The computer at Lawrence Livermore National Laboratory earned the crown by zipping along at 135.3 trillion operations per second (teraflops) on the industry-standard Linpack benchmark test. And the computer is only half completed. The National Nuclear Security Administration will eventually use the IBM computer to maintain the U.S. nuclear weapon stockpile without explosive testing. So far, scientists have used BlueGene/L for at lest two studies, one to model pressure-induced rapid resolidification of tantalum and the other to examine the effects of voids in metal failure. The latter task required modeling interactions between 2.1 billion atoms.