Reactor configurations to support advanced material research

The research goal is to configure a research reactor with multi-spectral capability for advance material research. This required the consideration of high and low-power levels alongside advanced fuel with high physical density and low enriched 235U. Selected fuel was U-10Mo with 19.75% 235U enrichment. The fuel and control rods system geometries were adopted from Missouri S&T Reactor (MSTR). A high-power configuration (HPC) at 2 megawatts and low-power configuration (LPC) at 200 kilowatts were considered. Neutronic performances of the configurations were modeled using Monte Carlo N-particle (MCNP) transport code, version 6. Thermal-hydraulic analysis was performed with ANSYS Fluent. The HPC was able to support high flux levels in the order of 1E14 n cm-2 s-1 with continuous operation over 2 months before refueling. The LPC provided flux between 1E12 and 1E13 n cm-2 s-1 with 6 irradiation locations, which supports multiple tests at a time. The LPC fuel loading was 64% higher than the HPC. A flexible power configuration (FPC) was developed to combine the high flux levels of the HPC and multiple irradiation facilities in the LPC. The FPC was able to replicate the neutronic performances of both LPC and HPC configurations. The FPC in low power mode sustained criticality for 2.4 years. The heat generated in high power mode was removed effectively. The calculated maximum temperatures for coolant outlet and hottest fuel plates were below the safety limits --Abstract, page iii