ML20059K127

Application for Amends to Licenses NPF-4 & NPF-7,eliminating Simulated Reactor Coolant Pump Seal Injection Flow Requirement for Flow Balancing of High Head Safety Injection Lines

ML20059K127
Person / Time
Site:	North Anna
Issue date:	11/10/1993
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20059K134	List: ML20059K127 ML20059K141
References
93-732, NUDOCS 9311150194
Download: ML20059K127 (9)

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, VIRGINIA EtecTHIC ann PownH CourAxy Ricnw oxo, Vino NIA 23261 November 10, 1993 i

U.S. Nuclear Regulatory Commission Serial No.93-732 l Attention: Document Control Desk NL&P/MAE: RO  ;

50-338 Washington, DC. 20555 Docket Nos.

r 50-339 License Nos. NPF-4 l NPF-7  :

'l Gentlemen:

VIRGINIA ELEC'RIC AND POWER COMPANY ,

NORTH ANNA POWER STATION UNITS 1 and 2 PROPOSED TECHNICAL SPECIFICATIONS CHANGES  !

HIGH HEAD SAFETY INJECTION FLOW BALANCING Pursuant to 10 CFR_50.90, the Virginia Electric and Power Company requests amendments, in the form of changes to the Technical Specifications, to Facility l Operating License Nos. NPF-4 and NPF-7 for North Anna Power Station Units 1 and 2, respectively. The proposed changes will eliminate the simulated reactor coolant pump  ;

sea! injection flow requirement for the flow balancing of the high head safety injection lines.

This Technical Specification change is requested on an emergency basis in accordance with 10 CFR 50.S1 (a) (5). The basis for an emergency change request is  !

included as Attachment 1. A discussion of the proposed changes is provided in  :

Attachment 2. The proposed changes are presented in Attachment 3. ,

It has been determined that the proposed Technical Specifications changes do not involve an unreviewed safety question as defined in 10 CFR 50.59 or a significant i hazards consideration as defined in 10 CFR 50.92. The basis for our determination that these changes do not involve a significant hazards consideration is provided in Attachment 4. The proposed Technical Specifications changes have beeri reviewed  ;

and approved by the Station Nuclear Safety and Operating Committee and the i Management Safety Review Committee. j Should you have any questions or require additional information, please contact us.  ;

i Very truly yours, -l W. L. Stewart Senior Vice President - Nuclear Attachments 9311150194 931110 P yDR ADOCK 05000338 I PDR L

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

Suite 2900 Atlanta, Georgia 30323 M. R. D. McWhorter NRC Senior Resident inspector  ;

North Anna Power Station Commissioner Department of Health Room 400  ;

109 Governor Street l Richmond, Virginia 23219 l

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COMMONWEALTH OF VIRGINIA )

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COUNTY OF HENRICO ).

The foregoing document was acknowledged before me, in and for the County.and Commonwealth aforesaid, today by R. F. Saunders, who is Assistant 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 dccument.

are true to the best of his knowledge and belief.

Acknowledged before me this //7 day of Myrn4ns,193 My Commission Expires: 1 d'/+ 3 / 199k.

6 NH Y L Notary'Pdblic

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Attachment 1 Basis For An Emergency Change Request

BASIS FOR EMERGENCY CHANGE REQUEST NRC regulations (10 CFR 50.91 (a)(5)) require that whenever an emergency situation j

exists, a licensee must explain why this emergency situation occurred and why it could not avoid this situation, and the Commission will assess the licensee's reasons for j failing to file an application sufficiently in advance of that event. An emergency situation exists when the Commission's failure to act in a timely way would result in derating or-1 shutdown of a nuclear plant, or in prevention of either resumption of operation or of .

increase in power output up to the plant's licensed power level, in such cases, the Commission 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, the regulations require that the Commission be particularly sensitive to environmental considerations. Our discussion of why this proposed change meets the conditions necessary for emergency consideration is provided below. '

