T he Nuclear Regulation Authority on Wednesday decided to order the Japan Atomic Energy Agency to not engage in further preparatory work to restart the trouble-plagued Monju prototype fast-breeder reactor until the operator improves its safety management to prevent a recurrence of trouble. Monju, located in Tsuruga, Fukui Prefecture, is a core component of Japan's nuclear fuel cycle project along with the spent nuclear fuel reprocessing plant in Rokkasho, Aomori Prefecture.

Monju has been inoperative for most of the past 19 years while Rokkasho reprocessing plant's full operation has been postponed 19 times due to a series of problems. Given this troubling history and the JAEA's slipshod safety management, the logical conclusion should be to decommission the Monju reactor and end the nuclear fuel cycle project. The NRA should unambiguously order the JAEA not to restart Monju.

The NRA pointed out that the JAEA had made light of the need to ensure safety at Monju and failed to inspect nearly 10,000 reactor components in an after 2010. Making matters worse, JAEA head Mr. Atsuyuki Suzuki, who resigned Friday, said that the failure to inspect the components was only a procedural matter and did not cause safety problems. Yet among the components are more than 50 parts vital for the safety of the reactor, including a neutron detector that reveals radiation leaks. His attitude is deplorable.