That reactor, a civilian one owned by the Tennessee Valley Authority, is used by the Energy Department to make tritium, a perishable material for nuclear bombs. (Submarine and aircraft carrier reactors can use highly enriched uranium from old inventories, some of it left over from decommissioned weapons.)

There is also the anxiety over the United States not being self-reliant. “How much more technology are we going to lose?” said Andrew C. Kadak, a senior nuclear expert who was formerly the head of a nuclear power company and later a professor at M.I.T. “There’s a policy question that needs to be answered: do we as a nation want to be independent of foreign sources of energy?”

Others are pushing support for USEC as a measure that will support American jobs and competitiveness. “I don’t understand why the government hasn’t provided a loan guarantee to USEC,” said Jim H. Key, the vice president of the United Steelworkers chapter that represents the workers at Paducah. The plant employs about 1,200 people. “I can’t see us as a country ever putting ourselves in a situation where we have to rely on a foreign country for another source for our energy needs,” he said.

USEC’s long-term future is in doubt for several reasons.

The company has kept itself afloat for 20 years in part by acting as the agent for the United States government in a deal with the Russians, to take uranium from former Soviet nuclear weapons and blend it down to a level useful in power reactors. But that deal comes to an end in 2013, and the American utilities have been discussing signing supply contracts directly with Russia, which would reduce their reliance on USEC.

A more immediate problem is that the company’s electricity supply contract with the Tennessee Valley Authority expires early next year and the future price is not certain. The company has an odd group of allies. Mr. Boehner, for example, recently posted an entry on his blog titled, “Will the Obama administration betray southern Ohio?” In the post, he tried to draw the contrast between Piketon and Solyndra. In the Solyndra case, the government “went the extra mile” to give the loan guarantee, he said, but in the USEC case, the company went the extra mile to show the project was worthy.