Irradiation testing of design models for the GCFR fuel pressure equalization (vent) system
The major consideration in the design of the pressure equalization system for the gas-cooled fast breeder reactor is the release and venting of gaseous and volatile fission products. Single vented rods have been irradiated in the thermal flux of the Oak Ridge Research Reactor (ORR) at GCFR operating conditions of 12 to 15 kW/ft and 565 to 685 deg C cladding outside temperature to determine the fission product release and to verify the design concept. Results obtained to date from measurements of fission gas release and transport have been compared with predictions based on design assumptions to verify analytical models and have established a degree of conservatism of design assumptions. The release of radioactive gases from the fuel matrix was measured directly at 12 kW/ft in an operating fuel rod and was found to be significantly less than the design assumption of 100% instantaneous release and less than predictions using the diffision model with Findlay's coefficients. Although solid state diffusion was found to be the dominant process delaying the venting of fission gases in the experimental irradiation, fission gas interdiffusion in helium will be the dominant venting transport process for the reactor design. Delay of fission gases by adsorption on charcoal was verified at trap operating temperatures for burnups up to 54,000 MWd/t. Volatile fission products (cesium and iodine) did not migrate beyond the fuel-blanket interface. The feasibility of the vented- fuel-rod design concept has been established. 16 references. (auth)
- Research Organization:
- Gulf General Atomic Co., San Diego, CA
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-29-026134
- OSTI ID:
- 4350290
- Journal Information:
- Nucl. Eng. Des., v. 26, no. 1, Journal Name: Nucl. Eng. Des., v. 26, no. 1; ISSN NEDEA
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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