to Japan contained in 2,054 kg of uranium. [7]

Fuel Return

In December 2008, Andrew Bieniawski, NNSA assistant deputy administrator for global threat reduction, announced that a total of 579.7 kg of HEU had been returned to the United States from Japan by summer 2008. [8] In 2009, the Foreign Research Reactor, Spent Nuclear Fuel (FRR SNF) Acceptance Program was extended, and under the extended contract all of the remaining HEU spent fuel elements from JMTRC are scheduled to be shipped to the United States by December 2013. [9] This will complete all of the planned HEU shipments of JAEA back to the United States, because all of the shipments from the JRR-3, JRR 4 and JMTR have been completed. The shipment of HEU spent fuel from KUR of Kyoto University under the FRR SNF acceptance program started in 1999. All seven scheduled shipments were successfully completed in 2007. [10] [11]

Between May 1996 and May 2010 Japan sent back spent fuel elements containing approximately 656 kg of HEU originally containing 354 kg of U-235. [12] During that time, nine shipments of spent fuel from JRR-3, JRR-4, JMTR, and JMTRC of JAEA were successfully completed. [13] Thus, according to rough estimates, Japan's HEU stockpile is approximately 1,200 to 1,400 kg. [14] GTRI also reportedly plans repatriation of Gap Materials from several Japanese facilities to the Savannah River Site in the near future. [15]

HEU Production

Because it possesses an advanced nuclear power program, since 1992 Japan Nuclear Fuel Ltd. has operated a facility at Rokkasho that enriches uranium for nuclear fuel. Rokkasho only produces low-enriched uranium (uranium enriched to below 20% U-235), and does not produce HEU. Expansion of this facility has been planned. [16] However, due to the devastating earthquake and tsunami that caused the worst nuclear accident in a quarter century at the Fukushima Daiichi nuclear power plant, the Japanese government intends to review its nuclear energy policy. [17]

Japan's other enrichment plants have been shut down. These are: JNC Ningyo-Toge Enrichment Demo. Plant and Ningyo-Toge Uranium Pilot Plant (both pilot centrifuge plants, shut down in 2004); the Asahi Uranium Enrichment Laboratory, Hyuga, Miyazaki prefecture (a pilot chemical exchange plant, shut down in 1991); and two laser enrichment labs in Tokai (shut down in 2003 and 2005). [18]

Continuing HEU Use

Japan currently operates eight research reactors and six critical assemblies. [19] Of these, two research reactors and two critical assemblies are HEU-powered. [20]

CONVERSION AND SHUTDOWN OF HEU-FUELED REACTORS AND CRITICAL ASSEMBLIES

Tokyo has closely cooperated with the RERTR program and is currently in the final stages of conversion and shutdown of most HEU-powered facilities. Since 1990, Tokyo has converted four of its eight operational research reactors. The JRR-3M, JRR-4, JMTR, and KUR, all operated by JAEA, were converted in 1990, 1998, 1994, and 2010, respectively.[21] The Japan Material Testing Reactor Critical Assembly (JMTRC) and the JRR-2 reactor were shut down in 1995 and 1996, respectively. Also shut down were the Toshiba Training Reactor (TTR) (2001), the Rikkyo TRIGA (2002), and the Musashi MuITR (2004). Decommissioning of the Very High Temperature Reactor Critical (VHTRC) Assembly and the DCA critical assemblies is pending. [22]

All new research reactors in Japan have been designed with the use of LEU fuel in mind. In February 1991, the Japanese government cancelled the HEU-powered Kyoto University High Flux Reactor (KUHFR) Project. However, the U.S.-origin HEU fuel intended for use in this reactor was used in the Kyoto University Research Reactor (KUR) until February 2006, upon U.S. approval in April 1994. The United States has been repatriating the fuel at Kyoto University; the full core conversion from HEU to LEU of the KUR was successfully completed in March 2010. [23] The conversion date had been delayed by difficulties in the development of high-density fuel. [24]

Two HEU-powered facilities, the Kyoto University Critical Assembly (KUCA), operated by Kyoto University's Research Reactor Institute, and the UTR KINKI research reactor, operated by Kinki University, are currently undergoing GTRI feasibility studies. GTRI aims to initiate the conversion of these reactors to LEU within the next four years. [25] The YAYOI reactor operated by Tokyo University had employed HEU, but was permanently shut down at the end of March 2011 after 40 years’ operation. It was decided that the spent HEU fuel from the reactor will be transferred to the JAEA. [26]

