ML18361A580
| ML18361A580 | |
| Person / Time | |
|---|---|
| Site: | Millstone, Surry, North Anna  |
| Issue date: | 12/19/2018 |
| From: | Mark D. Sartain Dominion Energy Nuclear Connecticut, Dominion Energy Virginia, Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 18-238 | |
| Download: ML18361A580 (6) | |
Text
Dominion Energy Services.
Inc. . -5000 Dominion Boulevard, Glen Allen, VA 23060 Domini~nEnergy.com
- *
- December 19, 2018 United States Nuclear Regulatory Commission Attention:
Document Control Desk Washington, D.C. 20555_-0001 Domil"IIOn Energy 10 CFR Part 21 Serial No.: NRA/GDM: Docket Nos.: 18-238 R9 50-336 50-338/339 50-280/281 License Nos:: DPR-65 NPF-4/7 DPR-32/37 VIRGINIA ELECTRIC.
AND POWER COMPANY (DOMNION ENERGY VIRGINIA}
DOMINION ENERGY NUCLEAR CONNECTICUT, INC. . MILLSTONE POWER STATION UNIT 2 . NORTH ANNA AND SURRY POWER STATIONS UNITS 1 AND 2 UPDATED ANCHOR DARLING DOUBLE DISC GATE VALVE INFORMATION AND REPAIR STATUS
References:
- 1) Letter from Virginia Electric and Power Company and Dominion Nuclear Connecticut, _Inc., to the US NRC dated December 18, 2017 (Serial No. 17-343A), for Millstone Power Station Units 2 and 3, North Anna and Surry Power Stations Units 1 and 2, "Anchor Darling Double Disc Gate Valve lnforniation and Status" [ADAMS Accession
- No. ML17362A043] . 2) Letter from Virginia Electric and Power Company and Dominion Nuclear Connecticut, Inc., to the US NRC dated August 31, 2017 (Serial No.17-343), for Millstone Power Station Units 2 and 3, North Anna and Surry Power Stations Units 1 and 2, "Commitments for Resolution of Anchor Darling Double Disc Gate Valve Part 21 Issues" [ADAMS Accession No. ML17250A157]
- 3) BWROG Topical Report TP-16-1-112, Revision 4, "Recommendations to Resolve Flowserve 10 CFR Part 21 Notification Affecting Anchor Darling Double Disc Gate Valve Wedge Pin Failure" [ADAMS Accession No. ML17243A137]
- 4) Part 21 Notification from Flowserve Corporation, "Part 21 -Wedge Pin Failure in Anchor Darling Motor Operated Double Disc Gate Valves with Threaded Stem to Upper Wedge Connections," dated March 1, 2013, as modified July 11, 2017 [ADAMS Accession No. ML17194A825]
Serial No.18-238 Docket Nos. 50-336/338/339/280/281 Updated ADDDGV Information and Status Page 2 of 4 In Reference 1, Virginia Electric and Power Company (Dominion Energy Virginia) and Dominion Energy Nuclear Connecticut, Inc. (DE.NC), provided a listing of the Anchor Darling double disc gate valve (ADDDGV) population with active safety functions for Millstone Power Station (MPS) Unit 2 and North Anna and Surry Power Stations (NAPS and SPS, respectively)
Units 1 and 2 that are subject to the Flowserve Part 21 (Reference 4). Subsequent to the submittal of Reference 1, an additional ADDDGV on each SPS unit was identified as having an active safety function.
Specifically, the SPS Units 1 and 2 Charging Pump Discharge Recirculation Isolation Valves, Mark Nos. 1-CH-MOV-1373 and 2-CH-MOV-2373, respectively, were originally classified as passive valves; however, upon further review the valves were subsequently reclassified as having active safety functions.
Consequently, the SPS valve information provided in Reference 1 for the ADDDGVs with active safety functions is hereby amended to include the same information for motor-operated valves (MOVs) 1-CH-MOV-1373 and 2-CH-MOV-2373.
The additional information is provided in the attachment.
Reference 1 also included relevant information for each valve listed pursuant to the recommendations provided in Reference 3, as well as the valves' repair status. As noted in Reference 1, repair schedules for the listed valves were not included since our review did not identify any susceptible valves, as defined in Reference
- 3. Nevertheless, since the Flowserve Part 21 was issued, Dominion Energy Virginia and DENC have repaired several valves subject to the Part 21 at NAPS and SPS, and MPS, respectively, to return them to full qualification.
