ML16020A332

North Anna, Units 1 and 2 - Intent to Implement Recommendations of Westinghouse Technical Bulletin 15-1 and Unlikely Loss of Both Rwsts

ML16020A332
Person / Time
Site:	North Anna
Issue date:	01/13/2016
From:	Sartain M D Virginia Electric & Power Co (VEPCO)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
15-558
Download: ML16020A332 (3)

Text

VIRGINIA ELECTRIC AND POWER COMPANYRICHMOND, VIRGINIA 23261January 13, 2016 10 CFR 50.90U.S. Nuclear Regulatory Commission Serial No. 15-558Attention:

Document Control Desk NLOS/DEA R0Washington, DC 20555 Docket Nos.: 50-338/339 License Nos.: NPF-4/7VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)

NORTH ANNA POWER STATION UNITS I AND 2INTENT TO IMPLEMENT RECOMMENDATIONS OF WESTINGHOUSE TECHNICAL BULLETIN 15-1 AND UNLIKELY LOSS OF BOTH RWSTSThis correspondence is to formally document an email communication sent to Mr. TonyBrown (NRC) from Mr. Mark Sartain (Dominion) on November 19, 2015. The purposeof the email was to; 1) discuss the status of Dominion's response to Westinghouse Technical Bulletin (TB) 15-1, and 2) provide supplemental information regarding theunlikely failure of both Refueling Water Storage Tanks (RWSTs) due to tornadogenerated missiles at North Anna Power Station.

The technical content of the email toMr. Brown is provided below:Westingqhouse Technical Bulletin 15-1. Reactor Coolant System Temperature andPressure Limits for the No. 2 Reactor Coolant Pump SealWestinghouse Technical Bulletin (TB) 15-1 was issued on March 17, 2015 andrecommended implementation of an extended cooldown of the Reactor Coolant System(RCS) to less than 350 degrees within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to maintain the integrity of the No. 2reactor coolant pump (RCP) seal following a loss of all RCP seal cooling event.Dominion reviewed the TB and entered the information into the Corrective Actionsystem for further evaluation.

Dominion has been assessing the recommendations of TB 15-1 with the understanding that Westinghouse is evaluating less stringent cooldown requirements and intends toissue a revision to the TB. Additionally, Dominion has been working closely withWestinghouse and the Pressurized Water Reactor Owner's Group to determine the bestsolution that could qualify the No. 2 seal for higher temperatures and allow for relaxation of the cooldown time and temperature requirements.

North Anna Power Station intends to implement the vendor recommendations of therevised TB to ensure integrity of the RCP seal package while avoiding concerns ofunintended consequences with TDAFW pump operation associated with the original TBrecommendations.

_Supplemental Information Reqardingq the Unlikely Failure of Both North AnnaPower Station RWSTs due to a Tornado Generated MissileThe Refueling Water Storage Tanks (RWSTs) at North Anna Power Station are safetyrelated structures that are seismically designed and protected from high winds, but are Serial No: 15-558Docket Nos.: 50-338/339 Page 2 of 3not protected from tornado generated missiles.

In the responses to Interim StaffEvaluation Confirmatory Item 3.2.1.9.A, Safety Evaluation (SE) #8, and SE #11,Dominion has stated that the loss of both site Refueling Water Storage Tanks (RWSTs)is highly unlikely.

