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Application for Amends to Licenses NPF-4 & NPF-7,revising TS to Ensure Design Basis Is Met for Component Cooling Water Sys
	ML20079P906
Person / Time
Site:	North Anna
Issue date:	11/07/1991
From:	Stewart W; VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	; NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20079P909	List: ML20079P906; ML20079P912;
References
	91-662, NUDOCS 9111140148
	Download: ML20079P906 (8)
	v • d • e

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YlRGINIA ElICTRic AND l' owl:R CONII'ANY RICllhlOND, VIRGINlA 23261 November 7, 1991 U.S. Nuclear Regulatory Commission Sorial No. 91662 Attention: Document Control Desk NAPS /JYR Washington, D.C. 20555 Docket Nos. 50 338 50 339 Licenso Nos. NPF 4 NPF 7 Gentlemen:

VIRGINlA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNLTL1 AND 2 PROPOSED TECHNICAL SPECIFICATION CH&tLGJJi Pursuant to 10 CFR 50.90, the Virginia Electric and Power Company requests amendments, in the form of_ changes to the Technical Specifications, to Operating License Numbers NPF 4 and NPF 7 for North Anna Power Station Units 1 and 2, respectively. The proposed changes will reviso the current Technical Specifications to ensure the deLign basis is mot for the component cooling water system.

A discussion of the proposed changes is provided in Attachment 1. The proposed changus are presanted in Attachments 2 and 3 for Units 1 and 2, respectively.

This request has been reviewed by the Station Nuclear Safety and Operating Committee and the Management Safoty Review Committee. It has been determined >

that this request does not involve an unroviewed safety question as defined in 10 CFR 50.59 or a significant hazards consideration as defined in 10 CFR 50.92. The basis for our determination that no significatica hazards consideration is involved is presented in Attachment 4 Should you have any questions or require additional information, please contact us at your earliest convenience.

l Very t uly y u ,

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.W. L. Ste art Senior Vice President - Nuclear

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Attachments

1. Discussion of Proposed Changes

2. Proposed Technical Specification Change for Nor1h Anna Unit 1

3. Proposed Technical Specification Change for North Anna Unit 2

4. 10 CFR 50.92 Evaluation oc: U.S. Nuclear Regulatory Commission Region ll 101 Marietta Street, N.W.

Suite 2900 Atlanta, GA 30323 Mr. M. S. Lesser NRC Senior Resident inspector North Anna Power Station Commissioner Department of Health Room 400 109 Governor Street Richmond, Virginia 23219 i

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e 8 COMMONWEALTH OF VIRGINIA )

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COUNTYOF HENRICO )

The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by E. W. Harrell, who is Vice President - Nuclear Operations, for W. L. Stewart, who is Senior Vice President - Nuclear, of Virginia Electric and Power Company. He is duly authorized to execute and file the foregoing document in behalf of that Company, and the statements in the document are true to the best of his knowledge and belief.

Acknowledged before me this 1. day of bn%nht ,19f\\.

My Commission Expires: bysk %\ ,19'\A.

Uue @kQi)t; Notary Public l

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(SEAL)

Attachment 1 DiscLosion of Proposed Changes North Anna Units 1 and 2 Virginia Electric and Power Company

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QJECJ)SSION OF PROP _Q. SED CH ANGE.S jntroduction The proposed changes described herein are being made as a result of an NPC violation regarding the service water system. Technical Specification changes for the service water system have been submitted to the NRC as a result of the violation. However, in the cover letter transmitting the service water Notification of Violation (dated February 1,1991) the NRC observed that the cperation of the component cooling water system was different than that described in the UFSAR. In addition, no formal safety evaluations were done to address this difference. It was recognized by the NRC that the intent to comply with the design basis for the component cooling system was accomplished through safety review committee meetings and administrative controls. The proposed Technical Specification change will ensure that operation of the component cooling water system is consistent with its design basis.

Background

The component cooling system is a closed cycle system. Cool water is circulated through various components in the plant for cooling and returned to heat exchangers for heat rejection to the service water system The component cooling water system consists of four subsystems shared between Units 1 and 2, with each subsystem containing one pump and one heat exchanger. The major components in the component cooling system are a surge tank, four pumps, four heat exchangers, and a radiation monitor. Component cooling water must be supplied to various components to accomplish the following functions:

a. Removal of residual heat from the reactor coolant system through the residual heat removal system during unit cooldown,

b. Cooling of letdown flow to the chemical and volume control system during power generation, and

c. Removal of heat from various NSSS components during power generation and normal unit cooldown.

The component cooling water system ensures that sufficient cooling capacity is available for continued operation of various equipment during normal unit cooldown. This system performs no design basis accident mitigation function.

The component cooling water system is not a system which functions to mitigate the failure of or presents a challenge to the integrity of a fission product barrier.

Complete redundancy to meet the single failure criteria is not a design basis feature of this system (other than the containment isolation associated functions). This system supports operation of the residual heat removal system.

The residual hem removal system does not perform a design basis accident mitigation function.

The current design basis foi the component cocling water system is a fast cooldown of one ur'it while maintaining normal loads on the other unit. Three component cooling water subsystems need to be OPERABLE to accomplish this function. The fourth subsystem is a spare and may be out of service indefinitely.

With only two component cooling water subsystems a slow cooldown on one unit while maintaining normal loads on the opposite unit can be accomplished witnout toliance on the main steam system below 350 F.

The component et ling water system is designed so that when one unit is being cooled dowi., two component cooling pumps and two component cooling heat exchangers for that unit supp'/ the residual heat removal, reactor coolant pumps, and nonregenerative and scal water heat exchanger flow paths while the common loads header is supplied from the other unit. If only ono component cooling pump and component cooling heat exchanger are operating, cooldown can be accomplished but will require more time.

