RT PTS Re -evaluation of Kori -1 RPV Beltline Weld by ... · Base Metal: SA508-cl.2 steel ... ASME...
Transcript of RT PTS Re -evaluation of Kori -1 RPV Beltline Weld by ... · Base Metal: SA508-cl.2 steel ... ASME...
RTRTPTSPTS ReRe--evaluation of Korievaluation of Kori--1 RPV 1 RPV Beltline Weld by Master Curve TestsBeltline Weld by Master Curve Tests
Bong-Sang Lee1, Jun-Hwa Hong1, Dong-Hwan Lee2, Dong-Gwan Choi2
1KAERI (Korea Atomic Energy Research Institute)2KHNP (Korea Hydro & Nuclear Power Co. Ltd)
Second International Symposium on Nuclear Power Plant Life Management 15-18 October 2007, Shanghai, China
�Westinghouse Design (2-loop PWR) Bobcock & Wilcox RPV & Weld
�Base Metal: SA508-cl.2 steel forging�Beltline circumferential weld
Linde 80 flux weld (WF-233)Weld wire heat no.= T27944Flux lot no.= 8790
�Size: 600 MW capacityID 132 inch (3.35m) Thickness 6.5 inch (165 mm)
�Design/Operating Pressure: 2485 / 2235 psig (170 / 152 atm)
�Design Life : 30 yr (FSAR), 40 yr (Equipment Spec. WH-676413, 1969)
Kori-1 PWR (launched in 1978)KoriKori--1 PWR (launched in 1978)1 PWR (launched in 1978)
Surveillance tests summarySurveillance tests summarySurveillance tests summary
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Temperature (oF)
C V En
ergy (
ft-lb)
Unirr. V, f=0.54 (x1019n/cm2) T, f=1.12 (x1019n/cm2) S, f=1.22 (x1019n/cm2) R, f=2.99 (x1019n/cm2) P, f=3.88 (x1019n/cm2)
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Linde 80 Weld (WF-233)Kori-1 RPV
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Temperature (oF)
C V En
ergy (
ft-lb)
Unirr. V, f=0.54 (x1019n/cm2) T, f=1.12 (x1019n/cm2) S, f=1.22 (x1019n/cm2) R, f=2.99 (x1019n/cm2) P, f=3.88 (x1019n/cm2)
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Base Metal (Tangential)Kori-1 RPV
2
Weld (Linde 80, WF-233) Base Forging (SA508-Cl.2)
High copper Linde 80 weld is the limiting material.- USE is lower than 50 ft-lb (after 6 EFPY)- RTPTS exceeds 300oF (after 27 EFPY)
Requires a plant-specific safety analysis based on F/M tests.
History of safety evaluation of irradiation embrittlement� 5th Surveillance tests (Charpy) (1980, 1984, 1986, 1990, 2000)
� Low upper-shelf evaluation (J-R tests by modified 1X-WOL specimens)• 1988, per NUREG-0744 • 1994 & 2005, per USNRC DG-1023 & USNRC RG-1.161
�Master curve fracture toughness tests (RTPTS re-evaluation)• Unirradiated archive weld (2000, ASTM E1921-97)• Irradiated tests by reconstituted specimens (2006, 3/4/5 capsules)• Additional unirradiated tests (2006, ASTM E1921-05)
� Plant-specific analysis of PTS, based on the probabilistic fracture mechanics, USNRC RG-1.154 (2003)
� P-T limit curve was revised by CC N-641 (circumferential flaw, 2004)
ASME KIC Curve:WRC Bulletin-175 (1972)Fracture toughness data were normalized by RTNDTparameter from Charpytests, conservatively.
Irradiated KIC curves :Those are shifted by the same amount of ∆T30ft-lbfrom Charpy tests.
ASME KIC Curve (lower bound) and its original database (1972)
C),mMPa(in)](036.0exp[*783.225.36 oNDTIC RTTK −+=
174 Data pointsEPRI NP-719-SR HSST-02 plate
A533B-1 steel
ASME KASME KICIC curve : CLB (Current Licensing Basis)curve : CLB (Current Licensing Basis)
assuming
How to get a fracture toughness data ?
� Large specimens should be used to get a valid fracture toughness.� Specimen size-dependence on the measured (cleavage) fracture
toughness can be compensated by a weakest-link theory.
� Cleavage fracture toughness data from the same (1 inch) size specimens show a single master curve shape for ferriticRPV steels.
� To (reference temperature) : at 100 MPa√m median value
Master Curve Test Method (ASTM E1921) Master Curve Test Method (ASTM E1921) KIC
KJC
T – To (oF)
Indexing Fracture Toughness For Many Different RPV Steels
(NUREG-1807, by Mark Kirk)Charpy-size specimens (PCVN) can be validfor direct indexing of fracture toughness.
