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Title: Response of PWR Baffle-Former Bolt Loading to Swelling, Irradiation Creep and Bolt Replacement as Revealed Using Finite Element Modeling

Abstract

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.

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
899819
Report Number(s):
PNNL-SA-46705
AF3510000; TRN: US0702054
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Conference
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
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; 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

Citation Formats

Simonen, Edward P, Garner, Francis A, Klymyshyn, Nicholas A, and Toloczko, Mychailo B. Response of PWR Baffle-Former Bolt Loading to Swelling, Irradiation Creep and Bolt Replacement as Revealed Using Finite Element Modeling. United States: N. p., 2005. Web.
Simonen, Edward P, Garner, Francis A, Klymyshyn, Nicholas A, & Toloczko, Mychailo B. Response of PWR Baffle-Former Bolt Loading to Swelling, Irradiation Creep and Bolt Replacement as Revealed Using Finite Element Modeling. United States.
Simonen, Edward P, Garner, Francis A, Klymyshyn, Nicholas A, and Toloczko, Mychailo B. 2005. "Response of PWR Baffle-Former Bolt Loading to Swelling, Irradiation Creep and Bolt Replacement as Revealed Using Finite Element Modeling". United States.
@article{osti_899819,
title = {Response of PWR Baffle-Former Bolt Loading to Swelling, Irradiation Creep and Bolt Replacement as Revealed Using Finite Element Modeling},
author = {Simonen, Edward P and Garner, Francis A and Klymyshyn, Nicholas A and Toloczko, Mychailo B},
abstractNote = {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.},
doi = {},
url = {https://www.osti.gov/biblio/899819}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Oct 01 00:00:00 EDT 2005},
month = {Sat Oct 01 00:00:00 EDT 2005}
}

Conference:
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