Response of PWR Baffle-Former Bolt Loading to Swelling, Irradiation Creep and Bolt Replacement as Revealed Using Finite Element Modeling
Baffle-former bolts in pressurized water reactors (PWRs) tend to degrade with aging, partially due to radiation-induced hardening and also due to the often complex stress history of the bolt in response to time-dependent and spatial gradients in temperature and neutron flux-spectra that can alter the stress distribution of the bolts. The time-integrated stresses must play some role in bolt cracking, however, and therefore it is of interest to study the time dependence of bolt stresses even for idealized cases. These stresses have been quantified in the present analysis using newly developed material constitutive equations for swelling and creep at light-water reactor (LWR)-relevant temperatures and dose rates. ABAQUS finite element calculations demonstrate that irradiation creep in the absence of void swelling tends to relax bolt tension before 10 dpa. Subsequent differential swelling leads to an increase in bolt tension, but only to stresses below the yield strength and usually below the initial bolt loading. Various assumed bolt replacement scenarios are considered with respect to their consequences on future failure possibilities.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 899819
- Report Number(s):
- PNNL-SA-46705; AF3510000; TRN: US0702054
- Resource Relation:
- Conference: Proceedings of the 12th International Conference on Environmental Degradation of Materials in Nuclear Power System - Water Reactors, 449-459
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
29 ENERGY PLANNING
POLICY AND ECONOMY
36 MATERIALS SCIENCE
AGING
CREEP
DOSE RATES
FASTENERS
HARDENING
IRRADIATION
NEUTRONS
NUCLEAR POWER
PWR TYPE REACTORS
SIMULATION
STRESSES
SWELLING
TIME DEPENDENCE
YIELD STRENGTH
swelling
irradiation creep
PWR baffle bol
FEA model