ML20116B544

Application for Amend to License NPF-4 to Revise Current TS SRs Re Auxiliary Feedwater Pump Relay Response Time Testing. TS Change Requested on Emergency Basis

ML20116B544
Person / Time
Site:	North Anna
Issue date:	10/26/1992
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20116B548	List: ML20116B544 ML20116B558
References
92-689, NUDOCS 9211020258
Download: ML20116B544 (10)

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VinotNIA EI.ncinic ann Pownn COMPANY RicnMoso. WuotNI A 2auer October 26, 1992 U.S. Nuclear Regulatory Commission Serial No.

92 689-Attention: Document Control Desk NAPS /MAE: R0 Washington, D.C. 20555 Docket Nos. 50 338 License Nos. NPF 4 Gentlemen:

VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNIT 1 PROPOSED TECHNICAL SPECIFICATION CHANGE Pursuant to 10 CFR 50.90, the Virginia Elecido and Power Company requests an -

amendment, in the form of changes to the Technical Specifications, to Operating License Number NPF-4 for North Anna Power Station Unit 1. The proposed changes-i will revise the current Technical Specification surveillance requirements pertaining to the auxiliary feedwater pump relay response time testing.

This Technical Specification change is requested on an emergency basis in accordance with 10 CFR 50.c 'a) (5). The basis for an emergency change request is included as Attachment 1.

A discussion of the proposed changes is provided in. The proposed changes are presented in Attachment 3.

-This request has been reviewed by the Station-Nuclear Safety and Operating -

Committee and the Management Safety Review Committee. It has been determined that this request does not involve an unreviewed 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 signification hazards consideration is involved is presented.

In Attachment 4.

Should you bave any questions e require additionalinformation, please contact us.

Very truly yours,

.., n W. L. Stewart a

Senior Vice President - Nuclear Attachments 9211020258 921026

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PDR ADOCK 05000338

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U.S. Nuclear Regulatory Commission Region 11 101 Marietta Street, N.W.

Suite 2900 Atlanta, Georgia 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

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COMMONWEALTH OF VIRGINIA )

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COUNTY OF HENRICO

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b The foregcing document was acknowledged before me, in and for the County and Commonwealth aforesaid, ioday by 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 2(e day of h/f' ofuJ,19ff(.

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My Commission Expires:

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i ;h (1 11 Notary Public l.

(SEAL)

ATTACHMENT 1 BASIS FOR EMERGENCY CH/ NGE REQUEST

4 Basis for Ernergency Change-Renuest NRC regulations (10 CFR 50.91(a)(5)) require that whenever an emergency situation exists, a licensee must' explain why this emergency situation occurred and why it could not avoid this situation, and the NRC will assess the licensee's reasons for falling to file an application sufficiently in advance of that event. An emergency situation exists when the NRC's failure to act in a timely way would result in derating or shutdown of a-nuclear plant, or in prevention of either resumption of operation or of increase in po.ver output up to the plant's licensed power level, in such cases, the NRC may issue a license amendment involving no significant hazards consideration without prior notice and opportunity for a hearing or for public comment.- Also, in-such cases,Lthe.

regulations require that the NRC be particularly s'ensitive to-environmental considerations. Our discussion of why this proposed change meets the conditions necessary for emergency consideration is provided below.

Why Emeraency Situation Occurred and Could Not Be Avoided Technical Speci9 cation surveillance requirement 4.3.2.1.3, Table 3.3 5,-Item 11 requires Enginee;ad Safety Feature (ESF) response time testing of the auxiliary-feedwater (AFW) pump circuit as a result of a main feedwater pump trip. The test is required at least once per 18 months. On October'21,1992 at 1245 hcurs it was i

determined that this requirement had not been met for North Anna Unit 1. INorth Anna Unit 2 is in full compliance with the surveillance requirement.) The requirements of-Technical Specification 4_.0.3 were i_mmediately invoked which permit conducting the required surveillance test within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following discovery of _ the missed-surveillance.

The need for the Technical Specification change was identified -during our-programmatic = review of Technical Specification -surveillance requirements as described in a letter to the NRC dated September 8,1992.(Serial No.92-482). : While-preparing a test procedure to conduct the required surveillance, it was datermined that -

the actuation of two relays in the AFW pump start circuit (Relays 3-CKT-1FWSA05 and :

3-CKT-1FWSB05) due to a main' feedwater pump trip would cause a turbine-trip.

Lifting a lead to prevent relay actuation is possible, however, an crror or an arc on the contacts could cause the relays to actuate and cause a turbine trip / reactor trip.

