ML021710074
| ML021710074 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna  |
| Issue date: | 06/13/2002 |
| From: | Christian D Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 02-332, LR/DEA RO | |
| Download: ML021710074 (25) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHXOND, VIRGINIA 23261 June 13, 2002 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 Serial No.:
LR/DEA Docket Nos.:
License Nos.:
02-332 RO 50-280/281 50-338/339 DPR-32/37 NPF-4/7 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)
SURRY AND NORTH ANNA POWER STATIONS UNITS 1 AND 2 REQUEST FOR ADDITIONAL INFORMATION LICENSE RENEWAL APPLICATIONS Based on several conversations with the NRC during March and April 2002, the staff requested supplemental information related to certain responses previously provided to Requests for Additional Information (RAIs) concerning the Surry and North Anna license renewal applications (LRAs).
The attachment to this letter contains the supplemental information for RAIs 4.3-4 and 4.3-6 as requested by the staff.
Should you have any questions regarding this submittal, please contact Mr. J. E.
Wroniewicz at (804) 273-2186.
Very truly yours, David A. Christian Senior Vice President - Nuclear Operations and Chief Nuclear Officer Attachment Commitments made in this letter: None p 6 ýa
Serial No.: 02-332 SPS/NAPS LR - Response to RAI cc page 1 of 4 cc:
U. S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW Suite 23T85 Atlanta, GA 30303-8931 Mr. M. J. Morgan NRC Senior Resident Inspector North Anna Power Station Mr. R. A. Musser NRC Senior Resident Inspector Surry Power Station Mr. J. E. Reasor, Jr.
Old Dominion Electric Cooperative Innsbrook Corporate Center 4201 Dominion Blvd.
Suite 300 Glen Allen, VA 23060 Ms. Ellie Irons, EIR Program Manager Virginia Dept. of Environmental Quality 629 East Main St., 6 th FI Richmond, VA 23219 Mr. David Paylor, Program Coordinator Virginia Dept. of Environmental Quality P.O. Box 10009 Richmond, VA 23240-0009 Mr. Joe Hassell, Environmental Manager Virginia Dept. of Environmental Quality Water Division P.O. Box 10009 Richmond, VA 23240-0009 Mr. Frank Daniel, Regional Director Virginia Dept. of Environmental Quality Tidewater Regional Office 5636 Southern Blvd.
Serial No.: 02-332 SPS/NAPS LR - Response to RAI cc page 2 of 4 Mr. Gregory Clayton, Regional Director Virginia Dept. of Environmental Quality Northern Virginia Regional Office 13901 Crown Ct.
Woodbridge, VA 22193 Mr. Frank Fulgham, Program Manager Virginia Dept. of Agriculture & Consumer Services Office of Plant & Pest Services 1100 Bank St.
Richmond, VA 23219 Mr. David Brickley, Agency Director Virginia Dept. of Conservation & Recreation 203 Governor St.
Richmond, VA 23219 Mr. William Woodfin, Director Virginia Dept. of Game & Inland Fisheries 4010 West Broad St.
Richmond, VA 23230 Mr. Robert Hicks, Director Virginia Dept. of Health Office of Environmental Health Services 1500 East Main St., Room 115 Richmond, VA 23219 Ms. Kathleen S. Kilpatrick, Director Virginia Dept. of Historic Resources State Historic Preservation Office 2801 Kensington Ave.
Richmond, VA 23221 Dr. Ethel Eaton, Archeologist Senior Virginia Dept. of Historic Resources State Historic Preservation Office 2801 Kensington Ave.
Richmond, VA 23221
Serial No.: 02-332 SPS/NAPS LR - Response to RAI cc page 3 of 4 Mr. Robert W. Grabb, Assistant Commissioner Virginia Marine Resources Commission 2600 Washington Ave.
Newport News, VA 23607 Dr. John Olney, Associate Professor Virginia Institute of Marine Science School of Marine Science Gloucester Point, VA 23062 Mr. John Simkins Virginia Dept. of Transportation Environmental Division 1401 East Broad St.
Richmond, VA 23219 Mr. Robert Burnley Virginia Economic Development Partnership 901 East Byrd St.
Richmond, VA 23219 Mr. William F. Stephens, Director Virginia State Corporation Commission Division of Energy Regulation 1300 East Main St., 4th Fl., Tyler Bldg.
Richmond, VA 23219 Mr. Michael Cline, State Coordinator Commonwealth of Virginia Department of Emergency Management 10501 Trade Rd.
