第38回原子力委員会
資料第3-1号
Provisional Translation

Plutonium Utilization in Japan

October 2017
Japan Atomic Energy Commission
1. Nuclear Power Generation in Japan(1) Energy Situation in Japan: Stable Supply of Energy
A stable supply of energy is indispensable for wholesome and cultured living of theJapanese people. Japan is poor in energy resources, and relies almost entirely on foreignimports for all fossil fuels such as coal, crude oil, and natural gas.
The “Long-term Energy Supply and Demand Outlook” (July 2015, Ministry of
Economy, Trade and Industry) presented an outlook of Japan’s electric power supplydemand structure in FY2030, where renewable energy accounts for 22-24%, nuclear
energy 20-22%. Nonetheless, the primary energy self-sufficiency ratio (including nuclear
power generation) is roughly 25%, which is lower than that of other advanced
industrialized countries.
(2) Nuclear Power Generation in Japan
Japan began addressing the peaceful use of nuclear energy prompted by the
President Eisenhower’s “Atoms for Peace” speech before the United Nations General
Assembly in 1953. A small test power reactor (JPDR: Japan Power Demonstration
Reactor, boiling water reactor) imported from the US started operation in 1959.
Commercial nuclear power reactors began with a Calder Hall type reactor (GCR,
graphite-moderated, carbon dioxide gas-cooled reactor) imported from the U.K. in 1965.
Since 1970, light water reactors (LWRs) have been used for power generation.
At the peak there used to be 60 commercial nuclear power reactors in Japan. Threeof them were designated to be decommissioned before TEPCO’s Fukushima Daiichi
Nuclear Power Station Accident (hereinafter called the Fukushima NPS Accident). Afterthe accident, six small and medium LWRs constructed in the early days, and six of
TEPCO Fukushima Daiichi Power Station were designated to be decommissioned. A totalof 12 were designated to be decommissioned after the Fukushima NPS Accident. There
are 45 LWRs remaining at present. Conformity review on the New Regulatory
Requirements introduced after the Fukushima NPS Accident is underway. Some LWRs
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have already received permission and are put back online.
2. History of the Use of Plutonium in Japan
Plutonium is produced and accumulated in spent nuclear fuel as a result of the useof nuclear power. Since Japan is poor in energy resources and reserves of uranium wereconsidered to be finite, Japan has adopted, from the beginning of nuclear energy use, anuclear fuel cycle policy that uses plutonium separated from spent nuclear fuel.
The Atomic Fuel Corporation--established in 1956--started the technology
development of uranium exploration and nuclear fuel manufacturing. Technology
development such as spent nuclear fuel reprocessing, uranium enrichment, radioactive
waste disposal also started. The project was taken over by the Power Reactor and Nuclear
Fuel Development Corporation founded in 1967, and the Tokai Reprocessing Plant started
its operation in 1977. The development of such technologies as uranium and plutonium
mixed oxide (MOX) fuel fabrication, uranium enrichment, and radioactive waste disposal
also continued. The Power Reactor and Nuclear Fuel Development Corporation became
the Japan Nuclear Cycle Development Institute in 1998, when the research anddevelopment was handed over to the Japan Atomic Energy Agency (JAEA) establishedin 2005.
In the field of nuclear reactor development, an advanced thermal reactor “Fugen,”an experimental fast reactor “Joyo,” and a prototype fast breeder reactor “Monju” werebuilt. “Fugen”--which began operation in 1979--was a nuclear power reactor (heavy watermoderated, boiling light water cooled, pressure tube type) capable of increasing theconversion rate of uranium to plutonium, and operating with a large number of MOX fuelassemblies loaded. It stopped its operation in 2003, and is now undergoing
decommissioning process. “Monju,” which began operation (first criticality) in 1994,
provided various experimental results and knowledge as a prototype reactor, but stopped
operation for a long period of time due to the sodium leak accidents, and other factors. In
December 2016, it was decided not to resume its operation as a nuclear reactor and to be
decommissioned in due course. The advanced boiling water reactor (ABWR) which was
jointly developed with the US can theoretically operate exclusively with MOX fuelassemblies. A demonstration reactor of the advanced thermal reactor (ATR) has not been
built.
Commercial nuclear power generation in Japan is carried out by privately owned
electric power companies (nine electric power companies including TEPCO, KEPCO as2

