PNP 2014-066, Supplemental Response to NRC Request for Additional Information - Palisades Nuclear Plant 10 CFR 50 Appendix G Equivalent Margin Analysis - Mf 2962

Supplemental Response to NRC Request for Additional Information - Palisades Nuclear Plant 10 CFR 50 Appendix G Equivalent Margin Analysis - Mf 2962

ML14177A707
Person / Time
Site:	Palisades
Issue date:	06/26/2014
From:	Vitale A Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
PNP 2014-066, TAC MF2962
Download: ML14177A707 (14)

Text

.-

~Entergy Entergy Nuclear Operations, Inc.

Palisades Nuclear Plant 27780 Blue Star Memorial Highway Covert, MI 49043-9530 Tel 269 7642000 Anthony J. Vitale Site Vice President PNP 2014-066 June 26, 2014 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

SUBJECT:

Supplemental Response to NRC Request for Additional Information -

Palisades Nuclear Plant 10 CFR 50 Appendix G Equivalent Margin Analysis - MF 2962 Palisades Nuclear Plant Docket No. 50-255 License No. DPR-20

REFERENCES:

1. Palisades Nuclear Plant, Application for Renewed Operating License, dated March 22, 2005 (ADAMS Accession No. ML050940446).

2. Entergy Nuclear Operations, Inc. letter PNP 2013-028, Palisades Nuclear Plant 10 CFR 50 Appendix G Equivalent Margins Analysis, dated October 21, 2013 (ADAMS Accession No. ML13295A448).

3. NRC email to Entergy Nuclear Operations, Inc., Request for Additional Information - Palisades Nuclear Plant 10 CFR 50 Appendix G Equivalent Margin Analysis - MF 2962, dated May 13, 2014 (ADAMS Accession No. ML14133A684).

4. Entergy Nuclear Operations, Inc. letter PNP 2014-054, Response to NRC Request for Additional Information - Palisades Nuclear Plant 10 CFR 50 Appendix G Equivalent Margin Analysis -

MF 2962, dated June 12, 2014 (ADAMS Accession No. ML14163A622).

Dear Sir or Madam:

In the Palisades Nuclear Plant (PNP) license renewal application (Reference 1),

Nuclear Management Company (NMC), the former license holder for PNP, committed to submit an equivalent margins analysis (EMA) for Nuclear Regulatory Commission

PLP 2014-066 Page 2 of 2 (NRC) approval at least three years before any reactor vessel beltline material Charpy upper-shelf energy (USE) decreases to less than 50 ft-Ib, in accordance with 10 CFR 50 Appendix G, Section IV, "Fracture Toughness Requirements."

Entergy Nuclear Operations, Inc. submitted the required EMA in Reference 2.

In Reference 3, ENO received a request for additional information (RAI) concerning the EMA submittal. The ENO response to RAI questions 1, 3, 4, 5, and 6 was provided in in Reference 4.

This letter supplements Reference 4 by providing the response to RAI question 2 in Reference 3. The response to RAI question 2 is provided in the attachment.

This letter contains no new commitments and no revised commitments.

This submittal contains no proprietary information.

I declare under penalty of perjury that the foregoing is true and correct; executed on June 26, 2014.

Sincerely,

.f

Attachment:

Supplemental Response to NRC Request for Additional Information -

Palisades Nuclear Plant 10 CFR 50 Appendix G Equivalent Margin Analysis - MF 2962 cc: Administrator, Region III, USNRC Project Manager, Palisades, USNRC Resident Inspector, Palisades, USNRC

ATTACHMENT SUPPLEMENTAL RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION -

PALISADES NUCLEAR PLANT 10 CFR 50 APPENDIX G EQUIVALENT MARGIN ANALYSIS - MF 2962 A request for additional information (RAI) was received from the Nuclear Regulatory Commission (NRC) by electronic mail on May 13, 2014 concerning the Palisades Nuclear Plant (PNP) equivalent margins analysis submittal.

Entergy Nuclear Operations, Inc. (ENO) responded to questions 1, 3, 4, 5, and 6 of the RAI on June 12, 2014.

The ENO response to RAI question 2 is provided below.

NRC Request (May 13,2014)

2. Section 5. 1 states, "Only circumferential base metal flaws are considered in this analysis, because only the "weak" orientation USE is projected to drop below 50 ft-Ibs as described below." Please demonstrate that assuming a circumferential flaw in the base metal with the weak Charpy V-Notch (CVN) value in the EMA is more limiting than assuming an axial flaw in the base metal with the strong CVN value. Please note that the significantly greater applied J integral associated with the axial flaw may challenge the fundamental assumption in the EMA submittal.

