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Monju decommissioning plan

December 6, 2017


Atomic energy agency submits Monju reactor decommissioning plan




The Japan Atomic Energy Agency (JAEA) submitted a plan to the Nuclear Regulation Authority (NRA) on Dec. 6 stating that it aims to complete decommissioning of the Monju prototype fast-breeder nuclear reactor in Tsuruga, Fukui Prefecture, by fiscal 2047.

If the NRA approves the plan, the JAEA will be able to go ahead with decommissioning work at the reactor. However, a range of issues such as where to place the spent nuclear fuel scheduled to be extracted from the site as well as how to remove liquid sodium still remain.

According to the plan, the decommissioning process will be split into four stages. The first stage is set to take place between fiscal 2018 and fiscal 2022 and will consist of removal of all 370 nuclear fuel assemblies from the reactor.


In the second and subsequent stages, which are scheduled to occur between fiscal 2023 and 2047, approximately 1,670 metric tons of liquid sodium coolant are planned to be extracted. Moreover, the building housing the reactor is set to be dismantled during this period.


The JAEA has not yet drawn up a specific schedule. However, it is planning to submit a more detailed plan to the NRA, with the view of undergoing some form of screening process.


The Monju reactor is unique because there are no previous examples of fast-breeder reactors being decommissioned in Japan. It differs to conventional nuclear power plants, as the method for extracting nuclear fuel from the site is complicated. Therefore, the NRA has decided to opt for the rare move of conducting screening from the relatively early stage of nuclear fuel removal.


With regard to the total amount of radioactive waste, it is estimated that approximately 26,700 tons will need to be removed from the reactor before the end of decommissioning.

In the morning on Dec. 6, JAEA executive director Hajime Ito visited the NRA to submit the decommissioning plan. "Taking various regrets into account, I want to win back the trust of the people by carrying out safe and reliable decommissioning," Ito said.


The decision to decommission the Monju reactor was made by the government in December 2016. However, the submission of the decommissioning plan was delayed as local representatives demanding regeneration of the area and enhanced safety measures failed to reach an agreement with the government.


Nuclear reactor operator submits 30-year plan to scrap trouble-prone Monju facility





The operator of the Monju prototype fast-breeder nuclear reactor submitted a plan Wednesday to decommission the trouble-plagued facility located in Fukui Prefecture.

The most recent plan presented to the Nuclear Regulation Authority lays out a 30-year time frame to complete the project despite a number of problems that remain unresolved, including where to store the spent nuclear fuel.


The government had originally hoped the Monju reactor would serve as a linchpin for its nuclear-fuel-recycling efforts as it was designed to produce more plutonium than it consumed.


But it experienced a series of problems, including a leakage of sodium coolant in 1995 and equipment failures in 2012. The plant has only operated intermittently over the past two decades.


Under the latest proposal, the facility’s operator, the Japan Atomic Energy Agency, plans to divide the 30-year disassembly period through 2047 into four phases. In the first phase, nuclear fuel will be extracted from the reactor core and other places by March 2022, followed by the second phase whereby pipes and pumps where sodium coolant was circulated will be disassembled. The agency will begin the primary scrapping of the reactor in the third phase.

In what is to be the first decommissioning of a fast-breeder reactor in the nation, some 26,700 tons of solid radioactive waste is expected to be produced. The local government is calling on the operator to swiftly remove the nuclear fuel and sodium from the prefecture.


After the central government decided to scrap the reactor in December last year, the Fukui Prefectural Government expressed concern over JAEA’s leading role as it had been judged unqualified to operate the reactor safely by the Nuclear Regulation Authority.


In response, the government beefed up oversight over the effort and the agency accepted external experts from electric utilities and manufacturers to play central roles in the decommissioning work.

Prior to the plan’s submis

sion, the agency on Tuesday concluded an agreement on safety measures and regional development plans with the Fukui Prefectural Government and the city of Tsuruga, which hosts the reactor.



Monju operator presents decommissioning plan




The Japan Atomic Energy Agency has presented a detailed plan for decommissioning its prototype fast-breeder nuclear reactor over 30 years.

The government decided last year to scrap the Monju reactor in Fukui Prefecture, central Japan, after a series of accidents and other safety problems.

The agency submitted its plan to the Nuclear Regulation Authority on Wednesday. It calls for dismantling the reactor in 4 phases, ending in fiscal 2047.

The first phase starts next year with the removal of 530 units of nuclear fuel over 5 years. Liquid sodium coolant that is free of radioactive substances will also be removed by April 2019.

Dismantling of the reactor and the building will follow.

The work begins once the Nuclear Regulation Authority approves the plan.

Japan Atomic Energy Agency board member, Hajime Ito, said they will focus first on fuel removal while continuing safety checks and educating and training staff.

The agency agreed with the Fukui prefectural government on Tuesday to report on the progress of the dismantling to the public.

The agency also plans to transport nuclear fuel and sodium outside the prefecture, but no decision has been made about where to take it.


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