, Whv Emeroencv Situation Occurred and Could Not Be Avoided

} At 09:30 hours and again at 14:45 hours on November 8,1993, North Anna Unit 2 entered an action statement to be in hot standby-within six hours as required by  ;

Technical Specification 3.0.3. It had been determined that Technical Specification 3.5.2, which requires two operable HHSI pumps, could not be met. The HHSI pumps j were determined to be inoperable because the total pump _ flow rate required by Technical Specification 4.5.2.h.1.b may not have been met. The limitation on seal ,

injection flow specified by Technical Specification 4.5.2.h.1.c contributed to this  ;

determ.ination.

i f Whv Emeroency Situation Exists On November 8,1993, the NRC verbally approved an enforcement discretion to '

eliminate the simulated reactor coolant pump seal injection flow requirement of 2 48.3 gpm in Technical Specification 4.5.2.h.1.c. Virginia Electric and Power Company letter  ?

dated November 9,1993 (Serial No.93-727) documented the requested enforcement i

discretion and committed to promptly submitting an Emergency Technical Specification  :

change request. Consistent with NRC policy on enforcement discretion, a licensee shall l submit an Emergency Technical Specification change to permanently implement a change initially supported through NRC's exercise of enforcement discretion. As  ;

defined in 10CFR50.91, NRC's failure to act on the proposed change would result in the r shutdown of North Anna Unit 2, and thus an emergency situation exists.

We have determined that the proposed Technical Specification changes invclve no significant hazards consideration. Therefore, we conclude that the condition in 10 CFR 1 50.91 (a)(5) regarding issuance only of a license amendment involving no significant i hazards consideration is met.

l Environmental Considerations Approval of a Technical Specification change as described above will not change the types of any effluents that may be released offsite, nor create a significant increase in individual or cumulative occupational radiation exposure.

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1 Attachment 2 ,

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Discussion of Changes 4

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I DISCUSSION OF CHANGES INTRODUCTION North Anna Unit 1 and 2 Technical Specification 4.5.2.h.1 specifies surveillance requirements for the flow balancing of the high head safety injection lines. Achieving an acceptable flow balance assures that adequate core cooling and negative reactivity is provided to mitigate the consequences of design basis accidents. Item a) under this surveillance requirement specifies that the sum of the injection line flow rates, ' excluding  :

the highest flow rate is 2 359 gpm with a single pump running. Item b) under this surveillance requirement specifies that the total charging /high head safety injection (HHSI) pump flow rate with a single pump running is s 660 gpm. Item c) under this i I surveillance requirement specifies that a value of 248.3 gpm be used to simulate reactor coolant pump seal injection flow during cold leg injection balancing.

The requirement to specify a simulated seal injection flow rate was added August 4, 1993 by License Amendment Nos.171 and 151 for Units 1 and 2 respectively. This requirement has been determined to be unnecessary and has, in practice, inhibited our ability to meet the minimum and maximum flow rate specifications. These proposed Technical Specification changes would allow the elimination of the simulated reactor ,

coolant pump seal injection flow requirement in Technical Specification 4.5.2.h.1.c and i make minor editorial changes to Technical Specifications 4.5.2.h.1.a and b to improve the readability.

BACKGROUND i At 09:30 hours and again at 14:45 hours on November 8,1993, North Anna Unit 2 entered an action statement to be in hot standby within six hours as required by Technical Specification 3.0.3. It had been determined that Technical Specification 3.5.2, which requires two operable HHSI pumps, could not be met. The HHSl pumps ,

were determined to be inoperable because the total pump flow rate required by '

Technical Specification 4.5.2.h.1.b may not have been met. In addition, the limitation on seal injection flow specified by Technical Specification 4.5.2.h.1.c contributed to this determination. On the same day, this condition was discussed with the NRC.

