International advisers to the Nuclear Regulation Authority are worried that a mandatory review of its performance could lead to a loss of independence for the body, created in the wake of the 2011 Fukushima nuclear disaster.

A lack of independent regulatory oversight of Tokyo Electric Power Co. and the Fukushima No. 1 nuclear plant was to blame for three meltdowns there after the March 2011 quake and tsunami, an official inquiry into the disaster found.

After the disaster, the NRA was launched under the Environment Ministry with more autonomy, but legislation provides for a review after three years of operation with a proviso to consider placing it under the Cabinet Office, involving closer political oversight.