Abstract
An iterative design process involving neutronic and thermal-hydraulic modeling and simulation has been employed to assess the feasibility of converting the Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR) from high-enriched uranium (HEU) to low-enriched uranium (LEU) silicide dispersion fuel. ORNL is funded by the National Nuclear Security Administration to evaluate HFIR conversion. Previous HFIR conversion studies focused on U-10Mo monolithic fuel; however, due to potential fabrication issues with the complex HFIR U-10Mo fuel design, ORNL is evaluating U 3 Si 2 -Al dispersion fuel as an alternative LEU fuel system. Fueled by 10.1 kg of HEU and operated at 85 MW, HFIR provides one of the highest steady-state neutron fluxes of any research reactor in the world. Retrofitting a compact, high-power density, HEU-based core with LEU is a challenging problem to solve, especially when considering the conversion requirements. Neutronic and thermal-hydraulic analyses were performed with Shift and HSSHTC, respectively, to predict reactor performance and thermal safety margins. A number of designs were proposed and evaluated using an iterative approach in an effort to show that reactor performance could match that obtained using HEU fuel and that thermal safety margins were adequate. This study concludes that conversion of HFIR with U 3 Si 2 -Al LEU fuel is feasible if, among other requirements, the fuel meat region is centered and symmetric about the fuel plate thickness centerline, the active fuel zone length is increased from 50.80 cm to 55.88 cm, the proposed fabrication tolerances can be met, and the fuel can be qualified for HFIR conditions.
| Original language | English |
|---|---|
| Pages (from-to) | 277-292 |
| Number of pages | 16 |
| Journal | Annals of Nuclear Energy |
| Volume | 130 |
| DOIs | |
| State | Published - Aug 2019 |
Funding
The authors would like to acknowledge the support and funding for this work provided by the Office of Material Management and Minimization of the US Department of Energy’s National Nuclear Security Administration. This material is based upon work supported by the US Department of Energy, Office of Science, Basic Energy Sciences under contract number DE-AC05-00OR22725. The authors would like to acknowledge A. Bergeron of Argonne National Laboratory (ANL) for suggesting that U 3 Si 2 -Al fuel be evaluated and E. Wilson of ANL for his support. The authors would also like to thank C.J. Hurt of ORNL for his technical review of this manuscript. The purpose of the work documented in this manuscript was to perform a feasibility study on converting the Oak Ridge National Laboratory’s multi-mission High Flux Isotope Reactor from HEU to LEU in the form of a silicide dispersion fuel. As part of the broader effort to minimize and, to the extent possible, eliminate the use of HEU in civilian nuclear applications, ORNL is funded by the US DOE National Nuclear Security Administration’s Office of Material Management and Minimization (M 3 ) to evaluate conversion of HFIR to LEU fuel. The program has pursued conversion of the five US high-performance research reactors with a U-10Mo monolithic fuel for over a decade. However, due to potential fabrication issues with the complex HFIR U-10Mo fuel design, M 3 requested ORNL to evaluate U 3 Si 2 -Al dispersion fuel as an alternative LEU fuel system.
| Funders | Funder number |
|---|---|
| HFIR | |
| US Department of Energy | |
| Office of Science | |
| Basic Energy Sciences | DE-AC05-00OR22725 |
| National Nuclear Security Administration | |
| Oak Ridge National Laboratory |
Keywords
- Depletion
- High Flux Isotope Reactor
- LEU
- Shift
- Silicide
- Thermal-hydraulics