ML18267A097
| ML18267A097 | |
| Person / Time | |
|---|---|
| Issue date: | 09/24/2018 |
| From: | Tregoning R L NRC/RES/DE |
| To: | |
| Shared Package | |
| ML18267A083 | List: |
| References | |
| Download: ML18267A097 (19) | |
Text
© 2018 Electric Power Research Institute, Inc. All rights reserved.Seiji AsadaMitsubishi Heavy Industries, Ltd.Gary StevensTechnical Executive, EPRIEAF Research and Related ASME Activities, NRC Public MeetingSeptember 25, 2018Non-Isothermal EAF Testing for 316 Stainless Steel in Simulated PWR Environment 2© 2018 Electric Power Research Institute, Inc. All rights reserved.OutlinesObjectivesExperimental ProcedureTest ConditionTest MatrixComparison of Experimental Fatigue Lives and PredictionsMeasurement of Crack Growth RateBeachmarkObservationExtended WKR Method to Non-Isothermal Condition Conclusions 3© 2018 Electric Power Research Institute, Inc. All rights reserved.ObjectivesFatigue Gap Analysis and Roadmapfor Future Research, -Isothermal S-Limited data available on the influence of variable temperature and variable strain rate within test cycles and of the influence of out-of-phase variations of temperature and strain rateInfluence of in-phase and out-of-phase temperature and strain variations to be identified by comparison with isothermal tests.Austenitic stainless steels in PWR environmental are highest priorityNon-isothermal & isothermal testing has been performed to address Gap 15.
4© 2018 Electric Power Research Institute, Inc. All rights reserved.R20GL(24mm)30160122061726Experimental ProcedureSpecimenT/C Extensometer(GL : 24mm)Induction heaterWater EnvironmentSimulates PWR primary water 500 ppm H3BO3as B 2 ppm LiOHas Li. Dissolved oxygen (DO) :< 0.005 ppmDissolved hydrogen (DH): 30 cc/kg H2OMaterialType 316 Stainless SteelCSiMnPSNiCrMoMin>+>+>+>+>+10.0016.002.00Max0.081.002.000.0450.03014.0018.003.00Heat0.040.610.920.0380.00110.2216.862.06m (Aqua regialiquid for 10 s) 5© 2018 Electric Power Research Institute, Inc. All rights reserved.Test ConditionIsothermal fatigue test & Non-isothermal fatigue testTemperature: 100>l325 ºC.Strain amplitude (a):0.6 %The period t1, t3, t3123are parameters.I1-1~4[addressed to positive strain rate changes]NI2-1~4Non-NI3-1Non-isothermal test with very high strain rate in compression (Very FastFast)NI4-1Non-isothermal test with the same condition of NI2-1 adding beach markingMeasure crack shape for fatigue lifeFastFastOut of phase (NI2-1)Strain Rate: SlowFast[Out-of-Phase]100Temp.(ºC)325a132aTimeFastSlowStrain (%)0.61321=600sec2=480sec3=1000 secOut of phase (NI2-4)Strain Rate: FastFast[In-Phase]
6© 2018 Electric Power Research Institute, Inc. All rights reserved.Test MatrixNoTemp.()Strain amp.(%)Temp. change PatternStrain rate change PatternPeriod (sec)Strain rate (%/sec>'t1t2t3I1-11000.60ConstantSlow-fast60048010000.0010.00250.0006I1-23250.60ConstantSlow-fast60048010000.0010.00250.0006I1-31000.60ConstantFast-fast60048010000.0010.00250.0006I1-43250.60ConstantFast-fast60048010000.0010.00250.0006NI2-1100-3250.60Out of phaseSlow-fast60048010000.0010.00250.0006NI2-2100-3250.60In-phaseSlow-fast60048010000.0010.00250.0006NI2-3100-3250.60In-phaseFast-fast60048010000.0010.00250.0006NI2-4100-3250.60Out of phaseFast-fast60048010000.0010.00250.0006NI3-1100-3250.60Out of phaseVery fast-fast600480300.0010.00250.02NI4-1100-3250.60Out of phaseSlow-fast60048010000.0010.00250.0006 7© 2018 Electric Power Research Institute, Inc. All rights reserved.Comparison of Experimental Fatigue Lives and