ML20005D927

Application for Amend to License DPR-35,reducing Min Acceptable Core Spray Flow Rate from 3,600 to 33 Gpm.Encl GE Proprietary Rept EAS-65-0989, Justification of Interim Operation of Pilgrim Nuclear... Withheld (Ref 10CFR2.790)

ML20005D927
Person / Time
Site:	Pilgrim
Issue date:	12/11/1989
From:	Bird R BOSTON EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML19310C585	List: ML20005D927 ML20005D938
References
BECO-89-179, NUDOCS 9001020275
Download: ML20005D927 (5)

Text

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10CFR50.90 i

h' 80S70N EDISON Pilgnm Nuclear Power station Rocky Hill Road Plymouth. Massachusetts 02360 Ralph G. Bird senior Vice President - Nuclear BECo 89- 17 9 December 11 .1989 U.S. Nuclear Regulatory Commission Document Control Desk Hashington, DC 20555 License DPR-35 Docket 50-293

' PROPOSED CHANGE TO TECHNICAL SPECIFICATION SECTION 3/4.5.A.l'.d: CORE SPRAY PUMP FLOW RATE TESTING Boston Edison Company (BEco) proposes the attached change to Appendix A of Operating License No.-DPR-35 in accordance with 10CFR50.90. The proposed change reduces the minimum acceptable core spray pump flow rate from 3600 gpm to 3300 gpm.

The Bases are changed to reflect this change. Attachment A to this letter provides details of the proposed change and the Safety Evaluation and Determination of No Significant Hazards considerations. Attachment B provides the amended pages to the Technical Specification and Attachment C shows the proposed changes on marked-up pages of the current Technical Specification.

Attachment D provides General Electric Company Proprietary Report EAS-65-0989,

" Safety Evaluation for Interim Operation of Pilgrim Nuclear Power Station with Reduced Core Spray System Flow Rate". EAS-65-0989 is a General Electric Company proprietary document and we request it be withheld from public disclosure in accordance with 10CFR2.790(b)(1).

This proposed change was compared to NEDC-31681, " Improved BWR Technical

. Specifications", for Boiling Hater Reactors (BWR)/4 that is currently under review but not approved by the NRC. This proposed change is consistent with the intent of the NEDC-31681 improvements, and future adoption of NEDC-31681 will not' result in substantive change to this proposed change.

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f :,t . BOSTON EDISON COMPANY-E . D0ccmber 11, 1989 U.:S. Nuclear Regulatory Commission f.

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He request an expedi_ted NRC review of this proposal to reduce the potential l for LCOs induced by the current Section.3/4.5.A.1.d required pump flow.

Br PHK/jcp/3650 Attachments: (A) Description of Proposed Change ,

(B) Amended Technical Specification Pages (C) Marked-up pages from Current Technical Specification (D) General Electric Proprietary Report EAS-65-0989 1 signed original and~ 37 copies Commonwealth of Massachusetts)

County'of Plymouth )

Then personally appeared before me, Ralph G. Bird, who being duly sworn, did state that he is Senior Vice President - Nuclear of Boston Edison Company and  ;

that he is duly authorized to execute and file the submittal contained herein l in the name and'on behalf of Boston Edison Company and that the statements in l said submittal are true to the best of his knowledge and belief.

My commission expires: d8Mc46. /W4' .

M/

DATE NOTARY PU 3LIC

[ l cc: Mr. D. Mcdonald, Project Manager Division of Reactor Projects - I/II L Office of Nuclear Reactor Regulation L Mail Stop: 14D1 l U. S. Nuclear Regulatory Commission 1 White Flint North 11555 Rockville Pike L Rockville, MD 02852 1:

U. S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 i Senior NRC Resident Inspector

! Pilgrim Nuclear Power Station Mr. Robert M. Hallisey, Director Radiation Control Program Massachusetts Department of Public Health 150 Tremont Street, 2nd Floor Boston, MA 02111

.% .g AUACHMENT A Etoposed Change This proposed change reduces the Core Spray pump flow rate minimum acceptance criterion for the core spray pump flow surveillance test. The currently required minimum flow rate of 3600 gpm would be reduced to 3300 gpm.

HERQn for Change e The Core Spray System (CSS) is part of the Emergency Core Cooling System (ECCS) and is designed to actuate and function to mitigate the consequences of

. Design Basis Accidents (DBA) as described in th e Pilgrim Nuclear Power Station (PNPS) Final Safety Analysis Report (FSAR).

Pilgrim's current Core Spray Pump flow surveillance test acceptance criterton, given in Technical Specification 4.5.A.I.d, is "... at least 3600 gpm..."

