ML101740061
| ML101740061 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 06/22/2010 |
| From: | Entergy Nuclear Palisades |
| To: | Division of Operating Reactor Licensing |
| Chawla M, NRR/DORL, 415-8371 | |
| References | |
| Download: ML101740061 (90) | |
Text
Palisades NRC Planning Meeting TLAA 10 CFR 54.21 (c)(1)(iii)
Pressurized Thermal Shock 10CFR50.61 June 22, 2010 One White Flint Rockville, MD 1
Agenda
- Introduction of Meeting Attendees
- Purpose of Meeting
- Historical Status of PTS at Palisades
- Current Activities to Manage PTS at Palisades
- Integration g of New Data
- Update of WCAP-15353
- Future Plans
- Proposed Schedule
- Questions
- Identification of Action 2
Introduction of Palisades Team
- Jeff Erickson, Licensing - Meeting Coordinator
- Paula Anderson, Licensing Manger
- Brian Kemp, Design Engineering Manager- Responsible Area Functional Manager
- Keith Smith, Design - License Renewal Implementation Project Manager
- Bill Server, ATI Consulting - Technical Presenter
- Tim Griesbach, SIA - Technical Presenter
- Stephen Byrne, Westinghouse - Technical Presenter 3
Meeting Agenda Leaders
- Introduction - Jeff Erickson
- Purpose - Brian Kemp
- Historical Status of PTS at Palisades - Bill Server
- Current Activities to Manage PTS - Bill Server
- Integration g of New Data - Bill Server
- Update of WCAP-15353 - Steve Byrne
- Future Plans - Brian Kemp
- Proposed Schedule - Brian Kemp
- Questions - All
- Identification of Action Items - Jeff Erickson 4
Purpose of Meeting
- Brief review of historical status of PTS at Palisades
- Communicate Information on activities performed in accordance with 10 CFR 54.21 (c)(1)(iii) For managing the PTS TLAA
- Share new information to assess limiting Palisades weld metal
- Updated fluence (WCAP-15353 Supplement 1)
- Updated chemistry, irradiation temperatures, TANH fits (SIA Report No. 0901132.401, Rev. 0)
- Discuss medium term actions: NRC review & approval of PTS evaluation and LAR for heat-up/cool-down curves
- Discuss potential long term actions: plan for resolution of PTS 5
Overview of Sequence of Events and Road Map for PTS at Palisades
- Validate timing of RV examination
- WCAP-15353 Supplement 1 (fluence update)
- SIA Report No. 0901132.401, Rev. 0 (timing for axial weld to reach PTS Screening Criteria)
- Update complete PTS assessment under 10CFR50.61 (later this year)
- Perform UT inspection of RV (2012)
- Reassess PTS using 10CFR50.61a (target submittal Fall 2012) 6
Historical Status of PTS at Palisades
- PTS evaluation submitted in 2000 used best estimates for fluence and vessel material properties available at that time
- Intermediate Shell Axial Welds 2-112A/B/C at the 60° azimuthal location fabricated with Weld Wire Heat No. W5214 were determined to be the limiting materials in the beltline region of the Palisades RPV
- The RPV was projected to exceed the PTS screening criterion of 270°F in January of 2014
- Fluence assumption in WCAP-15353 for 60 degree axial weld location was 1.58 E19 n/cm2 (E > 1 MeV)
- Ten years of additional plant operation have occurred since the last PTS evaluation including several years of very low load factor (e.g., extended outage in 2001) 7
Historical Status of PTS at Palisades (Cont.)
- ENO plans to conduct a RV examination during the 2010 outage
- WCAP-16168-NP-A Rev 2 allows inspections to be performed within 1 cycle of the proposed schedule Note: the current plan is to perform the inspection in 2012 and integrate the results into 10CFR50.61a evaluation and transmit to NRC for review and approval more than 3 years prior to reaching PTS screening criteria 8
Historical Status of PTS at Palisades (Cont.)
