Tokyo Electric Power Co. put reactors at its two nuclear power plants in Fukushima Prefecture back on line this summer without conducting inspections, even after the company received reports of possible problems, informed sources said Saturday.

The problems included a defect in a jet pump at the No. 6 reactor at the Fukushima No. 1 nuclear plant and a crack on a shroud at the No. 2 reactor at the Fukushima No. 2 nuclear plant.

General Electric Co. of the United States informed Tepco of more then 20 possible problems in June, but the Japanese utility did not inspect the problems even though it had already set up an in-house committee in May to investigate suspected coverups of damage that GE had informed it of in March.

The Japanese utility had outsourced inspections to General Electric International Inc., GE's Japan unit.

Tepco completed its regular inspection of the plants without checking the crack and the defect, putting the No. 2 reactor back on line on July 7 and operating the No. 6 reactor from Aug. 3, the sources said.

Tepco admitted covering up the problems and gave the Nuclear and Industrial Safety Agency the details on Aug. 7, more than one month after it had completed the inspection, they said.

The agency, affiliated with the Ministry of Economy, Trade and Industry, will ask Tepco why it resumed the operations of the two reactors even after it had set up the investigation committee.

"We can't comment, because we are still under investigation, including for these cases," a Tepco official said.

Tepco, Japan's largest power utility, earlier gave the agency a list of 29 possible false inspection reports dating from the late 1980s to 1990s on 13 of 17 reactors at the Kashiwazaki-Kariwa plant in Niigata Prefecture and the Fukushima plants.

It later admitted to falsifying the records.