Publications
Nuclear Fuel Cycle (NFC) Technology and Policy Program
Core Design Options for High Power Density BWRs
Principal Investigator:
Professor M.S. KazimiContributors:
J. Buongiorno, T. Conboy, T. Ellis, P. Ferroni, P. Hejzlar, S-P. Kao, A. Karahan, K. Kobayashi, E. Pilat, and N.E. TodreasMIT-NFC-PR-089 (December 2006)
Executive Summary
The overall objective of this research is to assess the feasibility of increasing the core power density of existing and future BWR designs by varying operating conditions, assembly geometry, fuel types, and fuel-pin designs, while maintaining the same accepted safety margins for today’s BWRs. While some progress has been achieved over the years towards increasing the power density of BWRs, it has mainly come by three methods: reducing the uncertainty about operating conditions, reducing the peak pin and assembly power factors and using a smaller diameter pin in the assemblies. This project will examine what can be achieved through innovative geometry of the fuel pins at fixed operating pressure, core inlet temperature, and power distribution, while independently exploring the impact of these operating conditions.
The project is broken down into the following five tasks, each concentrating on one engineering option of the feasibility study, as follows:
Task 1: Sensitivity of Reference Design to Operating Parameters
Task 2: A New Fuel-Assembly Geometry with Smaller Cylindrical Rods
Task 3 Fuel Assemblies with Cross Shaped Spiral Rods
Task 4: Annular Fuel Rods (Oxide and Nitride Fuel)
Task 5: Uranium Hydride Fuel (to be included in 2nd year effort)
A typical 9x9 GE fuel assembly was selected as a reference design. The new designs would be sought under the constraint of the same core average exit quality. Thus, the flow rate will be increasing proportionately with the power. Also, it was decided to limit the Critical Power margin to the same value as in the reference design
In the first year of this project, only the first four tasks have been addressed. The progress made in each task is briefly described in this summary, and detailed in the text of the report. Given that similar work to Task 5 was being conducted for a DOE NERI program, it was decided to delay that task until the NERI project findings become available, to avoid duplicative work and to benefit from these results.
