OAK HARBOR - FirstEnergy Corp. may know next week if its Davis-Besse nuclear power plant will be ready to restart before the end of summer.

Modifications to crucialDavis-Besse safety equipment, two high pressure injection pumps that would keep the nuclear fuel cool in the event of a major accident, have yet to pass all tests to show that they will not clog and break during an emergency, FirstEnergy andDavis-Besse executives told a Nuclear Regulatory Commission oversight panel on Wednesday.

If the modifications don't pass, then the Akron utility is faced with additional delays by having to replace the massive pumps with new ones that it already bought as a precaution.

The most recent tests using mockups show that insulation fiber mixed in reactor coolant can clog the modified pumps in as little as 15 minutes, the executives said during a meeting at Oak Harbor High School. The tests are designed to simulate a loss-of-coolant accident inside the containment chamber, which could blow loose insulation, concrete and metal pieces and possibly damage safety equipment.

But the executives are confident that additional modifications will resolve the clogging problem. Also, about 65 cubic feet of fibrous insulation, identical to what clogged the pumps in the tests, that is inside the containment chamber that surrounds the reactor can be easily replaced with a different kind of shielding, they said.

``We have to get through this HPI issue,'' said Lew Myers, chief operating officer for First-Energy's nuclear operating company subsidiary. Until the pump problem is resolved, he cannot give an accurate timetable on when the plant on Lake Erie will be ready for restart.

The pumps have to be functioning for other tests and inspections to be completed atDavis-Besse. The plant has been kept shut down since March 2002, when workers found a pineapple-sized corrosion hole that nearly went all the way through the top of the reactor vessel head that covers the nuclear fuel core. FirstEnergy has spent hundreds of millions of dollars on repairs and on buying replacement power while the plant has sat idle.

FirstEnergy spokesman Todd Schneider said the plant may be ready for restart in the ``August time frame, give or take a few weeks.''

The NRC oversight panel has a checklist of 31 items that must be completed and passed before Davis-Besse will be allowed to restart. The NRC, which has final say on restart, said Davis-Besse managers and workers must demonstrate that they can safely operate the plant.

So far, 13 of the 31 items have been completed, said Christine Lipa, NRC official from the commission's regional office in Lisle, Ill.

Also Wednesday, Amy Ryder of Ohio Citizen Action gave the NRC panel 450 letters she said were from 450 Northern Ohio residents who do not want Davis-Besse to restart.