The Nuclear Regulation Authority ordered Thursday that all efforts to restart the Monju prototype fast-breeder reactor be shelved until its operator improves its safety management.
The operator, the Japan Atomic Energy Agency, was found last year to have failed to conduct inspections at appropriate intervals on nearly 10,000 components of the Fukui Prefecture reactor.
The NRA looked into the case in detail and determined the government-affiliated agency's "safety culture is deteriorating," given that it could not address the problems despite being aware of the delayed inspections.
Under the order, JAEA will be barred from engaging in preparatory work for restarting the reactor until it rebuilds a maintenance and management system by appropriately allocating funds and human resources to prevent a recurrence.
JAEA President Atsuyuki Suzuki already has stepped down to take the blame for the operator's shortcomings.