ML13262A449
| ML13262A449 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 09/23/2013 |
| From: | Erickson J Entergy Nuclear Operations |
| To: | Office of Nuclear Reactor Regulation |
| Chawla M | |
| References | |
| TAC MF2744 | |
| Download: ML13262A449 (29) | |
Text
NRC and Palisades Pre-Submittal Conference October 9, 2013 Appendix G Equivalent Margins Analysis Submittal 1
Introduction
- Participant Introductions
- Purpose of Telecon
- Appendix G Equivalent Margins Analysis (EMA)
- Reactor Vessel Fluence Evaluation
- Reactor Vessel Extended Beltline Evaluation 2
Agenda
- Current Condition of Reactor Vessel
- Submittal Content
- Palisades Commitment
- Appendix G,Section IV.A.1
- Materials Evaluated in EMA
- Location of Three Materials Evaluated in EMA
- Fluence Evaluation
- Extended Beltline Evaluation
- Equivalent Margins Analysis
- Generic Combustion Engineering EMA
- Schedule
- Questions and Follow-Up Actions 3
Current Condition of Reactor Vessel
- Operating Cycle - 23 (May 12, 2012 through Jan 19, 2014)
- Projected - 26.1 effective full power years (EFPY) at end of cycle 23
- Projected Fluence - 2.340 x 1019 n/cm2 (75 Degree) 4
Submittal Content Cover letter with three attached reports:
- WCAP-15353 Supplement 2-NP, Rev 0, July 2011, Palisades Reactor Pressure Vessel Fluence Evaluation
- WCAP-17403-NP, Rev 1, January 2013, Palisades Nuclear Power Plant Extended Beltline Reactor Vessel Integrity Evaluation
- WCAP-17651-NP, Rev 0, February 2013, Palisades Nuclear Power Plant Reactor Vessel Equivalent Margins Analysis 5
Palisades Commitment In accordance with 10 CFR 50 Appendix G, Section IV, Fracture Toughness Requirements, Palisades Nuclear Plant (PNP) committed in its renewed license application dated March 22, 2005, to submit an equivalent margins analysis for NRC approval at least three years before any reactor vessel beltline material Charpy upper-shelf energy (USE) decreases to less than 50 ft-lbs.
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Appendix G,Section IV.A.1 Reactor vessel beltline materials must have Charpy upper-shelf energy in the transverse direction for base material and along the weld for weld material according to the ASME Code, of no less than 50 ft-lbs, unless it is demonstrated that lower values of Charpy upper-shelf energy will provide margins of safety against fracture equivalent to those required by Appendix G of Section XI of the ASME Code.
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Appendix G,Section IV.A.1 (continued)
The analysis for satisfying section IV.A.1 of Appendix G must be submitted for review and approval at least three years prior to the date when the predicted Charpy upper-shelf energy will no longer satisfy the requirements of section IV.A.1, or on a schedule approved by the NRC, as appropriate.
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Materials Evaluated in EMA As documented in the PNP license amendment request concerning primary coolant system (PCS) pressure-temperature limits, two beltline materials are predicted to drop below the 50 ft-lbs screening criterion prior to the operating license expiration date.
- Lower Shell (LS) Plate D-3804-1 is predicted to drop below the criterion in December 2016.
- Intermediate Shell (IS) to Lower Shell (LS) Circumferential Weld 9-112 is predicted to drop below the criterion in November 2027.
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Materials Evaluated in EMA (continued)
- An analysis was performed for the extended beltline materials. It included pressurized thermal shock (PTS),
upper-shelf energy (USE) and adjusted reference temperature (ART) evaluations.
- The analysis confirmed that all of the extended beltline materials are projected to remain below the PTS screening criteria values through end-of-license-extension (EOLE), 42.1 EFPY.
- All of the ART values for the extended beltline materials were confirmed to remain below those used in the analysis of record (WCAP-17341-NP, Revision 0) through EOLE. Therefore, the PNP pressure-temperature (P-T) limit curves continue to be governed by the traditional beltline only.