Specimen reconstitution for MC testsSpecimen reconstitution for MC testsA broken half of Charpy specimensfrom surveillance programs
A new PCVN specimenfor the master curve testing
• 3/4/5th surveillance specimens (broken Charpy halves)
• Fluence: 1.2, 3.0 & 3.9 (x1019 n/cm2, E>1MeV)
• It is a well established procedure in the ASTM E1253 standard.
• Stud arc welding is good enough to make PCVN specimens for MC tests.(fast & simple, and no effects on the data)
• Best-estimation To (-106.7oC) value (E1921-05) envelopes the all data by the ASME code case N-629, RTTo curve.
• A conservative To (-83.3oC) value was calculated from a minimum property data set at a single temperature for the initial RTTo value determination .(Implicit margin of about 23.4oC was added to Kori-1 safety analysis.)
UnUn--irradiated material data (WFirradiated material data (WF--233)233)
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KIC Curve onRTTo without margin
K1W Pre-irradiationPCVN specimensTo,ASTM= -106.7 oC
K JC, 1
T-adju
sted (M
Pa-m
0.5)
Test Temperature (oC)
0.5 mm/min 0.15 mm/min 0.15 mm/min (recon.)
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KIC Curve onRTTo without margin
K1W Pre-irradiationPCVN specimensTo, conservative= -83.3 oC
K JC, 1
T-adju
sted (M
Pa-m
0.5)
Test Temperature (oC)
0.5 mm/min 0.15 mm/min 0.15 mm/min (recon.)
Standard To value from all data(E1921-05)
Conservative To value from a data setat a single temperature (E1921-97)
Irradiated test data (3/4/5Irradiated test data (3/4/5thth capsules)capsules)
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300capsule S
median 5%/95%
Kori-1 WeldPCVN 20%-SG(1.22x1019n/cm2)To = 13.4oC
K JC
, 1T-a
djuste
d (MP
a-m0.5
)
Temperature (oC)-100 -50 0 50 100 1500
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median 5%/95%
Kori-1 WeldPCVN 20%-SG(2.99x1019n/cm2)To = 30.0oC
K JC, 1
T-adju
sted (M
Pa-m
0.5)
Temperature (oC)
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median 5%/95%
Kori-1 WeldPCVN 20%-SG(3.88x1019n/cm2)To = 31.5oC
K JC, 1
T-adju
sted (M
Pa-m
0.5)
Temperature (oC)
• Best-estimation To values were determined by the ASTM E1921-05.(13.4, 30.0, 31.5 oC)
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∆T 41J [oC]
∆To [oC]
Weld Fit (Slope=0.99)Plate Fit (Slope=1.10)Forging Fit (Slope=1.50)WeldPlateForgings
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Kori-1 Weld
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∆T 41J [oC]
∆To [oC]
Weld Fit (Slope=0.99)Plate Fit (Slope=1.10)Forging Fit (Slope=1.50)WeldPlateForgings
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Kori-1 Weld
(NUREG-1807 database)
<RPV steels & welds>
Transition temperature shifts after irradiationTransition temperature shifts after irradiation
(USNRC RG-1.99, Rev.2)
CF = 190.8oF (from Charpy, ∆T30ft-lb) CF = 191.6oF (Master Curve, ∆To)
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∆RT N
DT or
∆T o
(o F)Fluence (x1018 n/cm2)
K1W Linde 80, WF-233 ∆To (by E1921-05) ∆RTNDT (by Charpy) RG-1.99 (CF=190.8) + 2σ (σ
∆=28oF)
Similar to the Charpy data for Kori-1 weld (Linde 80 / WF-233)
Comparison with US data for Comparison with US data for LindeLinde 80 welds80 welds
Kori-1 RPV weld showed a better property than the generic Linde 80 data.
• 2σ= 65.8oF• PCVN bias = 18oF• Explicit margin terms will be added for integrity evaluation.
