Cambridge voters, including about 1000 Harvard students, will today select the people who will run the city and its schools and decide if nuclear arms-related work will continue to be allowed within its borders.

Every seat on the nine-member city council and seven-member school committee is being contested. Three referenda, including the Nuclear Free Cambridge question which has captured national attention, also appear on the ballot.

Because the current council is split between four neighborhood-oriented, conservative Independents and four liberal progressives backed by the Cambridge Civic Association (CCA), with Mayor Alfred E. Vellucci holding a swing vote, a shift in one seat could result in a significant shift in city policy.

Local observers have said, however, that maintaining the current balance of power is the most likely result, with the possibility that one of the CCA incumbents could be replaced by challenger Alice Wolf, who is also backed by the association.

Polls will be open from 8 a.m. to 8 p.m. Harvard students in the Yard and most of the River Houses will vote at the fire station across the street from Memorial Hall; Mother, Dunster, and Leverett Towers residents will cast ballots at Bruins playground on banks St., and Quad residents will vote at the Peabody School on Walker St.

The campaign has been the costliest in Cambridge history, with five candidates collecting more than $12,000 each by October 21.

The relatively quiet council race has contrasted sharply with a heated debate over the ballot's Question 2, which asks voters to enact a law prohibiting any work directly related to nuclear weapons inside the city limits.

Twenty-five cities around the United States have passed similar status, but Cambridge would be the first to ban existing companies. Charles Stark Drapen Laboratories, located in Tech Square, has contracts with the Department of Defense totaling $140,000 and the firm's officials have said that 85 percent of Draper's work including development of guidance systems for the MX and Poseidon missiles-would be outlawed.

Because Cambridge selects city officials with a complicated system of proportional representation voting first outlined by English lawyer Edward Hare in 1859, election results will not be available for several days. Counting the paper ballots involves transferring votes from one candidate to another as contenders either reach a quota of 10 percent of the votes cast or are eliminated for having the lowest total in a particular round of processing.

The ballots will be locked up tonight, with a Cambridge police officer standing guard. About 100 temporary city employees--most of them elderly women--will gather tomorrow at the Long fellow School to begin the time-consuming task of sorting the ballots from the city's 55 precincts.

The referenda ballots--which will also list a question asking if the city should establish a cable television authority to bid for the Cambridge franchise, and another non-binding measure concerning housing policy--are considered a low priority and counted separately