Year
2014
Abstract
The Y-12 National Security Complex develops Type B shipping containers for various U.S. Department of Energy (DOE) missions. For the past 10 years, new shipping container designs used a cast ceramic material as the insulation in the outer drum for the purpose of impact limiting and thermal resistance. The material used in these containers is a commercial product known as Kaolite 1600TM, which is a pre-mix concrete product. During fabrication of the latest Y-12 container (the MD-2), the Kaolite 1600TM casting densities were slightly above the required density in the specifications for this container. After repeated sample castings of Kaolite 1600TM, an acceptable density could not be achieved. Over a subsequent 6-month period, Y-12 worked with the supplier to understand the discrepancies and made many attempts to re-create the original product. As it turns out, changes in the batch mixing process and origin of raw materials now being obtained by the manufacturer resulted in a slightly different final product. Kaolite 1600TM still meets the needs of industrial users, but no longer meets the precise property requirements needed for Y-12 containers. It became apparent that Y-12 would have to substitute this material in the MD-2 and all future container fabrications. Thus, Y-12 embarked on a program to develop a substitute for Kaolite 1600TM. A mixture was made with essentially the same ingredients as Kaolite1600TM, but mixed to more exacting proportions for each container fabrication. The new mixture, termed Packcrete, is undergoing testing to compare properties and performance with Kaolite 1600TM. The testing was designed to show equivalency to Kaolite 1600TM, as specified in the MD-2 Safety Analysis Report for Packaging. Qualification included casting Packcrete samples of various sizes and testing to obtain mechanical properties, and also several MD-2s were fabricated with Packcrete and subjected to full- scale regulatory drop and burn testing in accordance with 10 CFR 71.71 and 71.73.This paper will discuss the process of developing the new mixture and the qualification testing for regulatory acceptance of Packcrete as a substitute for the insulation in a currently licensed shipping container and for future containers.