When nuclear power plant workers signed up for training by a Columbia, Md., engineering firm three years ago, they had no idea that their instruction would include how to deceive federal inspectors on safety matters.

But that is exactly what they were taught, according to documents from a Nuclear Regulatory Commission investigation completed this month.

The workers were advised, for example, that "springing changes" on the NRC "has the benefit of surprise," and they were urged not to tell government inspectors about failed equipment tests because "some smooth talkers have managed to get out of failures."

The pair of two-day training courses by General Physics Corp. encouraged workers to let NRC inspectors watch testing of equipment, but with the following proviso: "Don't be foolish. Note: perform demo on an 'easy' valve which has traditionally NOT been a problem leaker."

In response, the NRC has called General Physics' conduct "unacceptable" and has ordered the retraining of workers who took the courses, which were offered in 1983 and 1984. The NRC said the problem appears to have been an isolated one and that General Physics has taken steps to prevent a recurrence.

Robert Deutsch, president of General Physics, said this week that the NRC's response was fair and that any irregularities have been corrected for some time. "We made a mistake," he said. "The wording shouldn't have been in there."

Industry critics and one NRC commissioner say the incident raises a disturbing question of how much control the NRC has, or should have, over the companies that provide it with goods and services, called vendors. "I think it's clear that we don't do as much as we should be doing," said Commissioner James K. Asselstine.

The NRC, said Asselstine, does not "deal as well with questions of management and integrity as we do with hardware issues."

"We don't have specific regulations aimed at vendors, and the attitude of the majority of the commission over a number of years is that it's really up to the vendors to police the performance of their contracts."

A spokesman for the Atomic Industrial Forum, the chief trade association, said he believes that the NRC exercises adequate control over vendors.

"You can't judge a whole system by whether or not it works every single time, or whether there's ever a mistake made," said Carl Walske. "I think you have to judge it by the overall track record, which is pretty good."

Rep. Edward J. Markey (D-Mass.), whose House subcommittee on energy released the results of the NRC investigation this week, said he plans to ask the NRC whether additional authority or resources are needed to perform adequate reviews of contractors.

"The General Physics case raises the overarching question of whether screening standards or greater regulatory scrutiny needs to be devoted to the thousands of contractors and subcontractors serving the nuclear industry," he said.

Markey produced documents this week showing that in a related matter in 1982, General Physics hired a man who had left the Three Mile Island nuclear power plant in Pennsylvania after apparently cheating on operator license examinations required by the agency. The man, Gregory Hitz, was working on a General Physics-NRC contract, though the NRC was unaware of that until recently.

Hitz, who still works for General Physics, could not be reached for comment. Deutsch said this week that he hired Hitz only after "extensive soul-searching" and that Hitz had shown "remorse and regret."

Others see the Hitz hiring in broader terms.

The NRC should not have been surprised to find Hitz working for General Physics, said Ellyn Weiss, general counsel for the Union of Concerned Scientists, an advocacy organization that studies nuclear issues. After he was reprimanded for cheating on exams, she noted, he was not prohibited from working in the nuclear field. "Where do they think the man's going to work -- Woolworth's?" she asked.

The NRC did not recommend any action against General Physics stemming from its investigation, nor has it said what its future relationship will be with the firm. One commissioner -- Frederick J. Berthnal -- maintains that the NRC "could have and should have" terminated the three unrelated General Physics contracts it had when training course problems became known last August.

Because the NRC did not act in that manner, Berthnal says, two of the contracts have been completed. A third is being terminated for default based on NRC claims that the company failed to present an "acceptable" health physics course. General Physics is appealing.

Berthnal said the NRC's response constitutes a "slap on the wrist when a right cross to the chin long ago would have been more appropriate."

A similar view is offered in correspondence from Markey to the NRC: "It certainly is questionable whether any contractor that advises nuclear utilities on how to put one over on the federal government should also have the privilege of receiving taxpayers' money."

The first of the controversial courses concerned testing for leaks in the buildings that surround nuclear reactors. It was given to employes of General Public Utilities Nuclear Corp. At the time, the firm was under indictment on 11 counts of falsifying information concerning radiation leakage at its Three Mile Island plant, site of the nation's worst nuclear plant accident.

Wrote Markey to the NRC: "While I'm sure you would agree that General Public Utilities has been in need of help in this area, clearly this is not the type of assistance that the only nuclear utility ever indicted and convicted of criminal charges needs."

The second seminar was offered to employes from various utilities around the country, incuding Carolina Power & Light, which operates several nuclear power plants. Company officials later told the NRC that they had been surprised by the course material.

The NRC says it learned of General Physics' courses from a General Public Utilities employe who had taken one.

General Physics' Deutsch says that all training course material is now reviewed by a company committee or by the utility paying for the course. He said he continues to be disturbed by the interest in Hitz, who he says is a good employe.

An NRC official investigated the Three Mile Island cheating episodes of 1979 and 1981. That official, in a report to the commission, referred to Hitz as "Mr. O" and to his coconspirator as "Mr. W."

"O and W both engaged in a pattern of cheating over a period of time," the investigator wrote, according to a letter from Markey to the NRC.

"O, in particular, still fails to recognize the character of his acts. O and W were both fired when their guilt was established . . . . In the case of O, something stronger than dismissal will be required to convince him that the NRC licensing process is important."

The NRC did not take action against Hitz or any other person stemming from its Three Mile Island investigation.

Deutsch said Hitz is not in a "sensitive" position at General Physics. Hitz, he said, is the company's director of pressurized water reactor training services.