The House, in a victory for the nuclear power industry, has rejected a measure that could have helped block operating licenses for the Seabrook reactor in southern New Hampshire and the Shoreham plant on Long Island.

The amendment by Rep. Edward J. Markey (D-Mass.) was defeated 261 to 160 as a bloc of Democrats joined the Republican minority. It was a provision in a bill reauthorizing the Nuclear Regulatory Commission for two more years, which then passed by a 389-to-20 vote Wednesday night.

Markey said his measure would preserve the status quo by exempting the two plants from a proposed NRC rule change that would make it easier for the commission to approve utility-drafted evacuation plans in areas where local governments have refused to participate.

The NRC staff proposed the rules change after Massachusetts Gov. Michael S. Dukakis (D) and New York Gov. Mario M. Cuomo (D) refused to submit evacuation blueprints for the 10-mile emergency zones around the plants, a move that has held up operating licenses for the completed reactors.

The governors say it is impossible to safely evacuate the area around Seabrook, 40 miles north of Boston, and Shoreham, 75 miles east of New York City where the main escape is on the normally congested Long Island Expressway. But Republicans who back the NRC rules change argue that governors should not have veto power over nuclear power licenses.

"Congress never intended for states or local governments to be granted virtual veto authority over the operation of a nuclear reactor," said Rep. Jack Fields (R-Tex.).