ENO Response to RAI-2 As documented in WCAP-17651-NP, Revision 0, the PNP reactor vessel plates have sulfur content greater than the 0.018 wt_% value provided in Regulatory Guide 1.161 (Reference 1). Therefore, lower bound high-sulfur fracture toughness data from the V-50 plate included in NUREG/CR-5265 (Reference 7) was located, as documented in the WCAP, to provide justification for use of the J-R model included in Regulatory Guide 1.161.

However, since only transverse (T-L) direction, weak data, was available in this NUREG and since only the T-L upper-shelf energy (USE) dropped below 50 ft-Ibs, only circumferential flaws were considered in the original WCAP submittal since there was no longitudinal (L-T) direction, strong data, for which to compare with the axial J-applied values for PNP. The ENO interpretation of Regulatory Guide 1.161 was that this was allowable and axial flaws did not need to be considered since the longitudinal final USE values of the PNP plate materials were over the 50 ft-Ib limit of 10 CFR 50, Appendix G at end-of-license-1 of 12

extension (EOLE). However, per discussion during conference call between ENO and the NRC on June 6, 2014, axial flaws should still have been postulated, with longitudinal direction USE considered in the equivalent margins analysis.

Since the V-50 plate does not have L-T strong data reported in NUREG/CR-5265, the T-L data needs to be converted to L-T via an appropriate ratio to approximate the strong direction for direct comparison with axial flaws.

The standard ratio is 65% per Regulatory Guide 1.161. Data was located in NUREG/CR-6426 (Reference 6), which had fracture toughness data for both orientations for five of the eight plate codes tested in this report. New Table 5-7 documents the material properties, initial USE values and available fracture toughness data for these materials. The average L-T/T-L fracture toughness conversion was 68% with consideration of all data, and 64% when the Z1/Z2 plate codes were excluded, as they appear to be an outlier compared to the other data points. Either calculated percent conversion supports the generic 65% conversion, which was then selected for use to ratio up the V-50 plate data to L-T orientation for comparison with axial flaw J-Applied values at PNP.

New Table 5-8 details the axial flaw safety factors for all transients, Levels A, B, C and 0, with consideration of the Regulatory Guide 1.161 J-R model and limiting EOLE USE equal to 73 ft-Ibs per WCAP-17651-NP. New Table 5-9 details the axial flaw safety factors for all transients, Levels A, B, C and 0, with consideration of the V-50 plate data adjusted to the L-T orientation. New Figures 5-14 and 5-15 detail the applied J-Integral versus crack extension for axial flaws at 1/4t for Level A and B transients and applied J-Integral versus crack extension for axial flaws at 1/1 Ot for Levels C and 0 transients, respectively. New Figure 5-16 details the axial flaw J-Integral versus crack extension at 1/4t for Level A and B transients for base metal with Regulatory Guide 1.161 model J-R curves and V-50 plate data included. New Figure 5-17 details the axial flaw J-Integral versus crack extension at 1/4t, pressure = 2.75 ksi, and a 100°F/hr cooldown transient for base metal with Regulatory Guide 1.161 model J-R curves and V-50 plate data included. Lastly, new Figure 5-18 details the axial flaw J-Integral versus crack extension at 1/1 Ot for Levels C and 0 transients, for base metal with Regulatory Guide 1.161 model J-R curves and V-50 plate data included.

It should be noted, as discussed in detail in WCAP-17651-NP, that the V-50 plate data has a lower weight percent Ni value (0.23 wt_%), due to being A 302 B steel, and not SA 302 B, Modified, that contribute to the V-50 plate having lower fracture toughness than the PNP-specific plate materials. The PNP plates are SA 302 B, Modified, which means that they have at least 0.4% Ni. Nickel was added to increase toughness. Conservatively, the lowest J-R curve test data reported in NUREG/CR-5265, which is from a 6T size specimen, is used for comparison to the J-Applied values. The 6T data is considerably lower than test data for the 1T J-R data, which is the standard size specimen typically used.

Therefore, the V-50 plate 6T J-R data is a conservative lower bound, viewed as the worst possible case, and selected due to being the only available fracture toughness data with high-sulfur content.

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The minimum safety factor with consideration of the Regulatory Guide 1.161 J-R model, L-T orientation USE values and the PNP-specific axial flaw J-Applied values is 1.7 while the minimum safety factor with relative to the V-50 plate data and the PNP-specific axial flaw J-applied values is 1.4 at O.1-inch crack extension. All these cases have their structural factors above the minimum requirement of 1.15 per Regulatory Guide 1.161 and are deemed acceptable.

