Using Container Survey Data to Assign Risk to Nuclear Material Packages

Since the Defense Nuclear Facility Safety Board packaging recommendation in 1994 requiring engineered systems for plutonium storage, Los Alamos National Laboratory has gained valuable experience with the storage of legacy materials, and continues to learn and benefit from this experience to evaluate risk for older containers and to guide engineering new containers. The LANL plutonium facility uses a variety of containers to store a wide range of isotopic mixtures and chemical forms of nuclear material, and surveillance of containers in storage is critical to understand the potential for package failure. Over the past decade, as older style containers have been repackaged into engineered containers, information has been gathered regarding the condition of the inner packaging materials, e.g. bagout bag, inner container, tape, etc. This paper describes the results of some recent analysis of this data with the goal of identifying correlations between internal package degradation and the material (isotopic composition, wattage, radiation dose, chemical form), the external container size and package age. The results of this analysis will be used to refine the existing risk ranking methodology used at LANL to prioritize the repackaging and disposition of materials to meet the requirements of the DOE Nuclear Material Packaging Manual, M441.1-1. This information is also being used to improve the M441.1-1 container surveillance program for SAVY-4000 containers.