PredictionsStrainTempI1-2StrainTempI1-1IsothermalIsothermalIsothermalIsothermalNon-IsothermalOut-of-PhaseNon-IsothermalOut-of-PhaseNon-IsothermalOut-of-PhaseNon-IsothermalIn-PhaseNon-IsothermalIn-PhaseI1-3StrainTempI1-4StrainTempStrainTempNI2-1&NI4-1NI2-2StrainTempNI2-3StrainTempNI2-4StrainTempNI3-1StrainTemp100100010000I1-1I1-2I1-3I1-4NI2-1NI2-2NI2-3NI2-4NI3-1NI4-1Isothermal ConditionNon-Isothermal ConditionFatigue Life in PWR environmentPrediction by Draft NUREG/CR-6909 Rev.1Prediction by JSME S NF1-2009Experimental Fatigue lifeFactor of 2 with respectto NUREG 8© 2018 Electric Power Research Institute, Inc. All rights reserved.Comparison of Experimental Fatigue Lives and Predictions(continued)Considering the characteristic of the used material The experimental fatigue lives of non-isothermal conditions showed longer fatigue lives than the predictions.1.E+021.E+031.E+041.E+021.E+031.E+04Experimental Life (cycles)meanfactor of 2factor of 2[I1-1] 100 ºC Constant Slow-fast[I1-2] 325 ºC Constant Slow-fast[I1-3] 100 ºC Constant Fast-fast[I1-4] 325 ºC Constant Fast-fast[NI2-1] 100-325 ºC Out of phase Slow-fast[NI2-2] 100-325 ºC In-phase Slow-fast[NI2-3] 100-325 ºC In-phase Fast-fast[NI2-4] 100-325 ºC Out of phase Fast-fast[NI3-1] 100-325 ºC Out of phase Slow-fast[NI4-1] 100-325 ºC Out of phase Slow-fastAustenitic SSDraft NUREG CR6909 Rev.1 ExpressionsPredicted Life with factor (x0.52) (cycles)00.20.40.60.811.2I1-1I1-2I1-3I1-4Nleak/NwpPrediction by Draft NUREG/CR-6909 Rev.1Prediction by JSME S NF1-20090.77 for JSME0.52 for Draft NUREG 9© 2018 Electric Power Research Institute, Inc. All rights reserved.Measurement of Crack Growth RateTypical striation widths were measured and da/dNdata were obtained. da/dNof the isothermal tests show the dependency on temperatureda/dNof the non-isothermal tests are close to that of 100 ºC isothermal tests.Striation widthD!D D~D!D D~1.E-041.E-031.E-021.E-011.E+000.010.11da/dN (mm/cycle)Crack Depth, a (mm) I1-1 Constant Slow-fast 100 I1-2 Constant Slow-fast 325 I1-3 Constant Fast-fast 100 I1-4 Constant Fast-fast 325NI2-1 Out of phase Slow-fast 325100NI2-2 In phase Slow-fast 100325NI2-3 In phase Fase-fast 325100NI2-4 Out of phase Fast-fast 100325NI3-1 Out of phase Slow-fast 325100NI4-1 Out of phase Slow-fast 32510011.125 10© 2018 Electric Power Research Institute, Inc. All rights reserved.The 4thbeachmark was identified, but the 1st beachmark could not be found.The 2ndand 3rdbeachmarks could be identified only a few portion, and so the crack depths are estimated. Multiple crack coalescence may have been occurred around the 2ndto 3rdbeachmarks.012300.20.40.60.81Crack depth, a[mm]Fatigue life ratio,N/Nleak(No.2)(No.4)0.2(No.1)(No.3)Calculated by Best FittingBeachmark Observation of NI4-1 11© 2018 Electric Power Research Institute, Inc. All rights reserved.Kamaya et al.(*1)proposed stress intensity factor The stress intensity factor range () is transformed into the apparent effective strain intensity factor range ((eff)) by the following equation. By using (eff), da/dNcan be predicted.Next, the relations between measured da/dNand (eff)from the Japanese project data(*2)and I1-1~4 for isothermal testingby hollow specimens, of which material, strain rate and temperature condition are identified, are compared with the above correlation between da/dNand (eff).Because of plastic region, specimen shape, aspect ratio and so on, these prediction was not consist with measured da/dNand should be corrected.Dcpis defined as the plastic correction factor. Then (eff)can be converted to (eff)Extended WKR Method to Non-Isothermal Condition1.E-041.E-031.E-021.E-011.E-041.E-031.E-021.E-01Measured da/dN (mm/cycles)Analysis da/dN (mm/cycles)JPN Project100°C 0.6% 0.004%/s.325°C 0.6% 0.004%/s100°C 0.6% 0.4%/s325°C 0.6% 0.4%/sIsothermal TestsI1-1(100°C)I1-2(325°C)I1-3(100°C)I1-4(325°C)*1: Kamay, M., PVP2016-63434, ASME, 2016.