- For the License Renewal period, Palisades now plans to manage PTS for the reactor pressure vessel using:
- 10CFR50.61a, with new vessel ISI data, and new PTS assessment
- Results of inspection and assessment must be submitted to NRC at least 3 years prior to the vessel reaching PTS screening criteria 9
Current Status of PTS at Palisades
- PTS assessment for limiting RPV material being updated to more accurately determine the date to reach the PTS screening criteria in accordance with 10CFR50.61
- 10 years of operating history and core designs used to calculate current and projected fluences
- Performed P f dd data t survey ffor lilimiting iti vessell weld ld (h (heatt W5214) and incorporated all new materials data
- Used surveillance data to improve projection of RTPTS
- Determined revised date for vessel ISI and submittal of 10CFR50.61a assessment based on new information 10
Current Activities to Manage PTS at Palisades
- Survey of all available surveillance capsule data for limitingg weld heat No. W5214
- Consistent capsule fluence calculations and updated vessel calculation
- Irradiation temperatures for surveillance data
- Recalculated shift data (using consistent TANH fits) 11
Survey of All Available Surveillance Capsule Data for Weld Heat No. W5214
- Previous assessment based on 7 surveillance capsules: 2 HBR2, 2 IP2, and 3 IP3 (Note: surveillance data was not credited in previous PTS assessment))
- New assessment based on 11 surveillance capsules:
2 Palisades (Supplemental), 3 HBR2, 2 IP2, 4 IP3 12
Consistent Capsule Fluence Calculations
- Fluence assessment methodology per Regulatory Guide 1.190
- Same methodology used to compute fluence for each of 11 capsules from four vessels 13
Updated Vessel Fluence Calculation
- WCAP-15353 (January 2000) projections based on cycle 15 core design
- WCAP-15353 Supplement 1 (May 2010) provides updated fluence projections based on cycle 22 and later core designs 14
Irradiation Temperatures for Surveillance Data
- Surveillance irradiation temperatures need to be analyzed to correct shift data for temperature differences
- Previous analysis did not account for differences in irradiation temperatures of surveillance data relative to Palisades vessel
- New analysis incorporates temperature corrections into surveillance data best-fit and credibility assessment (per NRC guidelines) for differing capsule and vessel temperatures
- 2 Palisades (Supplemental) capsules, 2 IP2 capsules, 4 IP3 capsules [time weighted average temperature values]
- 3 HBR2 capsules [no variation in temperature reported]
15
Recalculated Shift Data (Using Consistent TANH Fits)
- All unirradiated and irradiated Charpy V-notch (CVN) data have been re-evaluated consistently using hyperbolic tangent (TANH) curve fitting software to calculate T30 values
- All CVN shift results have been recalculated to determine revised T30 values
- All CVN data processed with same fitting method and assumptions
- The TANH fitting method is an accepted industry practice 16
Integration of New Data
- Previous Evaluation Based on PTS Rule given in 10CFR50.61, Paragraph (c)(1) using the best estimate chemistry for this weld, the corresponding chemistry factor, CF, and the fluence values from the vessel fluence evaluation in WCAP-15353 (circa 1999)
- New Evaluation Considers All the Available Surveillance Data for Weld Heat No. W5214 that Can be Used to Refine the Projected RTNDT in Accordance with 10CFR50.61, Paragraphs (c)(2) and (c)(3), and fluence values from the latest vessel fluence evaluation in WCAP-15353 Supplement 1 (performed in 2010) 17
Previous Evaluation Using 10CFR50.61 Paragraph (c)(1)
- This method considers only the copper and nickel chemistry, fluence, and initial RTNDT of the weld, plate, or forging material in the reactor vessel beltline.
- For those beltline materials, Equation (1) is used to determine the adjusted RTNDT for comparison to the PTS screening criteria limits.
- Equation 1: RTNDT = Initial RTNDT + RTNDT + Margin where, RTNDT is the mean value of the transition temperature due to irradiation, and must be calculated using Equation 3 3.
- Equation (3): RTNDT = (CF) f (0.28-0.10 log f) where, CF (°F) is the chemistry factor, which is a function of the copper and nickel content. CF is determined by using Table 1 (from 10CFR50.61) for welds and by using Table 2 (from 10CFR50.61) for base metals (plates and forgings). Wt %
copper and Wt % nickel are the best-estimate values for the material, which will normally be the mean of the measured values for a plate or forging. For a weld, the best estimate values will normally be the mean of the measured values for a weld deposit made using the same weld wire heat number as the critical vessel weld.
18
Previous Evaluation Using10CFR50.61 Paragraph (c)(1) - Values
- The initial RTNDT for weld heat No. W5214 is determined from the generic value of -56°F for C-E fabricated Linde 1092 flux type welds
- The margin term for this case is 65.5°F based on 2 (I2 + 2)1/2
= 2 [(17°F)2 + (28°F)2]1/2
- The screening criteria for axial welds is 270°F 270 F
- Fluence to reach screening criterion is 1.595E19 n/cm2 19
New Evaluation Using 10CFR50.61 Paragraph (C)(2)
- To verify that RTNDT is a bounding value for the specific reactor vessel, licensees shall consider plant-specific information that could affect the level of embrittlement. This information includes but is not limited to the reactor vessel operating temperature and any related surveillance program results.
New information exists for weld heat W5214 and vessel fluence; this information is being presented now since it affects the RTPTS value for Palisades 20
New Evaluation Using 10CFR50.61 Paragraph (C)(2) - Credibility
- Results from the plant-specific surveillance program must be integrated into the RTNDT estimate if the plant-specific surveillance data has been deemed credible as judged by the following criteria:
- (A) The materials in the surveillance capsules must be those which are the controlling materials with regard to radiation embrittlement,
- (B) Scatter in the plots of Charpy energy versus temperature for the irradiated and unirradiated conditions must be small enough to permit the determination of the 30-foot-pound 30 foot pound temperature unambiguously unambiguously,
- (C) Where there are two or more sets of surveillance data from one reactor, the scatter of RTNDT values must be less than 28°F for welds and 17°F for base metal. Even if the range in the capsule fluences is large (two or more orders of magnitude), the scatter may not exceed twice those values (i.e., 56°F),
- (D) The irradiation temperature of the Charpy specimens in the capsule must equal the vessel wall temperature at the cladding/base metal interface within 25°F, and
- (E) The surveillance data for the correlation monitor material in the capsule, if present, must fall within the scatter band of the data base for the material.
21
New Evaluation Using 10CFR50.61 Paragraph (C)(2) - Revised CF Surveillance data deemed credible according to these criteria must be used to determine a material-specific value of CF for use in Equation (1). A material-specific value of CF is determined from Equation (5)
(5) where, n is the number of surveillance data points, Ai
is the measured value of T30 from the Charpy specimens, and fi is the fluence for each surveillance capsule data point.
22
New Evaluation Using 10CFR50.61 Paragraph (C)(2) - Chemistry Ratios If there is clear evidence that the copper or nickel content of the surveillance weld differs from that of the vessel weld, i.e., differs from the average of th weld the ld wire i h heatt number b associated i t d with ith th the vessel weld and the surveillance weld, the measured values of RTNDT must be adjusted for differences in copper and nickel content by multiplying them by the ratio of the chemistry factor for the vessel material to that for the surveillance weld.
