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

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

Full Record
Other Related Research

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 »« less

Authors:: Stoller, R E

Publication Date:: 1998-05-01

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.

Copy to clipboard


                    Stoller, R E. The impact of mobile point defect clusters in a kinetic model of pressure vessel embrittlement.  United States.

Copy to clipboard


                    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.

Copy to clipboard


                    
@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}

}

Copy to clipboard

Conference:

View Conference (1.26 MB)

Other availability

Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:

Export Metadata

Save to My Library

Similar records in OSTI.GOV collections:

Phase-field Model for Interstitial Loop Growth Kinetics and Thermodynamic and Kinetic Models of Irradiated Fe-Cr Alloys

Technical Report Li, Yulan ; Hu, Shenyang Y ; Sun, Xin ; ...

Microstructure evolution kinetics in irradiated materials has strongly spatial correlation. For example, void and second phases prefer to nucleate and grow at pre-existing defects such as dislocations, grain boundaries, and cracks. Inhomogeneous microstructure evolution results in inhomogeneity of microstructure and thermo-mechanical properties. Therefore, the simulation capability for predicting three dimensional (3-D) microstructure evolution kinetics and its subsequent impact on material properties and performance is crucial for scientific design of advanced nuclear materials and optimal operation conditions in order to reduce uncertainty in operational and safety margins. Very recently the meso-scale phase-field (PF) method has been used to predict gas bubblemore »« less
https://doi.org/10.2172/1049673

Full Text Available
Pressure vessel embrittlement predictions based on a composite model of copper precipitation and point defect clustering

Conference Stoller, R E

A theoretical model is used to investigate the relative importance of point defect clusters (PDC) and copper-rich precipitates in reactor pressure vessel (RPV) embrittlement and to examine the influence of a broad range of irradiation and material parameters on predicted yield strength changes. The results indicate that there are temperature and displacement rate regimes wherein either CRP or PDC can dominate the material`s response to irradiation, with both interstitial and vacancy type defects contributing to the PDC component. The different dependencies of the CRP and PDC on temperature and displacement rate indicate that simple data extrapolations could lead to poormore »« less
The role of point defect clusters in reactor pressure vessel embrittlement

Conference Stoller, R E

Radiation-induced point defect clusters (PDC) are a plausible source of matrix hardening in reactor pressure vessel (RPV) steels in addition to copper-rich precipitates. These PDCs can be of either interstitial or vacancy type, and could exist in either 2 or 3-D shapes, e.g. small loops, voids, or stacking fault tetrahedra. Formation and evolution of PDCs are primarily determined by displacement damage rate and irradiation temperature. There is experimental evidence that size distributions of these clusters are also influenced by impurities such as copper. A theoretical model has been developed to investigate potential role of PDCs in RPV embrittlement. The modelmore »« less
Full Text Available
The role of gamma rays and freely-migrating defects in reactor pressure vessel embrittlement

Conference Alexander, D E ; Rehn, L E

Gamma ray effects are often neglected when evaluating reactor pressure vessel (RPV) embrittlement. However, recent analyses indicate that in newer style light water reactors, gamma damage can be a substantial fraction of the total displacement damage experienced by the (RPV); ignoring this damage will lead to errors in embrittlement predictions. Furthermore, gamma rays may be more efficient than fast neutrons at producing freely-migrating defects and as such can impact certain embrittlement mechanisms more effectively than fast neutrons. Consideration of these gamma effects are therefore essential for a more complete understanding of radiation embrittlement.
Full Text Available
ATOMISTIC SIMULATION OF VACANCY AND SELF-INTERSTITIAL DIFFUSION IN Fe-Cu ALLOYS

Conference Marian, J ; Wirth, B D ; Perlado, J M ; ...

Neutron hardening and embrittlement of pressure vessel steels is due to a high density of nanometer scale features, including Cu-rich precipitates which form as a result of radiation enhanced diffusion. High-energy displacement cascades generate large numbers of both isolated point defects and clusters of vacancies and interstitials. The subsequent clustering, diffusion and ultimate annihilation of primary damage is inherently coupled with solute transport and hence, the overall chemical and microstructural evolutions under irradiation. In this work, we present atomistic simulation results, based on many-body interatomic potentials, of the migration of vacancies, solute and self-interstitial atoms (SIA) in pure Fe andmore »« less
https://doi.org/10.1557/PROC-650-R6.9

Full Text Available

Similar Records