The Reagan administration yesterday sharply criticized the American nuclear industry for its lack of enthusiasm for reprocessing plutonium from atomic power plants, and warned that "time is running out" on efforts to revive the controversial Barnwell reprocessing plant in South Carolina.

Kermit O. Laughon, the Energy Department official in charge of efforts to reverse the Carter administration's ban on commercial reprocessing in the United States, told the Atomic Industrial Forum he found it "frustrating that the U.S. nuclear industry is conspicuously silent on this matter."

"Administration support at the highest levels already exists, but this is of little value without industry leadership, involvement and commitment," Laughon said.

The White House is considering an Energy Department proposal to budget $250 million to buy the plutonium that would be produced by Barnwell. Some of this plutonium would then be used to fuel the Clinch River breeder reactor in Tennessee. The administration feels such an advance purchase commitment should serve as an incentive to private industry to complete and operate the plant.

Laughon said government funding of research and development work at the Barnwell plant -- which has kept the half-finished facility from closing since 1977 when Carter ordered the "indefinite deferral" of commercial reprocessing -- is not likely to continue beyond the current fiscal year.

"Even this funding may be lost due to opposition within the Congress as the final appropriation bills are developed in December," Laughon said.

The owners of Barnwell, a consortium made up of Allied Corp., Gulf Oil Corp. and Royal Dutch Shell, already have invested $250 million in the plant and have made it clear they are not willing to put up the additional $652 million they estimate it would cost to complete the facility.

But the administration has been hopeful a new consortium of companies, including some electric utilities, might emerge to finance the remaining construction and operate the plant.

Laughon, who also addressed the American Nuclear Society on Tuesday, was asked about the possibility of foreign participation in such a consortium. A West German utility has expressed interest in investing in Barnwell and shipping spent fuel from its atomic power stations to the plant to be reprocessed.

Laughon said, however, he felt this posed a problem because "the people in South Carolina are very concerned about foreign involvement. They are very provincial and somewhat parochial in their approach."

The Bechtel Corp., which has shown interest in participating in the completion of Barnwell, also reported to the American Nuclear Society on a detailed two-week operability study of Barnwell it conducted last year.

Robert E. Brooksbank, an official of Bechtel, said the study concluded that Barnwell could operate on a sustained basis at a capacity of 1,200 tons per year -- 20 percent lower than its designed capacity.

Brooksbank also discussed in detail a variety of systems and components that the Bechtel team felt would be difficult to repair once certain areas of the plant had become highly radioactive.

One problem that he said "gave the committee some heartburn" was the discovery that a solvent burner that used propane was located in one of the process cells where radioactive materials will be remotely handled.

Al Williams, a Barnwell official who subsequently addressed the meeting, conceded that the decision to "put the solvent burner in a process cell was dumb."

But Brooksbank and Williams both concluded that when the deficiencies that had been identified are corrected, the Barnwell plant could be operated successfully.