(FORTUNE Magazine) – As the Soviet threat fades and the need for fancy new nuclear bombs declines, America's three secret weapons labs -- Los Alamos and Sandia in New Mexico and Livermore in California -- are hustling hard for more commercial work. Boasts Ron Barks, director of the industrial applications office at Los Alamos: ''We are the world's largest scientific computing lab. We are tremendous in advanced materials, superb in lasers, and have excellent manufacturing capability as well.'' Commercial byproducts of nuclear research already used by industry include stretchable steel, cancer detectors, and a computer program that tells breweries how fast they can run assembly lines without denting the beer cans. Among Los Alamos' customers: Chrysler and General Motors, which hope to use computer models of the fluid dynamics of a nuclear blast to simulate the workings of internal combustion engines. Will foreigners be able to buy the labs' brains as well? ''Some Japanese executives were just in here,'' says Barks. But the U.S. will make customers sign contracts promising to design and manufacture any products that come out of this research in the U.S. -- and reciprocate by giving American companies their ideas. No guarantees that such contracts would be honored, but the U.S. could punish violators by banning their products.