ML16179A204
| ML16179A204 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 06/21/2016 |
| From: | Mark D. Sartain Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 16-227 | |
| Download: ML16179A204 (20) | |
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VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 June 21, 2016 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNIT 1 ASME SECTION XI INSERVICE INSPECTION PROGRAM Serial No.
NLOS/GDM Docket No.
License No.
10 CFR 50.55a 16-227 R1 50-280 DPR-32 RELIEF REQUESTS FOR LIMITED COVERAGE EXAMINATIONS PERFORMED IN THE FOURTH 10-YEAR INSERVICE INSPECTION INTERVAL RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION By letter dated October 9, 2015 (Serial No.15-446), Virginia Electric and Power Company (Dominion) submitted relief requests for the Surry Power Station Unit 1 fourth 10-year ISi interval.
The relief requests were for limited examinations where the.
required examination coverage was impractical due to physical obstructions an-d limitations imposed by design, geometry and materials of construction of the subject components. On May 17, 2016, the NRC Surry Project Engineer provided requests for additional information associated with Relief Requests LMT-R01, LMT-R02, LMT-R03 and LMT-P01. Dominion's response to the NRC RAls is provided in Attachments 1 through 4, respectively.
If you have any questions or require additional information, please contact Mr. Gary D. Miller at (804) 273-2771.
Sincerely, Mark D. Sartain Vice President-Nuclear Engineering Commitments made in this letter: None Attachments:
- 1. Response to NRC Request for Additional Information, Relief Request LMT-R01
- 2. Response to NRC Request for Additional Information, Relief Request LMT-R02
- 3. Response to NRC Request for Additional Information, Relief Request LMT-R03
- 4. Response to NRC Request for Additional Information, Relief Request LMT-P01
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cc:
U.S. Nuclear Regulatory Commission, Region II Marquis One Tower 245 Peachtree Center Avenue NE, Suite 1200 Atlanta, Georgia 30303-1257 Ms. K. R. Cotton-Gross, NRC Project Manager - Surry U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G9A 11555 Rockville Pike Rockville, Maryland 20852 Dr. V. Sreenivas, NRC Project Manager - North Anna U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G9A 11555 Rockville Pike Rockville, Maryland 20852 NRC Senior Resident Inspector Surry Power Station Mr. R. A. Smith Authorized Nuclear Inspector Surry Power Station Serial No.16-227 Docket No. 50-280 Page 2 of 2 Serial No.16-227 Docket No. 50-280 Response to NRC Request for Additional Information Relief Request LMT-R01 Virginia Electric and Power Company (Dominion)
Surry Power Station Unit 1
Request for Additional Information Serial No.16-227 Docket No. 50-280 Relief Request LMT-R01, Page 1 of 7 Relief Request LMT-R01 Regarding Weld Examination Coverage Surry Power Station, Unit 1 By letter dated October 9, 2015 (Accession Number ML15293A124), Virginia Electric and Power Company - Dominion (the licensee) requested relief from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (B&PV Code) specifically related to ASME Code Case N-460 Alternative Examination Coverage for Class 1 and Class 2 Welds,Section XI, Division 1." Relief request LMT-R01 pertains to the examination coverage of the Class 1 and 2 piping welds at the Surry Power Station (Surry), Unit 1.
To complete its review, the NRG staff requests the following additional information.
- 1. Tables 4a, 4b, and 4c of the relief request show pipe material.
The NRC staff assumes that the weld and the associated components (branch connection, valve, elbow, and pump) are made of the same material as the pipe. Confirm that the weld and the associated components are also made of the pipe material.
1f branch connection, valve, elbow, pump and weld material are made of different materials, please describe.
Dominion Response With two exceptions, Surry has verified that the weld material in all cases is stainless steel material. Additionally, all associated component materials (branch connection, valve, elbow and pump) have been ver~fied to be stainless steel.
