Preliminary Thermal Analysis of Fort Saint Vrain HTGR Fuel Elements in a Transportation Overpack Configuration

The Road-Ready Demonstration Project aims to demonstrate that Department of Energy (DOE) managed spent nuclear fuel (SNF) can be loaded into DOE Standard Canisters (SC) for interim storage at the Idaho Nuclear Technology and Engineering Center. The DOE-managed fuel evaluated in this paper is the Fort Saint Vrain (FSV) fuel element which was used in a high-temperature gas cooled reactor (HTGR). The DOESCs are envisioned to be loaded in a Type B transportation overpack designed to meet regulatory requirements in 10 CFR Part 71 which will be obtained from a commercial vendor. In this paper, the effect of two basket designs that hold the DOESCs in place inside the transportation overpack on thermal performance will be evaluated. It is important to conduct thermal analysis to ensure the fuel and overpack component temperatures are within safe range for operation and transportation. In this paper, the DOESC-transportation configuration is thermally evaluated for normal operating conditions and a hypothetical accident scenario as described under 10 CFR Part 71. Different thermal models are employed to understand their effect on the component temperatures including a mesh sensitivity analysis. Steady state analysis is conducted for the normal operating condition and a transient analysis is conducted for accident scenarios. Thermal analysis is carried out using the computational fluid dynamic (CFD) code StarCCM+.