In the June 2004 issue of Physics Today, (page 34), Jim Dawson reports on the American Physical Society (APS) discussion paper, published in April 2004, about a modern pit facility. That paper evaluates an MPF based on an overly optimistic combination of assumptions that obviate the need for planning such a facility. A parametric evaluation of the stockpile plan recently delivered to Congress and the current estimates of pit lifetimes by the National Nuclear Security Administration weapon laboratories show that continuous planning for an MPF is prudent risk management to meet national security needs. 1  

The NNSA advocates managing the risks to national security by uninterrupted planning for an MPF while obtaining further information for acquisition decisions. For example, initial results from accelerated pit-aging experiments and from the inevitable aging effects of plutonium on weapon performance are expected in 2007. The APS position paper advocates a high-risk approach of deferring or curtailing the MPF project until such information is available. The NNSA plan for an MPF includes a series of major system-acquisition critical decisions in 2007, in 2009, and at the start of construction in 2012. Based on the current plan, the Secretary of Energy will not be making irreversible decisions on constructing an MPF until early in the next decade. That is well beyond the 2006 minimum date suggested by the APS position paper for making such decisions.

The APS paper is replete with examples of unrealistic optimism and factual errors. Some examples include discounting the challenges of upgrading production capacity to 80 pits per year at the Los Alamos National Laboratory TA-55 facility or rapidly enhancing production outputs in a future facility. Although a small capacity of 125 pits per year is the most likely path forward, the MPF environmental impact statement provides analyses for capacities of 125 to 450 pits per year, not because of a desire to maintain large stocks of undeployed warheads as suggested by the APS paper, but to ensure that the maximum potential environmental impacts of an MPF have been considered for National Environmental Policy Act compliance purposes. APS asserts that pits in storage at the Pantex plant in Amarillo, Texas, could be used as replacements and thus obviate the need for a new facility. However, that assertion lacks technical foundation because pits stored at Pantex will age similarly to pits that are stockpiled.

Deferral of MPF planning, which was suggested in the APS paper, would negatively affect plans for a responsive pit manufacturing infrastructure that may be pivotal to further reducing the number of stockpile warheads—a cost-saving move for the nation. Similarly, the capability to manufacture replacement pits eliminates weapon-performance uncertainties that result from plutonium aging and is consistent with maintaining the moratorium on nuclear testing.

Current plans afford numerous review opportunities until early in the next decade. National security for the US should be based on a prudent assessment of risks and not the overly optimistic and unrealistic evaluation contained in the APS position paper. Early planning and development are essential to avoid cost overruns and delays.

US Department of Energy, National Nuclear Security Administration, Report to Congressional Defense Committees on “An Enhanced Schedule for the Modern Pit Facility, February
. Available at