With an opportunity to decide some of the state's most hotly contested intra-party battles, Northern Virginians go to the polls Tuesday to pick nominees from among 73 candidates in 22 separate local government and state legislative primaries.

Races are taking place in Alexandria, and in the counties of Arlington, Fairfax, Loudoun, and Prince William and include contests for sheriff, county prosecutor, board of supervisors, and the Virginia state legislature.

Polls will open at 6 a.m. Tuesday and close at 7 p.m. Although Virginia voters are not required to register by party, voters in areas with both Republican and Democratic primaries will be required to state their party preference at the polls and will be allowed to vote only in that party's contests.

In Arlington, the county's only primary is also one of the area's liveliest as the incumbent Democratic commonwealth's attorney there, William S. Burroughs Jr., tries to fend off a stiff party challenge from John W. Purdy, a member of the Arlington County Board.

The races that have generated the nastiest accusations are being held in Fairfax County, where the battle to replace a controversial sheriff and a delegate's challenge of an incumbent state senator have become extremely bitter.

In the sheriff's primary, two Democrats and three Republicans are competing to replace Sheriff James D. Swinson, a Republican who is retiring this fall. The candidates have accused one another of election fraud, ripping down one another's campaign signs, enlisting sheriff's deputies to put up signs, and of wanting too much money.

Candidates in the Republican primary include the current chief deputy in the sheriff's department, M. Wayne Huggins, who is considered to be locked in a close race with Myron L. (Bud) Greenquist, a former chief deputy who was fired by Swinson last year. Howard L. Miller, director of a security company, is the third candidate.

In the Democratic primary, where the main issue has been, Swinson's competence in running the county jail, Kenneth R. Wilson, recently retired deputy chief of the Fairfax County police, is running against former D.C. corrections officer Terry C. Armstrong.

Although Swinson has not involved himself in the primary, his strength as a Republican party leader and the severe criticism he has received over the handling of his sheriff's job is expected to influence the election's outcome. The Republican candidates have been afraid to speak ill of the sheriff for fear of angering the party faithful while Democrats haven't hesitated to blame Swinson for a problem-plagued jail.

In the only race for the Fairfax Board of Supervisors that is considered to be close, two well known and active Democrats in Mason District, Betsy W. Hinkle and Nancy L. Shands, are competing to fill the seat being vacated by retiring Supervisor Alan H. Magazine.

In the Springfield, and Mount Vernon districts, two candidates each are vying for supervisor openings. The Springfield primary is among Republican candidates, while the Mount Vernon race is among Democrats. In the Providence District, a longtime Republican party worker is considered the favorite over two lesser known Republican opponents.

Also in Fairfax County, the retirement of Sen. Omer L. Hirst has sparked energetic primary campaigns by both Democrats and Republicans in the 35th Senate District, the central and southern portion of the county. Two-term Del. Richard Saslaw and former Fairfax County Board chairman Jean Packard are in a close contest for the Democratic nomination. In a four-way Republican race, James Tate, a former delegate, is considered the front-runner for the GOP nomination.

The 34th Senate District, representing Fairfax City and the central part of the county, has another interesting primary contest between Republicans Cynthia Newman, former Virginia Commonwealth secretary, and John Thoburn, son of conservative state Del. Robert Thoburn.

But the hottest nominating battle is taking place in the 33rd Senate District, which includes the western part of the county and all of Loudoun County.

There, progressive incumbent Democratic Sen. Charles L. Waddell (D-Loudoun) is being challenged by three-term Del. Raymond E. Vickery Jr. (D-Fairfax), also a progressive, in a race that has focused on each candidate's effectiveness and split Democrats who previously supported both men.

The House of Delegates contests have drawn numerous Democratic and Republican candidates, and each of Fairfax County's two House districts have scheduled primaries for both political parties.

In Alexandria two Republicans are fighting for the chance to challenge the city's incumbent Democratic prosecutor and three Democratic newcomers are seeking their party's nominations for the city's two seats in the House of Delegates.

In Prince William County, two Democrats are in a primary contest for the seat representing the Dumfries District on the county Board of Supervisors. A sheriff's contest there has drawn three Democratic contenders.

Loudoun County is having a spirited sheriff's race of its own as Robert W. Legard, the Democratic incumbent, faces a battle with three party challengers. Two other Democrats are also seeking their party's nomination for the county board of seat representing the Dulles District.