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.

NRA Chairman Shunichi Tanaka did not comment on whether this means Monju will be decommissioned. He said it is too early to say.

But he said the recommendation has “significant meaning” because it is the first since issued by the NRA since its creation in 2012.

Tanaka was speaking after talks with science minister Hiroshi Hase in Tokyo on Friday.

If the ministry fails to find a new operator that meets the NRA’s approval, Monju, which has cost taxpayers more than ¥1 trillion, may face decommissioning.

Later in the day, Chief Cabinet Secretary Yoshihide Suga said the government “should take the recommendation from the NRA very gravely,” considering the slew of problems it has faced.

“We’d likely to respond sincerely,” Suga said.

But the government will maintain its policy of establishing a nuclear fuel recycling system regardless of Monju’s fate, Suga added.

“There is no change in our policy to promote (the nuclear fuel cycle), as decided in the Basic Energy Plan,” Suga said. The plan was adopted in April last year.

Hase said the ministry understands the gravity of the situation and will take action.

Fast-breeder reactors such as Monju use sodium as coolant and are designed to recycle nuclear fuel into another power source. Japan lacks significant energy sources of its own.

However, the Monju reactor has only briefly entered operation. It has been idle since a fire triggered by a vast sodium leak in 1995.

In 2012, it was found that JAEA had failed to inspect nearly 10,000 devices at the reactor despite being required to do so. Subsequently, dozens of monitoring cameras were found not to be functioning, and inspectors found a significant leak of radioactive liquid because an alarm had been ignored for more than a year.

In May 2013, the NRA ordered the suspension of Monju’s operation until the establishment of a system to prevent further safety slips.

JAEA President Toshio Kodama met NRA members earlier this month and vowed to improve the situation. the agency’s move Friday was an apparent sign that it has had enough — and an admission that despite repeated warnings the ministry has failed to come up to scratch.

Information from Kyodo added