There are two welds that Surry was unable to verify the weld filler material used. They are as follows:
Weld 1-018C on drawing 11448-WMKS-0127J2 Weld 1-01 BC on drawing 11448-WMKS-01°27J3 Based on research of available documentation, it appears these welds are associated with branch connections on reactor coolant piping that was provided by Westinghouse as part of original plant construction. No documentation could be located that identified the specific weld filler material used. However, in both cases, the branch connection material is stainless steel and the reactor coolant piping is also stainless steel.
Ba~ed on the other records reviewed for this relief request, the weld filler material would have been stainless steel.
This is consistent with past and current Surry Power Station welding practices,
Serial No.16-227 Docket No. 50-280 Relief Request LMT-R01, Page 2 of 7
- 2. In Section 4a of the relief request, the licensee stated that the mode of degradation for the welds listed in Table 4a is thermal fatigue. The NRG staff assumes that the subject welds are potentially susceptible to low cycle thermal fatigue. If the subject weld[s] are susceptible to high cycle thermal fatigue, please describe.
- 3. In Section 4c of the relief request, the licensee stated that the mode of degradation for some of the welds listed in Table 4c is thermal fatigue. The NRG staff assumes that these weld{s] are potentially susceptible to low cycle thermal fatigue. If these welds are susceptible to high cycle thermal fatigue, please describe.
Dominion Response to NRC Questions 2 and 3 The Surry Power Station Unit 1 fourth interval Risk-Informed lnservice Inspection (ISi)
Program was based on: 1) Code Case N-577, "Risk-Informed Requirements for Class 1, 2, and 3 Piping, Method A; 2) Westinghouse Owners Group WCAP-14572, Revision 1, "Westinghouse Owners Group Application of Risk-Informed Methods to Piping lnservice Inspection Topical Report; and 3) WCAP-14572, Revision 1, Supplement 1, "Westinghouse Structural Reliability and Risk Assessment (SRRA) Model for Piping Risk-Informed I nservice Inspection."
As part of the development of the fourth interval Risk-Informed ISi Program, a Dominion subpanel determined failure probability estimates for the postulated failure mechanism of each piping segment. The Westinghouse SRRA software program was used by the subpanel in conjunction with industry failure history, plant specific failure history and other relevant information to determine the final failure estimates.
Guidance for determining these inputs was flexible enough to address low cycle thermal fatigue attributable to normal plant transients and high cycle thermal fatigue such as that resulting from thermal stratification of fluids.
An experienced expert panel provided input as well.
Therefore, consideration of both high cycle and low cycle thermal fatigue was included in the calculation of failure probability for each risk segment.
This concept was acknowledged in the NRC Safety Evaluation Report letter dated December 15, 1998,
Subject:
Safety Evaluation of Topical Report WCAP-14572, Revision 1, "Westinghouse Owners Group Application of Risk-Informed Methods to Piping lnservice Inspection Topical Report", paragraph A.4.2 discussion on Fatigue. However, thermal fatigue was not specifically identified in the Risk-Informed ISi Program as high cycle or low cycle when failure mechanism assignment was made for the segments. Consideration for both high and low cycle thermal fatigue was given in the development of the fourth interval Risk-Informed ISi Program, but no distinction exists in program documentation.
- 4. Provide operating temperature and pressure for each weld.
