New Jersey regulators have recommended a new cooling-water tower at one of the nation's oldest nuclear plants, in a ruling widely expected to increase pressure for towers at the Salem nuclear plants on the Delaware River.

Energy giant Exelon immediately warned that it will "have no alternative" but to close the plant at Oyster Creek in Ocean County. Plant officials have warned that a new cooling system would cost hundreds of millions of dollars, with construction disrupting operations for years.

The issue, slated for public hearings on Feb. 24, will be decided by incoming Republican Gov. Chris Christie's new administration, with action on permits for intakes at PSEG Nuclear's Salem Units 1 and 2 expected to accelerate afterward.

Environmental and conservation groups have long argued that Oyster Creek and PSEG's Salem reactors all should use water recycling systems that cool hot water in huge spray towers, reducing the use of fresh water from rivers.

All now have designs that draw massive amounts of water from adjacent waterways for one trip through the plants. Critics say the practice needlessly sucks billions of fish and other aquatic organisms into deadly pipework and screens, in some cases threatening entire fisheries.

Christie, who takes office next Tuesday, said during his campaign that he would move quickly to reduce fish kills from Oyster Creek's cooling system, which takes 662 million gallons of water daily from Forked River off Barnegat Bay.

"It's a little late in coming," said Jane Nogaki, a member of the New Jersey Environmental Federation. "But we're very happy nevertheless that our concerns and fears for Oyster Creek have been proven justified, and that DEP agrees this technology should be used."