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, T. McKrell, E. Pilat, and N.E. TodreasMIT-NFC-PR-097 (November 2007)
Executive Summary
Increasing the power in existing and future Boiling Water Reactors will be beneficial for their economic performance. The overall objective of this research is to assess the feasibility of increasing the core power by increasing the power density of existing and future BWR , while maintaining the same accepted safety margins for today’s BWRs. In principle this may be achieved by varying the operating conditions, assembly geometry, fuel types, and/or fuel-pin designs. While some progress has been achieved over the years towards increasing the power density of BWRs, it has mainly come by three approaches: reducing the uncertainty about operating conditions, reducing the peak pin and assembly power factors and using a smaller diameter pins in the assemblies. This project will focus on what can be achieved through innovative geometry and/or materials of the fuel pins at fixed operating pressure, core inlet temperature, core exit enthalpy, and power distribution. Independently, the impact of these operating conditions will be explored. The reference BWR for this work was taken to be a BWR6 reactor.
The project has been divided into the following five tasks, each concentrating on one engineering option of the feasibility study, as follows:
Task 1: Assessment of Sensitivity of Reference Design to Operating Parameters (1st year)
Task 2: Design of a New Fuel-Assembly with Smaller Cylindrical Rods
Task 3 Design of Fuel Assemblies with Cross Shaped Spiral Rods
Task 4: Assessment of Annular Fuel Rods with Oxide and Nitride Fuel (1st year )
Task 5: Assessment of Uranium Hydride Fuel (2nd year)
We have addressed the first four tasks in the first year of this project. Task 1 has been completed and the results are documented in the 2006 Annual Report. A brief description of findings is given in this executive summary. The preliminary investigations of Tasks 2 through 4 have also been presented and discussed in the 2006 Annual Report. Based on the first year findings about their potentials for improving the BWR core performance, we have decided to continue investigating the two innovative designs of Tasks 2 and 3, while discontinuing work on Task 4.
Given that parallel work to the hydride fuel assessment (Task 5) was being conducted for a DOE NERI program, we decided to delay reporting on that task until the second year, when the NERI project findings became available, to avoid duplicative reporting and to benefit from the NERI results within our own assessment.
