The safety of Pajarito Site critical assembly operations depends upon protection built into the facility, upon knowledgeable personnel, and upon good practice as defined by operating procedures and experimental plans. Distance, supplemented by shielding in some cases, would protect personnel against an extreme accident generating 1019 fissions. During the facility's 28-year history, the direct cost of criticality accidents has translated to a risk of less than $200 per year.--P. 1.

The Los Alamos critical assembly layout is designed to facilitate personnel protection by means of remote operation and stringent procedural controls during nonoperating periods. Public protection is straightforward because of the small fission-product inventory, essentially ambient pressures, and moderate temperatures.

Detailed consideration of the Skua burst assembly is provided, thereby supplementing the facility Safety Analysis Report covering the operation of other critical assemblies at the Los Alamos Scientific Laboratory. As with these assemblies the small fission-product inventory, ambient pressure, and moderate temperatures in Skua are amenable to straightforward measures to ensure the protection of the public.

Emergency response at Los Alamos National Laboratory (LANL) is handled through a graded approach depending on the specific emergency situation . LANL maintains a comprehensive capability to respond to events ranging from minor facility events (alerts) through major community events (general emergencies), including criticality accidents . Criticality safety and emergency response apply to all activities involving significant quantities of fissile material at LANL, primarily at Technical Area 18 (TA-18, the Los Alamos Critical Experiments Facility) and Technical Area 55 (TA-55, the Plutonium Facility). This discussion focuses on response to a criticality accident at TA-55; the approach at TA-18 is comparable.