By Peter Weiss
The U.S. government proudly announced on March 7 that it has for the first time detonated a thermonuclear weapon–in a complete, three-dimensional computer simulation, that is.
Two year ago, researchers working for Lawrence Livermore (Calif.) and Los Alamos (N.M.) national laboratories had separately modeled the three-dimensional unfolding of a thermonuclear explosion’s two major parts: an initial blast powered by nuclear fission and the gargantuan fusion explosion that the first blast triggers.
The complete simulation represents a milestone for a program established in 1995 for sustaining the nation’s stockpile of warheads without actually detonating nuclear bombs. This so-called stockpile-stewardship program has driven rapid development of supercomputers that can carry out realistic simulations of these extremely complex processes (SN: 8/25/01, p. 118: New initiatives scale up supercomputing). The program’s number-crunching hardware includes Livermore lab’s so-called White machine–now the world’s fastest supercomputer at 12.3 trillion operations per second–which ran the unprecedented 3-D simulation.
In February, the National Nuclear Security Administration announced that the stockpile-stewardship program’s goals were being expanded to include something even more real–the design of new warheads. Such activity had been suspended for nearly a decade.
