The Nuclear Regulatory Commission conducted a surprise inspection of a nuclear power plant being built outside Houston because of allegations that inspectors working for Brown & Root Co. were not doing their jobs.

"We sent three people in there unannounced, who looked at certain things and interviewed a lot of people," Harry Thornburgh, director of the NRC's construction inspection division, said yesterday. "They haven't filed a full report yet but I've heard they didn't find a lot that was irregular."

One reason the NRC ordered the inspection of the South Texas Nuclear Project, which will supply electricity to Houston, Austin and San Antonio, is a 20-minute news film to be aired today on the season's premiere of the "CBS Magazine."

During the program, CBS reporter George Crile interviews a man named Dan Swayze, who was an inspector for Brown & Root for two years on the South Texas Nuclear Project. Swayze said he stopped inspecting concrete pours when concrete workers threatened his life and beat an inspector working for him.

"It reached a point in July of '77 that we attempted to stop a pour for major deficiencies. They threatened to kill me," Swayze told Crile. "That night, they assaulted one of my inspectors. Physically, beat the hell out of him. Put him in the hospital for doing his job.

"The next day we took a vote. It was 100 percent. All the inspectors decided obviously they wanted us to do exactly nothing but fill paper out. We took a vote, we started filling paper out, and we did it for five months."

Thornburgh said the NRC had heard the same allegations, investigated them and found there was some truth to them.

"There was some harassment of quality inspectors," Thornburgh said. "So we went to Brown & Root and told them they had to do something about it and I believe things got a lot better."