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Materials Evaluated in EMA (continued)
The extended beltline analysis identified a third material, Upper Shell (US) Plate D-3802-3, as marginally meeting the USE screening criterion before EOLE.
The analysis calculated US D-3802-3 EOLE USE values based on using two different methods:
- CV Graph Refitted Initial USE = 50.1 ft-lbs
- 95% Shear Initial USE = 47.5 ft-lbs 11
Materials Evaluated in EMA (continued)
Although the analysis determined that the 50 ft-lbs USE criterion is satisfied through end of license renewal period, the US D-3802-3 plate material was included in the EMA analysis because of the potential for future changes in fluence to cause the material to drop below the USE criterion.
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Locations of Three Materials Evaluated in EMA 13
WCAP-15353 - Supplement 2-NP Palisades Reactor Pressure Vessel Fluence Evaluation
- Method used to model extended beltline region
- Reg Guide 1.190 compliant method
- Method previously reviewed and approved by NRC
WCAP-17403-NP, Palisades Nuclear Power Plant Extended Beltline Reactor Vessel Integrity Evaluation
- Evaluated materials in the reactor with the potential to exceed a fluence of 1.0E+17 n/cm2 (E > 1.0 MeV)
- Extended beltline region does not reach nozzle material
- Additional material consists of:
- Upper Shell Plates (D-3802-1, D-3802-2, D-3802-3)
- Upper Shell Axial Welds 1-112 A/B/C
- Upper Shell to Intermediate Shell Circumferential Weld 8-112 15
Extended Beltline Evaluation (continued) 16
Extended Beltline Evaluation (continued)
- RTPTS values of extended beltline materials bounded by traditional beltline materials
- ART1/4T and ART3/4T values of extended beltline materials bounded by traditional beltline materials
- No impact on LTOP 17
WCAP-17651-NP, Palisades Nuclear Power Plant Reactor Vessel Equivalent Margins Analysis
- Combustion Engineering Plant Generic Equivalent Margin Analysis is documented in CE-NPSD-993.
- Submitted formally to the NRC in 1995.
- CE-NPSD-993 also included in a package of documents submitted by Maine Yankee, also in 1995.
- Palisades Plant Specific Equivalent Margin Analysis:
Equivalent Margins Analysis (continued)
- Three materials evaluated
- LS Plate D-3804-1
- IS to LS Circumferential Weld 9-112 (Heat #
27204)
- US Plate D-3802-3 (selected from extended beltline evaluation) 19
Equivalent Margins Analysis (continued)
- Evaluation Based Upon
- ASME Section XI, Appendix K Methodology
- Various postulated flaw depths, locations, and orientations, as well as the applied J-integral and stability criteria.
- Level A & B Service Loads
- flaw is an interior semi-elliptical surface with a depth of one-quarter of the vessel wall thickness and an aspect ratio (length over depth) of 6:1
- Level C & D Service Loads
- flaw is an interior semi-elliptical surface with a depth of 1/10 of the base metal wall thickness plus the cladding thickness (with a total depth not exceeding 1 inch) 20
Equivalent Margins Analysis (continued)
- Evaluation Based Upon
- Regulatory Guide 1.161 Methodology
- Selection of transients.
- 21 Transients Evaluated/Considered
>> 18 Design Basis Transients
>> 3 Cool down Events from Reg Guide 1.161
- Appropriate material properties
- Material fracture toughness J-resistance 21
Equivalent Margins Analysis (continued)
- Evaluation Based Upon
- Regulatory Guide 1.161 Methodology
- The J-R model is for materials with high fracture toughness.
For plate material with sulfur content less than 0.018 wt. %,
the J-R model may be used.
- For plate material with sulfur content greater than 0.018 wt. %,
the model may be used if it can be justified as conservative or a material-specific justification can be made based on other data.
- The PNP plates have a sulfur content slightly greater than the high-toughness model limit of 0.018 wt. % specified in RG 1.161.