This criterion is very close to the limit of pump capacity. Small variations in pump performance or testing can result in a core spray pump falling to deliver a flow rate of 3600 gpm, resulting in Pilgrim entering a Limiting Condition of Operation (LCO). The proposed change reduces the potential for entering unnecessary LCOs caused by Core Spray pump flow surveillance testing.

The Core Spray System must maintain fuel Peak Clad Temperature (PCT) below 2200'F to meet the requirements of 10CFR50.46 (Acceptance Criteria for Emergency Core Cooling Systems for Light Hater Nuclear Power Reactors) and 10CFR50, Appendlx K (ECCS Evaluation Models). General Electric Company, Pilgrim's NSSS vendor, reanalyzed the limiting DBA case and determined a 101.

decrease of core spray flow (3240 gpm) results in a PCT increase of approximately 45'F; that is, PCT is 2185'F with a minimum flow of 3240 gpm instead ol' 2140*F at the currently specified 3600 gpm. This change requests a minimum flow of 3300 gpm instead of 3240 gpm to reflect the impact of degraded voltage on pump performance. The change will provide greater margin in the test acceptance criterton without reducing safety because the PCT will remain below 2200'F.

$1faty_Eytlyation and Determination of No Stanificant Hazards Considerations The Code of Federal Regulations (10CFR50.91) requires licensees requesting an amendment to provide an analysis, using the standards in 10CFR50.92, that determines whether a significant hazards consideration exists. The following analysis is provided in accordance with 10CFR50.91 and 10CFR50.92 for the proposed amendment reducing the Core Spray Pump acceptance criterion from 3600 gpm to 3300 gpm.

1. The operation of Pilgrim Station in accordance with the proposed amendment will not involve a significant increase in the probability or consequences of any accident previously evaluated.

The safety function of the Core Spray System is to provide essential cooling water to the reactor vessel when normal reactor coolant is incapable of preventing overheating of the fuel and cladding. The system is designed to automatically inject water drawn from the torus onto the top of the core following a loss of Coolant Accident (LOCA) and vessel 1 of 2

depressurization. Lowering the threshold defining acceptable pump i performance to 3300 gpm minimum flow does not affect the safety function of the Core Spray System.

The Core Spray system will continue to protect the fuel and cladding against overheating and degradation following the Loss of Coolant Accident (LOCA) DBA by maintaining peak clad temperatures below 2200'F, <17% local L

metal-water reaction, and (1% core wide metal-water reaction, thereby meeting 10CFR50.46 requirements.

Since the proposed change is bounded by the existing parameters defining the design basis of Core Spray pump flow performance, operating Pilgrim in  !

accordance with the change does not involve a significant increase in the probability or consequences of an accident previously analyzed.

2. The operation of Pilgrim Station in accordance with the proposed amendment l l will not create the possibility of a new or different kind of accident I from any accident previously evaluated.

l The new analyzed value of 3240 gpm increases DBA PCT by 45'F to 2185'F.

This value is below the 2200'F PCT required by 10CFR50.46 and used in l Pilgrim's FSAR. l l

The proposed pump flow rate of 3300 gpm is greater than the analyzed value )

necessary to maintain PCT below the required 2200*F; therefore, the effect  ;

of 3300 gpm on PCT is bounded by the analyzed value. No physical change i is being made to Pilgrim. The Core Spray System is unchanged except for a lowering of pump performance acceptance criteria. The system will L continue to perform its function and continue to remain in conformance L with the requirements of 10CFR50.46 and Appendix K. Hence, the change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

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3. The operation of Pilgrim Station in accordance with the proposed amendment l

will not involve a significant reduction in the margin of safety.

Reducing the current Core Spray pump flow rate of 3600 gpm by 10% results in a calculated PCT increase of 45'F to a value of 2185'F. This PCT is j i less than the 2200'F safety limit. The postulated worst case accident 1 scenario assumes pump flow performance at the reduced rate of 3240 gpm, I the worst postulated LOCA event occurring in conjunction with a loss of I offsite power, and an additional failure of an active component.

Hence, the small reduction in the acceptable core spray flow rate does not impact the safety margin during accidents requiring mitigation by ECCS, and the proposed change results in a PCT within the acceptable range as l defined by Pilgrim's FSAR. Therefore the proposed change does not involve i a'significant reduction in the margin of safety.

This change has been reviewed and approved by the Operations Review Committee and reviewed by the Nuclear Safety Review and Audit Committee.

Schedule of Change This change will be implemented within 30 days following BECo's receipt of its approval by the Commission.

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