Dominion Response Drawing I Line#/ ID Operating Table System I Class Temperature Risk-Informed Segment (Estimated) 11448-WMKS-0100AZ-1 27.5"-
4a RC-3-2501R / 1-12 540 °F Reactor Coolant / 1 Segment RC-010 J
11448-WMKS~0101AZ-1 27.5"-
4a RC-6*2501R/ 1-12 540 °F Reactor Coolant / 1 Segment RC-011 11448-WMKS-0102AZ-1 27.5"-
4a RC-9-2501R / 1-12 540 °F Reactor Coolant / 1 Segment RC-012 11448-WMKS-0122K1/6-RC-18 4b
/ 2-08 606 °F Reactor Coolant / 1 Segment RC-017 11448-WMKS-0122J1 / 6-RC-21 /
4b 1-08 606 °F Reactor Coolant / 1 Segment RC-018
- 11448-WMKS-0122H1 / 6-RC-16 4b
/ 1-09 606 °F Reactor Coolant / 1 Segment ECC~om~
11448-WMKS-0122H1 / 6-RC-16 4b
/ 1-10 606 °F Reactor Coolant / 1 Segment ECC-005 Serial No.16-227 Docket No. 50-280 Relief Request LMT-R01, Page 3 of 7 Operating Pressure (Estimated) 2235 psig 2235 psig 2235 psig 2235 psig 2235 psig 2235 psig 2235 psig
Drawing I Line# / ID Table System I Class Risk-Informed Segment 11448-WMKS-0122J1 I 6-RC-21 I 4b 1-09 Reactor Coolant I 1 Segment ECC-007 11448-WMKS-0122J1 I 6-RC-21 I 4b 1-10 Reactor Coolant I 1 Segment ECC-007 11448-WMKS-0127J2 I 6-RC-19 I 1-02 4b Reactor Coolant I 1 Segment RC-042 11448-WMKS-0127J2 I 6-RC-19 I 4b 1-04 Reactor Coolant I 1 Segment RC-042 11448-WMKS-0127J2 I 6-RC-19 I 4b 1-01BC Reactor Coolant I 1 Segment RC-042 11448-WMKS-0127J3 I 6-RC-20 I 4b 1-01BC Reactor Coolant I 1 Segment RC-043 11448-WMKS-0127J3 I 6-RC-20 I 4b 1-02 Reactor Coolant I 1 Segment RC-043 11448-WMKS-0127J3 I 6-RC-20 I 4b 1-03A Reactor Coolant I 1 Segment RC-043 Operating Temperature (Estimated) 606 °F 606 °F 540 °F 540 °F 540 °F 540 °F 540 °F 540 °F Serial No.16-227 Docket No. 50-280 Relief Request LMT-R01, Page 4 of 7 Operating Pressure (Estimated) 2235 psig 2235 psig 2235 psig 2235 psig 2235 psig 2235 psig 2235 psig 2235 psig
Drawing I Line# / ID iable System I Class Risk-Informed Segment 11448-WMKS-0122K1 / 6-Sl-48 /
4c 2-09 Safety Injection/ 1 Segment ECC-006 11448-WMKS-0122K1 / 6-Sl-48 /
4c 2-10 Safety Injection/ 1 Segment ECC-006 11448-WMKS-1101A5 / 12-RS-7 /
4c 1-06 Recirculation Spray / 2 Segment RS-004A 11448-WMKS-1101A5 / 12-RS-8 /
4c 1-03 Recirculation Spray / 2 Segment RS-003A 11448-WMKS-1106A4 / 3-Sl-70 I 4c 5-AF Safety Injection/ 2 Segment HHl-011 11448-WMKS-1106A7 / 12-Sl-1 /
4c 1-13 Safety Injection / 2 Segment LHl-004A 11448-WMKS-1106A7 / 12-Sl-2 /
4c 1-15 Safety Injection I 2 Segment LHl-003A 11448-WMKS-0122A1/3-RH-13 4c
/ 3-02 Residual Heat Removal I 2 Segment RH-013 Operating Temperature (Estimated) 606 °F*
606 °F*
Ambient Ambient 540 °F**
Ambient Ambient 350 °F Serial No.16-227 Docket No. 50-280 Relief Request LMT-R01, Page 5 of 7 Operating Pressure (Estimated) 2235 psig*
2235 psig*
Slight vacuum***
Slight vacuum***
2235 psig**
Slight vacuum***
Slight vacuum***
450 psig
Drawing I Line#/ ID Table System I Class Risk-Informed Segment 11448-WMKS-0122A1/3-RH-13 4c
/ 3-03 Residual Heat Removal / 2 Segment RH-013 Operating Temperature (Estimated) 350 °F Serial No.16-227 Docket No. 50-280 Relief Request LMT-R01, Page 6 of 7 Operating Pressure (Estimated) 450 psig
- This is an emergency system, normally not in operation. Under unit operation, this segment has typically equalized to the reactor coolant nominal operating pressure and temperature for the Hot Leg. These are maximum pressure and temperature values.
