Experts from the Nuclear Regulation Authority were split Monday over whether a fault under Tohoku Electric Power Co.'s Higashidori nuclear power plant in Aomori Prefecture is active.
During talks based on on-site inspections conducted by the NRA last year, some expressed understanding of the plant operator's claim that the fault is not active.
Taking the results of its additional survey into account, Tohoku Electric claimed the fault was not caused by seismic activity but is a crack created by the swelling of weathered minerals due to water absorption.
Some experts criticized the utility's claim.