With thousands of antinuclear-power protesters chanting "No nukes" 30 miles away at the proposed $2.3 billion seabrook nuclear power plant, hundreds here shouted "Seabrook now" in a counter rally supporting nuclear power.

The rally - billed as a "clambake" in opposition to the three-day demonstration in Seabrook this weekend staged by the Clamshell Alliance, a coalition of New England antinuclear groups - was underlined by a call for voter support of pronuclear-power political randidates.

Many in the crowd of labor, business and consumer groups from around New England here - estimated at fewer than 1,000 by organizers and police - carried placards attacking the Clamshell group and touting the benefits of nuclear power to the job market and the economy while they listened to speeches and feasted on steamed clams and beer.

"We do stand for energy in the future, said Marc Goldsmith of the Massachusetts Voice of Energy, a consumer group sponsoring the rally here at John F. Kennedy Ciliseum, the site of a similar demonstration by about 3,000 advocates of nuclear power last year. "We do stand for jobs; we do stand for Seabrook.

"We need to shout "Seabrook now," he urged, and the crowd responded with the slogan.

The partially completed, 1,150-megawatt, twin-reactor Seabrook plant - unveiled at a projected cost of $793 million a decade ago by the Public Service Co., a private utility, is scheduled to supply energy to New Hampshire, Massachusetts and Maine. Construction has been stalled by vehement protests by environmental groups that claim it is potentially hazardous to people and sea life. The Environmental Protection Agency and the Nuclear Regulatory Commission are scheduled to hold further hearings here today.

"Washington's business acumen is not very high," said Avi Nelson, a Massachusetts senatorial candidate who is challenging incumbent Edward W. Brooke for the Republican nomination.

"I wouldn't turn over to them the management of a corner candy store, let alone the nuclear power industry," he said, continuing his attack. "If you turn over to Washington control of the Sahara desert, in a few years you would see a shartage of sand.

"Part of our problem stems from the fact that we have people in Congress and in our own legislature who do not want to go forward with construction of the nuclear plant," said Gov. Meldrim Thomson, a staunch advocate of nuclear power, who is running for a fourth term. "Those people should be removed from office. . . ."