23
New Evaluation Using 10CFR50.61 Paragraph (C)(2) - Margin Term
- For cases in which the results from a credible plant-specific surveillance program are used, the value of to be used is 14°F for welds and 8 5°F ffor b 8.5°F base metal;l the h value l off needd not exceed one-half of RTNDT.
- The use of results from the plant-specific surveillance program may result in RTNDT that is higher or lower than those determined in paragraph (c)(1).
24
New Evaluation Using 10CFR50.61 Paragraph (C)(2) - Temperature Adj.
- From NRC guidance, published in Memorandum to Edmond Sullivan, November 19, 1997, further adjustment to the RTNDT data from other sources is needed if there is a difference between the capsule temperature from the other plant and the plant of interest.
interest
- A temperature correction of 1°F/°F is made to the RTNDT values to account for this difference; i.e., a positive (increased) temperature adjustment is made to capsules exposed to (time-weighted average) temperatures below the mean vessel temperature, and a negative (decreased) temperature adjustment is made to capsules exposed to (time-weighted average) temperatures above the mean vessel temperature.
25
New Evaluation Using 10CFR50.61 Paragraph (C)(3) - Reporting New Data Any information that is believed to improve the accuracy of the RTPTS value significantly must be reported to the Director, Office of Nuclear Reactor Regulation g or Director,, Office of New Reactors,, as appropriate. Any value of RTPTS that has been modified using the procedures of paragraph (c)(2) is subject to the approval of the Director, Office of Nuclear Reactor Regulation or Director, Office of New Reactors, as appropriate.
26
- Previous assessment based on the fluence analysis described in WCAP-15353, Revision 0
- Use of Regulatory Guide 1.190 methodology
- Analysis based on cycle-specific cycle specific evaluation through Cycle 14
- Benchmarked to in-vessel surveillance capsule and ex-vessel dosimetry measurements
- Methodology reviewed by NRC contractors and approved 27
Update of WCAP-15353 WCAP-15353 Supplement 1 Supplement 1 to WCAP-15353 provides an updated neutron fluence assessment for the Palisades reactor vessel beltline
- Use of previously approved methodology validated by benchmarking to Palisades dosimeter measurements (in-vessel (in vessel and ex-vessel) ex vessel)
- Based on fuel cycle-specific transport calculations through Cycle 21 and projection to 44 effective full power years (EFPY)
- Includes a compilation of previously submitted fluence values for each of 11 surveillance capsules from four vessels based on the use of the approved Regulatory Guide 1.190 methodology to put on same basis 28
Projections of Calculated Maximum Vessel Neutron Fluence for Palisades Vessel Cycles 21 through 36 29
30 Update of WCAP-15353 WCAP-15353 Supplement 1 (Cont.)
Supplement 1 to WCAP-15353 provides a list of updated neutron fluence values based on the approved Westinghouse fluence methodology for each of 11 surveillance capsules from four vessels
- Use of previously approved methodology that meets the requirements of Regulatory Guide 1 1.190 190
- Use of same methodology puts all data on same fluence basis.
- Applies to data on weld heat W5214 from surveillance capsules irradiated in Palisades, H.B. Robinson Unit 2, Indian Point Unit 2 and Indian Point Unit 3
- Data being used for evaluation of RTPTS for the Palisades reactor vessel weld seams 2-112 A/C 31
Summary of Revised Capsule Fluence Values Containing Weld Heat No. W5214 Surveillance Fluence Reactor Capsule (E > 1.0 Mev) Reference Designation [n/cm2]*
Palisades A240 4.09 E+19 WCAP-15353, Rev. 0 Palisades W290 9.38 E +18 WCAP-15353, Rev. 0 Palisades W100-1 1.64 E +19 WCAP-15353, Rev. 0 Palisades SA60-1 1.50 E +19 WCAP-15353, Rev. 0 Palisades SA240-1 2.38 E +19 CPAL-01-009 Palisades W100-2 2.09 E +19 CPAL-04-8 Indian Point 2 T 2.53 E +18 WCAP-15629, Rev. 1 I di P Indian Point i t2 Y* 4 55 E +18 4.55 18 WCAP 15629 Rev.
WCAP-15629, R 1 Indian Point 2 Z 1.02 E +19 WCAP-15629, Rev. 1 Indian Point 2 V* 4.92 E +18 WCAP-15629, Rev. 1 H. B. Robinson S 4.79 E +18 WCAP-15805, Rev. 0 H. B. Robinson V* 5.30 E +18 WCAP-15805, Rev. 0 H. B. Robinson T* 3.87 E +19 WCAP-15805, Rev. 0 H. B. Robinson X* 4.49 E +19 WCAP-15805, Rev. 0 Indian Point 3 T* 2.63 E +18 WCAP-16251-NP, Rev. 0 Indian Point 3 Y* 6.92 E +18 WCAP-16251-NP, Rev. 0 Indian Point 3 Z* 1.04 E +19 WCAP-16251-NP, Rev. 0 Indian Point 3 X* 8.74 E +18 WCAP-16251-NP, Rev. 0
- All fluences determined by identical method meeting requirements of Regulatory Guide 1.190 32
Steps in Evaluation of Surveillance Data for Limiting Weld Heat W5214
- 1. Assess all eleven capsules w/W5214 surv. data
- 2. Include updated capsule fluence results
- 3. Refit Charpy test data using TANH curve-fits 4
- 4. Adjust T30 values for chemistry differences
- 5. Adjust T30 values for temperature differences
- 6. Determine the best-fit CF value for the measured T30 vs. fluence results. Perform data credibility assessment and project the RTNDT for the Palisades limiting vessel weld.
