Effect of Loading Pattern on Thermal and Shielding Performance of a Spent Fuel Cask
This study analyzes the effect of non.-uniform load patterns on peak fuel cladding temperatures and cask surface dose rates using previously validated analytical methods. The study was performed using a spent fuel storage cask that was designed to hold 24 spent fuel assemblies with a decay heat load of 24 kW. The fuel was selected to have cooling times of 3.5 to 10 years, burnups of 20 to 60 GWd/MTU, and enrichments of 2.4 to 4.8%. Three radial power distributions were considered in the study: uniform loading, hotter assemblies in the center of the cask, and hotter assemblies near the wall of the cask. Seventeen different load patterns were selected. For a given decay heat load in the cask, loading assemblies with higher decay heat output around the outside of the cask results in lower peak fuel cladding temperatures than loading hotter assemblies in the center of the cask. Several of the load patterns resulted in a peak cladding temperature that was lower than for a uniformly loaded cask. Seven source terms were selected to provide the thermal output used in the thermal analysis. A constant power density of 32 MW/MTU was used for all irradiation calculations. Cooling times were selected to provide the decay heat values used in the thermal analysis. Photon dose rates are dominated by the cobalt-60 in the bottom-end fittings, top-end fittings, and plenum and are proportional to fuel burnup. For short cooling times, photon dose rates on the side of the cask are somewhat higher due to short-lived fission products. Cask loadings with high decay heat assemblies near the periphery exhibit increased photon dose rates on the side surface and top and bottom surfaces away from the centerline. Near the centerline, on the top and bottom of the cask, the dose rates are reduced substantially. Neutron dose rates increase exponentially with burnup and are nearly independent of cooling time.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 958254
- Report Number(s):
- PNNL-SA-35024; DC1012030; TRN: US1000371
- Resource Relation:
- Conference: Proceeding of the 8th International Conference on Radioactive Waste Management and Environmental Remediation, ICEM'01, 2:1199-1204
- Country of Publication:
- United States
- Language:
- English
Similar Records
Modeling Validation Exercises Using the Dry Cask Simulator
Blind Modeling Validation Exercises Using the Horizontal Dry Cask Simulator
Related Subjects
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
BURNUP
CASKS
COBALT 60
COOLING TIME
DOSE RATES
FISSION PRODUCTS
IRRADIATION
NEUTRONS
PERFORMANCE
PHOTONS
POWER DENSITY
POWER DISTRIBUTION
RADIOACTIVE WASTE MANAGEMENT
SHIELDING
SOURCE TERMS
SPENT FUEL CASKS
SPENT FUEL STORAGE
SPENT FUELS
THERMAL ANALYSIS