AUGUSTA, GA., SEPT. 20 -- -- The operator of the Savannah River nuclear arms plant has uncovered up to 2,000 problems in one of the three reactors that could delay the year-end deadline for restarting operations, according to an Energy Department official.

Westinghouse Savannah River Co., which runs the plant for the government, has discovered the faults since mid-August, said Assistant Secretary Steve Richardson.

"It's like taking your car in and the mechanic really starts working on it and finds more things wrong," Richardson said. "Those things were not anticipated in the schedule; there was no way you could."

The plant, in South Carolina across the Savannah River from Augusta, has been shut down since August 1988 because of safety concerns. Westinghouse, which assumed control of the plant from Du Pont in April 1989, did not specify the nature of the latest problems.

Westinghouse and Energy Department officials will recommend to Energy Secretary James D. Watkins within three weeks whether to delay the restart, Richardson said.

"It's too early to tell whether we would recommend any schedule changes," Westinghouse spokesman Bruce Cadotte said. "We are still going through the analysis with the Department of Energy."

In May, Watkins said the reactor would begin low-power testing in December and start producing materials for nuclear weapons later that month or early in January. The other two reactors would begin production by October 1991, he said.

The Savannah River reactors are the sole producers of tritium, a radioactive gas used to boost the explosive power of nuclear weapons.

Because it decays 5.5 percent annually, tritium-loaded warheads must be periodically replenished.