33
PTS Assessment for Limiting Weld Metal - First Step
- Gather and assess all data from the eleven capsules with W5214 weld metal
- The data were considered without any adjustments for differences (in chemistry and irradiation temperature) to determine the mean trend in irradiation damage behavior
- The original fluences and reported shift values were used in the initial assessment
- The mean trend, or average chemistry factor, was calculated from a least squares fit to the data using Equation (5) from 10CFR50.61 34
PTS Assessment for Limiting Weld Metal - First Step (Cont.)
- The least squares fit method was used to determine a best fit chemistry factor (CF) of 217.67°F (see Table 1)
- The predicted (average) chemistry factor for the surveillance specimens based on chemistry (from the PTS Rule Table 1) was CF = 234.37°F
- The mean fit to the data shows that the CF value and the fitted trend for these data is well below that determined from the PTS Rule tables (i.e.,
surveillance data not available) 35
Table 1.
Results for all W5214 Surveillance Data with Reported Fluence and Vendor Reported Shift Results Reported Reported Predicted Measured -
Capsule %Cu (a)
%Ni (a)
CF (F) Fluence (b) FF RTndt RTndt Predicted (n/cm^2) (F) (F) RTndt (F)
SA-60-1 0.307 1.045 266.5 1.61E+19 1.13 259 246.3 12.7 SA-240-1 0.307 1.045 266.5 2.60E+19 1.26 280.1 273.4 6.7 HB2 T 0.34 0.66 217.7 3.87E+19 1.35 288.15 293.6 -5.5 HB2 V 0.34 0.66 217.7 5.30E+18 0.82 209.32 179.1 30.3 HB2 X 0.34 0.66 217.7 4.49E+19 1.38 265.93 300.5 -34.6 IP2 V 0.20 1.03 226.3 5.59E+18 0.84 204 182.3 21.7 IP2 Y 0.20 1.03 226.3 5.89E+18 0.85 195 185.4 9.6 IP3 T 0.16 1.12 206.2 2.63E+18 0.64 151.6 138.6 13.0 IP3 Y 0.16 1.12 206.2 6.92E+18 0.90 172 195.2 -23.2 IP3 Z 0.16 1.12 206.2 1.04E+19 1.01 229.2 220.1 9.1 IP3 X 0.16 1.12 206.2 8.74E+18 0.96 193.2 209.4 -16.2 Average = 0.243 0.965 Table CF = 234.37°F Best fit CF = 217.67°F (a) Measured capsule weld materials Cu and Ni values obtained from [6, 12, 13, 14, 15, 20, 26]
(b) Reported capsule fluence values from [6, 7, 12, 13, 28]
36
Best Fit to Data for all W5214 Surveillance Data with Reported Fluence and Vendor Shift Values 37
PTS Assessment for Limiting Weld Metal - Second Step
- The second step is to use the new calculated fluence results (shown in Table 2) that were used to re-evaluate all the relevant surveillance data
- The same Westinghouse fluence methodology was used to calculate fluence in the wall of the Palisades vessel for prediction of the vessel embrittlement 38
39 PTS Assessment for Limiting Weld Metal - Third Step
- The third step is to refit all the W5214 CVN data
- The original Charpy V-notch energy data from Palisades, Indian Point 2, Indian Point 3, and H.B. Robinson were refitted using the CVGRAPH 5.0 hyperbolic tangent curve-fittingg method for consistencyy
- TANH fits can produce different T30 values (eg., see figures for IP2)
- The results of the refitted and reanalyzed weld heat No.
W5214 data for 30 ft-lb shift (T30) are shown in Table 3; these refitted Charpy data results have been verified for use in the new credibility evaluation 40
Example of Reported CVN Results for Indian Point 2 Surveillance Weld Data
Reference:
SwRI-17-2108 41
Example of TANH Fit CVN Results for Indian Point 2 Surveillance Weld Data 42
43 PTS Assessment for Limiting Weld Metal - Fourth Step
- The fourth step involves using the ratio procedure to account for differences in Cu and Ni content between the surveillance capsule material and the Palisades limiting vessel weld best estimate chemistry
- Accounting for differences in chemical content of the materials is necessary when applying data from other plants to the plant of interest (i.e., Palisades)
- These adjustments will affect the fitted CF value and the scatter in the data to determine its credibility
- The ratio adjusted shift values are shown in the following table 44
45 PTS Assessment for Limiting Weld Metal - Fifth Step
- The fifth step involves adjustments to shift data using surveillance capsule irradiation temperatures relative to the irradiation temperature for the plant of interest - 1 degree of shift for 1 degree of irradiation temperature difference
- Time-weighted average temperatures were determined for the Palisades capsules, Indian Point 2 capsules, and Indian Point 3 capsules containing weld heat No. W5214
- The RTNDT shift values with the ratio and temperature adjustments are shown in the following table 46
47 PTS Assessment for Limiting Weld Metal - Sixth Step
- The sixth step is to:
- Determine the best-fit CF value for the measured and adjusted T30 vs. fluence results for the W5214 surveillance data
- Perform data credibility assessment, project the RTNDT for the Palisades limiting vessel weld, and determine critical fluence at RTPTS = 270oF
- Determine the date to reach the screening criteria limit based on reaching critical fluence 48
PTS Assessment for Limiting Weld Metal - Sixth Step - Application
- 10CFR50.61 describes general procedures acceptable to the NRC staff for calculating the effects of neutron radiation embrittlement of low-alloy steels currently used for light-water-cooled reactor vessels. 10CFR50.61 provides two methods for calculating the adjusted reference temperature of the reactor vessel beltline materials materials. The first method is described in paragraph (c)(1). The second method is described in paragraphs (c)(2) and (c)(3). The procedures in paragraphs (c)(2) and (c)(3) can only be applied when two or more credible surveillance data sets become available.
