New York ? The investigative arm of Congress is looking into the federal government’s handling of problems at a nuclear plant owned by FirstEnergy — the Ohio-based utility at the center of the investigation into last week’s blackout.

FirstEnergy’s nuclear plant, shuttered since March, is the subject of an investigation by the Nuclear Regulator Commission. The General Accounting Office, in turn, is exploring the adequacy of NRC’s inspection of the plant.

“The objectives of the job are to look at events surrounding the shutdown of the nuclear plant and the angle the GAO is studying in the NRC’s oversight of that plant,” said Jim Wells, the GAO’s chief for nuclear-related investigations.

Wells said the investigation, which began in December, would be completed in April and that results would be made public after they were sent to Congress.

The request came after criticism of the NRC’s handling of the Davis-Besse plant owned by FirstEnergy Corp., the Akron-based electric conglomerate that owns four of the five Ohio power lines that tripped, a major failure during last week’s blackout.

The plant along western Lake Erie hasn’t been operational since it went down for maintenance in February 2002. A month later, a leak was discovered where boric acid had eaten through much of a 6-inch-thick steel cap covering the plant’s reactor vessel.

It was the most extensive corrosion ever at a U.S. nuclear reactor and led to a nationwide review of 69 other plants.