Uncertainty quantification methodologies development for stress corrosion cracking of canister welds
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
This letter report presents a probabilistic performance assessment model to evaluate the probability of canister failure (through-wall penetration) by SCC. The model first assesses whether environmental conditions for SCC – the presence of an aqueous film – are present at canister weld locations (where tensile stresses are likely to occur) on the canister surface. Geometry-specific storage system thermal models and weather data sets representative of U.S. spent nuclear fuel (SNF) storage sites are implemented to evaluate location-specific canister surface temperature and relative humidity (RH). As the canister cools and aqueous conditions become possible, the occurrence of corrosion is evaluated. Corrosion is modeled as a two-step process: first, pitting is initiated, and the extent and depth of pitting is a function of the chloride surface load and the environmental conditions (temperature and RH). Second, as corrosion penetration increases, the pit eventually transitions to a SCC crack, with crack initiation becoming more likely with increasing pit depth. Once pits convert to cracks, a crack growth model is implemented. The SCC growth model includes rate dependencies on both temperature and crack tip stress intensity factor, and crack growth only occurs in time steps when aqueous conditions are predicted. The model suggests that SCC is likely to occur over potential SNF interim storage intervals; however, this result is based on many modeling assumptions. Sensitivity analyses provide information on the model assumptions and parameter values that have the greatest impact on predicted storage canister performance, and provide guidance for further research to reduce uncertainties.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE Office of Nuclear Energy (NE), Fuel Cycle Technologies (NE-5). Used Fuel Disposition Campaign (UFDC)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 1333707
- Report Number(s):
- SAND2016-9487R; 647678; TRN: US1700774
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
STRESS CORROSION
WELDED JOINTS
CONTAINERS
CRACKS
SENSITIVITY ANALYSIS
SPENT FUEL STORAGE
STRESSES
CRACK PROPAGATION
CHLORIDES
SURFACES
PROBABILISTIC ESTIMATION
HUMIDITY
PERFORMANCE
STRESS INTENSITY FACTORS
FAILURES
PROBABILITY
SIMULATION
WALLS
TEMPERATURE DEPENDENCE