Basis for Emergency Change Reauest On October 22,1992, we requested a temporary waiver of compliance from Technical' Specification surveillance requirement 4.3.2.1.3, Table 3.3-5, item 11 which requires'

~a Engineering Safety Feature (ESF) response time testing of the auxillary feedwater (AFW) pump circuit as a result of a main feedwater pump trip.- This was documented in our letter to the NRC, dated October 22,1992 (Serial No. 92 687); The NRC verbally approved the waiver request on October 22,1992, and requested that we propose'an emergency Technical Specification change by October 26,1992, to appropriately

. modify the surveillance requirement.

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1 Unit 1 is currently in coastdown operation at approximately 70% power and near the end of its operating cycle prior to the 1993 Steam Generator Replacement Outage scheduled to begin January 2,1993. When the temporary waiver expires in the near future, the surveillance requirement will again be controlling. The surveillance test that is then required to meet the surleillance requirement is usually performed while the unit is in a sheldown condition.

The potential exists for a turbine trip / reactor trip if an error or arc occurs during the surveillance test while the unit is operating, and the possibility of a subsequent plant transient. Without NRC approval of the proposed emergency Technical Specification change, either the surveillance test would have to be conducted by the tinie the waiver expires--with the possibility of a plant trip or transient--or the unit would be shut down in accordance with Technical Specifications. Clearly, it is desirable to avoid the potential for an unnecessary plant trip. Similarly, in the event the unit is shut down, a management decision whether to begin the steam generator outage early would be required since the unit is near the end of its current operating cycle.

However, in iating the outage prior to the scheduled January 2,1993, date would result in a

ir, dequate resources being available to support the early outage, an unproductive period at the beginning of the outage as forces are mobilized, and substantial replacement power costs. Therefore, we conclude that the NRC's failure to act could reasonably be expected to result in an unnecessary shutdown of the unit and therefore meets the criteria in 10 CFR 50.91(a)(5) for an emergency situation.

As discussed in Attachment 4, we have determined that the proposed change involves no significant hazards consideration. Therefore, we conclude that the condition in 10 CFR 50.92(a)(5) regarding issuance only of a license amendment involving no significant hazards consideration is met.

Environmental Considerations Approval of this Technical Specification change as described in this document will not chtms the types of any effluents that may be released offsite, nor create a significant increase in individual or cumulative occupational radiation expo;;ure. The Technical Specification change involves only surveillance requirements.

Therefore, the consequences of accidents related to or dependent on response time testing the AFW pump start circuit due to a main feedwater pump trip remain unaffected.

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9 ATTACHMENT 2 DISCUSSION OF CHANGES F

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t DELQQSilON -OF CHANGES INTRO D UCTIQ.N e

Technical Specification surveillance requirement 4.3.2.1.3. Table 3.3 5, item 11 requires Engineered Safety _ Feature (ESF) response time testing of the auxiilary_

feedwater (AFW) pump circuit as a result of a main feedwater pump trip. ~ The test is e

required _at least once per 18 months. On October 21,.1992 at 1245 hour0.0144 days <br />0.346 hours <br />0.00206 weeks <br />4.737225e-4 months <br />s-it was determined that this requirement had not been met for North Anna Unit 1. (North Anna Unit 2 is'in full compliance with the surveillance requirement.) The requirements of Technical Gpecification 4.0.3 were immediately invoked.which permit conducting the required surveillance test within -24 hours following discovery of the missed-j surveillance.

The need for the Technical Specification change was identified during our programmatic review of Technical Specification surveillance requirements as described in a letter to the NRC dated September 8,1992 (Serial Noi 92 482). _While preparing a test procedure to conduct the required surveillance, it was determined that -

the actuation of two relays in the AFW pump start' circuit (Relays 3-CKT-1FWSA05 and-3 CKT 1FWSB05) due to-a main feedwater pump trip would cause a turbine trip.

Lifting a lead to prevent relay actuation is possible, however, an error o'r an arc on thei contacts could cause the relays to actuate and cause a turbine trip / reactor trip.

BACKGROUND On October 22,1992, we requested a temporary waiver of compliance from Technical Specification surveillance requirement 4.3.2.1.3, Table 3.3-5; llem 11 which r_equires Engineered Safety Feature (ESF) response. time testing of the auxiliary feedwater.

(AFW) pump circuit as a result of a main feedwater pump trip. This was documented in a letter to the NRC' dated October 22,E1992 (Serial No' 92 687). (The NRC verbally approved our waiver request on October 22,1992, and requested that we propose an emergency Technical Specification change'by-October 26,1992, to appropriately modify the Technical Specification surveillance requirement 4.3.2.1.3L Table 3.3 5, Item 11.

.This_ surveillance test is usually perfurmed:while the unit is in'a shutdown condition.

