Spent Fuel Sabotage Test Program, Surrogate and Fission Product Aerosol Results

We provide an overview and summarization of recent results from a multinational, spent fuel sabotage aerosol test program. This research study is quantifying aerosol particles produced when the products of a high energy density device (HEDD) interact with and explosively particulate test rodlets containing pellets of either surrogate or actual spent fuel materials, all within a contained test chamber. Results from this multi-year program provide needed source term data that are relevant to plausible sabotage attack scenarios on spent fuel transport and storage casks. A prime program objective is to support Department of Energy (DOE) assessments for physical protection requirements of nuclear materials in use, storage, and transport. Similarly, the Nuclear Regulatory Commission (NRC) needs the resultant aerosol source-term data and supporting analyses for a defensible validation of vulnerability studies associated with spent nuclear fuels. Testing results and design are tailored to support follow-on computer modeling of aerosol dispersal hazards and radiological consequence assessments. We summarize some of the significant findings on aerosol results and observations from the recently completed Phase 2 surrogate material tests using cerium oxide ceramic pellets in test rodlets plus non-radioactive fission product dopants. Results include: respirable fractions produced; particle size distributions and morphology; determination of the Spent Fuel Ratio (SFR), the ratio of respirable particles from real spent fuel/respirables from surrogate spent fuel); and, measurements of enhanced volatile fission product species sorption onto respirable particles. We discuss progress and results for the recently initiated Phase 3 tests using depleted uranium oxide, DUO2, test rodlets. We will also review the status of preparations and the final Phase 4 tests in this program, using short rodlets containing actual spent fuel from U.S. PWR reactors, with both high- and lower-burnup fuel. This test program, performed primarily at Sandia National Laboratories, with support provided by both the U.S. DOE and the NRC, had significant inputs from, and is strongly supported and coordinated by both the U.S. and international program participants in Germany, France, and the U.K., as part of the International Working Group for Sabotage Concerns of Transport and Storage Casks (WGSTSC).