B15962, Forwards Response to GL 96-06, Assurance of Equipment Operability & Containment Integrity During Design-Basis Accident Conditions

Forwards Response to GL 96-06, Assurance of Equipment Operability & Containment Integrity During Design-Basis Accident Conditions

ML20134E595
Person / Time
Site:	Millstone, Seabrook, Haddam Neck  File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	10/30/1996
From:	Feigenbaum T CONNECTICUT YANKEE ATOMIC POWER CO., NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO), NORTHEAST NUCLEAR ENERGY CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
B15962, GL-96-06, GL-96-6, NUDOCS 9611010221
Download: ML20134E595 (6)

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, Utilities System sorthen.i utiutie service cmopany P.O. Ikin 27' liartford. Ur 06141-0270 (860) 665-5323 Ted C. Feigenbaurn -

Executive Vice President and Chief Nuclear Officer October 30,1996 Docket No. 50-213 .

50-245 50-336 50-423 >

50-443 ,

B15962  :

Re.: 10CFR50.109 10CFR50.54(f)

U.S. Nuclear Regulatory Commission Attention: Document Control Desk l Washington, DC 20555 Millstone Nuclear Power Station, Unit Nos.1,2 and 3 Haddam Neck Plant Seabrook Station Response to Generic Letter 96-06 Assurance of Equipment Operability and Containment Integrity During Desian-Basis Accident Conditions in a letter dated September 30,1996W, the NRC transmitted Generic Letter (GL) 96- l 06, " Assurance of Equipment Operability and Containment Integrity During Design-  !

Basis Accident Conditions." The NRC requested that licensees submit a letter within 30 days of the date of the subject GL indicating whether the Requested Actions will be i completed and Requested Information will be submitted within 120 days of the date of j the GL. Specifically, the GL requests licensees to determine: ,

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• T. T. Martin letter dated September 30,1996, " NRC Generic Letter 96-06:  !

Assurance of Equipment Operability and Containment Integrity During Design-Basis Accident Conditions" f i 9611010221 961030 4o7;L

/ I PDR ADOCK 05000213 P PDR

. U.S. Nucl: r R::gul: tory Commission i

B15962/Page 2 l

(1) If containment air cooler cooling water systems are susceptible to either waterhammer or two-phase flow conditions during postulated accident l

conditions; and l (2) If piping systems that penetrate containment are susceptible to thermal i

expansion of fluid so that overpressurization of piping could occur.

The GL requests that Items 1 and 2 above be reviewed based on the plant's postulated

accident conditions, as well as with respect to the scenarios referenced in the GL.

Operability of affected systems should be assessed and corrective actions taken, as l

appropriate in accordance with 10CFR50, Appendix B and the plant operating license.

The GL requests licensees to submit the following requested information within 120 days of the date of the GL:

A written summary report stating:

(1) Actions taken in response to the requested actions, l (2) Conclusions that were reached relative to susceptibility for waterhammer and l two-phase flow in the containment air cooler cooling water system and overpressunzation of piping that penetrates containment, l

1 l (3) Basis for continued operability of affected systems and components, as

! applicable, l (4) Corrective actions implemented or are planned to be implemented, and

) (5) If systems were found to be susceptible to the conditions discussed in the l

GL, identify the systems affected and describe the specific circumstances involved.

Accordingly, Millstone Unit Nos.1 and 2, and Seabrook Station will complete the requested actions and submit the written summary report within 120 days of the date of l the Generic Letter (January 28,1997).

The response to requested actions 1 and 2 for Haddam Neck Plant is provided in Attachment 1. No further actions are planned for Haddam Neck Plant at the present time in response to the GL until a decision has been made with regard to plant restart.

A letter will be submitted to the NRC within 120 days of the date of the GL providing a status of Haddam Neck Plant's plan for responding to the GL.

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U.S. Nucicer Regulatory Commission i

B15962/Page 3

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Millstone Unit No. 3 will complete requested action 1 and submit the written summary report for requested action 1 within 120 days of the date of the Generic Letter (January 28, 1997). However, the engineering review of isolated water-filled piping systems that penetrate containment to determine if any piping sections are susceptible to thermally induced overpressurizatiori during Design Basis Accidents (requested action 2) is scheduled to be completed in conjunction with a review of Stress Dah Packages (SDP) for Category I piping systems. The review of the SDP's is scheduled to be completed prior to unit startup as part of the unit recovery plan. The course of action outlined above provides an efficient method of complying with the information i request given the current shutdown conditions of Millstone Unit No. 3. Therefore, completion of requested action 2 and submittal of the written summary report will be completed prior to Millstone Unit No. 3 startup.