The flaw extension figures demonstrate that the NRC Regulatory Guide 100°F/hr cooldown transient with the accumulation pressure levels governs the Level A and B transients, which is the limiting case. All cases, where the Regulatory Guide 1.161 J-R material correlation is considered with axial flaw J-Applied pressure loadings, are acceptable with the applied J-integral values at O.1-inch crack extensions below the material J-resistance (J O.1 ) as required by the ASME Code Appendix K. In some instances with consideration of the V-50 plate data adjusted to the L-T orientation, the J-Material curves, adjusted to transient temperature, are either slightly below or just over the J-applied values, specifically for the Regulatory Guide 1.161 100°F/hour cooldown transient.

However, as discussed above, the V-50 data is a lower bound high-sulfur data set, that is not fully representative of the PNP actual plate materials, and this result can be considered acceptable with consideration of the associated Regulatory Guide 1.161 model, and the structural factor (SF) calculations shown in Tables 5-8 and 5-9. Finally, as discussed above, the Regulatory Guide 1.161 100°F/hour cooldown transient is more limiting than the PNP-specific transients, as shown in the comparison of J-Applied curves in Figures 5-16 and 5-17. Note that the Regulatory Guide 1.161 100°F/hour cooldown transient with pressure of 2.75 ksi is more conservative than PN P cooldown transient with pressure of 2.13 ksi.

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Table 5-7: NUREG/CR-6426 L-T (Strong) vs. T-L (Weak) Charpy USE and Fracture Toughness Data Initial USE USE J 0.1 J 0.1 Chemistry T= 180F Plate Code (ft-Ibs) Ratio (in/lb/in2) Ratio Cu Ni S Longitudinal Transverse Longitudinal Transverse Z1, Z2 0.17 0.47 0.011 160 126 78.8% 3810 3300 86.6%

Z5 0.16 0.60 0.016 153 95 62.1 % 2640 1630 61.7%

Modified Z6A 0.18 0.49 0.013 129 113 87.6% 3570 2325 65.1 %

A3028 Z68 0.21 0.51 0.023 117 64 54.7% 2360 1470 62.3%

Z7 0.16 0.53 0.014 126 96 76.2% 4500 3000 66.7%

Average (All) 71.9% Average (All) 68.5%

Average (Exclude Average 70.1% 64.0%

Z1, Z2) (Exclude Z1, Z2) i 4 of 12

Table 5-8: Available Margins on Pressure Load for All Transients, Levels A, B, C and D, Axial Flaws Level Base Metal- R. G. 1.161 Base Metal- R. G. 1.161 Base Metal - R. G. 1.161 LevelC LevelD Aand B Axial Flaw J O*1 Axial Flaw J O.1 Axial Flaw J O*1 Time J-applied x SF material Time J-applied x SF material Time J-applied x SF material SF 2 SF 2 SF 2 (sec) (in-lb/in 2 ) (in-lb/in ) (sec) (in-lb/in 2 ) (in-lb/in ) (sec) (in-lb/in 2 ) (in-lb/in )

0 1.8 985 986 0 3.4 987 986 0 2.9 682 682 2800 1.7 1096 1096 1,197 5.0 1212 1213 798 4.1 831 830 3600 1.7 1138 1139 4,122 5.2 2218 2218 2,748 3.4 1490 1491 5400 1.7 1249 1249 7200 1.8 1376 1376 9000 1.9 1518 1518 10800 18.5 1676 1676 Minimum Minimum SF 1 17

. 1 1 Min~~um 3.4 SF 2.9 1 1 5 of 12

Table 5-9: Available Margins on Pressure Load for All Transients, Levels A, B, C and D, with Consideration of V-50 Plate Data and Axial Flaws Level V-50 Plate V-50 Plate V-50 Plate LevelC LevelD Aand B Axial Flaw J O.1 Axial Flaw J O*1 Axial Flaw J O*1 Time J-applied x SF material Time J-applied x SF material Time J-applied x SF material SF 2 SF 2 SF 2 (sec) (in-lb/in 2 ) (in-lb/in ) (sec) (in-lb/in 2 ) (in-lb/in ) (sec) (in-lb/in 2 ) (in-lb/in )

