(FORTUNE Magazine) – Not since Central States Electric of Richmond, Virginia, went into receivership in 1942 has a major U.S. utility gone bankrupt. Several power companies are vying for the honor of being next. The Great Depression felled Central States; today's contenders struggle with the newer nemesis of nuclear power plants. Two Northeastern utilities own part or all of completed reactors that are blocked from operation by state regulators on environmental and economic grounds. The first, Public Service of New Hampshire, missed October interest payments on unsecured debt from the ill-starred Seabrook plant. Now the utility must persuade thousands of creditors to refrain from forcing it into Chapter 11 -- any three of whom can do the job. Long Island Lighting, owner of the infamous Shoreham reactor, is locked in battle with New York State. A panel set up by Governor Mario Cuomo will decide soon whether the state should take over the private company. A pair of Mississippi Delta utilities face a slightly different problem. The nuclear plants of Gulf States Utilities and Middle South Utilities have run successfully, but state regulators have denied them the rate increases necessary to recoup most of their costs. Without rate hikes, as Gulf States Chairman Linn Draper says, ''We could be in a bad state.'' Having struggled to get nuclear reactors up and running, utilities are already starting to worry about shutting them down. The licenses for about 70 commercial plants will expire by 2015. At that point, they will have to be dismantled or relicensed and rebuilt, says William Murphie, who is responsible for shutting down the U.S. Department of Energy's civilian reactors. About 25 small commercial plants are unlikely to be replaced. Currently the Energy Department is dismantling the world's first commercial reactor, Shippingport, near Pittsburgh. The five-year process, begun in 1985, will cost $98 million.