Richmond, VA 23236-3713 Mr. Terry Lewis, County Administrator P.O. Box 65 Surry, VA 23883 Mr. Lee Lintecum Louisa County Administrator P.O. Box 160 Louisa, VA 23093
Serial No.: 02-332 SPS/NAPS LR - Response to RAI cc page 4 of 4 Mr. Douglas C. Walker Acting Spotsylvania County Administrator P.O. Box 99 Spotsylvania, VA 22553 Ms. Brenda G. Bailey, County Administrator P.O. Box 11 Orange, VA 22960 Chairman Reeva Tilley Virginia Council on Indians P.O. Box 1475 Richmond, VA 23218 Mr. Don Lillywhite, Director Economics Information Services Virginia Employment Commission State Data Center 703 East Main St., Room 213 Richmond, VA 23219 Mr. Alan Zoellner Government Information Department Swem Library College of William and Mary Landrum Dr.
P.O. Box 8794 Williamsburg, VA 23187-8794 Mr. Walter Newsome Government Information Resources Alderman Library University of Virginia 160 McCormick Rd.
P.O. Box 400154 Charlottesville, VA 22904-4154
Serial No.: 02-332 SPS/NAPS LR - Response to RAI COMMONWEALTH OF VIRGINIA
) )
COUNTY OF HENRICO
)
The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by David A. Christian who is Senior Vice President and Chief Nuclear Officer of Virginia Electric and Power Company. He has affirmed before me that he is duly authorized to execute and file the foregoing document in behalf of that Company, and that the statements in the document are true to the best of his knowledge and belief.
Acknowledged before me this /3 day of L 4
, 2002.
My Commission Expires:
Notary Public (SEAL)
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 1 of 19 Attachment License Renewal - Response to RAI Serial No.02-332 Response to Request for Supplemental Information Surry and North Anna Power Stations, Units 1 and 2 License Renewal Applications RAIs 4.3-4 and 4.3-6 Virginia Electric and Power Company (Dominion)
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 2 of 19 RAI 4.3-4:
The Westinghouse Owners Group issued Topical Report WCAP-14575-A, "Aging Management Evaluation for Class I Piping and Associated Pressure Boundary Components," to address aging management of the RCS piping.
In both LRAs, Section 3.1.1, the applicant addresses the applicability of WCAP-14575-A to North Anna and Surry. Table 3.1.1-WI of the LRAs contain the response to the renewal applicant action items developed as a result of the staff review of the topical report.
Renewal Applicant Action Item 8 requests that applicants address components labeled I-M and I-RA in Tables 3-2 through 3-16 of WCAP-14575-A. The applicant indicates that the components in Tables 3-2 through 3-16 were addressed by an aging management activity, plant-specific fatigue evaluation, or code evaluation. However, the applicant did not provide specific details for each component. Provide a summary of the resolution for each of the components labeled I-M and I-RA in Tables 3-2 through 3-16.
Dominion Response:
The components labeled I-M and I-RA in Tables 3-2 through 3-16 are all piping components such as elbows, nozzles, straight pipe etc., which are Class 1 piping and associated pressure boundary components.
These components are analyzed in accordance with the rules of B31.7 for NAPS and the rules of B31.1 for SPS, satisfying the requirements of the appropriate code.
Supplemental Information:
RAI 4.3-4, Supplemental Request Since the original analyses were performed for forty years, provide an explanation how the analyses were extended for sixty years. Also provide an explanation how environmentally assisted fatigue was addressed.
Response
As identified in Section 4.3.1 of the application, the number of transients used in the original design analyses of the piping components envelop the projected number of transients for sixty years of operation. The continuation of the cycle counting activity during the period of extended operation will assure that the design cycle limits are not exceeded. As for the effects of environmentally assisted fatigue, these are addressed in Section 4.3-4 of the application.
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 3 of 19 RAI 4.3-6:
In both LRAs, Section 4.3.4, the applicant discusses the impact of the reactor water environment on the fatigue life of components. The applicant references the fatigue sensitive component locations for an early vintage Westinghouse plant identified in NUREG/CR-6260, "Application of NUREG/CR-5999 Interim Fatigue Curves to Selected Nuclear Power Plant Components."
The LRAs indicates that the results of the NUREG/CR-6260 studies were used to scale up the North Anna and Surry plant specific usage factors for the same locations to account for environmental effects. The LRAs also indicates that the later environmental fatigue correlations contained in NUREG/CR-6583, "Effects of L WR Coolant Environments on Fatigue Design Curves of Carbon and Low-Alloy Steels," and NUREG/CR-5704, "Effects of LWR Coolant Environments on Fatigue on Fatigue Design Curves of Austenitic Stainless Steels,"
were considered in the evaluation. Provide the results of the usage factor evaluation for each of the six component locations listed in NUREG/CR-6260. Discuss how the factors used to scale up the North Anna and Surry plant-specific usage factors were derived. Also discuss how the later environmental data provided in NUREG/CR-6583 and NUREG/CR-5704 were factored in the evaluations. Discuss the how the North Anna charging line flow transients monitored by the TCCP are factored in these evaluations.
