Argonne National Laboratory, the nuclear research facility in the Chicago suburbs that midwifed the atomic bomb, is ending its use of highly radioactive materials - much to the relief of its neighbors - in favor of supercomputers that will allow it to pursue a broader palate of scientific research.

As Argonne reduces the laboratory's nuclear footprint, it will dismantle the Experimental Boiling Water Reactor, used as a temporary collection site for radioactive waste from other facilities.

Argonne hopes to lure more federal dollars to help its scientists develop technologies that could support innovations in energy conservation and other fields. It is taking a big step in that direction with plans to update its existing supercomputers with some of the world's fastest machines, including the Blue Gene/Q, the latest top-speed computer from I.B.M.

"The past was the past, and that really involved reactor experiments," said Eric D. Isaacs, the director of the laboratory. "The future is about a lot more computer-based types of design."

Although Argonne's new strategy represents a reversal of fortune for the laboratory, it also demonstrates its ability to adapt its resources to changing trends in science and engineering.

Established in 1946, Argonne is a direct descendant of the World War II Manhattan Project, which led to the first atomic bombs. Four years earlier, Enrico Fermi and several dozen colleagues at the University of Chicago's metallurgical lab created the world's first controlled nuclear chain reaction in an abandoned squash court on the campus. Further reactions were moved from the city to a suburban forest preserve and eventually sited at what is now Argonne.

Over the years, the laboratory has focused on improving the design of nuclear reactors, the composition of nuclear fuel and other aspects of atomic power.

Argonne officials say the laboratory - which is a major employer in the area, with a staff of 2,900 - will continue to do nuclear-related work, but its scientists will use the new computers to simulate conditions inside reactors. If hands-on experiments with radioactive materials are necessary, the laboratory will conduct them at a facility outside Illinois.

Although it has never had an episode even remotely like the 1979 radiation leak at Three Mile Island, near Harrisburg, Pa., Argonne