CONCORD, N.H., JAN. 29 -- The possible sale of a large share in the Seabrook nuclear power plant -- one of the nation's most expensive reactors -- loomed in the aftermath of the bankruptcy court filing by the project's principal owner.

Analysts said they were uncertain about the course of Public Service Company of New Hampshire's request for financial reorganization, but some predicted the utility might sell its 36 percent share of the $5.2 billion Seabrook project.

"It's certainly possible," said Martin Klein, a New York bankruptcy lawyer. "One of the things you can try and do in a bankruptcy proceeding is sell assets."

Broken by its $2.1 billion investment in the stalled Seabrook plant, Public Service filed late Thursday for protection from creditors under Chapter 11 of federal bankruptcy laws. It was the first time since the Depression that a major public utility turned to bankruptcy court.

The lack of recent precedents for such public utility actions left financial and legal analysts puzzled as to what would happen to Public Service's $3 billion in assets.

The filing came two days after the New Hampshire Supreme Court denied the company an emergency rate increase by upholding a 1979 law against charging ratepayers for power plants in advance of commercial operation.

Public Service President Robert Harrison, promising that the flow of electricity would not be disrupted for the utility's 365,000 customers, said it was too early to determine how the assets would be treated in a reorganization that some estimated could take two years.

Harrison acknowledged Thursday that the sale of Public Service's share in Seabrook could be considered if the "price was right." Seabrook is owned by Public Service and 11 other New England utilities.

United Illuminating Co. of New Haven, Conn., owns the second-largest share of Seabrook. Spokeswoman Margaret Melady said the Connecticut utility has no immediate plans to increase its 17.5 percent share in Seabrook.

A spokesman for Eastern Utilities, a Boston holding company that has a 15 percent Seabrook share, said purchasing an additional share of Seabrook was a possibility.

"The classic response to that is what's the price. It's something that's fraught with uncertainty," said Webster Francis, an Eastern Utilities spokesman.

Eastern Utilities became the third-largest Seabrook owner in 1986, purchasing the Seabrook shares of three Maine and two Vermont utilities for $173.6 million, or about 24 cents on the dollar of the initial investment.

James Bennett, a utility analyst with R.D. Smith and Co. in New York, said Public Service's share in Seabrook is a "huge asset" for the utility's creditors who would be "crazy" to let go of it.

Seabrook opponents, however, said Public Service's Chapter 11 filing cast further doubt on the reactor's ability to obtain a federal operating license.

Opponents questioned whether the Nuclear Regulatory Commission would grant an operating license to a utility that is in the midst of financial reorganization.

The nuclear power plant on New Hampshire's coast was completed 18 months ago, but has not received an operating license because of disputes over federally required emergency evacuation plans for nearby communities.

Seabrook's reactor initially was scheduled for operation by 1979, but financial and other problems delayed the project and pushed its estimated cost to about $5.2 billion, about 10 times initial estimates.

The Vogtle nuclear power plant in Georgia is believed to be the most expensive reactor in the nation at $8.87 billion.