TY - GEN
T1 - Nonlinear ultrasonic characterization of radiation damage using charpy impact specimen
AU - Matlack, Kathryn H.
AU - Kim, Jin Yeon
AU - Wall, James J.
AU - Qu, Jianmin
AU - Jacobs, Laurence J.
N1 - Publisher Copyright:
Copyright © 2014 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959.
PY - 2015
Y1 - 2015
N2 - Radiation damage occurs in reactor pressure vessel (RPV) steel, causing microstructural changes such as point defect clusters, changes in dislocation density, and precipitates. These radiation-induced microstructural changes cause material embrittlement. Radiation damage is a crucial concern in the nuclear industry because many nuclear plants throughout the United States are entering the first period of life extension, and older plants are currently undergoing assessment of technical basis to operate beyond 60 years. The result of extended operation is that the RPV and other components will be exposed to higher levels of neutron radiation than they were originally designed to withstand. There is currently no nondestructive evaluation technique with which to unambiguously assess the amount of radiation damage in RPV steels. The development of such a technique would enable the assessment of the integrity of a vessel, allowing operators to determine whether reactors can continue to operate safely, and would directly support the nuclear industry Long Term Operation and U.S. Department of Energy Light Water Reactor Sustainability initiatives. Nonlinear ultrasound (NLU) is a nondestructive evaluation technique that is sensitive to microstructural features such as dislocations, precipitates, and their interactions in metallic materials. The physical effect monitored via NLU is the generation of higher harmonic frequencies in an initially monochromatic ultrasonic wave, arising from the interaction of the ultrasonic wave with microstructural features. Recent research has demonstrated that NLU is sensitive to radiation-induced microstructural changes in RPV steel. NLU measurements were made on various Charpy specimen sets of typical RPV material to investigate the applicability of NLU in characterizing radiation damage over a range of fluence levels, irradiation temperatures, and material compositions. These previous experimental results are interpreted with a newly developed analytical model that combines irradiation-induced precipitate and vacancy contributions to the nonlinearity parameter.
AB - Radiation damage occurs in reactor pressure vessel (RPV) steel, causing microstructural changes such as point defect clusters, changes in dislocation density, and precipitates. These radiation-induced microstructural changes cause material embrittlement. Radiation damage is a crucial concern in the nuclear industry because many nuclear plants throughout the United States are entering the first period of life extension, and older plants are currently undergoing assessment of technical basis to operate beyond 60 years. The result of extended operation is that the RPV and other components will be exposed to higher levels of neutron radiation than they were originally designed to withstand. There is currently no nondestructive evaluation technique with which to unambiguously assess the amount of radiation damage in RPV steels. The development of such a technique would enable the assessment of the integrity of a vessel, allowing operators to determine whether reactors can continue to operate safely, and would directly support the nuclear industry Long Term Operation and U.S. Department of Energy Light Water Reactor Sustainability initiatives. Nonlinear ultrasound (NLU) is a nondestructive evaluation technique that is sensitive to microstructural features such as dislocations, precipitates, and their interactions in metallic materials. The physical effect monitored via NLU is the generation of higher harmonic frequencies in an initially monochromatic ultrasonic wave, arising from the interaction of the ultrasonic wave with microstructural features. Recent research has demonstrated that NLU is sensitive to radiation-induced microstructural changes in RPV steel. NLU measurements were made on various Charpy specimen sets of typical RPV material to investigate the applicability of NLU in characterizing radiation damage over a range of fluence levels, irradiation temperatures, and material compositions. These previous experimental results are interpreted with a newly developed analytical model that combines irradiation-induced precipitate and vacancy contributions to the nonlinearity parameter.
KW - Nondestructive evaluation
KW - Nonlinear ultrasound
KW - Radiation damage
KW - Reactor pressure vessel steel
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U2 - 10.1520/STP157620140007
DO - 10.1520/STP157620140007
M3 - Conference contribution
AN - SCOPUS:84939439347
T3 - ASTM Special Technical Publication
SP - 227
EP - 243
BT - Small Specimen Test Techniques
A2 - Lucon, Enrico
A2 - Sokolov, Mikhail A.
PB - ASTM International
T2 - 6th International Symposium on Small Specimen Test Techniques
Y2 - 29 January 2014 through 31 January 2014
ER -