- This is an emergency system, normally not in operation. Under unit operation, this segment has typically equalized to the reactor coolant nominal operating pressure and temperature for the Cold Leg. These are maximum pressure and temperature values.
- This is an emergency system, normally not in operation.
Maintained water filled; however, at a slight vacuum, pump suction piping from sub-atmospheric containment sump.
- 5. For the welds listed in Table 4b, discuss whether the Electric Power Research Institute (EPRI) interim guidance MRP 2015-025 "EPRl-MRP Interim Guidance for Management of Thermal Fatigue" (Accession Number ML15189A100) is applicable.
If yes, please describe.
Dominion Response The Electric Power Research Institute (EPRI) interim guidance MRP 2015-025, "EPRl-MRP Interim Guidance for Management of Thermal Fatigue," is applicable to the welds listed in Table 4b with respect to MRP-146.
The Surry Power Station Augmented Program, "MRP-146 Thermal Stratification Inspections," has been updated with the guidance of MRP-146, Rev. 1, Final Report, June 2011, "Materials Reliability Program Management of Thermal Fatigue on Normally Stagnant Non-isolable Reactor Coolant System Branch Lines," and MRP 2015-019 letter, "Implementation of NEI 03-08 Needed and Good Practice Interim Guidance Requirements for Management of Thermal Fatigue."
MRP-192, "Materials Reliability Program: Assessment of Residual Heat Removal Mixing Tee Thermal Fatigue in PWR Plants," is not applicable to these welds.
Serial No.16-227 Docket No. 50-280 Relief Request LMT-R01, Page 7 of 7
- 6. Confirm that the welds in Tables 4a and 4c are not part of an augmented inspection program (for example: ASME Code Case N-770-1, MRP-146, and/or the EPRI interim guidance MRP 2015-025 "EPRl-MRP Interim Guidance for Management of Thermal Fatigue" (Accession Number ML15189A100)). If these welds are part of an augmented program, please describe.
Dominion Response The welds included in Tables 4a and 4c are not part of an augmented inspection program.
Serial No.16-227 Docket No. 50-280 Response to NRC Request for Additional Information Relief Request LMT-R02 Virginia Electric and Power Company (Dominion)
Surry Power Station Unit 1
Request for Additional Information Serial No.16-227 Docket No. 50-280 Relief Request LMT-R02 ; Page 1 of 3 Relief Request LMT-R02 Regarding Weld Examination Coverage Surry Power Station, Unit 1 By letter dated October 9, 2015 (Accession Number ML15293A124), Virginia Electric and Power Company - Dominion (the licensee) requested relief from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (B&PV Code) specifically related to ASME Code Case N-460 Alternative Examination Coverage for Class 1 and Class 2 Welds,Section XI, Division 1." Relief request LMT-R02 pertains to the examination coverage of the Class 2 and non-Class welds at the Surry Power Station (Surry), Unit 1.
To complete its review, the NRG staff requests the following additional information.
- 1. Table R02 of the relief request shows pipe material (i.e., "600 lb ASA Std.'J. The NRG staff assumes that the weld and the associated components (valve) are made of the same material as the pipe.
Confirm that the weld and the associated components are also made of the pipe material. If valve and weld material are made of different materials, please describe. Please also describe in detail this material type "600 lb ASA Std."
Dominion Response The weld metal and associated valve components described in Relief Request LMT-R02, Table R02, have been verified as carbon steel.
The specified pipe material for the welds in this relief request is "600 lb. ASA Std". This pipe material is Surry pipe classification 601, 600 lb. carbon steel lines up to 775° F.
This specification describes the material as ASTM A 106, Grade B, 600 lb. carbon steel for 12" to 24" lines, and ASTM A691, Grade CMS75, Class 32 for lines 26" and larger.
- 2. Provide operating temperature and pressure for each weld.