Enforcement discretion was requested for 1) a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period to readjust the seal injection flows to the reactor coolant pumps in order to meet the total pump flow rate in Technical Specification 4.5.2.h.1.b of s 660 gpm, and 2) to eliminate the simulated reactor coolant pump seal injection flow requirement of Technical Specification 4.5.2.h.1.c of 2 48.3 gpm. The requested enforcement discretion was verbally approved by Mr. G. C. Lainas of the NRC on November 8,1993. Virginia Electric and Power Company letter dated November 9,1993 (Serial No.93-727) documented the requested enforcement discretion and committed to promptly submitting an Emergency Technical Specification change request.

The need for enforcement discretion, and consequently the proposed Technical Specification changes, is due in part to an unintended consequence of a previous l license amendment issued on August 4,1993 involving Technical Specification  ;

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I 4.5.2.h.1. That license amendment added, as item c, a specific range of calculated  !

values for seal injection flow to be used during the actual flow balancing process. Prior  ;

to this amendment, the specific flowrate had not appeared in the Technical '

Specifications. It was believed that by specifying the value in the Technical l

Specifications, a more complete picture of the flow balance process would be provided  ;

in the document. The primary purpose of seal injection flow is to provide the required minimum seal flows specified by the reactor coolant pump vendor. These f!aws are. ,

adjustable and may be changed due to plant operations and pump seal conditions.' ,

When the Reactor Coolant System (RCS) is depressurized during the design basis. i accident, the differential pressure between the safety injection flow header and the RCS increases and causes the seal injection flow to increase. The accident analysis takes  :

no credit for this flow, and it is presumed to be lost. By meeting Technical '

Specifications 4.5.2.h.1.a and b, the limits of safety analysis are met with margin. The i requirement to specify a simulated seal injection flow rate has, in practice, inhibited our i ability to meet the minimum and maximum flow rate specifications. The proposed Technical Specification changes do not affect the ability of the HHSI system to perform its intended safety function.

SPECIFIC CHANGES ,

The Technical Specification changes described herein apply to North Anna Units 1 and

2. The proposed changes delete Technical Specification 4.5.2.h.1.c. Minor editorial-changes are then made to Technical Specifications 4.5.2.h.1.a and b. to reflect the E deletion of 4.5.2.h.1.c and improve the readability on the remaining specifications.

SAFETY SIGNIFICANCE I A safety evaluation has been performed for the propose ~d Technical Specification I changes. By meeting Technical Specifications 4.5.2.h.1.a and b, the limits of safety .

analysis are met with margin. The proposed Technical Specification changes do not j affect the ability of the HHSl system to perform its intended safety function. '

r Continued operation of North Anna Power Station in accordance with the proposed  ;

Technical Specification changes will not:  !

1. Involve an increase in the probability or consequences of an accident or malfunction previously evaluated. The proposed Technical Specification j changes continue to require that with one HHSI pump running, the sum of the flows through the two lowest flow branch lines shall be 2 359 gpm and the total i HHS1 pump flow rate shall be 5; 660 gpm. These requirements ensure the i correct flow balance alignment and flow rates required to meet the' safety  !

analysis.

t Likewise, the consequences of the accidents or malfunctions previously  !

) evaluated will not increase as a result of the proposed Technical Specification changes. The system performance will remain bounded by the existing safety 1 analysis for all postulated accident conditions. j t

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2. ' Create the possibility of a new or different kind of accident or malfunction from $

any previously evaluated. The proposed Technical Specification changes will not affect the capability of the HHSI System to perform its intendo function. 3 The proposed Technical Specification changes are bounded by the existing safety analysis and do not involve operation of plant equipment in a different -

manner from which it was designed to operate. Since a new failure mode is not ,

created, a new or different type of accident or malfunction is not created.  !

3. Involve a reduction in a margin of safety. The system performance will remain '!

bounded by the existing safety analysis at the specified flow rates, therefore,  ;

safety margins are not reduced.

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