Unit 1 is currently in-coastdown operation at approximately 70% power and'near the

.end of its cycle, prior to its 1993 Steam Generator-Replacement Outage which is scheduled to begin -January 2,1993. The initiation of the outage prior'to:the scheduled date would result.in inadequate resources being available to support the -

. outage, an unproductive period at the beginning of the. outage and substantialL replacement power costs.

. SP ECIFIC_QHANG ES-

- 4 The proposed. change will modify Technical Specification surveillance' requirement

' 4.3.2.1.3, Table 3.3-5, Item 11 which currently reads as follows:

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1NIII/QNG SIG% LAND FUNCTION RES_P_QRSE TIME IN SECOND3

11. Main Feedwater Pumo Tdg a.

Auxihary Feodwater Pumps s 60.0 The revised Technical Specification surveillance requirement 4.3.2.1.3, Table 3.3. 5, item 11 will read as follows:

1NITIATING SIGNAL AND FUNCTION RESPONSE TIME IN SECONDS

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11. Main Feedwater Pumn Tda s.

Auxiliary Feedwater Pumps s 60.c ####

9 A footnote will be added to page 3/4 3-30 which reads as follows:

1. 1. 1. 1. Response time testing of the two relays in the auxiliary feedwater pump start circuit (Relays 3-CKT-1FWSAos and 3-CKT 1FWSB05) due to a main feedwater pump trip is suspended for the duration of Cycle 9.

To better understand the basis for the Technical Specification change, a description of the affected ESF features is necessary. There are four events that automatically start the AFW pumps. These are: 1) safety injection,2) steam generator low-low water level, 3) loss of offsite power, and 4) main feedwater pump trip. Response time testing is required to provide assurance that the protective and ESF actuation functions are completed within the time limits assumed in the accident analysas. However, the main feedwater pump trip signal is anticipatory and no credit is taken in any safety analysis for that event. Technical Specification 4.3.2.1.3, Table 3.3-5, item 11 requires the initiation of the AFW pumps within 60 seconds of a main feedwater pump trip.

The basis for suspending the response time test requirement for the two relays in the AFW pump start circuit for the remainder of the operating cycle involves several factors. First, the relays have repeatedly been demonstrated to perform as expected' during periodic functional testing as required by the Technical Specifications. (The only aspect not specifically addressed during the functional test has been the relay response time. The functionality of the system has been repeatedly demonstrated.)

Second, no credit is taken in the safety analysis for an AFW pump start on a main feedwater pump trip. Third, the affected relays are HFA relays, which are used throughout the plant.

Response time testing of those relays in other instailed configurations has consistently denmnstrated a response time, typically much less than 0.1 seconds, well within that assumed in the response time acceptance criterion

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that forms the basis for the Technical Specification requirement. In addition, in August 1991, a safety injection occurred on Unit 1. The sequence of events recorc r during that event documented that the required relay function occurred well within the Technical Specification requirement. Similar i.Ermation is documented for an August 1992 safety injection on North Anna Unit 2. Although the sequence of events recorder oniv documented the first of the two relays to actuate, it clearly showed that one relay functioned as expected and had a responsa time well within that required. Finally, the type of relays for which a Technical Specification change is being sought are reliable and generally known to have acceptable response times.

Although the Technical Specification change does r.ot pose a significant safety impact, several compensatory measures have been iden'ified that will provide additional assurance of safe operation during the interval until the unit completes its current operating cycle. Therefor 3, for the remainder of the current Unit 1 operating cycle, the following compensatory measures will be in place:

1) The standby main feedwater pump will not be removed from service for pro-planned maintenance. This will ensure that one standby main feedwater pump will 4

be available to auto-start in the event of a loss of the other main feedwater pumps.

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2) The Emergency Operating Procedures (EOPs) currently require the manual start of the AFW pomos in the event that all normal feedwater flow is lost. This requirement will be reviewed with operations personnel.

3) Operations will review the materiel condition of the main feedwater pumps during each operating shift.

SAFEETY SIGJIFICANCE A safety eveN ation has been performed for the Technical Specification change.

i Suspending tne requirement to response time tent the two relays in the AFW pump start circuit due to a main feedwater pump trip for the remainder of the operating cycle does not pose a significant safety impact. No credit is taken for it in the plant's safety analysis, instead, the safety analysis assumes an AFW pump start on steam generator low-low level in the event of a loss of normal feedwater. The start of the auxiliary feedwater system on a main feedwater pump trip is considered anticipatory in nature and provides a diverse protection feature not credited directly in the accident analysis.

Furthermore, because the unit is in a coastdown mode with power levels currently about 70% and decreasing daily, any plant transient would be initiated from a reduced power condition and be less severe than those that would occur starting from full power. The potential consequences of any such reduced power transients are well within the limits of the current safety analysis.

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