- NRC provided additional guidance for evaluation and use of surveillance data in Attachment 3 of Memorandum to Edmund Sullivan, November 19, 1997.
49
PTS Assessment for Limiting Weld Metal - Sixth Step - Credibility
- Criterion 1: The materials in the surveillance capsules must be those which are the controlling materials with regard to radiation embrittlement
- At the end of Cycle 11, the Palisades surveillance capsule program was augmented to contain two supplemental surveillance capsules capsules, designated as SA-60-1 and SA-240-1 SA-240-1, installed in the capsule holders located on the core support barrel
- Surveillance capsule SA-60-1 and SA-240-1 contained test specimens from the following material heat No.s: W5214, 34B009, 27204, and standard reference material HSST-02.
- Thus, Criterion 1 is satisfied 50
PTS Assessment for Limiting Weld Metal - Sixth Step - Credibility (Cont.)
- Criterion 2: Scatter in the plots of Charpy energy versus temperature for the irradiated and unirradiated conditions should be small enough to permit the determination of the 30 ft-lb temperature and upper shelf energy unambiguously.
- Unirradiated and irradiated Charpy energy versus temperature data for the weld metal were fitted and plotted using the CVGRAPH TANH fitting program program.
- Based on engineering judgment by looking at the fitting parameters and the plots, the scatter in the data is small enough, and the correlation coefficients are high enough, to permit the determination of the 30 ft-lb temperature and upper shelf energy of the surveillance weld materials unambiguously.
- Thus, Criterion 2 is satisfied.
51
PTS Assessment for Limiting Weld Metal - Sixth Step - Credibility (Cont.)
- Criterion 3: When there are two or more sets of surveillance data from one reactor, the scatter of RTNDT values about a best-fit line drawn as described in Position 2 (surveillance data available) normally should be less than 28°F for welds and 17°F for base metal. Even if the fluence range is large (two or more orders of magnitude), the scatter should not exceed twice those values. Even if the data fails this criterion for use in shift calculations, they may be credible for determining decrease in upper shelf energy if the upper shelf can be clearly determined, following the definition in ASTM E185.
- Criterion 3 has been assessed for 2 Cases:
- Case 4a Credibility Assessment - Only Palisades W5214 Capsule Data
- Case 4b Credibility Assessment - All W5214 Surveillance Capsule Data 52
PTS Assessment for Limiting Weld Metal -
Sixth Step - Credibility (Cont.) Case 4a
- The data most representative for the Palisades limiting vessel weld are the supplemental surveillance capsules containing weld heat No. W5214 since the irradiation environment of the surveillance capsules and the reactor vessel are the same. The data requires the least adjustment. An adjustment can be made for the difference between the chemistry of the capsule specimens (CF = 266.5°F) and the best estimate chemistry of the vessel (CF = 230.73°F) using the ratio procedure.
The updated fluence and ratio adjusted shift values were used to calculate a new least-squares fitted chemistry factor. The Palisades capsule data are shown in Table 5 along with the fitted solution (i.e., mean shift prediction) result, and the comparison of the measured - predicted scatter from the fitted CF of 198.8°F. A plot of the measured T30 vs. fluence results for the Palisades supplemental capsule weld (W5214) is shown in Figure 2 along with the +/- 1 bounds for credible data scatter. The data clearly fall within the 1-sigma scatter band for credible surveillance data and the margin term can be reduced when using credible data.
- Based on criterion 3, the Palisades surveillance data is credible since the scatter is less than 28°F for both of these surveillance capsules.
53
Results for Case 4a Data Credibility Assessment Note: The Palisades only W5214 surveillance data has a lower fitted CF value = 198.8°F and the data scatter is less than 28°F.
54
Palisades Supplemental Surveillance Data (W5214) with Revised Fluence and Refitted Shift (Case 4a) 55
PTS Assessment for Limiting Weld Metal -
Sixth Step - Credibility (Cont.) Case 4b
- Following the NRC guidance for Case 4, the data from all sources also should be considered. For weld heat No. W5214, there are a total of eleven surveillance capsules from Palisades, Indian Point Unit 2, Indian Point Unit 3, and H.B. Robinson Unit 2. Since data are from multiple sources, the data must be adjusted first for chemical composition differences and then for irradiation temperature differences before determining the least-squares fit.
- For a credibility determination, the measured and refitted T30 shift data for all the relevant plant data were normalized to the mean chemistry factor of the vessel (230.73°F) using the ratio procedure and then to the mean operating temperature (535.2°F) for the Palisades vessel . The fitted CF value, shown in Table 6, is determined to be 227.74°F for this case.
