The Nuclear Regulatory Commission yesterday named Washington attorney Mitchell Rogovin to head an independent investigation of the events surrounding the nuclear plant breakdown at Three Mile Island in Pennsylvania.

Rogovin, 49, has a solid reputation as an investigator respected on all sides of the political spectrum. A former assistant U.S. attorney general of the tax division under President johnson, he became general counsel for Common Cause, the self-described citizen's lobby, in 1970 and left to represent the Central Intelligence Agency before congressional investigators in 1975.

"He saved the CIA and he's probably one of the few people who could save the nuclear industry," commented Richard Pollock, head of the antinuclear group Critical Mass.

"We wouldn't want to see a guy in that role with an ax to grind, and it's not obvious that he has any," echoed a spokesman for the Atomic Industrial Forum, the industry trade association. "We'll support him in any way we can."

Rogovin and his law firm - Rogovin, Stern and Huge - will be paid about $450,000 to probe the accident at Middletown, Pa., and the NRC contributions before and after the event, but they will also have the services of 45 NRC staffers who have been gathering data for the inquiry full-time during the two months in which the NRC sought a director. In addition, the firm will have subpoena power and free access to consultants. The entire six-month operation is expected to cost about $2 million, an NRC spokesman said.

"We are satisfied with the guarantee of independence we have received," the law firm said in a statement.

The probe is "not intended to duplicate the efforts of the President's Commission," but rather to enable the NRC "to take whatever further steps may be necessary to prevent any similar accident in the future, and to improve the NRC's ability to respond to accidents," the NRC announcement said.

Rogovin said he was "overwhelmed" to learn that all sides of the issue seemed pleased with his appointment. After a week or so seeing "what spadework has been laid" in the NRC, he said, "we'll be looking for the truth . . . it'll be Three Mile Island-oriented, but there's an ability for us to branch out. If we see things that are appropriate for us to chase down, we'll do it.

"We're going to work like hell," he added.