Nuclear regulators have decided to gear up the safety assessment of two reactors operated by Tokyo Electric Power Company Holdings Inc. in central Japan, raising the possibility of finishing the process by next March, sources said Tuesday.

Reactor Nos. 6 and 7 at the Kashiwazaki-Kariwa plant in Niigata Prefecture are boiling water reactors, the same type as the ones that suffered core meltdowns in 2011 at Tepco's Fukushima No. 1 complex.

All reactors in Japan — either BWRs or pressurized water reactors — are required to meet tougher safety criteria imposed after the Fukushima crisis, but the BWR assessment has been delayed due to the need to install safety equipment that involves extensive work.