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Title: The impact of mobile point defect clusters in a kinetic model of pressure vessel embrittlement

Abstract

The results of recent molecular dynamics simulations of displacement cascades in iron indicate that small interstitial clusters may have a very low activation energy for migration, and that their migration is 1-dimensional, rather than 3-dimensional. The mobility of these clusters can have a significant impact on the predictions of radiation damage models, particularly at the relatively low temperatures typical of commercial, light water reactor pressure vessels (RPV) and other out-of-core components. A previously-developed kinetic model used to investigate RPV embrittlement has been modified to permit an evaluation of the mobile interstitial clusters. Sink strengths appropriate to both 1- and 3-dimensional motion of the clusters were evaluated. High cluster mobility leads to a reduction in the amount of predicted embrittlement due to interstitial clusters since they are lost to sinks rather than building up in the microstructure. The sensitivity of the predictions to displacement rate also increases. The magnitude of this effect is somewhat reduced if the migration is 1-dimensional since the corresponding sink strengths are lower than those for 3-dimensional diffusion. The cluster mobility can also affect the evolution of copper-rich precipitates in the model since the radiation-enhanced diffusion coefficient increases due to the lower interstitial cluster sink strength. Themore » overall impact of the modifications to the model is discussed in terms of the major irradiation variables and material parameter uncertainties.« less

Authors:
Publication Date:
Research Org.:
Oak Ridge National Lab., Metals and Ceramics Div., TN (United States)
Sponsoring Org.:
USDOE Office of Energy Research, Washington, DC (United States)
OSTI Identifier:
658212
Report Number(s):
ORNL/CP-98106; CONF-960643-
ON: DE98005578; BR: KC0201040;4181098L; TRN: 98:011258
DOE Contract Number:  
AC05-96OR22464
Resource Type:
Conference
Resource Relation:
Conference: 18. symposium on effects of radiation on materials, Hyannis, MA (United States), 25-27 Jun 1996; Other Information: PBD: May 1998
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 21 NUCLEAR POWER REACTORS AND ASSOCIATED PLANTS; PRESSURE VESSELS; WATER COOLED REACTORS; RADIATION EFFECTS; MATHEMATICAL MODELS; MORPHOLOGICAL CHANGES; MICROSTRUCTURE; POINT DEFECTS; EMBRITTLEMENT; FERRITIC STEELS; YIELD STRENGTH

Citation Formats

Stoller, R E. The impact of mobile point defect clusters in a kinetic model of pressure vessel embrittlement. United States: N. p., 1998. Web.
Stoller, R E. The impact of mobile point defect clusters in a kinetic model of pressure vessel embrittlement. United States.
Stoller, R E. Fri . "The impact of mobile point defect clusters in a kinetic model of pressure vessel embrittlement". United States. https://www.osti.gov/servlets/purl/658212.
@article{osti_658212,
title = {The impact of mobile point defect clusters in a kinetic model of pressure vessel embrittlement},
author = {Stoller, R E},
abstractNote = {The results of recent molecular dynamics simulations of displacement cascades in iron indicate that small interstitial clusters may have a very low activation energy for migration, and that their migration is 1-dimensional, rather than 3-dimensional. The mobility of these clusters can have a significant impact on the predictions of radiation damage models, particularly at the relatively low temperatures typical of commercial, light water reactor pressure vessels (RPV) and other out-of-core components. A previously-developed kinetic model used to investigate RPV embrittlement has been modified to permit an evaluation of the mobile interstitial clusters. Sink strengths appropriate to both 1- and 3-dimensional motion of the clusters were evaluated. High cluster mobility leads to a reduction in the amount of predicted embrittlement due to interstitial clusters since they are lost to sinks rather than building up in the microstructure. The sensitivity of the predictions to displacement rate also increases. The magnitude of this effect is somewhat reduced if the migration is 1-dimensional since the corresponding sink strengths are lower than those for 3-dimensional diffusion. The cluster mobility can also affect the evolution of copper-rich precipitates in the model since the radiation-enhanced diffusion coefficient increases due to the lower interstitial cluster sink strength. The overall impact of the modifications to the model is discussed in terms of the major irradiation variables and material parameter uncertainties.},
doi = {},
url = {https://www.osti.gov/biblio/658212}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1998},
month = {5}
}

Conference:
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