Technical Snecification Chanaos General All Technical Specification changes described herein apply to North Anna Units 1 and 2.

The current Technical Specifications refer to the component cooling water subsystam when discussing the component cooling function. The component cooling water subsystem consists of one pump and one heat exchanger with two subsystems per unit. The subsysters can be cross-connected between units. To meet the design basis a minimum of three subsystems is necessary (i.e., three pumps and three heat exchangers). The proposed Techriical Specification changes have been modified to define what constitutes a subsystem.

Technical Soecification 3.7.3.1 The numbering of the Technical Specification was changed from 3/4.7.3 to 3/4.7.3.1 to allow for the addition of a new component cooling water Technical Specificatien when both unitc are in modes 5 or 6 (which is numbered 3.7.3.2).

In addition, the title of this Technical Specification was changed to add the word

" operating" to ' jentify that this specification applies to whenever either unit is in modes 1 through 4.

The Limiting Condition for Operation is changed to require three subsystems (shared between both units) to be operable and to define what an operable component cooling water subsystem consists of. Two component cooling water subsystems provide the minimum heat removal capability to accomplish a slow

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cooldown on one unit while maintaining normalloads on the opposite unit. To f

- ensure the design basis requirement of a fast cooldown on one unit and normal !

operationalloads on the opposite unit is met, three subsystems of component !

cooling water must be_ OPERABLE. In addition, a footnoto was added to further :

clarify when a subsystem is considered OPERABLE. !

The Applicability statement is changed to clarify that this Technical Specifcation i applies if either or both units are in modes 1 through 4. This change will ensure i that sufficient cooling capacity is available for both units.

The current Action statement was deleted and replaced with Action statements a and b.

Action statement 3.7.3.1.a is added to require that if one of the three required subsystems becomes inoperable, that the subsyMem be returned to an i operable status within seven days. The specified et ">letion time is consistent >

with the residual heat removal system for the loss o a te train of a residual heat removal system. The completion time of seven uays is based on industry

accepted practice, and engineering judgment, considering the number of available systems and the time required to reasonably complete the required action. The completion time of seven days is also consistent with MERITS.

Action statement 3.7.3.1.a also specifies that if the required component cooling water system subsystem cannot be restored in the required completion time, both units must be placed in a mode in which the risk to the unit is minimized.

This is done by placing both units in HOT STANDBY in six hours and in COLD SHUTDOWN in the next 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The completion time of six hours is a reasonable time, based on operating experience to reach HOT STANDBY from full power without challenging safety systems or operators. Similarly, the completion time of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is reasonable considering that a unit can cooldown in-such a time frame on one subsystem if_the main steam system :s used to supplement residual heat removal cooling. ;

Action statement 3.7.3.1.b is added to requin . hat if two of the three required -

subsystems become inoperable,_ that both units shall be placed in HOT l SHUTDOWN within the next 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and that actions be initiated to place both ,

e units in COLD SHUTDOWN within the next hour and continue to COLD SHUTDOWN if component cooling water is available to supply the residual heat removal heat exchangers to further cool the units. The units are first placed in a condition where decay heat can be removed by the steam generators. This can be achieved in HOT SHUTDOWN. - Twelve hours is a reasonable time, based on operating experience, to place the unit in HOT SHUTDOWN from full power ,

conditions without challenging safety systems or operators.-

- Action statement 3.7.3.1;c is added to require that with no component cooling

'- water available to supply the residual heat removal heat exchangers to further cool the units, both units must be placed in HOT SHUTDOWN within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months The units may remain in HOT SHUTDOWN until alternate means of decay heat l removal can be implemented, if component cooling is P.n11able and a heat sink L

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to further cool the units is available, unit cooldown shall continue until COLD SHUTDOWN is achloved under Action statement 3.7.3.1.b. This Actlun statomont is consistent with MERITS.

Surveillance Roquiremont 4.7.3.1.a was modified to replace " safety related equipment" with *in too flow path of the residual heat removal system" for clarity.

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Surveillanco Requirement 4.7.3.1.b was added to specify survoillanco testing for OPERABILITY determination of the component cooling water pumps in accordance with Specification 4.0.5, the ASME Sectinn XI program.

Technical Soecification 3.7.3.2 This Technical Specification was added to support our current UFSAR design bases when both onits are in Modos 5 or 6.

A now Limiting Condition for Operation is established for modos 5 and 6. This ;

new limiting Condition differs from Specification 3.7.3.1 by requiring that two of the four component cooling water subsystems bo OPERABLE. Component cooling water is required to provido a heat sink for the residual heat romoval system to remove decay heat from the reactor core. However, there is a significant reduction In potential heat loading on component cooling water with the reduced operational requirements of the other systems that are cooled by component cooling water. The major reduction in heat loads is due to the fact that by mode 5 reactor decay heat has already dropped off significantly and that reactor coolant pumps and control rod drive mechanisms are not required to be operating in modos 5 and 6. Thorofore, only two component cooling water subsystems are required to be OPERABLE.

If only one of the two required component cooling water subsystems is OPERABLE, Action. Statomont 3.7.3.2 requires all operations involving an increase in the reactor decay heat load or a reduction in boron concentration of the Reactor Coolant System must be immediately suspended. This is consistent with the action requirements for a totalloss of residual heat removal capability during shutdown conditions.

The Surveillance Requirements are the same as those of Specification 3.7.3.1.

Bases Sections 3/4.7.3.1 and 3/4.7.3.2 The existing bases section (3/4.7.3) was expanded to provido a more detailed I

description of the component cooling water system. This bases section was l also split to provido a description for operating and shutdown conditions l

(3/4.7.3.1 and 3/4.7.3.2, respectively).

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ML20079P906

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