The Fairfax County Board of Supervisors, amid sharp partisan debate, yesterday called for major reforms of Virginia's troubled Correctional Unit 30, and the eventual closing of the prison, located two miles west of Fair Oaks Mall.

The supervisors also voted unanimously to oppose any construction at the District's Lorton Reformatory that would allow more prisoners to be placed in the facility in southern Fairfax. A federal judge last week ordered that the city not accept new prisoners at the crowded D.C. jail and Fairfax officials are concerned the order could be used to expand Lorton.

The supervisors' actions followed a ringing speech by Fairfax prosecutor Robert F. Horan Jr., who called for new state guidelines for running Camp 30, but criticized "the pie-in-the-sky notion" that the state should close the facility.

County Board Chairman John F. Herrity, a Republican, last week called on the state to shut Camp 30. Horan and some other Demcratic officials say Herrity has emphasized recent escapes and security lapses at the state-run prison to embarrass Democratic Gov. Charles S. Robb and Democratic gubernatorial candidate Gerald L. Baliles during this year's elections.

Robb last week ordered a review of the management and security at the camp and state officials are to meet with county officials Thursday over the issue.

"There were more escapes at Camp 30 under the administration of Republican Gov. John B. Dalton," Horan said yesterday. "It's a politics-blind facility."

"We always seem to hear about these prison problems at election time," said Supervisor Audrey Moore, a Democrat. Moore denounced Herrity's demand that Camp 30 be closed as "irresponsible," citing severe overcrowding in state prisons and local jails. She urged that the proposals advanced by Herrity be introduced at Camp 30, but that the board reject Herrity's call for the immediate closure of the facility.

Republican supervisors insisted their concerns were not partisan. "I wish the prisoners could schedule their escapes in nonelection years, but somehow it doesn't work out that way," said Supervisor Thomas M. Davis III, a Republican.

After a motion by Moore was defeated on a 7-to-2 vote, the board voted unanimously for Herrity's proposal that Camp 30 be closed eventually. The proposal also called for a state review of the prisoners at the facility, and notification procedures to be used after escapes.

Horan reviewed Camp 30's recent history, stressing its parallels with the Lorton Reformatory, whose conditions county officials long have protested.

Both prisons, Horan said, started as facilities housing misdemeanants such as "drunks and fist fighters" but now hold felons who have been convicted of violent crimes.

He said that despite the changed type of prisoner, the state has failed to update policies there, and treats it as a medium-security institution. "We've got to get the state to acknowledge that with this crowd of inmates , we've got a different breed," Horan said.

"The people who say that Camp 30 will be gone are wrong," he said. "It's going to be there in my lifetime . . . and probably in yours."

The prison, one of 26 road camps in Virginia, has had 74 escapes in the last 10 years, more than any other state facility of its kind.

In other action, the Fairfax board:

*Approved an agreement with the District and Montgomery and Prince George's counties to expand by about 20 percent the regional Blue Plains waste water treatment plant.

*Endorsed a county plan to hire 10 engineers from The Bechtel Group Inc. to help with the flood of building plans the county must review.

*Rejected a bid by Moore to have the county review a proposed land swap between developer John T. (Til) Hazel and the county park authority.