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Title: Low-temperature swelling in LWR internal components: a computational assessment

A modern cluster dynamics model has been used to investigate the materials and irradiation parameters that control microstructural evolution under the relatively low-temperature exposure conditions that are representative of the operating environment for in-core light water reactor components. The focus is on components fabricated from austenitic stainless steel. The model accounts for the synergistic interaction between radiation-produced vacancies and the helium that is produced by nuclear transmutation reactions. Cavity nucleation rates are shown to be relatively high in this temperature regime (275 to 325 °C), but are sensitive to assumptions about the fine-scale microstructure produced under low-temperature irradiation. The cavity nucleation rates observed run counter to the expectation that void swelling would not occur under these conditions. This expectation was based on previous research on void swelling in austenitic steels in fast reactors. This misleading impression arose primarily from an absence of relevant data. The results of the computational modeling are generally consistent with recent data obtained by examining ex-service components. The long-term objective of this research is to provide a predictive model of void swelling at relevant lifetime exposures to support extended reactor operations.
Authors:
 [1] ;  [1] ;  [2]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
Publication Date:
OSTI Identifier:
1214033
DOE Contract Number:
AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: 17. International Conference on Environmental Degradation of Materials in Nuclear Power Systems Water Reactors, Ottawa, ON (Canada), 9-12 Aug 2015
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; 36 MATERIALS SCIENCE; REACTOR COMPONENTS; AUSTENITIC STEELS; STAINLESS STEELS; PHYSICAL RADIATION EFFECTS; TEMPERATURE RANGE 0400-1000 K; SWELLING; WATER MODERATED REACTORS; VACANCIES; FAST REACTORS; VOIDS; WATER COOLED REACTORS; CAVITIES; MICROSTRUCTURE; NUCLEATION; MICROSTRUCTURE; INTERSTITIAL HELIUM GENERATION; COMPUTERIZED SIMULATION void swelling; reactor internals; life extension; modeling