Fairfax County, responding to a court order, filed its plan yesterday to improve Lorton prison and said essentially that the best way to do so is to close it - some of it right away and the rest by 1980.

Although Lorton is in Fairfax County, it houses persons convicted of crimes in the District of Columbia. The county has complained continually about the prison and, as a result of a suit it filed two years ago.U.S. District Court Judge Albert V. Bryan Jr. last July declared teh prison "a public nuisance." His order called for submission of improvement plans by the county and the District.

The Fairfax County calls for an interim phase-out of the prison to be diercted by the U.S. Bureau of Prisons and a reduction from about 2,300 inmates to 1,375 when the prison is closed in 1980. The county said the housing of the prisioners after 1980 was a District problem.

Fairfax County Board of Supervisors chairman John F. Herrity said he did not want D.C. Department of Corrections Director Delbert C. Jackson Jr. to oversee the proposed phased out because "Delbert Jackson is basically incompetent."

Jackson said he would not respond to the county's plan because he has not seen it. In response to Herrity's characterization of him, Jackson said, "I feel the same way about him. We always exchange that adjective. There's nothing new about that."

The District submitted its Lorton improvement plan May 10 stating that improvements in security were being made and capital projects including more lighting, new security equipment and repairs were planned.

But Fairfax County's plan has asked that no more capital improvements be made at Lorton except those needed to upgrade the water pollution.

Poor lighting and disrepair "are not the problem," Herrity said. "The problem is primarily the way the thing is laid out there - it's all spread out - and the incompetent management of the facility. Cosmetic approaches will not remedy the situation out there."

The county also said it wants its officials to be notified immediately on any escapes, assaults, disturbances and riots during the interim period. It is partly because of complaints of county residents about escapes that the suit against the District was filed two years ago.

The minimum security facility, where many of the escapes or "walkaways" (inmates can walk out of the prison) occur, should be closed immediately and relocated in the District, the county said, because "walkaways will have an opportunity to walk into the District of Columbia rather than through Fairfax County."

The plan, based on recommendations by two national correctional facility experts who testified at the hearings last year, also recommends appointing a prison expert to monitor the transition and would require the District to file in court, within 60 days, a list of alternative sites in the District to relocate the prisoners during the phaseout.

A hearing on the county and District plans is scheduled June 10, after which the court will issue an order about what should be done with the prison.