56
Note: the revised CF using all Weld Heat No. W5214 surveillance data = 227.74°F 57
PTS Assessment for Limiting Weld Metal -
Sixth Step - Credibility (Cont.) Case 4b
- The results for (measured - predicted) scatter for all the W5214 surveillance data results are shown in Table 7. The results for all the surveillance capsule data are plotted in Figure 3 along with the +/- 2 sigma scatter bands. The scatter in the measured - predicted values exceeds 28°F (1- sigma) for a few points. Four of the measured - predicted RTNDT values are outside the 1-sigma band of 28°F, but all data points are within the 56°F (2-sigma) scatter band for welds. According to 10CFR50.61 paragraph (c)(2)(iv), the use of results from the plant-specific surveillance program may result in an RTNDT that is higher or lower than that d
determined i d ffrom the h chemistry h i off the h weld ld and d a chemistry h i ffactor using i the h
tables. If the CF value is higher, it must be used for vessel RTPTS predictions, if the CF value is lower, it may be used.
- The chemistry factor from paragraph (c)(1) is 230.73°F, and the adjusted chemistry factor using the Palisades surveillance capsule data is 227.74°F. It is noted that per NRC guidance that it is possible to use a lower value of chemistry factor based upon all sources of surveillance capsule data with a full margin term (i.e., 56°F) if the data is credible in all other ways but the scatter.
- Criterion 3: Using all W5214 surveillance data, the fitted CF is lower than the chemistry tables (227.74°F vs. 230.73°F), however the data scatter is greater than 28°F but less than 56°F.
58
Best Fit for all W5214 Surveillance Data with Revised Fluence and Refitted Shift (Case 4b) 59
60 PTS Assessment for Limiting Weld Metal - Sixth Step - Credibility (Cont.)
- Criterion 4: The irradiation temperature of the Charpy specimens in the capsule should match the vessel wall temperature at the cladding/base metal interface within +/- 25°F.
- For Palisades, the location of the specimens with respect to the reactor vessel beltline assured that the reactor vessel wall and the specimens have experienced equivalent operating conditions such th t th that the ttemperatures t did nott diff differ b by more th than 25°F 25°F. Therefore, Th f criterion 4 is satisfied for the Palisades capsules.
- The Indian Point Unit 2 and Indian Point Unit 3 average surveillance capsule temperatures have been also reviewed and updated. The H.
B. Robinson Unit 2 average capsule temperature was confirmed by the utility. The time-weighted average temperature values for these capsules are listed in Table 2, and the method for calculating these temperatures is given in Appendix H of SIA Report No. 0901132.401, Rev. 0. Criterion 4 has been met for the other capsules.
61
PTS Assessment for Limiting Weld Metal - Sixth Step - Credibility (Cont.)
- Criterion 5: The surveillance data for the correlation monitor material in the capsule should fall within the scatter band for that material.
- The Palisades supplemental surveillance capsules, SA-60-1 and SA-240-1, both contain standard reference material HSST02 plate. Plots of the Charpy energy versus temperature for the irradiated condition of correlation monitoring material (HSST Plate 02, Heat A1195-1) from SA 60 1 and SA-60-1 d SA SA-240-1 240 1 are documented d d iin BAW BAW-2341 2341 Rev R 2 and d BAW-BAW 2398, respectively. Charpy energy versus temperature for the unirradiated correlation monitoring material (HSST Plate 02, Heat A1195-1) is taken from NUREG/CR-6413, ORNL/TM-13133. Tables 9 and 10 provide the updated calculation of (measured - predicted) scatter versus fast fluence in the correlation monitor material (HSST
- 02) data. Figure 4 (from Reference 24) shows that the measured scatter band for the correlation monitor materials is 50°F.
- Thus, Criterion 5 is satisfied.
62
Fitted Chemistry Factor for HSST02 From Palisades Supplemental Surveillance Capsules Fitted CF = 108.853°F for Correlation Monitor Materials 63
Correlation Monitor Material HSST02 from Palisades Capsules Calculation of Data Scatter Data points within predicted scatter for Correlation Monitor Materials 64
Residual Scatter in HSST-01/
HSST-02 Correlation Monitor Materials 65
PTS Assessment for Limiting Weld Metal -
Sixth Step - Limiting Value of PTS Fluence
- WCAP-15353 Supplement 1 gives projected fluences for the Palisades vessel beltline region for future operation
- The projected neutron fluence values for the limiting 60° weld location were presented earlier
- Note: the cycle specific projections for the fuel designs of Cycles 21 and beyond assumed 95% capacity factor for future plant operation
- Limiting values of fluence can be determined based upon CF and Margin terms for different cases 66
Fluence Calculations and Projections from Revised Fluence Evaluation 67
PTS Assessment for Limiting Weld Metal - Summary of Results
- Four specific cases have been reviewed/evaluated:
- First Case, identified as Case 1, uses Table 1 of the PTS Rule using the current licensing basis method for CF and considering the revised fluence calculations and projections
- Second Case, identified as Case 2, uses Table 1 of the PTS Rule with the current licensing basis method and considering the revised fluence calculations and projections along with lower nickel as determined by the CEOG report
- Third Case, identified as Case 4a, employs a credibility assessment, and has a calculated fitted chemistry factor of 198.8°F from the two Palisades capsule data points with a reduced margin term
- Fourth Case, identified as Case 4b, employs a credibility assessment, and has a calculated fitted chemistry factor of 227.74°F based on data from all 11 capsules with no reduced margin term 68
Summary of Results for Case 1
- Case 1 is based on Table 1 of the PTS Rule using the current licensing basis method and considering the revised fluence calculations and projections, as shown in Table 11.
- The chemistry factor for the weld heat No. W5214 was based on best-estimate Cu = 0.213%, Ni = 1.01%, and a CF = 231.08°F. The maximum fluence limit was calculated to be 1.584 E19 n/cm / 2 according to the embrittlement prediction method when surveillance data is not available.
