Computational and Experimental Benchmarking for Transient Fuel Testing

An effort is presently underway to restart the Transient Reactor Test (TREAT) Facility, located at the Idaho National Laboratory (INL) by 2018. The TREAT Facility has historically been utilized to provide empirical data to support the comprehensive characterization of light water reactor fuel and sodiumcooled fast reactor fuel under a variety of conditions. The TREAT Facility is an air cooled, graphite moderated, (presently) highly enriched uranium fueled test reactor that comprises a square lattice configuration of solid fuel assemblies. In the central fuel assembly locations, one may remove select assemblies and insert a fueled-experimental loop in place. Due to the large thermal and reactive mass of the core the TREAT Facility has the ability to operate (and impose) nearly an infinite number of temporal boundary conditions on such an experimental loop and the fuel located in the loop, accordingly. This test reactor provides the capability of significantly expanding upon the existing empirical data available for traditional light water reactor fuel, supporting the accident tolerant fuel program in the U.S., and efforts to license next generation sodium-cooled reactors (such as TerraPower’s reactor). The restart of this unique test reactor has pushed the capabilities of historically developed codes, used to provide the safety case for experimental conduct and design. However, significant progress in the development and implementation of mechanistic-based models has been underway in recent years through large integrated programs such as the Department of Energy’s (DoE’s) Nuclear Energy Advanced Modeling and Simulations (NEAMS) program. In addition to these ‘next-generation’ computer codes, instrumentation capabilities and experimental hardware design has significantly improved since the shutdown of the TREAT Facility in 1994. Leveraging such advancements in computational tools, along with new experimental instrumentation and hardware developments, this team proposes a work scope which will lead to the following outcomes: (1) a comprehensive evaluation of existing TREAT Facility neutronics data according to established guidelines per the International Handbook of Evaluated Reactor Physics Benchmark Experiments (IRPhEP Handbook); (2) a complete characterization of existing sodium loop experimental data; (3) a compilation of relevant empirical data of a representative TREAT Facility flow loop; and (4) an integrated instrumentation plan for the TREAT Facility.