Prince George's County Executive Parris Glendening has accepted the resignation of Corrections Director Arnett W. Gaston, whose management of the county jail was criticized after published reports of rapes, sexual assaults and other security problems among inmates there.

Glendening said yesterday that he had discussed with Gaston several times his efforts to correct conditions in the jail but that both men finally agreed that "under the circumstances [Gaston] would not be able to meet the standards I wanted for that institution."

Gaston, who has run the county corrections department since July 1979, could not be reached for comment yesterday.

Sources said Glendening will announce the departure of Gaston, 44, today.

County sources said Gaston will leave his post as county jailer today, and will be detailed immediately to the county executive's office. He will assist in plans for a new jail, they said, and help prepare a response to an audit of the jail by the National Sheriffs' Association.

That audit, released yesterday, criticized the jail for meeting only about half the association's criteria for a well-run jail. "The problem lies not only with the first-line supervisors," the auditors concluded, "but from top to bottom, beginning with the director of the center Arnett Gaston ."

Gaston, the county's highest-ranking black appointee, will reportedly retain his $55,000 annual salary while in Glendening's office but leave the county payroll within 90 to 120 days.

"He is a good person and valued professional in this area," said a high-ranking Glendening aide.

Gaston's job will reportedly be taken over, at least temporarily, by Michael Flaherty, 40, whom Glendening appointed last month to be the jail's director of security. Flaherty had been commander of the county police department's patrol officers.

Glendening and his closest staff members have expressed concern about what they described as Gaston's "insensitive" and defensive response to a series of articles published in The Washington Post last fall that detailed accounts of rapes and sexual assaults in the county jail. Gaston said in an article that accompanied the series that he didn't believe statements by inmates and guards that male inmates raped or assaulted other men as often as 12 times a week. Such estimates were exaggerated, Gaston said. But he recently told a reporter he was "shocked" to learn such assaults were taking place and that he now believes a problem exists.

Gaston's supervision of the jail first came under scrutiny after nine prisoners escaped last July and another escape attempt was made in August.

Security was one of the areas criticized in the sheriffs' association audit. The 256-page audit said the jail met only about 53 percent of the association's national standards for adult local detention facilities. Among its specific findings were:

* Jail inmates control the institution "in the sense that they act and the staff reacts . . . The inmates are not running rampant, but certainly dictate the security environment of the facility."

* Violence in the jail, involving assaults, sexual assaults and escape attempts, occurs because of overcrowding, design problems and guards who are poorly positioned. The jail, designed to hold about 320 prisoners, has about 529 inmates.

* Guards who ignore problems in the jail are not reprimanded by their supervisors.

* Hallways and cells are dirty and full of uncollected trash, mop buckets and newspapers.

* Lighting in the jail is not bright enough and inmates often cover lightbulbs with clothing.

* Inmates' clothing is not washed once a week, as it should be. Inmates sometimes have to give an inmate trusty cigarettes to get clothing washed.

The report was particularly critical of the jail's security and leadership problems. "It is time for all members of the senior staff and all supervisors they command to 'roll up their sleeves,' regain control of the facility and deal with the numerous symptoms that are indicative of not only a need for leadership improvements but of a high potential for serious breaches in security," the report states.

The report commended the jail, however, for its fiscal management, its computerized record-keeping, and for its medical staff members.

The audit was requested by former County Executive Lawrence J. Hogan last summer. It was conducted by four jail experts hired by the sheriffs' association. They spent a week visiting the jail and five weeks reviewing jail records and documents.

The Prince George's jail "wasn't totally unlike some of the jails that have requested audits," according to Dick Ford, jail operations director for the sheriffs' association. Ford declined to be more specific in his comparison of the Prince George's jail with 34 other jails that the association audited last year.

The purpose of the audits, Ford said, was to measure operation of the jails against standards recognized by the courts and professionals in criminal justice. The audits were funded by a $149,000 grant from the National Institute of Corrections, a division of the U.S. Justice Department.

The auditors recommended that the jail, among other things, hire 17 more guards and increase guards' $13,500 starting salaries nearly $2,000 a year.