Planning the HEU to LEU Transition for the NBSR
A study has been carried out to understand how the NIST research reactor (NBSR) might be converted from using high-enriched uranium (HEU) to using low-enriched uranium (LEU) fuel. An LEU fuel design had previously been determined which provides an equilibrium core with the desirable fuel cycle length - a very important parameter for maintaining the experimental, scientific program supported by the NBSR. In the present study two options for getting to the equilibrium state are considered. One option starts with the loading of an entire core of fresh fuel. This was determined to be unacceptable. The other option makes use of the current fuel management scheme wherein four fresh fuel elements are loaded at the beginning of each cycle. However, it is shown that without some alterations to the fuel cycle, none of the transition cores containing both HEU and LEU fuel have sufficient excess reactivity to operate the reactor for the optimum length. It was determined that operating the first mixed cycle for a sufficiently reduced length of time provides the excess reactivity which enables subsequent cycles to be run for the desired number of days.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 1029258
- Report Number(s):
- BNL-96348-2011-CP; TRN: US1105716
- Resource Relation:
- Conference: TRTR 2011 (Test, Research & Training Reactors); Idaho Falls, Idaho; 20110912 through 20110915
- Country of Publication:
- United States
- Language:
- English
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