Dominion Response Drawing / line#/ ID Operating Operating Table System I Class Temperature Pressure Risk-Informed Segment (Estimated)
(Estimated) 11448-WMKS-0103A2-1 I 30-R02N SHP-1/2-28 505 °F 760 psig Main Steam I 2 Segment MS-004
Drawing / line#/ ID Table System I Class Risk-Informed Segment 11448-WMKS-0103A2-1 / 30-R02Y SHP-1/2-31 Main Steam I 2 Segment MS-007 11448-WMKS-0103A2-2 / 30-R02 SHP-2 / 4-31 Main Steam I Non Class Segment MS-008 11448-WMKS-1018A3 / 14-R02N WFPD-17 / 1-22 Feedwater I Non Class Segment FW-012 11448-WM KS-1018A3 I 14-WFPD-R02 9 / 3-19 Feedwater I 2 Segment FW-016 Operating Temperature (Estimated) 505 °F 505 °F 435 °F 435 °F Serial No.16-227 Docket No. 50-280 Relief Request LMT-R02 ; Page 2 of 3 Operating Pressure (Estimated) 760 psig 760 psig 900 psig 900 psig
- 3. Confirm that the welds under consideration are not part of any augmented inspection program (for example: ASME Code Case N-770-1 or MRP-146). If these welds are part of an augmented program, please describe.
Dominion Response The welds listed below were not selected to receive specific volumetric or surface exarriination, but were included in the weekly visual walkdown of high energy lines outside of containment to detect through-wall leakage. This high energy line walkdown originated in Surry Technical Specification 4.15, "Augmented lnservice Inspection Program for High Energy Lines Outside of Containment". However, this requirement has since been relocated to the Surry Technical Requirements Manual, Section 6.2.
Weld 11448-WMKS-0103A2-1 / 30-SHP-1 / 2-28 Weld 11448-WMKS-0103A2-1 / 30-SHP-1 / 2-31 Weld 11448-WMKS-0103A2-2 / 30-SHP-2 / 4-31 Weld 11448-WMKS-1018A3/14-WFPD-17/1-22 Weld 11448-WMKS-1018A3/14-WFPD-9 / 3-19
Serial No.16-227 Docket No. 50-280 Relief Request LMT-R02 ; Page 3 of 3 The discussion presented in the relief request addressed the entire segment for each individual weld.
Serial No.16-227 Docket No. 50-280 Response to NRC Request for Additional Information Relief Request LMT-R03 Virginia Electric and Power Company (Dominion)
Surry Power Station Unit 1
Request for Additional Information Serial No.16-227 Docket No. 50-280 Relief Request LMT-R03 ; Page 1 of 2 Relief Request LMT-R03 Regarding Weld Examination Coverage Surry Power Station, Unit 1 By letter dated October 9, 2015 (Accession Number ML15293A124), Virginia Electric and Power Company - Dominion (the licensee) requested relief from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (B&PV Code) specifically related to ASME Code Case N-460 Alternative Examination Coverage for Class 1 and Class 2 Welds,Section XI, Division 1." Relief request LMT-R03 pertains to the examination coverage of the Class 1 steam generator (SG) nozzle to safe end dissimilar metal (DM) welds at the Surry Power Station (Surry),
Unit 1.
To complete its review, the NRG staff requests the following additional information.
- 1. In Attachment 3 to the relief request, the licensee provided the following materials of construction for the welds and associated components:
"Material:
Steam Generator Side:
Carbon Steel SA-216 with Stainless Steel Buttering Cast Stainless Steel" Safe End Side:
Also, Table R03 of Attachment 3 to the relief request contains the following, "SIG side: SA-216 Gr. WCC with SS buttering RCS pipe: SA-351 Safe End Side: Cast SS" Furthermore, the licensee stated that, "Welds 1-05 and 1-06 are the hot and cold leg, respectively, dissimilar metal nozzle to safe-end welds on "C" steam generator (S/G).
The carbon steel nozzles were buttered with stainless steel to assist the welding process to the stainless steel pipe."
The NRG staff notes that materials of construction are provided for the nozzle, the buttering, and the safe end. The NRG staff assumes that the weld material is also stainless steel. Please confirm the weld filler metal used.
Dominion Response The weld filler material for both welds described in Relief Request LMT-R03 has been verified as stainless steel.
