PLiM Symposium in Shanghai Structural Integrity Evaluation of Cast Austenitic Stainless Steel Reactor Coolant Piping for Continued Operation of Nuclear Power Plants PLiM Symposium in Shanghai Structural Integrity Evaluation of Cast Austenitic Stainless Steel Reactor Coolant Piping for Continued Operation of Nuclear Power Plants 2007 년 년 년 10 월 월 월 18 일 일 일 YOUNG JONG KIM GNEC 2007 년 년 년 10 월 월 월 18 일 일 일 YOUNG JONG KIM GNEC
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PLiM Symposium in Shanghai
Structural Integrity Evaluation of Cast Austenitic Stainless Steel
Reactor Coolant Piping for Continued Operation of Nuclear Power Plants
PLiM Symposium in Shanghai
Structural Integrity Evaluation of Cast Austenitic Stainless Steel
Reactor Coolant Piping for Continued Operation of Nuclear Power Plants
2007년년년년 10월월월월 18일일일일
YOUNG JONG KIMGNEC
2007년년년년 10월월월월 18일일일일
YOUNG JONG KIMGNEC
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INTRODUCTIONIIII
SUSCEPABILITY EVALUATIONIIIIIIII
CONCLUSIONIVIVIVIV
Contents
FLAW TOLERANCE EVALUATIONIIIIIIIIIIII
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I . INTRODUCTIONI . I . INTRODUCTION
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I . INTRODUCTIONI . I . INTRODUCTION
• NPP Life Extension - 40 years � 60 years, 48 NPP in the USA; - 30/40 years � 40/50 years in some European Countries
• In Korea, - 20 nuclear power plants (16 PWRs and 4 CANDUs) in operation. - Licensed design lifetime: Kori Unit 1(PWR) & 4 CANDUs: 30 yearsOthers: 40 years
• NPP life extension in Korea- 10 year extension is now under review for Kori Unit 1:- the first NPP in Korea, - operated since 29 April 1978.
susceptibility susceptibility susceptibility susceptibility evaluationevaluationevaluationevaluation for thermal aging for thermal aging for thermal aging for thermal aging embrittlementembrittlementembrittlementembrittlement
reduction of fracture toughnessreduction of fracture toughnessreduction of fracture toughnessreduction of fracture toughness
CASS material CASS material CASS material CASS material ---- RCPB componentsRCPB componentsRCPB componentsRCPB componentsCASS material CASS material CASS material CASS material CASS material CASS material CASS material CASS material -------- RCPB componentsRCPB componentsRCPB componentsRCPB componentsRCPB componentsRCPB componentsRCPB componentsRCPB components
III. FLAW TOLERANCE EVALUATIONIII. III. FLAW TOLERANCE EVALUATION
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III. III. FLAW TOLERANCE EVALUATION
Flaw Tolerance Evaluation Procedureto ensure the structural integrity of CASS reactor coolant piping subparts
NUREG-1801Two evaluation methods recommended - to demonstrate the integrity through enhanced volumetric examination- to perform plant specific and component specific flaw tolerance evaluation considering material property changes due to thermal aging embrittlement .
flaw tolerance evaluation proceduresand acceptance criteria for CASS piping - ASME Code Section XI , IWB-3640.
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Flow Chart for Flaw Tolerance Evaluation Procedure
Failure mode Evaluation- ASME B&PV Code, Sec.XI, App.C, Article C-4000- failure modes of almost all subparts : FPF- fully-plastic fracture (FPF) � ductile fracture (DF), because tensile property may increase, while fracture toughness may decrease due to thermal aging embrittlement.
FPF (limit load analysis)0.177203.520.5550°°°° fittingHot leg
RemarksSC(=K’r/S’r)
Min. fracture toughness
KIc(MPa m0.5)
Max. SIF at final crack size
KI-max(MPa m0.5 )Subparts
Note) FPF if SC<0.2; DF if 0.2≤≤≤≤SC<1.8
III. III. FLAW TOLERANCE EVALUATION
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Flaw Tolerance Evaluation Results for Axial Cracksthe results of flaw tolerance evaluation for axial cracks at the end of continued operationstructural integrity of CASS RC piping be maintained over 40 years
0.440.14835°°°° elbowCold leg
0.70.14790°°°° elbow with splitter
0.70.14790°°°° elbow0.70.14040°°°° fitting
Cross-over leg
0.70.144Straight pipe Structural integrity
will be maintained over the continued operation period.
0.70.15050°°°° fittingHot leg
RemarksAllowable
crack depth ratios
Evaluated crack depth
ratiosSubparts
III. III. FLAW TOLERANCE EVALUATION
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IV. CONCLUSIONIV. IV. CONCLUSION
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CONCLUSIONCONCLUSION
integrity evaluation of CASS RC piping of Kori Unit 1considering the change of material properties due to thermal aging embrittlement.
predicted fatigue crack growths- not significant for all CASS RC piping.
final crack sizes (40 years) - satisfied in accordance with the ASME Section XI acceptance criteria.
structural integrity of CASS reactor coolant piping- maintained over 40 years.