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well as JAPC and EPDC 1 );a pluthermal 2 plan was formulated by the Federation ofElectric Power Company (FEPC) based on the agreement among those electric powercompanies. Commercial nuclear fuel cycle business i.e. low-level radioactive waste
disposal project, uranium enrichment project, reprocessing project, and a high-level
radioactive waste management project, is also run by Japan Nuclear Fuel Ltd (JNFL) in
Rokkasho Village, Aomori Prefecture, a private enterprise owned by electric powercompanies. While the Rokkasho Reprocessing Plant (RRP) has had once an active testrun (using actual spent nuclear fuel), it is now undergoing a Nuclear Regulation Authority(NRA) review process to ascertain it meets the new safety requirements including seismic
performance evaluation based on the new regulatory requirements established after the
Fukushima NPS accident. The JNFL currently expects to start operating the RRP after
completing necessary works to fulfill the new safety requirements and construction plan
approval. An adjoining plant for the manufacturing of MOX fuel is expected to become
operational following the start of the reprocessing project.
Prior to the commencement of the commercial reprocessing operation in Japan,
electric power companies reprocessed their spent nuclear fuel and manufactured MOX
fuel assemblies using the separated plutonium by contracting out to the U.K. and France,transported them to Japan, and used them in LWRs, and thus accumulated the experienceof MOX fuel utilization.
The use of MOX fuel in LWRs started at Tsuruga Unit 1 of JAPC in 1986 using a
few MOX fuel assemblies, and now each electric power company plans to use MOX fuelin about 1/4 to 1/3 of the reactor core. Before the Fukushima NPS Accident, there had
been a track record of commercial pluthermal usage in four LWRs.
3. Japan’s Policy of Plutonium Utilization
The Atomic Energy Basic Act of Japan stipulates that the research, development
and utilization of nuclear energy shall be limited to peaceful purposes. As a nation that
suffered from the atomic bombings in Hiroshima and Nagasaki, Japan has neither
developed any nuclear weapons nor intended to do so. This led to the Three Non-Nuclear
Principles3. Japan aims to realize a world without nuclear weapons.
Japan has been assuring the peaceful use of nuclear energy under stringent
safeguards of the IAEA and firmly maintains the principle of not possessing plutonium
1

EPDC owns one reactor which is under construction in the Ohma NPS.

2

The term “pluthermal” refers to the use of plutonium in thermal reactors (i.e. LWRs).

3

the Three Non-Nuclear Principles; not possessing, not producing and not permitting

the introduction of nuclear weapons
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without specified purposes. Under this principle, Japan continues its efforts to gain
understanding of the Japanese people and the international community and enhancestransparency of its use of plutonium. At the Hague Nuclear Security Summit held in 2014,
Prime Minister Shinzo Abe stated that he would fully mind the balance between
separation and utilization of plutonium. The communiqué adopted at the summit
encouraged States to keep their stockpile of separated plutonium to the minimum level.
(1) Stringent Implementation of the IAEA Safeguards for Peaceful Use
Japan concluded the NPT, and its entire materials and activities are subject to the
IAEA Comprehensive Safeguards Agreement (CSA) and its Additional Protocol (AP)that were agreed to by the Japanese government.
As a reprocessing plant that reprocesses large quantities of nuclear material under
the CSA, the Rokkasho Reprocessing Plant (RRP) was subject to a close examination incooperation with the IAEA and U.S., through its design and construction phases todetermine how best to carry out the safeguards procedure. Consequently, it will receive
an unprecedented safeguard verification that will continually monitor the amount and the
movements of nuclear material throughout the reprocessing process.
Japan has a track record of accepting the IAEA safeguards inspection for years andhas been granted “Broader Conclusion” (that there is no indication of diversion ofdeclared nuclear material from peaceful nuclear activities and no indication of undeclared
nuclear material and nuclear activities in the state.) by the IAEA from 2003 to 2016;
therefore, it is safe to say that the peaceful use of the Japanese plutonium is secured at ahigh level. Japan also promotes the strengthening of nuclear security measures.
(2) Publication of Plutonium Management Status
With a view to enhancing transparency and gaining understanding of the public andthe international community, Japan has been annually publishing since 1994 a status
report on the management of separated plutonium that is used or held within and outsideof Japan, and reporting it to the IAEA in conformity with the “Guidelines for theManagement of Plutonium” since 1997.
The amount of plutonium is reported in two categories; a) the amount of unirradiated separated plutonium and b) estimated amount of the plutonium contained inspent nuclear fuel.
As of the end of 2016, the amount of Japanese un-irradiated separated plutonium
was approximately 47 tons, approximately one ton less than the previous year as a resultof the irradiation of MOX fuel at Units 3 and 4 of Takahama Nuclear Power Plant, and4