Dominion Response:
Section 4.3.4 of the LRA describes Dominion's evaluation of the impact of the reactor water environment on the fatigue life of the components identified in NUREG/CR-6260, "Application of NUREG/CR-5999 Interim Fatigue Curves to Selected Nuclear Power Plant Components." In particular, that evaluation relies on several industry background studies that have been performed to address EAF effects in RCS components. Those studies have been used to provide an assessment of NAPS and SPS environmental effects on the locations identified in NUREG/CR-6260, using a scaling factor approach.
These locations are identified in Table 4.3-6-1.
Table 4.3-6-1. Older Vintage Westinghouse Plant Locations Identified in NUREG 6260 At core support guide weld Reactor vessel Inlet Nozzle Outlet Nozzle Surge line Hot leg nozzle safe end Charging nozzle Nozzle Safety injection nozzle Nozzle Residual heat removal line Tee
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 4 of 19 Because of the more recent issues raised by the NRC staff relative to the use of the EPRI/GE Fen methodology (Reference EPRI Report No. TR-105759, "An Environmental Factor Approach to Account for Reactor Water Effects in Light Water Reactor Pressure Vessel and Piping Fatigue Evaluations") in various industry applications as well as additional laboratory fatigue data in simulated LWR environments that have been generated by Argonne National Laboratory (ANL) for carbon, low-alloy, and stainless steels, calculations have been revised since the original submittal of the LRA, for the seven locations identified in NUREG/CR-6260 for NAPS and SPS. These calculations are summarized below, and utilize the most recent Fen methodology, as published in NUREG/CR-6583 and NUREG/CR-5704. The conclusions identified in the LRA for NAPS and SPS, which were reached based on the original calculations have been validated by the revised calculations.
RPV Locations The environmental fatigue calculations for the three RPV components identified in NUREG/CR-6260 (RPV shell at core support pads, RPV inlet nozzle, and RPV outlet nozzle) are shown in Table 4.3-6-2. The results show EAF-adjusted CUF values for these three locations of less than 1.0, which are acceptable.
The results shown in Table 4.3-6-2 are very conservative, in that the maximum bounding Fen multiplier was conservatively used.
Table 4.3-6-2. Plant-Specific EAF Evaluation for RPV Locations and Surge Line Original Design Basis CUFs Environmental CUFs LocationU UNAPS U SPS RPV Shell at Core Support Pads 0.092 0.01 2.53 0.233 0.025 RPV Inlet Nozzle 0.022 0.011 2.53 0.056 0.028 RPV Outlet Nozzle 0.074 0.256 2.53 0.187 0.648 Surge Line Hot Leg Nozzle 0.966 0.861 See Note 1 N/A N/A Note: 1. Inspection aging management will be used for this location.
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 5 of 19 Table 4.3-6-2. Plant-Specific EAF Evaluation for RPV Locations and Surge Line (cont.)
Low Alloy Steel Fen = exp(0.929 - 0.00124T - 0.101S*T*O*e*)
For a PWR environment, DO < 0.05, so O* = 0.
Therefore, Fe, is only dependent upon T.
T (°C)
Fen 0
2.53 50 2.38 100 2.24 150 2.10 200 1.98 250 1.86 300 1.75 Thus, maximum F
= 2.53 Carbon Steel Fen = exp(0.585 - 0.00124T - 0.101S*T*O*s*)
For a PWR environment, DO < 0.05, so 0* = 0.
Therefore, Fen is only dependent upon T.
T (°C)
Fen 0
1.79 50 1.69 100 1.59 150 1.49 200 1.40 250 1.32 300 1.24 Thus, maximum Fen = 1.79 Stainless Steel Fen = exp(0.935 - T*s*O*)
For a PWR environment, DO < 0.05, so 0* = 0.260 T* = 0 for T < 2000C or T* = 1 for T > 2000C. Conservatively use T* = 1 Therefore, Fen is only dependent upon the strain rate parameter, F*.
P* = 0 for e > 0.4%/sec so Fen = 2.55 F* = In(s/0.4) for 0.0004 <= F <= 0.4%/sec so Fen = 2.55 to 15.35 F* = In(0.0004/0.4) for e < 0.0004%/sec so Fen = 15.35 Thus, maximum Fen = 15.35 I
I
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 6 of 19 Charging Nozzle Location For the charging nozzle, CUF results exist only for NAPS, because the design basis for the SPS piping is USAS B31.1, which does not require explicit fatigue analysis.
