Work to Remove Fuel from Monju Reactor Begins

August 30, 2018

Fukui- The Japan Atomic Energy Agency started on Thursday work to remove nuclear fuel assemblies at its Monju prototype fast-breeder reactor in Tsuruga, Fukui Prefecture.

In the first stage of the 30-year project to decommission the reactor in central Japan, the JAEA plans to relocate a total of 530 assemblies from the reactor and a storage tank outside the reactor, both filled with sodium coolant, to a water pool by December 2022.

But optimism for smooth fuel transfer cannot be warranted, as sodium violently reacts with water and oxygen and the JAEA lacks sufficient know-how in nuclear fuel transfer, pundits pointed out.

The removal work started with the storage tank. At 10:30 a.m. (1:30 a.m. GMT), an operator switched on a fully automated system to take out an assembly.

The agency aims to relocate one assembly per day from the tank and a total of 100 assemblies by the end of year. It also plans to withdraw some 760 tons of untainted sodium from the so-called secondary cooling system by the year's end.

Fuel transfer work at the reactor is scheduled to start in July next year.

In 1994, the Monju reached criticality, a self-sustained nuclear chain reaction, for the first time. But its operation was halted after a sodium leak the following year. The experimental reactor was restarted in 2010, but it faced a series of accidents and problems, such as a drop of a fuel exchanger.

The Japanese government officially decided in 2016 to decommission the Monju. In March this year, the Nuclear Regulation Authority approved the JAEA's decommissioning plans. Jiji Press