APPLICATIONS

Nuclear weapons, while simple in principle, are technically complex devices with a multitude of components. As with any complicated piece of equipment, there may be concern that, over time, a weapon’s reliability could decline. To coordinate efforts to maintain the nation's existing nuclear weapons, the Department of Energy developed a Stockpile Stewardship Program (SSP). A recently released Federation of American Scientists Occasional Paper, The Stockpile Stewardship Program: Fifteen Years On, by FAS analysts Anne Fitzpatrick and Ivan Oelrich, reviews the status of the experimental devices that support the SSP, describes how each experiment is supposed to work, and identifies the problems that have been encountered. "All of the expensive SSP experiments were initiated because of the cessation of nuclear testing, with the expectation that they would be essential to maintaining the nuclear stockpile," said Ivan Oelrich, vice president of strategic security at the Federation of American Scientists. "We understand nuclear weapons much better now than we did when we were testing. It is time to reevaluate which of these expensive experiments we still need. The DOE is even proposing to move away from stockpile stewardship to a reliable, replacement warhead, which could avoid the need for the SSP experiments altogether." How essential is it for these megaprojects to continue? The SSP supports three projects: the National Ignition Facility (NIF) to use laser beams to compress a hydrogen target to densities and pressures where fusion would occur; the Dual-Axis Radiographic Hydrodynamic Test (DARHT) Facility uses x-rays to follow the shape of sections of plutonium when they are compressed as they would be in the primary; and the Accelerated Strategic Computing Initiative (ASCI)—renamed Advanced Simulation and Computing (ASC) — to build supercomputers and associated software to use the information from other experiments to model nuclear warheads and predict their behavior. The National Ignition Facility (NIF) should have been finished four years ago and was originally budgeted at just over one billion dollars. Now its first experiments are expected to occur in 2010 to a cost of more than another billion dollars to complete – greater than the original estimates of total cost. "Based on unclassified sources, it appears that the connection between NIF and the current SSP is at best indirect," said Oelrich. "We believe that NIF could be ended without reducing the confidence in the existing nuclear stockpile." Being able to model a nuclear weapon on a computer is one of the critical substitutes for nuclear testing. Although the Advanced Simulation and Computing (ASC) program has already made important contributions to understanding the behavior of nuclear weapons, it too has been plagued with problems. It is not at all clear when the ASC program will be "done." Construction on some computers was started but never completed while some computers suffered from low reliability because of their complexity. In many cases, Herculean hardware developments were not matched by development of software that could fully exploit the capabilities of these new machines. Even successes were short lived – the world's fastest computer today will be overtaken by some rival within months. All of the SSP experiments, but NIF in particular, are promoted as a means to attract top new scientific talent to DOE and the SSP. Universities and industry are now at the cutting edge of scientific and technical advance. Even if NIF did contribute to this goal to some degree, it is far from being the most efficient means of applying those billions of dollars. Those funds could go directly to support university research of interest to DOE or to create smaller but scientifically more interesting experiments within the labs. "Even without NIF, the United States can maintain its existing nuclear weapons without a return to testing," said Oelrich. Download the paper at: http://fas.org/2007/nuke/Stockpile_Stewardship_Paper.pdf