Updating Materials Management Methods Using a Discrete Event Simulation

The National Nuclear Security Administration has tasked Y-12 National Security Complex’s Nuclear Materials Management group with developing and maintaining plans for nuclear materials and their usage. While this has historically been done using Microsoft® Excel, a new tool has recently been developed. It uses ExtendSim® software, which is a discrete event, rate-based simulation program. The updated model offers several advantages over the previous model, including determination of rate limiting steps, supply-demand analysis over time versus at threshold periods (i.e., yearly), and ready application of material stream characteristics for inventory tracking. The updates also allow for probabilistic application of inventory characteristics to future steps rather than a deterministic analysis, which does not provide for prediction of the probability of successes or failures. In addition, the new tool facilitates better control of model results and planning ownership, which tend to develop rogue versions when created in Excel because of the program’s ubiquity. A discussion of both the implementation of the model and its capabilities along with the method of configuration management will be provided.