The chairman of the Nuclear Regulatory Commission, expressing alarm at the public availability of U.S. studies he thinks could benefit nuclear saboteurs, said yesterday his agency is seeking new powers from Congress to bar their distribution.

Joseph M. Hendrie said legislation approved in May by the House Interior Committee would allow the commission to withhold reports such as "Barrier Penetration Database," an illustrated document published by the commission that describes how to break through security barriers at nuclear power plants.

"It is unnecessary and unwise to supply people who hve bad ideas with a little extra help that these kinds of reports might provide," Hendrie said in a telephone interview.

Hendrie said that while much of the report's material might be obtainable from other public sources, "when you title it - my God - 'Barrier Penetration Database, published by the Nuclear Regulatory Commission,' it's like saying, 'Hi there, guess what I'm about'."

The Washington Post reported yesterday that the 48-page commission report and a larger, companion manual, "Barrier Technology Handbook," published by the Department of Energy, were publicly available at many of the agency's more than 130 public documents rooms throughout the United States.

The two reports and at least four other government manuals that analyze weaknesses of security systems at nuclear sites can also be bought from the government's National Technical Information Service.

Officials say the studies are designed to help federal agencies and nuclear facility operators evaluate security at their sites. Commission regulations require all such studies be made public unless they reveal security secrets at specific plants.

"If we went these reports to the operators without putting them in the public docket, we'd right away be in deep trouble for violating our now rules," Hendrie said.

"You can bet that within 90 days, someone would be somewhere on H Street [the location of the Commission headquarters] screaming that Hendrie's covering up for the nuclear industry."

Under present law, Hendrie said, his only other option is to classify reports as national security materials - a move that would deny access to the public but also to most members of the nuclear industry, who lack classified status.

The bill proposed by the nuclear energy would create a new category of "safeguard information" that it could withhold from disclosure.

The measure is opposed by antinuclear groups who believe it would give the agency the power to hide from the public damaging information about nuclear safety problems.

"It's a throwback to the days of the old Atomic Energy Commission when secrecy was the password," said Richard Pollock, director of the Naderfounded Critical Mass Energy Project. "Civil libertarians who look at this legislation would be aghast."