POLICY ISSUES [27]

As an active participant in HEU minimization efforts since their inception, Tokyo has made an important contribution to minimizing the use of this material. However, Japan's policy on how to handle its HEU materials has been less clear. Tokyo has considered storing spent HEU fuel in Japan, repatriating it to the United States, or sending it abroad to France or the United Kingdom for reprocessing. [28] There have been some shipments of HEU to the United States, but other HEU fuel remains in Japan. Furthermore, while the JAEA and Kyoto University reportedly paid for spent fuel shipping, storage, and handling expenses related to repatriation operations, the Japanese government does not appear to have contributed money or manpower for this purpose. [29] Some Japanese institute officials have suggested that the Japanese government consider deeper engagement in repatriation operations. [30]

Sources:
[1] Yukiya Amano, "Reducing the Enrichment Level of Uranium Fuel: Japan's Experience," presented at the Minimization of Highly Enriched Uranium in the Civilian Sector Symposium, Oslo, Norway, June 19, 2006, www.nrpa.no.
[2] Yukiya Amano, "Reducing the Enrichment Level of Uranium Fuel: Japan's Experience," presented at the Minimization of Highly Enriched Uranium in the Civilian Sector Symposium, Oslo, Norway, June 19, 2006, www.nrpa.no.
[3] Yukiya Amano, "Reducing the Enrichment Level of Uranium Fuel: Japan's Experience," presented at the Minimization of Highly Enriched Uranium in the Civilian Sector Symposium, Oslo, Norway, June 19, 2006, www.nrpa.no.
[4] Keiichi Ohki et al., "Status of Reduced Enrichment Program for Research Reactors in Japan," (Paper presented at the 2010 RERTR International Meeting, October 2010, Lisbon, Portugal), www.rertr.anl.gov.
[5] Approximately 500 kg of HEU at Japan's FCA critical assembly are of UK origin. David Albright and Kimberly Kramer, "Civil HEU Watch: Tracking Inventories of Civil Highly Enriched Uranium," in Global Stocks of Nuclear Explosive Materials, Institute for Science and International Security Chapter III, www.isis-online.org.
[6] David Albright and Kimberly Kramer, "Civil HEU Watch: Tracking Inventories of Civil Highly Enriched Uranium," in Global Stocks of Nuclear Explosive Materials, Institute for Science and International Security Chapter III, www.isis-online.org.
[7] Of this total, 507 kg U-235 were contained in 1,523 kg of uranium enriched up to 90%, while the remaining 493 kg of U-235 were contained in fuel enriched to over 90% U-235. Highly Enriched Uranium: Striking a Balance, Department of Energy, released January 2001, p. 100, www.fas.org.
[8] Keiichi Ohki et al., "Status of Reduced Enrichment Program for Research Reactors in Japan," (Paper presented at the 2010 RERTR International Meeting, October 2010, Lisbon, Portugal), www.rertr.anl.gov.
[9] Keiichi Ohki et al., "Status of Reduced Enrichment Program for Research Reactors in Japan," (Paper presented at the 2010 RERTR International Meeting, October 2010, Lisbon, Portugal), www.rertr.anl.gov.
[10] Keiichi Ohki et al., "Status of Reduced Enrichment Program for Research Reactors in Japan," (Paper presented at the 2010 RERTR International Meeting, October 2010, Lisbon, Portugal), www.rertr.anl.gov.
[11] "Kyoudai Genshiro no Kyuu Hairo Mondai [On the Issue of Shutdown of Kyoto University's Research Reactor] (in Japanese)" http://homepage3.nifty.com.
[12] "Uranium for 20 Nukes Repatriated from Japan in Special U.S. Operation," Japan Economic Newswire, Kyodo, 27 December 2008. In this article, GTRI's Andrew Bieniawski noted that 523 kg of HEU were from JAEA facilities and JAEA had, thusfar, completed shipment of 95% of materials from its facilities. A JAEA official noted that the remaining 5% would be repatriated by 2014. By summer 2008, Kyoto University had sent back 50 kg of HEU.
[13] International Panel on Fissile Materials, Global Fissile Materials Report 2010, fn. 764, p. 203, www.fissilematerials.org.