However, the detailed plant-specific charging nozzle fatigue calculations for NAPS are not readily retrievable. Therefore, NAPS plant-specific fatigue calculations have been reconstituted based on the inputs used in NUREG/CR-6260. A detailed EAF evaluation for this location was subsequently performed.
The environmental fatigue charging nozzle calculations are shown in Table 4.3-6-3. The results show an EAF adjusted CUF value of less than 1.0, which is acceptable.
Since the SPS design code for the charging piping is USAS B31.1, no explicit fatigue analysis has been performed. However, since the physical attributes of the SPS piping, nozzles, and transient characteristics are similar to those at NAPS, it is concluded that the SPS charging nozzles are likewise acceptable with consideration of EAF.
Table 4.3-6-3. Plant-Specific EAF Evaluation for Charging Nozzle Step #1: Reproduce NUREG/CR-6260 Calculations from Table 5-90 Note 1: S,, = SNB-3600 since this is the limiting NB-3600 CUF location.
Branch b
ody Sat N,11ow n
U Comments body (NB-3600) 363.53 44 20 0.452 46.00 51,814 80 0.002 Note 2 46.00 51,814 120 0.002 Note 2 Total = 0.456 Note 2: Small difference from NUREG/CR-6260; neglected.
Nozzle-to-pipe weld SIt Niow n
U (NB-3600) 84.62 3,340 20 0.006 70.04 6,951 80 0.012 52.11 27,505 120 0.004 Total =0.022 Note 3 Note 3: S, = Salt-NB_3200 ' Although this is not the limiting NB-3200 CUF location (by only a very small amount), the strain rate is lower than for the nozzle-to-pipe weld location, so this location becomes limiting when environmental effects are considered.
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 7 of 19 Table 4.3-6-3. Plant-Specific EAF Evaluation for Charging Nozzle (cont.)
Branch connection/nozzle boySalt Nallow n
U body (NB-3200) 87.69 2,922 20 0.007 80.94 3,947 80 0.020 29.47 724,304 120 0.000 Total = 0.027 Note 4 Note 4: Limiting NB-3200 location; see note 3 above.
Nozzle region upstream of San Na,,ow n
U Note 5 thermal sleeve (NB-3200) 84.79 3,314 20 0.006 82.86 3,614 80 0.022 46.15 50,897 120 0.002 Total = 0.031
==
Conclusions:==
- 1. NUREG/CR-6260 calculations are reproduced.
- 2. Appropriate values of "n" are obtained.
Step #2: Reproduce NAPS CUF by scaling up Sall for Limiting NB-3600 Location Note 5: S, = SafNB.3600_NAPS Multiplier for Sall
= 1.313 Branch connection/nozzle body:
S N
n U
(NB-3600) 477.31 24 20 0.850 60.40 13,253 80 0.006 60.40 13,253 120 0.009 Total = 0.8647 Note 6 Note 6: The difference is insignificant between this value and NAPS design basis CUF of 0.8646
==
Conclusion:==
- 1. Above calculation is a reconstituted calculation for NAPS.
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 8 of 19 Table 4.3-6-3. Plant-Specific EAF Evaluation for Charging Nozzle (cont.)
Step #3: Create a NAPS NB-3200 CUF from the NB-3600 Calculation Note 7:
Sa, = Sa,_NB-3600.NAPS * (SahNB_3200'Sat.NB.3600)
Branch connection/nozzle boy:
5at Na,,ow U
Note 7 body:
(NB-3200) 115.14 1,118 20 0.018 106.27 1,468 80 0.055 38.69 133,333 120 0.001 Total = 0.0733 Note 8 Note 8: Predicted UNB-3 20 0 for NAPS
==
Conclusion:==
- 1. Above calculation is reconstituted for NAPS.
Step #4: Determine F.. Multiplier and Environmental CUF F., for Stainless Steel:
F.. = exp(O.935 - T*e*O*)
For a PWR environment, DO < 0.05, so O* = 0.260 T* = 0 for T < 2000C or = 1 for T > 2000C. Conservatively use T* = 1 S = 0.08%/sec per strain rate calculation, so sF* = ln(f/0.4) for 0.0004 < F < 0.4 %/s.
Calculated Fe, = 3.87 Environmental CUF for NAPS = Foe
- UNB_3200 for NAPS = 0.284 Safety Injection Nozzle Location For the safety injection nozzle, CUF results exist only for NAPS, because the design basis for the SPS piping is USAS B31.1, which does not require explicit fatigue analysis. However, the detailed plant-specific safety injection nozzle fatigue calculations for NAPS are not readily retrievable. Therefore, plant-specific fatigue calculations have been reconstituted for NAPS based on the inputs used in NUREG/CR-6260. A detailed EAF evaluation was subsequently performed for this location.