Specifically, three of the twelve NAPS Units 1 and 2 MOVs, nine of the twenty-eight SPS Units 1 and 2 MOVs, and four of the six MPS Unit 2 MOVs have been repaired by installing new high strength lnconel pins, and new stems having integral collars that were torqued into the upper wedges of the repaired MOVs. MOVs categorized as "high risk" were prioritized for repair during the recently completed fall 2018 refueling outages at MPS Unit 2 and SPS Unit 2. For the valves listed in Reference 1, as well as the two additional SPS
- valves noted above, that have not been repaired, Dominion Energy Virginia and DENC completed performance monitoring as prescribed in Reference 3 including stem rotation checks, . diagnostic testing, stroke time reviews, wedge pin analyses, etc., with satisfactory results, thus providing reasonable assurance the valves are fully capable of performing their design functions.
Additionally, for the valves that have been repaired and internally inspected, the following observations were noted:
- Existing wedge pins were intact with no evidence of damage caused by overloading,
- Threads of the stem-to-wedge connection threaded joint were in good condition with no evidence of excessive wear,
- Stem to wedge connections were found to be dry (unlubricated).
Serial No.18-238 Docket Nos. 50-336/338/339/280/281 Updated ADDDGV Information and Status Page 3 of 4 The condition of the wedge pins and the absence of lubrication on the threaded joints continue to validate stem-to-wedge thread coefficient of friction assumptions made in the susceptibility analysis.
In summary, the valve repairs, inspections, stem rotation checks, and diagnostic test results indicate the ADDDGVs subject to the Part 21 are capable of performing their required safety functions.
Dominion Energy Virginia and DENG continue to follow and participate in industry efforts to determine whether any additional actions are required to provide further assurance that plant ADDDGVs subject to the Part 21 will continue to perform their required safety functions.
Should you have any questions or require additional information, please contact Mr. Gary D. Miller at (804) 273-2771.
Respectfully, Mark D. Sartain Vice President
-Nuclear Engineering and Fleet Support Virginia Electric and Power Company Dominion Energy Nuclear Connecticut, Inc. Summary of Regulatory Commitments:
None
Attachment:
Anchor Darling Double Disc Gate Valve Information for 01-CH-MOV-1373 and 02-CH-MOV-2373 Serial No.18-238 Docket Nos. 50-336/338/339/280/281 Updated ADDDGV Information and Status Page 4 of 4 cc: U.S. Nuclear Regulatory Commission
-Region I 2100 Renaissance Blvd, Suite 100 King of Prussia, Pennsylvania 19406 -2713 U.S. Nuclear Regulatory Commission
-Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, Georgia 30303-1257 NRC Senior Resident Inspector Millstone Power Station NRC Senior Resident Inspector North Anna Power Station NRC Senior Resident Inspector Surry Power Station Mr. R. Guzman NRC Senior Project Manager -Millstone U.S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 C2 11555 Rockville Pike Rockville, Maryland 20852-2738 Mr. J. R. Hall NRC Senior Project Manager -North Anna U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 B 1 A 11555 Rockville Pike Rockville, Maryland 20852-2738 Ms. A. Schiller NRC Project Manager -Surry U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 07 E5 11555 Rockville Pike Rockville, Maryland 20852-2738 Mr. Marcus Harris Old Dominion Electric Cooperative Innsbrook Corporate Center 4201 Dominion Blvd., Suite 300 Glen Allen, Virginia 23060 Attachment Serial No.18-238 Docket Nos. 50-280/281 ANCHOR DARLING DOUBLE DISC GATE VALVE INFORMATION FOR 01-CH-MOV-1373 AND 02-CH-MOV-2373 Virginia Electric and Power Company (Dominion Energy Virginia)
Surry Power Station Units 1 and 2 01-CH-MOV-Charging Pump SPS I 1373 Charging Discharge Recirculation 3 Both No Low Line Isolation 02-CH-MOV-Charging Pump SPS 2 2373 Charging Discharge Recirculation 3 Both No Low Line Isolation (A) Applied Wedge Pin Torque must bound anticipated design basis operating torque requirements and current maximum total torque. Not Susceptible Yes Yes, >0.10 Yes,::;_5 deg. Not Susceptible Yes Yes, >0.10 Yes,:,;5 deg. Serial No.18-238 Docket Nos. 50-280/281 Attachment Page 1 of 1 Yes Not repaired Yes Not repaired