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Equivalent Margins Analysis (continued)
- J-R Model
- The V-50 plate in NUREG/CR-5265 is used to bound the properties of the PNP Plates
- V-50 plate is SA-302 with high content of sulfur
- PNP Plates are Modified SA-302 B
- Modified, means that they have at least 0.4 wt. % nickel. Nickel was added to increase toughness.
- The J-applied in the PNP SA-302 B Modified plate remains below the measured very conservative lower-bound V-50 A-302 B plate J-R data.
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Equivalent Margins Analysis (continued)
- Service Level A and B Transients
- Intermediate to lower shell circumferential weld 9-112 (Heat #27204) is governing for EOLE USE margin at the 1/4-thickness location for normal Level A and B load conditions, based on the Reg Guide 1.161 fracture toughness methodology.
- The applied J-integral values for the assumed 1/4-thickness inside-surface circumferential flaws in the base metal and circumferential flaws in the weld metal with a safety margin of 1.15 on pressure loading are within the material fracture toughness J-resistance at 0.1-inch crack extension.
- The assumed flaw is ductile and stable with crack extension with a safety margin of 1.25 on pressure loading.
- The equivalent margins analyses for the plate materials are acceptable and bounded by the conservative test data reported in NUREG/CR-5265 in all cases for Service Level A and B transients.
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Equivalent Margins Analysis (continued)
- Service Level C Condition with 400°F/hr Cooldown Transient
- Intermediate to lower shell circumferential weld 9-112 (Heat #27204) is governing for EOLE USE margin at the 1/10-thickness location for the Service Level C load condition, based on the Reg Guide 1.161 fracture toughness methodology.
- The applied J-integral values for the assumed 1/10 base metal thickness inside-surface circumferential flaws in the base metal and circumferential flaws in the weld metal with a safety margin of 1.00 on loading are within the material fracture toughness J-resistance at 0.1-inch crack extension.
- The assumed flaw is ductile and stable with crack extension with a safety margin of 1 on pressure loading.
- The equivalent margins analyses for the plate materials are acceptable and bounded by the conservative test data reported in NUREG/CR-5265 in all cases for the Service Level C transient 25
Equivalent Margins Analysis (continued)
- Service Level D Condition with 600°F/hr Cooldown Transient
- Intermediate to lower shell circumferential weld 9-112 (Heat #27204) is governing for EOLE USE margin at the 1/10-thickness location for the Service Level D load condition, based on the Reg Guide 1.161 fracture toughness methodology.
- The applied J-integral values for the assumed 1/10 base metal thickness inside-surface circumferential flaws in the base metal and circumferential flaws in the weld metal with a safety margin of 1.00 on loading are within the material fracture toughness J-resistance at 0.1-inch crack extension.
- The total flaw depth after a stable flaw extension is well within 75 percent of the vessel wall thickness, with the remaining ligament stable for crack propagation.
- The equivalent margins analyses for the plate materials are acceptable and bounded by the conservative test data reported in NUREG/CR-5265 in all cases for the Service Level D transient.
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Generic Combustion Engineering EMA (CE-NPSD-993)
- Minimum acceptable USE values
- Plate materials, Level A and B Transients
- Longitudinal direction 30 ft-lbs is acceptable.
- Transverse direction 19.5 ft-lbs is acceptable.
- Weld materials, Level A and B Transients
- Longitudinal welds need to exhibit at least 34 ft-lbs
- Circumferential welds need exhibit at least 19.5 ft-lbs
- Plate materials, Level C and D Transients
- Longitudinal direction 30 ft-lbs is acceptable
- Transverse direction 19.5 ft-lbs is acceptable
- Weld materials, Level C and D Transients
- Longitudinal and circumferential welds need to exhibit 30 ft-lbs to provide equivalent margins of safety
- All three PNP materials, two plate and one weld, with USE predicted to drop below 50 ft-lbs, meet the acceptance criteria of CE-NPSD-993.
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Schedule
- PNP plans to submit the equivalent margins analysis in November 2013.
- This is prior to the required submittal date in December 2013 based on the most limiting material, as documented in the PNP license amendment request concerning PCS pressure-temperature limits.
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Questions and Follow-up Actions 29