The environmental fatigue calculations for the safety injection nozzles are shown in Table 4.3-6-4. The results show an EAF adjusted CUF value of less than 1.0, which is acceptable.
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 9 of 19 Since the design code for the safety injection piping is USAS B31.1 for SPS, no explicit fatigue analysis has been performed. However, since the physical attributes of the SPS piping, nozzles, and transient characteristics are similar to those at NAPS, it is concluded that the SPS Safety Injection nozzles are likewise acceptable with consideration of EAF.
Table 4.3-6-4. Plant-Specific EAF Evaluation for Safety Injection Nozzle Step #1: Reproduce NUREG/CR-6260 Calculations from Tables 5-93 and 5-94 Note 1: Safi = Sa,.-N..3600 since this is the limiting NB-3600 CUF location.
Branch Sal Naow n
U Note 1 connection/nozzle body (NB-3600) 400.22 35 70 1.976 Note 2 Total 1.976 Note 2:The Saf values for the two other load pairs are unknown; however, the CUF matches so their contribution is negligible.
Nozzle-to-pipe weld Sat Naiiow N
U (NB-3600) 102.57 1,655 70 0.042 46.79 47,408 50 0.001 Note 3 45.49 55,079 150 0.003 Note 3 Total = 0.046 Note 3: S., and n values obtained from Table 5-94.
Branch connection/nozzle body N30o N
U (NB-3200) 32.88 346,189 70 0.000 0.002 Note 4 Total = 0.002 Note 4: The S., values for the two other load pairs are unknown; this equivalent incremental CUF is chosen so the total CUF results agree.
Nozzle region upstream of Sa, Na,,ow N
U thermal sleeve (NB-3200) 92.48 2,393 70 0.029 0.002 Note 5 Total = 0.031 Note 6 Note 6: Sa, = Sat.NB.3200 since this is the limiting NB-3200 CUF location.
Note 5: The Sat values for the two other load pairs are unknown; this equivalent incremental CUF is chosen so the total CUF results agree.
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 10 of 19 Table 4.3-6-4. Plant-Specific EAF Evaluation for Safety Injection Nozzle (cont.)
Nozzle-to-pipe weld Salt Nallow N
U (NB-3200) 125.14 852 70 0.082 0.013 Note 7 Total 0.095 Note 7: The S., values for the two other load pairs are unknown; this equivalent incremental CUF is chosen so the total CUF results agree.
==
Conclusions:==
- 1. NUREG/CR-6260 calculations are reproduced.
- 2. Appropriate values of "n" are obtained.
Step #2: Reproduce NAPS CUF by scaling up Sal for Limiting NB-3600 Location multiplier for Sat = 0.669 Note 8: S,, = SatNB-3600-NAPS Branch salt N a,,ow n
Note 8 connectionlnozzle body:
(NB-3600) 267.75 94 70 0.746 Total = 0.746 Note 9 Note 9: Matches NAPS design basis CUF of 0.746.= UNB.3600 for NAPS
==
Conclusion:==
- 1. Above calculation is a reconstituted for NAPS.
Step #3: Create a NAPS NB-3200 CUF from the NB-3600 Calculation Note 10: Sat = Sat-NB-3600-NAPS * (Saft.NB.320/Sal,.NB.3600)
Branch Sal Naow n
U Note 10 connection/nozzle body:
(NB-3200) 83.72 3,477 70 0.020 0.013 Note 11 Total = 0.033 Note 12 Note 11: Conservatively use this incremental CUF.
Note 12: Predicted UB.3200 for NAPS
==
Conclusion:==
- 1. Above calculation is a reconstituted for NAPS.
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 11 of 19 Table 4.3-6-4. Plant-Specific EAF Evaluation for Safety Injection Nozzle (cont.)
Step #4: Determine Fe, Multiplier and Environmental CUF:
Fen for Stainless Steel:
Fen = exp(0.935 - T*F*O*)
For a PWR environment, DO < 0.05, so O* = 0.260
- = 0 for T < 200°C or = 1 for T > 200'C. Conservatively use T* = 1 S = 1.23%/sec per strain rate calculation, so E* = 0 for E > 0.4 %/s.
Calculated Fen = 2.55 Environmental CUF for NAPS = 0.084 = Fen
- UNB-3200 for NAPS RHR Tee Location Detailed plant-specific fatigue calculations are available for the NAPS RHR tee.
Therefore, appropriate detailed Fen factors have been calculated for this location to apply to the individual fatigue contributing load pairs and a resulting EAF-adjusted CUF value has been determined.
