Fresh faults found with Monju management

September 3, 2015

Errors found in safety management of Monju reactor

Nuclear & Energy

Sep. 3, 2015 - Updated 13:07 UTC+2

http://www3.nhk.or.jp/nhkworld/english/news/20150903_28.html

Japan's nuclear regulators have found fresh faults with the safety management of the country's fast-breeder reactor, which is currently offline.

They say they have found thousands of errors in safety classifications of the equipment and devices at the Monju reactor.

The operator of the prototype reactor in Fukui Prefecture, central Japan, has been banned from conducting test runs since 2013 following discoveries of a large number of safety inspection oversights.

The Nuclear Regulation Authority says it has recently found at least 3,000 mistakes with safety classifications of equipment and devices at the reactor during its regular inspections which are conducted 4 times a year.

Its officials say, equipment and devices with high importance were, in some cases, classified in lower ranks in the 3-level system, which suggest the operator might have failed to carry out necessary inspections for them.

The errors found recently include those going as far back as 2007. The fact suggests that government inspectors have also overlooked the operator's mistakes.

The operator, Japan Atomic Energy Agency, built the Monju fast-breeder reactor in the early 1990s to reuse the spent nuclear fuel MOX, a mixture of plutonium extracted from spent fuel and uranium.

But it has been offline for most of the period after it underwent a fire from a leak of sodium, the reactor's coolant, in 1995.

The operator aims to conduct the reactor's test run by next March. But it is uncertain when the ban by the authority will be lifted.

The plant's director, Kazumi Aoto, says he will take the government's report seriously.

An NRA inspector, Yutaka Miyawaki, says the regulators will try to identify the actual effects of the errors.