Un-irradiated Irradiated
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ASME KIC curve by RTTo without any marginbased on the generic value of -47.6oF
Linde 80 Unirradiated Data
BAW-2308 Kori-1 ('97) Kori-1 ('05)
K JC - a
djuste
d to 1
T (MP
a-m0.5 )
Test Temperature (oC)-50 0 50 100 1500
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100
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Fluence (x1019 n/cm2)BAW-2308 : 0.8 ~ 2.0 Kori-1 weld : 1.1 ~ 3.9
KIC - RTTo curve without any marginbased on the 5th capsule fluence
K JC, 1
T-adju
sted (M
Pa-m
0.5)
Temperature (oC)
BAW-2308 Kori-1 (3rd) Kori-1 (4th) Kori-1 (5th)
304260.0RTPTS (oF) at 40 yr3.943.94Fluence at EOLE (40 yr)5665.8Margin (oF)
190.8191.6CF (oF)-10 (RTNDT)-65Initial RTTo (oF)
--53.9Initial RTTo (oC)-19.4RTTo correction (oC)-10PCVN Bias (oC)--83.3Initial (conservative) To (oC)--106.7Un-irradiated To,ASTM (oC)
Charpy basedMaster curve
RTRTPTSPTS rere--evaluation (from conservative initial data)evaluation (from conservative initial data)BAW-2308 approach
222.3 oFRTPTS (averaged)212.4 216.7 237.8 ARTTo,vessel
18 oFPCVN Bias factor65.8 oFMargin35 oFRTTo (= To + α)
93.6 97.9 119.0 To,vessel
253.7 258.0 279.0 △To,vessel (oF)3.938 (40 yr)Vessel Fluence at EOLE
3.883 2.989 1.222 Fluence (x1019n/cm2)248.9 241.9 214.2 △To,surveillance
88.9 81.9 54.1To,surveillance
-160 oFTo,unirradiated (PCVN)PRS
Kori-1 surveillance capsule
RTRTPTSPTS rere--evaluation (from irradiated data)evaluation (from irradiated data)
Kewauneeapproach
RTPTS evolution curve revised for Kori-1 weldRTRTPTSPTS evolution curve revised for Korievolution curve revised for Kori--1 weld1 weld
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Fracture toughness evaluationby the master curve testsincluding safety margin
Approximate Calendar Year of Kori-1
Surveillance Charpy dataincluding safety margin
Regulatory Reference
RTPT
S (o F)
Neutron Fluence (x1018n/cm2)
Master curve fracture toughness data (36 un-irradiated & 45 irradiated)showed a sufficient RTPTS margin for another 10 years and more operation.
Supplement 1: Low upperSupplement 1: Low upper--shelf energy => Jshelf energy => J--R dataR data•Elastic-plastic fracture mechanics methodology (J-R) :
J-T method, DPFAD, J-R CDF •USNRC RG-1.161 (1995) provides the safety criteria and J-R database.•Kori-1 produced its plant specific J-R data from irradiated WOL specimens.
J-R test data at 288oC demonstrated that the safety evaluation based on the USNRC RG-1.161 database was sufficiently conservative for Kori-1.
S2: PS2: P--T (pressureT (pressure--temperature) operation limit curvetemperature) operation limit curve•ASME Code Section XI, App.G assumes an axial surface crack of 1/4t depth.•The operating window was too narrow for Kori-1, which has no axial weld.•ASME Code Case N-641 permits a postulate flaw with a circumferential orientation, if there are only circumferential welds.=> This could reduce the stress intensity and the P-T curve constraint.
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Temperature (Deg. F)
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sure
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ASMEsec.XI,App. G.
Code caseN-641
150 oF
800p
sig
Operating window was increased by the code case N-641 application.
Master curve data is not applied to the P-T curve generation for Kori-1.
S3: ExS3: Ex--Vessel Vessel DosimetryDosimetry
DOSIMETRY CAPSULE (54)Fe, Ni, Cu, Ti, Co, Co-Cd, Nb, U & Np
DOSIMETRY CAPSULE (54)Fe, Ni, Cu, Ti, Co, Co-Cd, Nb, U & Np
BEAD CHAINS (156)Fe, Ni & Co
BEAD CHAINS (156)Fe, Ni & Co
Dosimetry Set
• Continuation of monitoring the intensity of neutron irradiation after removal the normal surveillance capsules.
• Enhancement of accuracy of dosimetry calculation.
SummarySummary�An application for a 10 year extension of the operating license for the first PWR in Korea, Kori-1, has been submitted to the government after a stable operation of its initial licensing period of 30 years. �Irradiation embrittlement of the beltline circumferential weld, Linde 80 WF-233, was the limiting issue of aging management.�Safety evaluation and aging management actions on irradiation embrittlement of Kori-1 RPV were successfully performed.• RTPTS was re-evaluated through the master curve test method using a total of 45 irradiated and 36 un-irradiated PCVN specimens for the limiting material, WF-233.• Low upper-shelf toughness issues were resolved by J-R testing of irradiated WOL specimens and USNRC RG-1.161 procedure.• P-T limit curve was revised by using the Code Case N-641.• An ex-vessel dosimetry system was installed for a continuous monitoring and improvement of calculation accuracy of neutron fluence during a continued operation of Kori-1.