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the removal of plutonium fuel from the Fast Critical Assembly (FCA). Approximately 10
tons are held in Japan while the remaining major portion (approximately 37 tons), is heldin the U.K. and France. The amount of plutonium contained in spent nuclear fuel, asreported to the IAEA, is estimated to be approximately 164 tons.
All of this plutonium is, as mentioned above, kept under the stringent IAEA
safeguards.
(3) Proliferation resistance of the plutonium held by Japan
Besides the stringent safeguards procedure, Japan has adopted a reprocessing
process called co-conversion, in which both uranium and plutonium are recovered in
mixture and then converted to a mixed oxide (MOX). Therefore, Japan does not keep
separated plutonium oxide as a singular substance (except for trace amounts for the
purpose of research and analysis). MOX itself cannot be used for nuclear weapons, andconsidered to be nuclear proliferation resistant.
As the Japanese plutonium separated in the U.K. and France is shipped to Japanafter being fabricated into MOX fuel assemblies, there is less apprehension about nuclear
proliferation either. The amount of plutonium contained in MOX fuel returned to Japanis added to that of domestic plutonium holdings.
When MOX fuel assemblies are loaded into the reactors and irradiated, the amountof plutonium contained in them is deducted from the plutonium holdings because theradiation levels after irradiation are so high making themselves inaccessible.
Estimated amount of the plutonium contained in spent nuclear fuel is also reported
to the IAEA and the plutonium will not be separated before reprocessing. Because spent
nuclear fuels have high levels of radiation, there is little concern over nuclear proliferation.
(4) Japan’s Basic Policy on the Utilization of Plutonium
In August 2003, the Japan Atomic Energy Commission (JAEC) adopted “the Basic
Policy on the Utilization of Plutonium in Japan”. It stated that Japan would not possess
plutonium without specific purposes. Since then the JAEC has asked electric powercompanies and the Japan Nuclear Cycle Development Institute (now the Japan Atomic
Energy Agency) to submit plans for the use of plutonium and has ascertained the policy
is maintained in practice. This basic policy remains unchanged and consistent to date.
Furthermore, the JAEC has decided on “the Basic Policy for Nuclear Energy” on
20 July 2017. It stated that “In pursuing the effective use of plutonium, peaceful use is amajor precondition. Japan, therefore, should continue to adhere strictly to the principle ofnot possessing plutonium without a specific purpose so as to secure international
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understanding and to contribute to nuclear non-proliferation. In doing so a good attention
should be paid to the balance between the production and the consumption of plutonium.”,“Japan needs to ensure the steady consumption of plutonium in the form of MOX fuel for
LWRs, which is the only practical way of using plutonium as of today. At the same time,
Japan needs to continue its unceasing efforts toward gaining the understanding andconfidence of the international community on these plutonium related policies.” and “Toutilize LWRs over long periods, nuclear energy-related organizations need to strengthen
their efforts to upgrade facilities and capabilities for intermediate storage of spent nuclear
fuel.”The Cabinet decided, in its meeting on July 21, 2017, that this “Policy” should be
respected by the entire government.
4. Future Prospect(1) Use of Plutonium in Light-water Reactors（LWRs）
In the Plutonium Utilization Plan presented by the FEPC in September 2010, 5.56.5 tons per year of fissile plutonium was to be used as MOX fuel in 16-18 LWRs by FY
2015. However, after the Fukushima NPS Accident of March 2011, all the LWRs in Japan
stopped their operation and are undergoing a Nuclear Regulation Authority (NRA) review
process to ascertain they meet the new regulatory requirements.
Six years after the accident, the NRA so far has cleared 12 LWRs. Out of them, five
LWRs are back online. Of these reactors, pluthermal operation is conducted at threereactors (KEPCO’s Takahama Units 3 and 4, and Shikoku Electric Power Company’s
Ikata Unit 3). The remaining LWRs will be put back online after they receive NRA
clearance and finish required works. By the time the RRP starts its operation, electric
power companies are to announce officially a revised plutonium utilization plan on thebasis of the state of their LWRs operation resumption and the progress of pluthermal, andthe Japanese government (JAEC) is to assess the appropriateness of the plans.