Regardless, the North Anna Power Station FLEX strategies canconservatively accommodate the loss of both RWSTs.The loss of both RWSTs due to a tornado generated missile is highly unlikely based onthe following:

1) the two RWSTs are approximately 450 feet apart and are located onopposite ends of the power block; separated by the Auxiliary Building and theContainment buildings,

2) a portion of the Auxiliary Building and the Containment buildings are tornado generated missile protected structures and the RWST topelevations are below the top elevations of the Auxiliary Building and Containments, 3)each RWST is further shielded by several other structures (including the Safeguards Buildings, Emergency Condensate Storage Tanks (ECSTs),

the AFW Pumphouses, theMain Steam Valve houses, and the Service Building) on three of four sides. All of thesestructures, except the Service Building, are protected from tornado generated

missiles, and 4) the side of each RWST that is not shielded by other structures is exposed totornado generated missiles coming from opposite directions, thus minimizing thelikelihood that missiles generated by a tornado would impact and damage both RWSTs.Therefore, it is unlikely that tornado generated missiles will damage both RWSTs and itis reasonable to conclude that one of the two RWSTs would remain available as aborated water source following a tornado event.Should you have any questions in regard to this submittal, please contactMs. Diane E. Aitken at (804) 273-2694.

Si nce rely,Mar D"SrtinVicki L. Huill " tMakD.Srti

• NOTARY PUBLICVice President

-Nuclear Engineering of eg Virgi04 a Expires May 31, 2018COMMONWEALTH OF VIRGINIA)

)COUNTY OF HENRICO)The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today byMark D. Sartain, who is Vice President

-Nuclear Engineering of Virginia Electric and Power Company.

He has affirmedbefore me that he is duly authorized to execute and file the foregoing document in behalf of that Company, and that thestatements in the document are true to the best of his knowledge and belief.Acknowledged before me this day of2,2016.My Commission Expires:

________

oO.

Serial No: 15-558Docket Nos.: 50-338/339 Page 3 of 3Commitments made in this letter: No new regulatory commitments.

cc: U.S. Nuclear Regulatory Commission

-Region IIMarquis One Tower245 Peachtree Center Avenue, NE Suite 1200Atlanta, GA 30303-1 257Dr. V. Sreenivas NRC Project Manager -North AnnaU.S. Nuclear Regulatory Commission One White Flint NorthMail Stop 08 G-9A11555 Rockville PikeRockville, MD 20852-2738 Ms. Karen Cotton-Gross NRC Project ManagerU.S. Nuclear Regulatory Commission One White Flint NorthMail Stop 08 G-9A11555 Rockville PikeRockville, MD 20852-2738 NRC Senior Resident Inspector North Anna Power Station VIRGINIA ELECTRIC AND POWER COMPANYRICHMOND, VIRGINIA 23261January 13, 2016 10 CFR 50.90U.S. Nuclear Regulatory Commission Serial No. 15-558Attention:

Document Control Desk NLOS/DEA R0Washington, DC 20555 Docket Nos.: 50-338/339 License Nos.: NPF-4/7VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)

NORTH ANNA POWER STATION UNITS I AND 2INTENT TO IMPLEMENT RECOMMENDATIONS OF WESTINGHOUSE TECHNICAL BULLETIN 15-1 AND UNLIKELY LOSS OF BOTH RWSTSThis correspondence is to formally document an email communication sent to Mr. TonyBrown (NRC) from Mr. Mark Sartain (Dominion) on November 19, 2015. The purposeof the email was to; 1) discuss the status of Dominion's response to Westinghouse Technical Bulletin (TB) 15-1, and 2) provide supplemental information regarding theunlikely failure of both Refueling Water Storage Tanks (RWSTs) due to tornadogenerated missiles at North Anna Power Station.

The technical content of the email toMr. Brown is provided below:Westingqhouse Technical Bulletin 15-1. Reactor Coolant System Temperature andPressure Limits for the No. 2 Reactor Coolant Pump SealWestinghouse Technical Bulletin (TB) 15-1 was issued on March 17, 2015 andrecommended implementation of an extended cooldown of the Reactor Coolant System(RCS) to less than 350 degrees within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to maintain the integrity of the No. 2reactor coolant pump (RCP) seal following a loss of all RCP seal cooling event.Dominion reviewed the TB and entered the information into the Corrective Actionsystem for further evaluation.

