The federal government, which battled for decades to keep the workings of the hydrogen bomb secret, is beginning to declassify some of the most sensitive aspects of its design and to let American scientists publish them in scientific literature.
The reason for this reversal is not internal policy considerations, the end of the cold war or the collapse of the Soviet Union as a military threat. Rather it is foreign competition.
Scientists in Japan, Germany, Spain and Italy, striving to harness the power of tiny, repeated hydrogen-bomb-like blasts for the generation of electrical energy, have published the "secrets" for years.
Continued secrecy for similar research in the United States was seen as stifling the exchange of ideas, inhibiting progress and limiting international cooperation.
At times American scientists have been ordered not to attend meetings with foreign scientists, because they would have run the risk of discussing classified information.
As a result, the Department of Energy, the keeper of the secrets, carried out one round of declassification in 1990, and says it is readying another.
"It's a landmark," says Dr. Ray E. Kidder, a senior physicist at the Lawrence Livermore National Laboratory in California who helped pioneer hydrogen bombs and the field of small-scale blasts. "In view of the fact that this material has been withheld for so long, and that many people for perfectly sound reasons wanted to have it declassified, it's very important."
An Energy Department spokesman says he has no idea when the second round of declassification would take place. Scientists involved in the process say it has been held up by election-year politics.
Nobody in a position of technical authority in the government thinks the nuclear declassifications are a bad idea, says a senior Energy Department official, speaking on the condition of anonymity.
"There's no question that in declassification you give something up, that you provide information to people who didn't have it before. But it's risk vs. benefit. Everybody agrees that the gains are bigger than the losses."
The official says the general idea behind the hydrogen bomb was already out and that continued secrecy over its peaceful application in the form of small-scale fusion was isolating the United States from work overseas that increasingly was on the cutting edge of research.
"Half the world is publishing this material," he says. "People in other countries are very good and competitive and bring new things to the table. The benefit for us in declassification is what we stand to gain in terms of international cooperation" aimed at harnessing nuclear fusion as a new kind of energy source in the 21st century.