*2: JNES, Report on Environmental Fatigue Tests of Nuclear Power Plant Materials for Reliability Verification [General Version] 2006FYDcp=0.628JPN PJ (*2) 12© 2018 Electric Power Research Institute, Inc. All rights reserved.The WKR method is extended to non-isothermal condition.STwas modified to reflect the effect of temperature change; STi.E, was modified to reflect the effect of temperature change; Ei.Proposed expanded WKR method>&for NI evaluation>'Extended WKR Method to Non-Isothermal Condition(continued)Temp.ST(Tc) 13© 2018 Electric Power Research Institute, Inc. All rights reserved.Extended WKR Method to Non-Isothermal Condition(continued)1.E-041.E-031.E-021.E-011.E+001.E-041.E-031.E-021.E-011.E+00Measuredda/dN (mm/cycle)Extended WKR da/dN (mm/cycle)I1-1I1-2I1-3I1-4NI2-1NI2-2NI2-3NI2-4NI3-1NI4-1 14© 2018 Electric Power Research Institute, Inc. All rights reserved.The comparison between the experimental fatigue lives and the predicted fatigue lives with the factor that considered the material variability showed that the experimental fatigue lives of non-isothermal condition were greater than the predicted fatigue lives.The da/dNcurves of the non-isothermal tests do not show great difference while those of the isothermal tests depended on the temperature and the strain history. It is suggested that the effect of EAF on fatigue crack growth for non-isothermal condition is different from isothermal condition and/or the relation between microstructurally small crack (MSC) stage (Stage I) and crack growth stage (Stage II) for non-isothermal condition is different from isothermal condition.The WKR method was modified to apply to non-isothermal condition by incorporating and plastic correction. This extended WKR method was applied to the isothermal and non-isothermal tests and could estimate the test data with the factor of 2.Conclusions 15© 2018 Electric Power Research Institute, Inc. All rights reserved.Backup Slides 16© 2018 Electric Power Research Institute, Inc. All rights reserved.Test FacilityWater temp.Outer surface temp.Loop control panelFatigue test control unitElectric powerFlowLoadDisp.StrainTime synchronizationSpecimenT/C ExtensometerGL : 24mmInduction heaterFlowFatigue test sectionHeaterInduction heateroutputElectric poweroutputInputoutputTest control unit.
17© 2018 Electric Power Research Institute, Inc. All rights reserved.Observation of Crack Surfaces Crack surface of NI2-1 has relatively large arc-like sub cracksThe axial distance between the main crack and the sub crack of NI2-1 was larger than those of NI3-1 and NI4-1.Main crack growth could be effected by interference by sub cracksAbout 4mmMainCrackSubCrackAbout 1.5mmMainCrackSubCrackAbout 0.5mmMainCrackSubCrackNI2-1NI3-1NI4-1 18© 2018 Electric Power Research Institute, Inc. All rights reserved.Proposal to incorporate the effect of non-isothermal condition into UFen;If the crack growth is dominant, NIcan be expressed by only crack growth life. If the extended WKR method is improved and an appropriate initial crack is assumed, then Stage II fatigue life can be calculated and NIcan be obtained.Proposal of a New MethodCorrection factor for NI conditionStage I fatigue life under NI conditionStage I fatigue life under isothermal conditionStage II fatigue life under NI conditionStage II fatigue life under isothermal condition 19© 2018 Electric Power Research Institute, Inc. All rights reserved.