- That prediction of RTNDT shift is shown in Table 12, and the corresponding date to reach the PTS screening criteria limit of 270°F for axial welds is March 2014 using the fluence interpolation given in Table 16. The current licensing basis date to reach the PTS screening criteria date is January 2014. It has been determined that the Palisades plant is still operating within that licensing basis.
69
- This is the currently licensing basis limiting fluence value 70
- Maximum fluence limit = 1.584x1019 n/cm2 for current licensing basis material case, CF = 231.08°F
Summary of Results for Case 2
- Case 2 follows Table 1 of the PTS Rule, but considers that the actual best-estimate chemistry for weld heat No. W5214 has slightly lower nickel as determined by the CEOG report in 1998.
- This evaluation was performed after the initial PTS submittal in 1995 and, using this information, the revised Ni = 1.007% which gives a new value of CF = 230.73°F.
- It is p permitted under the PTS Rule in 10CFR50.61 to use the best-estimate values for Cu and Ni, however there is only a slight difference in the maximum fluence to reach the PTS screening criteria limit (i.e., 1.595 E19 n/cm2) as shown in Table 13.
- The projected date to reach that limit using the interpolated fluence projections is July 2014 as shown in Table 16.
- Although this case does not show much additional margin from the January 2014 date, it is provided here to show that there is still slightly more time to be gained within the Position 1 approach of the PTS Rule method before the vessel reaches the 270°F screening criteria limit.
72
- This is the limiting fluence using the revised best-estimate Ni value and CF for weld heat No. W5214 from the CEOG report 73
Summary of Results for Case 4a
- The Case 4a credibility assessment calculated a fitted chemistry factor of 198.8°F from the two Palisades capsule data points.
- The data were deemed to be credible based on meeting all the credibility criteria including scatter within the 1-sigma (i.e., 28°F) scatter bounds.
- The limiting fluence for the vessel for this case is shown in Table 14.
- Using these results and a reduced margin term to account for credible data, the projected date to reach the PTS screening criteria limit would be beyond 2034 for the limiting vessel weld heat No.
W5214, as shown in Table 18.
- Note: It is likely that some other beltline material would become limiting if this case was used for weld heat No. W5214. However, this case demonstrates that surveillance data can provide significant improvement in determining the effects of embrittlement on the limiting vessel beltline weld material.
74
- This is the limiting fluence value using only the Palisades surveillance weld data (that is credible) and a reduced margin term 75
Summary of Results for Case 4b
- The Case 4b credibility assessment uses all sources of surveillance data that match the limiting weld heat No. W5214.
- For Case 4b, the credibility assessment determined the fitted CF =
227.74°F.
- The data meet credibility criteria 1, 2, 4, & 5, and the scatter of the (measured - predicted) data was within 2-sigma (i.e., 56°F) such that it can be considered to be credible data for the chemistryy factor;; however,,
the margin term, , cannot be reduced in half. Use of Case 4b for the Palisades vessel is acceptable because the (measured - predicted) scatter in the weld data is within the acceptable range of 56°F for a wide range of fluence.
- The limiting fluence for Case 4b is 1.685 E19 n/cm2 (E > 1 MeV) as shown in Table 15. Table 17 interpolates the vessel fluence and shows the projected date to reach the screening criteria limit is April 2017, a difference of three years compared to the first case using the current licensing basis and Position 1 approach.
76
- This is the limiting fluence considering all surveillance data for weld heat No. W5214 with no reduced margin term 77
- Maximum fluence limit = 1.685x1019 n/cm2 for Case 4b using revised fluence and W5214 surveillance data CF = 227.74°F and full (2-sigma) margin term 78
Comparison of All Results
- A summary of the four cases considered in this analysis is given in Table 18
- The results are show graphically in Figure 5 79
Summary of PTS Limit Results for Four Cases Studied for Weld Heat No. W5214 Table 18.
