The Nuclear and Industrial Safety Agency launched special safety inspections Tuesday at Tokyo Electric Power Co.'s three nuclear plants as part of punitive administrative steps over recent revelations it tried to coverup faults in its reactors.

The agency plans to carefully scrutinize Tepco's safety measures, paying particular attention to its decision-making process, internal-reporting practices and documentation methods, they said.

The inspections of the nation's largest utility could take as long as seven weeks, much longer than the quarterly inspections that run about three weeks. The agency will also employ a larger number of inspectors than usual.

In late August, Tepco was found to have covered up problems at several reactors at the Fukushima No. 1 and No. 2 nuclear plants in Fukushima Prefecture, as well as at the Kashiwazaki-Kariwa facility in Niigata Prefecture.

Economy, Trade and Industry Minister Takeo Hiranuma, who oversees the agency, issued a five-point administrative measure Oct. 1 designed to penalize Tepco, along with a written warning against any further wrongdoing.