Commitments The following are the commitments associated with this letter:

B15962-1 Within 120 days of the date of the GL, Millstone Unit Nos.1 and 2, and Seabrook Station will complete the requested actions and submit the requested information to the NRC per the recommendations of Generic Letter 96-06.

B15962-2 Within 120 days of the date of the GL, Millstone Unit No. 3 will complete requested action 1 and submit the requested information to the NRC per the recommendations of Generic Letter 96-06.

B15962-3 Within 120 days of the date of the GL, a letter will be submitted to the NRC providing a status of Haddam Neck Plant's plan for responding to the GL.

I B15962-4 Prior to Unit startup, Millstone Unit No. 3 will complete requested action 2 and submit the requested information to the NRC per the recommendations of Generic Letter 96-06.

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U.S. Nucirr R gulatory Commission l

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B15962/Page 4 1

Should you have any questions regarding this submittal, please contact  !

Mr. Richard T. Laudenat at (860) 437-5248. l l

Very truly yours, i

NORTHEAST NUCLEAR ENERGY COMPANY CONNECTICUT YANKEE ATOMIC POWER COMPANY NORTH ATLANTIC ENERGY CORPORATION NORTH ATLANTIC ENERGY SERVICES CORPORATION

. l hMP T. C. Feigenba6m Executive Vice President and Chief Nuclear Officer i

Subscribed and sworn to before me this 30n._ day of dlbr ,1996 l 1 l(112 l

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Date Commission Expires:

iG. /a # /4 O cc: H. J. Miller, Region i Administrator W. D. Lanning, Director, Millstone Oversight Team T. A. Eastick, Senior Resident Inspector, Millstone Unit No.1 J. W. Andersen, NRC Project Manager, Millstone Unit No.1 Senior Resident inspector, Millstone Unit No. 2 D. G. Mcdonald, Jr., NRC Project Manager, Millstone Unit No. 2 A. C. Cerne, Senior Resident Inspector, Millstone Unit No. 3 V. L. Rooney, NRC Project Manager, Millstone Unit No. 3 W. J. Raymond, Senior Resident inspector, Haddam Neck Plant S. Dembek, NRC Project Manager, Haddam Neck Plant J. B. Macdonald, Senior Resident inspector, Seabrook Station A.W. De Agazio, NRC Project Manager, Seabrook Station i

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Docket No. 50-213 50-245 l

50-336  :

50-423 l 50-443 B15962  :

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Attachment 1 Haddam Neck Plant I

Response to Generic Letter 96-06 t

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. U.S. Nuclear R:gulatory Commission B15962/ Attachment 1/Page 1

Reauested Action 1 Determine if containment air cooler cooling water systems are susceptible to either water hammer or two phase flow conditions during postulated accident conditions.

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Response

The Haddam Neck Plant is susceptible to water hammer and two phase flow as reported to the Nuclear Regulatory Commission in LER 96-013-00 " CAR Fan Service Water Piping Susceptible to Water Hammer"W An engineering analysis determined that if a loss of coolant accident (LOCA) or main steam line break inside containment occurred, coincident with a loss of offsite power, the service water piping inside ,

containment, downstream of the Containment Air Recirculation (CAR) fan coolers would reach saturation. Upon restart of the service water pumps, a water hammer could develop that would exceed the structural design of the piping, rendering the CAR fans inoperable.

At the present time, the decision to restart the Haddam Neck Plant is on hold pending a l final decision by the joint owners. The plant is currently in cold shutdown and there is i no accident for which the CAR fans are required for accident mitigation (LOCA and j Main Steam Line Break) in this mode. Modifications will not be implemented unless a decision is made to restart the plant.

Reouested Action 2 Determine if piping systems that penetrate containment are susceptible to thermal expansion of fluid so that overpressurization of piping could occur.

Response

This issue will not be investigated under the present plant status as stated above. If a decision is made to restart the plant, a determination whether other piping systems are susceptible to overpressurization will be completed prior to restart.

• J. J. LaPlatney letter to the USNRC, dated August 19,1996, Reportable Occurrence LER 50-213/96-013-00