Dominion has been assessing the recommendations of TB 15-1 with the understanding that Westinghouse is evaluating less stringent cooldown requirements and intends toissue a revision to the TB. Additionally, Dominion has been working closely withWestinghouse and the Pressurized Water Reactor Owner's Group to determine the bestsolution that could qualify the No. 2 seal for higher temperatures and allow for relaxation of the cooldown time and temperature requirements.

North Anna Power Station intends to implement the vendor recommendations of therevised TB to ensure integrity of the RCP seal package while avoiding concerns ofunintended consequences with TDAFW pump operation associated with the original TBrecommendations.

_Supplemental Information Reqardingq the Unlikely Failure of Both North AnnaPower Station RWSTs due to a Tornado Generated MissileThe Refueling Water Storage Tanks (RWSTs) at North Anna Power Station are safetyrelated structures that are seismically designed and protected from high winds, but are Serial No: 15-558Docket Nos.: 50-338/339 Page 2 of 3not protected from tornado generated missiles.

In the responses to Interim StaffEvaluation Confirmatory Item 3.2.1.9.A, Safety Evaluation (SE) #8, and SE #11,Dominion has stated that the loss of both site Refueling Water Storage Tanks (RWSTs)is highly unlikely.

Regardless, the North Anna Power Station FLEX strategies canconservatively accommodate the loss of both RWSTs.The loss of both RWSTs due to a tornado generated missile is highly unlikely based onthe following:

1) the two RWSTs are approximately 450 feet apart and are located onopposite ends of the power block; separated by the Auxiliary Building and theContainment buildings,

2) a portion of the Auxiliary Building and the Containment buildings are tornado generated missile protected structures and the RWST topelevations are below the top elevations of the Auxiliary Building and Containments, 3)each RWST is further shielded by several other structures (including the Safeguards Buildings, Emergency Condensate Storage Tanks (ECSTs),

the AFW Pumphouses, theMain Steam Valve houses, and the Service Building) on three of four sides. All of thesestructures, except the Service Building, are protected from tornado generated

missiles, and 4) the side of each RWST that is not shielded by other structures is exposed totornado generated missiles coming from opposite directions, thus minimizing thelikelihood that missiles generated by a tornado would impact and damage both RWSTs.Therefore, it is unlikely that tornado generated missiles will damage both RWSTs and itis reasonable to conclude that one of the two RWSTs would remain available as aborated water source following a tornado event.Should you have any questions in regard to this submittal, please contactMs. Diane E. Aitken at (804) 273-2694.

Si nce rely,Mar D"SrtinVicki L. Huill " tMakD.Srti

• NOTARY PUBLICVice President

-Nuclear Engineering of eg Virgi04 a Expires May 31, 2018COMMONWEALTH OF VIRGINIA)

)COUNTY OF HENRICO)The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today byMark D. Sartain, who is Vice President

-Nuclear Engineering of Virginia Electric and Power Company.

He has affirmedbefore me that he is duly authorized to execute and file the foregoing document in behalf of that Company, and that thestatements in the document are true to the best of his knowledge and belief.Acknowledged before me this day of2,2016.My Commission Expires:

________

oO.

Serial No: 15-558Docket Nos.: 50-338/339 Page 3 of 3Commitments made in this letter: No new regulatory commitments.

cc: U.S. Nuclear Regulatory Commission

-Region IIMarquis One Tower245 Peachtree Center Avenue, NE Suite 1200Atlanta, GA 30303-1 257Dr. V. Sreenivas NRC Project Manager -North AnnaU.S. Nuclear Regulatory Commission One White Flint NorthMail Stop 08 G-9A11555 Rockville PikeRockville, MD 20852-2738 Ms. Karen Cotton-Gross NRC Project ManagerU.S. Nuclear Regulatory Commission One White Flint NorthMail Stop 08 G-9A11555 Rockville PikeRockville, MD 20852-2738 NRC Senior Resident Inspector North Anna Power Station