The Nuclear Regulation Authority on Friday asked the science minister to find a new operator to manage Monju, the troubled prototype fast-breeder reactor that is the centerpiece of the nation's nuclear fuel cycle program.

The NRA said it lacks confidence that the semi-public Japan Atomic Energy Agency can continue running the costly and accident-prone facility in Fukui Prefecture.

Although the request is nonbinding, the NRA said the Education, Culture, Sports, Science and Technology Ministry, which oversees the Monju project, has about six months to look for a new operator and report back. If it fails to find one, the ministry should "fundamentally review" what to do with the reactor.