(2) The Rokkasho Reprocessing Plant (RRP) and MOX Fuel Fabrication Plant of JNFL
At present, JNFL’s RRP and MOX Fuel Fabrication Plant are undergoing a NRA
review process to ascertain they meet the new regulatory requirements.
The JNFL plan is to complete the construction of the RRP in the first half of FY
2018 and the MOX Fuel Fabrication Plant in the first half of FY 2019.
As the review process is taking more time than expected, the completion of theplants’ construction may be delayed; however, the time lag between the completion of theworks on the two plants would not be significantly extended.
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The RRP does not plan to operate up to its maximum reprocessing capacity
immediately after it completes the construction works; it plans to gradually increase its
workload.
When the MOX Fuel Fabrication Plant starts operation, a certain amount of mixed
oxide powder will need to be stocked as its feedstock. In case the completion andoperation of the RRP goes ahead of the MOX Fuel Fabrication Plant, the amount of mixed
oxide powder stock will temporarily increase. Yet it should be done that way because acertain amount of mixed oxide powder will need to be stocked for the fabrication of MOX
fuel.
In addition, the “Supplementary Resolution to accompany the Bill to amend theSpent Nuclear Fuel Reprocessing Fund Act” (Committee on Economy, Trade andIndustry - House of Representatives on April 20, 2016, Committee on Economy, Tradeand Industry - House of Councilors on May 10, 2016) stipulates that the Minister of
Economy, Trade and Industry, in the process of approving the mid-term implementation
plan for spent nuclear fuel reprocessing (MRP) of the Nuclear Reprocessing Organizationof Japan (NuRO), should ask for the view of the JAEC from the viewpoint of peacefuluse of nuclear energy and securing the supply-demand balance of plutonium. In October,
2016, the JAEC accordingly requested the Minister of Economy, Trade and Industry tosubmit, before the reprocessing is carried out, the MRP showing the timing and theamount of reprocessing and fabrication related to reprocessing. The Minister of Economy,
Trade and Industry has also announced that he will never approve the MRP if it is devised
not in line with the government policy.
(3) Ensuring Plutonium Supply-Demand Balance
Japan firmly maintains the principle of not possessing plutonium without specificpurposes, including separated plutonium held abroad which was derived from past
reprocessing overseas which was derived from past reprocessing overseas.
Japan can also secure the appropriate supply-demand balance of plutonium by
consuming it through pluthermal operation.
Regarding plutonium used in Commercial reactors a) electric power companies
utilize it through pluthermal operation; b) the RRP will not operate immediately at full
reprocessing capacity but do only in a step-by-step manner; c) while the operation of the
RRP will proceed that of the MOX Fuel Fabrication Plant due to the recessing of a certain
amount of feedstock for the MOX Fuel Fabrication Plant’s operation, the startup of the
MOX Fuel Fabrication Plant will not significantly lag behind that of the RRP; d) theJapanese government assesses the plutonium utilization plans held by nuclear operations
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As to the plutonium used for research and development activities, the government(JAEC) will ascertain appropriateness of the plutonium utilization plan held by national
research institutes such as the Japan Atomic Energy Agency and enhance the transparency
by publishing it while paying due consideration to nature of the activities that require
flexibly to respond to changes in the situation of research and development.
In this way, the plutonium in Japan will not keep accumulating, be managed in a
steady balance although there may be some ups and downs due to the operation andprocessing works of the RRP and other facilities. It is the recognition of the JAEC thatthe goal of reducing the amount of plutonium stock held by Japan will be achieved in thelong term.
It is the intention of the Japanese government (JAEC) to remain engaged to secure
appropriate supply-demand balance of plutonium under the current framework ofassessing future plutonium consumption by fully grasping the nuclear operators’ demandfor plutonium and their consumption and verifying its appropriateness.
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