Reactor Pressure Vessel Fracture Analysis Capabilities in Grizzly
Abstract
Efforts have been underway to develop fracture mechanics capabilities in the Grizzly code to enable it to be used to perform deterministic fracture assessments of degraded reactor pressure vessels (RPVs). Development in prior years has resulted a capability to calculate integrals. For this application, these are used to calculate stress intensity factors for cracks to be used in deterministic linear elastic fracture mechanics (LEFM) assessments of fracture in degraded RPVs. The integral can only be used to evaluate stress intensity factors for axisaligned flaws because it can only be used to obtain the stress intensity factor for pure Mode I loading. Offaxis flaws will be subjected to mixedmode loading. For this reason, work has continued to expand the set of fracture mechanics capabilities to permit it to evaluate offaxis flaws. This report documents the following work to enhance Grizzly’s engineering fracture mechanics capabilities for RPVs: • Interaction Integral and stress: To obtain mixedmode stress intensity factors, a capability to evaluate interaction integrals for 2D or 3D flaws has been developed. A stress evaluation capability has been developed to evaluate the constraint at crack tips in 2D or 3D. Initial verification testing of these capabilities is documented here. • Benchmarking formore »
 Authors:
 Idaho National Lab. (INL), Idaho Falls, ID (United States)
 Univ. of Tennessee, Knoxville, TN (United States)
 Univ. of Idaho, Moscow, ID (United States)
 Publication Date:
 Research Org.:
 Idaho National Lab. (INL), Idaho Falls, ID (United States)
 Sponsoring Org.:
 USDOE Office of Nuclear Energy (NE)
 OSTI Identifier:
 1235198
 Report Number(s):
 INL/EXT1534736
 DOE Contract Number:
 AC0705ID14517
 Resource Type:
 Technical Report
 Country of Publication:
 United States
 Language:
 English
 Subject:
 22 GENERAL STUDIES OF NUCLEAR REACTORS; 97 MATHEMATICS AND COMPUTING; Fracture Mechanics; Mixed Mode; Reactor Pressure Vessel; Stress Intensity Factor
Citation Formats
Spencer, Benjamin, Backman, Marie, Chakraborty, Pritam, and Hoffman, William. Reactor Pressure Vessel Fracture Analysis Capabilities in Grizzly. United States: N. p., 2015.
Web. doi:10.2172/1235198.
Spencer, Benjamin, Backman, Marie, Chakraborty, Pritam, & Hoffman, William. Reactor Pressure Vessel Fracture Analysis Capabilities in Grizzly. United States. doi:10.2172/1235198.
Spencer, Benjamin, Backman, Marie, Chakraborty, Pritam, and Hoffman, William. 2015.
"Reactor Pressure Vessel Fracture Analysis Capabilities in Grizzly". United States.
doi:10.2172/1235198. https://www.osti.gov/servlets/purl/1235198.
@article{osti_1235198,
title = {Reactor Pressure Vessel Fracture Analysis Capabilities in Grizzly},
author = {Spencer, Benjamin and Backman, Marie and Chakraborty, Pritam and Hoffman, William},
abstractNote = {Efforts have been underway to develop fracture mechanics capabilities in the Grizzly code to enable it to be used to perform deterministic fracture assessments of degraded reactor pressure vessels (RPVs). Development in prior years has resulted a capability to calculate integrals. For this application, these are used to calculate stress intensity factors for cracks to be used in deterministic linear elastic fracture mechanics (LEFM) assessments of fracture in degraded RPVs. The integral can only be used to evaluate stress intensity factors for axisaligned flaws because it can only be used to obtain the stress intensity factor for pure Mode I loading. Offaxis flaws will be subjected to mixedmode loading. For this reason, work has continued to expand the set of fracture mechanics capabilities to permit it to evaluate offaxis flaws. This report documents the following work to enhance Grizzly’s engineering fracture mechanics capabilities for RPVs: • Interaction Integral and stress: To obtain mixedmode stress intensity factors, a capability to evaluate interaction integrals for 2D or 3D flaws has been developed. A stress evaluation capability has been developed to evaluate the constraint at crack tips in 2D or 3D. Initial verification testing of these capabilities is documented here. • Benchmarking for axisaligned flaws: Grizzly’s capabilities to evaluate stress intensity factors for axisaligned flaws have been benchmarked against calculations for the same conditions in FAVOR. • Offaxis flaw demonstration: The newlydeveloped interaction integral capabilities are demon strated in an application to calculate the mixedmode stress intensity factors for offaxis flaws. • Other code enhancements: Other enhancements to the thermomechanics capabilities that relate to the solution of the engineering RPV fracture problem are documented here.},
doi = {10.2172/1235198},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2015,
month = 3
}

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Efforts are underway to develop fracture mechanics capabilities in the Grizzly code to enable it to be used to perform deterministic fracture assessments of degraded reactor pressure vessels (RPVs). A capability was previously developed to calculate threedimensional interaction integrals to extract mixedmode stressintensity factors. This capability requires the use of a finite element mesh that conforms to the crack geometry. The eXtended Finite Element Method (XFEM) provides a means to represent a crack geometry without explicitly fitting the finite element mesh to it. This is effected by enhancing the element kinematics to represent jump discontinuities at arbitrary locations inside ofmore »