The environmental fatigue calculations for the RHR tee shown in Table 4.3-6-5 are based on NAPS plant-specific input. The results show an EAF adjusted CUF value of less than 1.0, which is acceptable. Since the design code for the SPS RHR piping is USAS B31.1, no explicit fatigue analysis has been performed. Transient stresses are expected to be similar for NAPS and SPS, since the geometry and material are similar for all four units. Therefore, the results are considered to apply to SPS as well.
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 12 of 19 Surge Line/Nozzle Location For the surge line, which is a high CUF location, an aging management program that includes inspection has already been planned to satisfy EAF considerations, as discussed in Sections 4.3.4 and B4.0 of the LRA. Therefore, additional EAF evaluation for this location has not been performed.
Summary of Results for EAF Evaluation The EAF results for all NAPS/SPS locations evaluated above are summarized in Table 4.3-6-6. The results demonstrate that the CUFs for all locations, including postulated environmental effects, remain within the allowable value of 1.0 for 60 years.
Table 4.3-6-5. Plant-Specific EAF Evaluation for RHR Tee Step #1: Reproduce design basis fatigue calculation Note 1: NUREG-6260 calculations are not required for this location since a plant-specific calculation exists.
Tee Sf, N8,o0 n
U (NB-3600) 126.161 657 200 0.304 Total = 0.304
==
Conclusion:==
- 1. Design basis fatigue calculation is adequately reproduced.
Step #2: Determine Fen Multiplier and Environmental CUF:
Fen for Stainless Steel:
Fen = exp(0.935 - T*E*O*)
For a PWR environment, DO < 0.05, so 0* = 0.260.
T* = 0 for T < 200'C or = 1 for T > 2000C.
All temperatures for the controlling RHR transient are less than 2000C (3920F),
so T* = 0.
E* does not matter when T* = 0.
Calculated Fen = 2.55 Environmental CUF for NAPS = 0.775
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 13 of 19 Table 4.3-6-6.Summary of NAPS/SPS Environmental Fatigue Calculations Environmental No.
Component Maximum Design CUF Multiplier CUF 1
RPV Shell at Core Support Pads 0.092 2.53 0.233 2
RPV Inlet Nozzle 0.022 2.53 0.056 3
RPV Outlet Nozzle 0.256 2.53 0.648 4
Charging Nozzle 0.073 3.87 0.283 5
Safety Injection Nozzle 0.033 2.55 0.084 6
RHR Tee 0.304 2.55 0.775 Charging Line Flow Transients Temperature data (as an indication of flow transients) from the existing plant instrumentation is being collected so that a comparison of operating and design transients for the charging nozzles can be made to validate the design transients.
These data are planned to be used only for validating the design transients. They are not included in the above evaluations.
Supplemental Information:
RAI 4.3-6, Supplemental Request Explain how the results of NUREG-6260 analyses were used in evaluating environmentally assisted fatigue (EAF) for charging and SI nozzles. Since the analyses for an older vintage Westinghouse plant in the NUREG/CR-6260 were for Turkey Point Nuclear Power Plant, provide a comparison of the geometry and material of components justifying the approach used in assessing EAF for these nozzles for SPS and NAPS.
Response
NAPS Charging and Safety Injection Nozzles:
In order to evaluate EAF in the previous response to this RAI, the usage factors for individual load pairs were reconstituted by applying a scaling factor to the alternating stresses identified in NUREG/CR-6260 to match the final cumulative usage factor (CUF) values available from the stress reports. These stresses were reduced based on the ratios of NB-3200 stresses to the NB-3600 stresses contained in NUREG/CR-6260.
An appropriate Fen multiplier was computed and applied to the CUF values derived for NAPS using NB-3200 methodology. The resulting CUF, with Fen applied, represented
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 14 of 19 the environmentally adjusted CUF value for 60 years for NAPS.
The CUF values calculated for charging and SI nozzles were considered acceptable since they were less than the allowable value of 1.0.
Comparisons of the localized geometry of the nozzles of NAPS with those of NUREG/CR-6260 were performed to confirm the applicability of the above approach.
Even though the configurations for these nozzles at North Anna are similar to those of NUREG/CR-6260, there are some differences. Hence, the charging and SI nozzles for NAPS were re-analyzed using a simplified NB-3200 methodology.