Projected Maximum Fluence and Estimated PTS Limit Dates for Palisades Weld W5214 Case No. CF IRTNDT Fluence FF RTNDT Margin RTPTS Est. PTS Date 19 2
(°F) (°F) (10 n/cm ) (°F) (°F) (°F)
(1) Current LB w/revised 231.08 -56 1.584 1.1270 260.5 65.5 270 March 2014 fluence (2) Current LB w/revised
/ d 230.73 -56 1.595 1.1289 260.5 65.5 270 July 2014 fluence and revised CF value 4a 198.80 -56 5.438 1.4185 282 44 270 > 2034*
4b 227.74 -56 1.685 1.1437 260.5 65.5 270 April 2017
- Other beltline materials will likely become more limiting and will affect this date Case 1 - Current licensing basis CF value for W5214 weld and revised fluence calculation Case 2 - CEOG best estimate chemistry and CF value for W5214 weld and revised fluence calculation Case 4a - Use of credible Palisades W5214 surveillance data and revised fluence with reduced margin term Case 4b - Use of all W5214 surveillance data and revised fluence with full margin term 80
Figure 5. Projected Peak Fluence at 60° Weld Location and Revised RTPTS Limit Dates for Four Cases Studied 81
Future Plans for Palisades Regarding PTS
- Based upon the new projection when the PNP RPV will reach the PTS screening criteria, ENO has identified the need for the following future activities:
- Continue to interact with NRC through meetings and correspondence on status
- Reschedule of the volumetric inspection for the PNP RPV from the fall 2010 refueling outage to the spring 2012 refueling outage
- Update PTS evaluation and transmit to NRC for review and approval
- Confirm that the PNP RPV heat-up and cool-down curves located in the Plant Technical Specifications are good for operation through March 2014
- Following inspection of the PNP RPV in spring 2012, perform an assessment of the PNP RPV in accordance with 10CFR50.61a
- Following NRC review and approval of the PTS assessment of the PNP RPV under 10CFR50.61 or 10CFR50.61a, update and transmit the PNP RPV heat-up and cool-down curves located in the Plant Technical Specifications for operation through the balance of the licensed life of the plant in March 24, 2031
- The ultrasonic inspection of the PNP RPV planned in the spring of 2012 and subsequent evaluation in accordance with 10CFR50.61a will satisfy the PTS regulatory requirements through the remaining period of extended operation 82
Palisades Implementation of 10 CFR 50.61a
- Palisades was one of plants used in the development of the Alternate PTS Rule
- Plant-specific assessment of PTS risk for the Palisades reactor pressure vessel was performed
- Palisades was one of vessels used to develop the technical basis for the PWROG Reactor Vessel In-Service Inspection interval extension
- Implementation I l t ti off RV ISI IInterval t l EExtension t i requires i evaluation l ti off ththe main elements of 10 CFR 50.61a
- Evaluation of ISI data against PTS flaw limits has been performed using both RG 1.150 and Appendix VIII ISI data
- 17 submittals have been approved to date by the NRC
- 2 approved submittals have included qualitative evaluations of ISI data that exceeded alternate rule flaw limits
- 4 approved submittals have included surveillance data assessment
- Palisades has implemented the ISI interval extension 83
Palisades Implementation of 10 CFR 50.61a (cont.)
- Palisades intends to perform evaluations required for implementation of 10 CFR 50.61a in advance of the 2012 RV ISI
- Calculation of RTMAX values will be performed based on updated fluence values from WCAP-15353, Supplement 1-NP
- Surveillance data assessment will be performed for those materials with 3 or more points of plant specific data - (2 Palisades-specific data for W5214; 11 overall measurements includingg other plants) p )
- ISI data assessment
- Evaluation previously performed as part of ISI interval extension submittal
- Used 1995 ISI results (Regulatory Guide 1.150 Examinations); results acceptable
- Experience from ISI interval extension indicates that RG 1.150 examinations have resulted in conservative sizing of indications and false characterization of reflections as indications
- Expect acceptable results based on evaluation of Palisades Appendix VIII Exam data
- Assessment will be updated using results from Appendix VIII qualified exam to be performed in 2012
- Surface exam may be required due to known areas of underclad cracking
- Evaluations will be updated following 2012 RV ISI 84
Proposed Timeline for Future Actions Target Action to Be Taken June 22, 2010 Present new and pertinent surveillance data for Palisades Today limiting weld metal relative to RTPTS in a consistent manner Summer/Fall Initiate activities relative to 10CFR50.61a evaluation prior to 2010 inspection in Spring 2012 Submit complete PTS assessment for 10CFR50.61 utilizing new and pertinent data presented on June 22 22, 2010; also Late 2010 validate date of March 2014 for current heat-up and cool-down curves Spring 2012 Perform ISI inspection of PNP RPV Complete 10CFR50.61a assessment for PNP RPV and submit Fall 2012 to NRC for review and approval Late 2012 Submit revised PNP RPV heat-up and cool-down curves March 24, 2031 Continued plant operation under renewed license 85
Questions 86
Identification of Action Items
- Review and record action items for meeting 87
BACKUP INFORMATION IF NEEDED 6/8/2010 88
WCAP-15353 Supplement 1 Neutron Flux Projections Fuel Cycle Cycle Time (EFPY) Neutron (E>1.0 MeV)
Flux (n/cm2-s) 60 Degree Location 15 1.1 1.105E+10 16 12 1.2 1 135E 10 1.135E+10 17 1.3 9.781E+09 18 1.3 1.088E+10 19 1.3 1.090E+10 20 1.4 1.161E+10 21 1.4 1.172E+10 22 Projected 1.128E+10 23+ Projected 1.172E+10 89
Future Plans Validation of PTS Evaluation Palisades RT PTS Values on March 24, 2031 (Low Leakage Core)
Values Taken From LT-TR-021-RPV-R0 Evaluation of Palisades Nuclear Plant Reactor Pressure Vessel Through the Period of Extended Operation CNS-04-02-01, Revision 1 RPV Material Cu% Ni % EOLE RT NDT (U) Margin RT PTS o o o Material Heat # Fluence F F F (n/cm2)
Axial W5214 0.213 1.01 2.084 x -56 65.5 287 Welds 2- 1019 112A/C Axial W5214 0.213 1.01 2.084 x -56 65.5 287 Welds 3- 1019 112A/C 34B009 0.192 0.980 2.084 x -56 65.5 271 1019 Circumfer 27204 0.203 1.1018 2.998 x -56 65.5 302 ential 1019 Weld 9-112 Plate D- C-1279 0.24 0.50 2.998 x -5 17 209 3803-1 1019 Plate D- A-0313 0.24 0.52 2.998 x -30 34 210 3803-2 1019 Plate D- C-1279 0.24 0.50 2.998 x -5 17 209 3803-3 1019 Plate D- C-1308A 0.19 0.48 2.998 x 0 34 200 3804-1 1019 Plate D- C-1308B 0.19 0.50 2.998 x -30 34 173 3804-2 C 1019 Plate D- C-1308B 0.12 0.55 2.998 x -25 34 115 3804-3 1019 90