- 2. The licensee stated that, Serial No.16-227 Docket No. 50-280 Relief Request LMT-R03 ; Page 2 of 2 "Examinations were performed using personnel, equipment and procedures qualified in accordance with ASME Section XI, Appendix Ill."
Paragraph 6 line 5 of the request states that the original classification of this weld was B-P. The NRG staff believes that a more appropriate classification would be B-J item 89. 11. Please justify the classification of these welds and their inspection requirements especially with respect to the use of Appendix Ill instead of Appendix VIII.
Dominion Response Relief Request LMT-R03, paragraph 6, includes a description of the on-going ASME Section XI system pressure testing that is performed on these Class 1 welds. Category B-P is the correct reference for this discussion as taken from the IWB 2500-1 Tables in ASME Section XI. There is no reference to the original ASME Section XI classification of the dissimilar metal welds.
These welds are cast stainless steel. to carboh steel. The ultrasonic (UT) scanning could only be performed from the cast stainless steel side of the weld. No qualified Section XI, Appendix VIII, UT techniques exist for performance on cast stainless steel.
Therefore, Appendix Ill was used.
- 3. Please confirm that the welds under consideration are not part of an augmented inspection program such as ASME Code Case N-770-1 or MRP-146. If these welds are part of an augmented program, please describe.
Dominion Response These dissimilar metal welds are not examined under an augmented inspection program.
Serial No.16-227 Docket No. 50-280 Response to NRC Request for Additional Information Relief Request LMT-P01 Virginia Electric and Power Company (Dominion)
Surry Power Station Unit 1
Request for Additional Information Serial No.16-227 Docket No. 50-280 Relief Request LMT-P01 ; Page 1 of 2 Relief Request LMT-P01 regarding Weld Examination Coverage Surry Power Station, Unit 1 By letter dated October 9, 2015 (Accession Number ML15293A124), Virginia Electric and Power. Company - Dominion (the licensee) requested relief from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (B&PV Code) specifically related to ASME Code Case N-460 Alternative Examination Coverage for Class 1 and Class 2 Welds,Section XI, Division 1." Relief request LMT-P01 pertains to the examination coverage of the Class 2 piping welds at the Surry Power Station (Surry), Unit 1, during preservice inspection (PSI).
To complete its review, the NRG staff requests the following additional information.
- 1. For the subject welds, did the licensee achieve essentially 100 percent coverage of the required surface area during the ASME Code required surface examinations following reconstruction and before returning to service?
Dominion Response In all three cases, there were no limitations documented on the NOE reports regarding the ASME Code required surface examinations, i.e., 100% coverage was obtained.
- 2. Table P01 of the relief request shows pipe material. The NRG staff assumes that the weld and the associated components (valve, elbow, and flange) are made of.the same material as the pipe. Confirm that the weld and the associated components are also made of the pipe material. If valve, elbow, flange, and weld are made of different materials, please describe.
Dominion Response It has been verified that the weld and the associated components are made of the same material as the pipe.'
Serial No.16-227 Docket No. 50-280 Relief Request LMT-P01 ; Page 2 of 2
- 3. Provide operating temperature and pressure for each weld.
Dominion Response Drawing / line# / ID Operating Operating Table System I Class Temperature Pressure ASME Category (Estimated)
(Estimated) 11448-WMKS-110585 I 3-CH-3 I P01 2-AW-B Ambient 2500 psig Chemical and Volume Control I 2 11448-WMKS-0118A2-1 I 6-P01 WAPD-1I0-34A Containment Ambient 900 psig*
Feedwater I 2 11448-WMKS-0118G1-1I6-P01 WAPD-2 I 0-1A Ambient 900 psig*
Feedwater I 2
- Auxiliary feedwater system is normally not inservice, maximum back pressure from the feedwater system.
- 4. Confirm that the welds under consideration are not part of any augmented inspection program (for example: ASME Code Case N-770-1 or MRP-146). If these welds are part of any augmented program, please describe.
Dominion Response The welds discussed in Relief Request LMT-P01 are not part of an augmented inspection program.