Simplified NB-3200 Analyses:
This methodology employed finite element analyses to obtain stresses for various loads, particularly thermal transients. However, the stress intensities due to each load (e.g., pressure, moment, thermal transients) were first determined separately, and then combined to determine total stress in a manner similar to the NB-3600 approach. This produces conservative results compared to combining load stress components, and then calculating stress intensity, as in a detailed NB-3200 evaluation. The CUFs for charging and SI nozzles were recalculated using plant design transients. The fatigue calculation methodology was based on the 1977 Edition through Summer 1979 Addenda of the ASME code. The CUFs with EAF have been calculated at the safe ends, which are the most limiting locations and are presented below:
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 15 of 19 Table 4.3-6-3A. Plant-Specific EAF Evaluation for Charging Nozzles Event Occurrences Charging trip with delayed return to service 10 Normal charging and letdown Shutdown and return to service 10 Charging rate increase by 50%
24000 Charging rate decrease by 50%
24000 Letdown rate increase by 50%
24000 Letdown rate decrease by 50%
2000 Load pairs Transient Events Cycles First Charging trip with delayed return to service, and Normal 20 charging and letdown Shutdown and return to service - paired between the shutoff and return conditions. (Note: They have identical transient conditions.)
Second All others including Charging rate increase by 50%, Charging 74000+
rate decrease by 50%, Letdown rate increase by 50%, and Letdown rate decrease by 50%
Load Pair Sat*ps)
N3"° N
U T(°F)
Fen Uen First 163.3 290 20 0.069 0.093 560 2.481 0.172 Second See Note See Note See Note 0.097 0.002 560 6.548 0.636 1
1 1
1 1 CUF = 0.166
_CUF En = 0.808 Note 1:
The 0.097 usage factor is included to account for a group of contributing transient combinations, which include auxiliary line flow changes and loop transients.
Fen for Stainless Steel:
Fon = exp(0.935 - T*E*O*)
For a PWR environment, DO < 0.05, so 0* = 0.260 T* = (T-180)/40 (180°C < T < 220°C)
T* = 1.0 (T > 220°C)
F'* = 0 (s' > 0.4%/sec)
F'* = ln(s'/0.4)
(0.0004 < s' < 0.4%/sec)
F'* = ln(0.0004/0.4)
(F' < 0.0004%/sec)
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 16 of 19 Since the CUFs with EAF for charging and Sl nozzles are less than 1.0, they are acceptable. The CUF values of Tables 4.3-6-3A and 4.3-6-4A are higher than the values of Tables 4.3-6-3 and 4.3-6-4 because the former are based upon simplified NB 3200 analyses whereas the latter are based on more detailed NB-3200 analysis reductions of NUREG/CR-6260.
==
Conclusion:==
NAPS charging and Sl nozzles are considered to be acceptable based on the EAF CUF calculations performed in Tables 4.3-6-3A and 4.3-6-4A, respectively.
SPS CHARGING AND SAFETY INJECTION NOZZLES:
SPS, being a B31.1-designed plant, had no explicit fatigue usage analyses performed for the charging nozzles and the safety injection nozzles. Since the physical attributes of the SPS piping, nozzles, and operating characteristics are similar to those at NAPS, Table 4.3-6-4A. Plant-Specific EAF Evaluation for Accumulator/Safety Injection Nozzles**
Event Occurrences Inadvertent RCS Depressurization 20 Accumulator nozzle Sl 5
SI return 5
OBE 5
Load pairs Transient Events Cycles First Inadvertent RCS depress - Return of SI 5
Second Inadvertent RCS depress - OBE 5
Third Inadvertent RCS depress - zero load 10 Fourth Accumulator nozzle SI - zero load 1
5 Load Salt (psi)
N° 0w N
U T(°F)
F en Uen PairTI First 327.4 46 5
0.109 0.026 560 3.442 0.375 Second 269.6 74 5
0.068 0.026 560 3.442 0.234 Third 193.7 176 10 0.057 0.026 560 3.442 0.196 Fourth 79.3 3106 5
0.002 0.014 400 2.890 0.005 1_CUF = 0.236 CUF en 0.810 F., for Stainless Steel:
TFen = exp(0.935 - T*s*O*)
For a PWR environment, DO < 0.05, so 0* = 0.260 T* = (T-180)/40 (I180°C < T <! 220°C)
T* = 1.0 (T > 220°C)
F_'*
= 0
(, > 0.4%/sec)
F'* = In(1'/0.4)
(0.0004 < e' < 0.4%/sec)
F'* = ln(0.0004/0.4)
(F' < 0.0004%/sec)
- Only the contributing transients are listed.
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 17 of 19 it was concluded that the SPS charging and SI nozzles are likewise acceptable with consideration of EAF based on the calculations performed for NAPS.
Comparisons of the localized geometry of the SPS nozzles with those of NUREG/CR 6260 were also performed to confirm the applicability of the above approach and conclusion. The comparisons for SPS nozzles showed that they are similar to NUREG/CR-6260 as described in the following sections.
