New operator sought for Japan's Monju reactor

01 June 2016

A committee considering the future of Japan Atomic Energy Agency's (JAEA's) Monju prototype fast breeder reactor (FBR) has set out the requirements for an alternative operator for it.  

Last November, Japan's Nuclear Regulation Authority (NRA) said it had determined JAEA was not competent to operate the reactor in Fukui prefecture. The decision followed revelations of a history of insufficient inspections of equipment. At that time, it recommended to the Ministry of Education, Culture, Sports, Science and Technology (MEXT) that it should find an alternative operator for Monju.

A special committee under MEXT considering the status and future of the FBR reactor issued a report on 27 May detailing the necessary requirements for the new operator.

According to the Japan Atomic Industrial Forum, the committee said the operator should firstly be able to "issue and carry out a safety plan based on the characteristics of a reactor at the research and development stage". The operator should also be capable of carrying out maintenance and managing the site to the same standard as any other nuclear power plant.

The committee also said the organization should be able to gather and utilize useful information, "including that concerning commercial power plants". It must also be able to take over and advance development of FBR technology from JAEA. The new operator must also have strong governance "allowing for the proper reflection of the interests and demands of society on Monju's operation".

The committee's report stressed the need to establish a management liaison council with the participation of external specialists.

MEXT will now begin considering a new operating body for Monju in cooperation with related ministries and agencies. In November, the ministry warned that if a replacement operator for Monju cannot be found, the future of the reactor should be fundamentally reviewed, including the possibility of decommissioning it.

Monju mishaps

A key part of Japan's nuclear energy program, Monju initially started in August 1995, but was shut down only four months later after a serious incident. About 700 kilograms of liquid sodium leaked from the secondary cooling loop and, although there were no injuries and no radioactivity escaped plant buildings, this was compounded by operator attempts to cover up the scale of the damage.

Monju was allowed to restart in May 2010 after JAEA carried out a thorough review of the design of the plant, as well as safety procedures, which were shown to have been inadequate. However, the reactor's operation was again suspended in August 2010 after a fuel handling machine was accidentally dropped in the reactor during a refuelling outage. The device was eventually retrieved almost one year later.

In November 2012, it was revealed that JAEA had failed to conduct regular inspections on almost 10,000 out of a total 39,000 pieces of equipment at Monju. Some of these included safety-critical equipment. In January 2013, the NRA ordered JAEA to change its maintenance rules and inspection plans. However, following a review of JAEA's performance since then, the NRA found that the agency has failed to formulate and adhere to a strict inspection schedule. The regulator said JAEA would not be permitted to make preparations for the restart of the 280 MWe Monju FBR until it could confirm improvements to its inspection procedures. The reactor has been offline since August 2010.

Researched and written
by World Nuclear News