0 1.5 611 611 0 2.8 611 611 0 2.8 611 611 2800 1.4 679 679 1,197 4.0 751 751 798 3.9 743 743 3600 1.4 706 706 4,122 4.0 1,374 1,374 2,748 3.1 1335 1,335 5400 1.4 774 774 7200 1.5 853 853 9000 1.5 941 941 10800 15.0 1039 1039 Minimum 1.4 I Min~~um I 2.8 I Minimum -

2.8 SF I I SF 6 of 12

Applied J-Integral - Axial Flaw, Level A & B, a/t=1/4t, SF=1 ..25 1000 Ir;ansient # I 900 ~ 1- - -- 2 1

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2.1 2.2 2.3 2.4 2.5 2.6 2.7 Flaw Depth a (in)

WCAP-17651-NP New Figure 5-14: Applied J-Integral versus Crack Extension for Axial Flaw -1/4t, Level A and B 7 of 12

Applied J-Integral-Axial Flaw, level C & D" a = 1/10t, SF=1 400

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- - - Level D Load

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0.8 0.9 1.1 1.2 1.3 1.4 Flaw Depth in Base Metal a (in)

WCAP-17651-NP New Figure 5-15: Applied J-Integral versus Crack Extension for Axial Flaw - 1/10t, Levels C and D 8 of 12

Axial Flaw Stability - Base Metal, Level A & B, a/t=1/4t, SF=1.25 1800 I Transient # I 1600

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- - 17 1400 ~I = = JR Base 1f4t400F

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2.1 2.2 2.3 2.4 2.5 2.6 2.7 Flaw Depth a (in)

WCAP-17651-NP New Figure 5-16: Axial Flaw J-Integral versus Crack Extension - tl4, Level A and B, Base Metal, with V-50 Plate Data Included 9 of 12

Axial Flaw Stability - Base Metal, P=2.75ksi 100F/hr Cooldown , a/t=1/4t, SF=1.25 1800

- - Jappl ied T=313F

- - Japplied T=4tlOF

- - Jappl ied T=480F 1600 - - Japplied T=5-33F

=~ JR BaseT =313F

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~- JR Base T =533F da =0.1" Line 1200 .. fiT V-50 @ 313F adjusted to L.-T

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2.1 2.2 2.3 2.4 2.5 2.6 2.7 Flaw Depth a (in)

WCAP-17651-NP New Figure 5-17: Axial Flaw J-Integral versus Crack Extension - tl4, P=2.75 ksi, 100°F/hr Cooldown, Base Metal, with V-50 Plate Data Included 10 of 12

Axial Flaw Stability, Base Metal, level C & D, a = 1/10t, SF=1 1800

- - Level C Load

- - - Level 0 load 1600 II = = JRBaset/10400F

- = JR BaseU10 500F

= = JR Base1l10610F 1400 c::::s c:::o da = 0.1"

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0.8 0.9 1.1 1.2 1.3 1.4 Flaw Depth in Base Metal a (in)

WCAP-17651-NP New Figure 5-18: Axial Flaw J-Integral versus Crack Extension - tl10, Levels C and D Loads, Base Metal, with V-50 Plate Data Included 11 of 12

References

1. Regulatory Guide 1.161, "Evaluation of Reactor Pressure Vessels with Charpy Upper-Shelf Energy Less than 50 Ft-Lb," U. S. Nuclear Regulatory Commission, June 1995.

2. Westinghouse Report WCAP-17651-NP, Revision 0, "Palisades Nuclear Power Plant Reactor Vessel Equivalent Margins Analysis," February 2013 (ADAMS Accession No. ML13295A451).

3. Code of Federal Regulations, 10 CFR Part 50, Appendix G, "Fracture Toughness Requirements," U.S. Nuclear Regulatory Commission, Washington, D.C., Federal Register, Volume 60, No. 243, dated December 19, 1995.

4. ASME Boiler and Pressure Vessel (B&PV) Code,Section XI, Division 1, Appendix K, "Assessment of Reactor Vessels with Low Upper Shelf Charpy Impact Energy Levels,"

2007 Edition up to and including 2008 Addenda.

5. ASME B&PV Code,Section XI, Division 1, Appendix G, "Fracture Toughness Criteria for Protection Against Failure," 1998 Edition up to and including 2000 Addenda.

6. NUREG/CR-6426, Volumes 1 and 2, "Ductile Fracture Toughness of Modified A 302 Grade B Plate Materials, Data Analysis," U.S. Nuclear Regulatory Commission, January and February 1997.

7. NUREG/CR-5265, "Size Effects on J-R Curves for A 302-B Plate," U.S. Nuclear Regulatory Commission, January 1989.

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