A comparison of the nozzle geometry between the Surry, North Anna, and NUREG/CR 6260 locations is given in Table 4.3-6-7. The original design vendor (Westinghouse) was requested to compare the configurations of the charging and Safety Injection/Accumulator reactor coolant loop (RCL) nozzles of Surry to those of Turkey Point, with respect to the applicability of evaluations performed in NUREG/CR-6260 to address reactor water environmental effects on fatigue, since the analyses for an older vintage Westinghouse plant performed in NUREG/CR-6260 were for the Turkey Point plant. The comparisons were based on material and geometric effects on stresses that influence the fatigue evaluations of the controlling locations in the nozzles.
The material properties of the Surry nozzles are the same as those of the corresponding Turkey Point nozzles. Therefore, the influence of the material properties on stress and fatigue evaluations would be the same. The results for the geometrical comparison are discussed below.
SPS CHARGING NOZZLE GEOMETRY EVALUATION:
The Surry 1 & 2 charging nozzles and the Turkey Point 4 charging nozzle were built to the same nozzle drawing. Hence, they are identical.
Loop thicknesses are slightly different from Turkey Point, but the geometric discontinuity (ta/tb) at the branch is enveloped by Turkey Point.
Therefore, the NUREG/CR-6260 evaluation applies to Surry 1 & 2 charging nozzles.
SPS SI/ACCUMULATOR NOZZLE GEOMETRY EVALUATION:
The Surry 1 & 2 SI/accumulator nozzles are 12"-140 vs. 10"-140 on Turkey Point. The 10"-140 SI/accumulator nozzle evaluation for Turkey Point is applicable to the Surry 12"-140 SI/accumulator nozzles for the following reasons.
Branch region:
The nozzle reinforcement is thicker. However, this results in less discontinuity (ta/tb) effect for the branch location. Since there is a thermal sleeve, the discontinuity effect (vs. through wall effect) will control the stresses in the nozzle reinforcement region.
Therefore, the NUREG/CR-6260 evaluation is representative, if not conservative.
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 18 of 19 Safe End Region:
The safe end region of the Surry SI nozzle is only about 13% thicker than Turkey Point. This will have a negligible impact on through wall stress. This is reinforced by the fact that Westinghouse generic analyses were done for 10"-140 nozzles, and were applied to both 10"-140 and 12"-140 nozzles for plant specific fatigue conformance evaluations, including those done for North Anna 12"-140 nozzles.
In addition, the discontinuity (ta/tb) effect is close to that of Turkey Point 3, and enveloped by Turkey Point 4. Therefore, the NUREG/CR-6260 evaluation is representative.
Transition Region:
The through wall effect at the transition is the same as for the safe end, and the effect on stress remains negligible. The geometric discontinuity (ta/tb) at the transition is only 5% more than Turkey Point, which will also have an insignificant impact on the discontinuity stresses. Given the margin in the NUREG/CR-6260 results after accounting for environmental effects, it can be concluded that the NUREG results are applicable for the Surry nozzles.
Table 4.3-6-7 Comparison of Nozzle Geometry for Surry, North Anna, and NUREG/CR-6260 Piping Plant Diameter Thickness Charging Line NUREG/CR-6260 Nominal Diameter = 3" 0.4375" Charging Line Surry Nominal Diameter = 3" 0.4375" Charging Line North Anna Nominal Diameter = 3" 0.4375" Safety Injection NUREG/CR-6260 Nominal Diameter = 10" 1.000" (Accumulator)
Safety Injection Surry Nominal Diameter = 12" 1.13" (Accumulator)
Safety Injection North Anna Nominal Diameter = 12" 1.01" (Accumulator)
Cold Leg NUREG/CR-6260 ID = 27.5" 2.375" Cold Leg Surry ID = 27.5" 2.215" Cold Leg North Anna ID = 27.5" 2.211" Hot Leg NUREG/CR-6260 ID = 29" 2.50" Hot Leg Surry ID = 29" 2.50" Hot Leg North Anna ID = 29" 2.50"
Docket Nos. 50-280/281 50-338/339 Serial No.: 02-332 Attachment Page 19 of 19
==
Conclusion:==
The geometry and material for SPS are very similar to those of NUREG/CR-6260 (i. e.
Turkey Point), and it can be concluded that the conclusions of NUREG/CR-6260 are applicable, and therefore the SPS nozzles are acceptable.
In addition, differences between the SPS and NAPS nozzles are insignificant at the safe ends, which are the most limiting locations for these nozzles. Since the operation of SPS and NAPS are similar, it can also be concluded that the SPS nozzles are acceptable based on the detailed EAF CUF calculations performed for NAPS. Based on these comparisons to both the NUREG/CR-6260 nozzles and the NAPS nozzles, the SPS charging and SI nozzles are considered acceptable with regards to EAF.