[14] Global Fissile Material Report 2010, Fifth Annual Report of the International Panel on Fissile Materials, 2010.
[15] For a useful map, see Japan's Commercial and Research Nuclear Facilities, Citizen's Nuclear Information Center, January 2009, http://cnic.jp. Notes: Todd Jacobson, "NNSA Makes Plans To Ship More Spent Fuel to SRS," Nuclear Weapons & Materials Monitor, February 2, 2009; Department of Energy, Revised Record of Decision for the Environmental Impact Statement on a Proposed Nuclear Weapons Nonproliferation Policy Concerning Foreign Research Reactor Spent Nuclear Fuel, Federal Register, Vol. 74. No. 14, January 23, 2009.
[16] For a primer on Japan's nuclear power program, see "Nuclear Power in Japan," World Nuclear Association, March 2009, www.world-nuclear.org.
[17] Jun Hongo, "Nuclear Energy at a Crossroads," The Japan Times, 12 May 2011, www.japantimes.co.jp.
[18] Arjun Makhijani, Lois Chalmers, and Brice Smith, "Uranium Enrichment: Just Plain Facts to Fuel an Informed Debate on Nuclear Proliferation and Nuclear Power," Institute for Energy and Environmental Research website, 15 October 2004, p. 25, www.ieer.org.
[19] Toshinobu Ohba, Takeshi Inoue, and Hironobu Unesaki, "Status of Reduced Enrichment Program for Research Reactors in Japan," paper presented at the 2008 RERTR International Meeting, October 2008, Washington, DC.
[20] Keiichi Ohki et al., "Status of Reduced Enrichment Program for Research Reactors in Japan," (Paper presented at the 2010 RERTR International Meeting, October 2010, Lisbon, Portugal), www.rertr.anl.gov.
[21] Keiichi Ohki et al., "Status of Reduced Enrichment Program for Research Reactors in Japan," (Paper presented at the 2010 RERTR International Meeting, October 2010, Lisbon, Portugal), www.rertr.anl.gov.
The JMTR was initially converted from 93% HEU fuel to 45% enriched fuel in 1991, and then to the current 19.8% enriched fuel in 1994. Masataka Miyazawa, Masao Watanabe, Makoto Yokokawa, Hiroshi Sato,and Haruhiko Ito, "Present Status of JMTR Spent Fuel Shipment," RERTR-2002, www.rertr.anl.gov.
[23] Toshinobu Ohba, Takeshi Inoue, and Hironobu Unesaki, "Status of Reduced Enrichment Program for Research Reactors in Japan," paper presented at the 2008 RERTR International Meeting, October 2008, Washington, DC.
[23] Unesaki, Sano, Misawa, and Nakajima, "Full Core Conversion of the Kyoto University Research Reactor (KUR) from HEU to LEU, paper presented at the 2010 RERTR International Meeting, October 2010, Lisbon, Portugal, www.rertr.anl.gov.
[24] Ann MachLachlan, "Kyoto Reactor Institute Mulls Extension of HEU operation," NuclearFuel, April 17, 2000, p. 15.
[25] Jeff Chamberlin, "Research Reactor Conversion Program," U.S. National Academies Russian Academies of Science, Symposium on Research Reactor Conversion, November 29, 2010. http://dels.nas.edu.
[26] The University of Tokyo’s Yayoi Reactor Website, www.tokai.t.u-tokyo.ac.jp/~rokan/; Japan Atomic Energy Commission website, www.aec.go.jp/jicst/NC/iinkai/teirei/siryo2012/siryo10/siryo3-1.pdf.
[27] For discussion of policy issues regarding Japan's plutonium stockpile, see Tadahiro Katsuta and Tatsujiro Suzuki, "Japan's Spent Fuel and Plutonium Management Challenges," International Panel on Fissile Materials Research Report #2, September 2006, www.fissilematerials.org. For a discussion of other nuclear-related policy issues, see Emma Chanlett-Avery and Mary Beth Nikitin, "Japan's Nuclear Future: Policy Debate, Prospects, and U.S. Interests," Congressional Research Service Report RL34487, February 19, 2009, www.fas.org.
[28] Ann MachLachlan, "Kyoto Reactor Institute Mulls Extension of HEU operation," NuclearFuel, April 17, 2000, p. 15.
[29] "Uranium for 20 Nukes Repatriated from Japan in Special U.S. Operation," Japan Economic Newswire, Kyodo, 27 December 2008.
[30] "Uranium for 20 Nukes Repatriated from Japan in Special U.S. Operation," Japan Economic Newswire, Kyodo, 27 December 2008.