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 Laboratories (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
- Country of Publication:
- United States
- Language:
- English
Similar Records
FY17 Status Report: Research on Stress Corrosion Cracking of SNF Interim Storage Canisters.
SNF Interim Storage Canister Corrosion and Surface Environment Investigations (FY2020 Status Report)
Related Subjects
42 ENGINEERING
CHLORIDES
CONTAINERS
CRACK PROPAGATION
CRACKS
FAILURES
HUMIDITY
PERFORMANCE
PROBABILISTIC ESTIMATION
PROBABILITY
SENSITIVITY ANALYSIS
SIMULATION
SPENT FUEL STORAGE
STRESS CORROSION
STRESS INTENSITY FACTORS
STRESSES
SURFACES
TEMPERATURE DEPENDENCE
WALLS
WELDED JOINTS