ML20127C995

Application for Amends to Licenses DPR-53 & DPR-69,changing TS 3.8.2.1 Re Ac Distribution by Adding Addl Requirements to LCO to Ensure Two Independent & Redundant Power Source Trains Supplying ESF Sys During Power Operation

ML20127C995
Person / Time
Site:	Calvert Cliffs
Issue date:	09/01/1992
From:	Creel G BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20127C998	List: ML20127C995 ML20127D003
References
NUDOCS 9209110094
Download: ML20127C995 (6)

Text

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B ALTIMORE GAS AND ELECTRIC 1650 CALVERT CUFFS PARKWAY

• LUSBY. MARYLAND 20657 4702 G' * ' C Cat" September 1,1992 VICE Pat stDENT NucLEAM LNtmov i.m. ..n U. S. Nuclear Regulatory Commission Washington, DC 20555 A*ITENTION: Document Control Desk

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & $0-318 License Amendment Request: A.C. Distribution Gentlemen:

The Baltimore Gas and Electric Company (BO&E) hereby requests an Amendment to its Operating License Nos. DPR-53 and DPR-69 for Calvert Cliffs Unit Nos. I and 2, respectively, with the submittal of the proposed changes to the Technical Specifications.

I)ESCitiI' TION The proposed amendment will make changes to Technical Specification 3.8.2.1, A.C. Distribution -

Operating, for Units 1 and 2, by adding additional requirements to the Limiting Condition for Operation ('LCO).

IIACKGitOUNI)

The AC Distribution System (xc Attachment 1) is designed to supply power during normal operation and under accident conditions. The four safety-related 480-volt busses and the two 4804 ult Motor Control Centers (MCCs) supply power to the engineered safety features system. he enginected safety features electrical system uses the two channel concept to provide redundancy in anticipation of a single failure. Emergency power for the 480-volt busses and MCCs is supphed by separate emergency diesel generators. Operability of the 480-volt system is required to ensure the p; ant can mitigate a design basis accident.

During a technical ruiew of the Technical SpeciGcations an apparent discrepancy was discovered with Technical Specification 3.8.2.1. The curren' Technical Specification could be interpreted in a non-conservatise way such that two 4804 ult emergency busses on one unit could be inoperable without entering an Actinn Statement. Research into this discrepancy found that the original issue custom Technical SpeciGeations for Calvert Cliffs Unit I required the four safety-related 480-volt busses ano the two safety-related MCCs to be operable. In the conversion to ste Jard technical specification format, the requirements for the busses were changed such that the LCO could be interpreted tt, allow two emergency 480-volt busses to be inoperable. The conversion also deleted the two safety-related MCCs from the I CO.

090014 Mo/ ? M pp 92o9110o94 92o9o1 / C/

PDR ADOCK 05000317 (/

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Document Control Desk September 1,1992 Page 2 It has been our practice to maintain all four 480-volt busses operable in hiodes 1 through 4 and to enter the Action Statements for any supported safety systems when a bus was declared inoperable.

Administrative controls are in place which require entering the Action Statement of Technical Specification 3.8.2.1 if a 480-volt emergency bus is inoperable. If one of the safety-related htCCs is inoperable, current practice is to review the affected equipment and enter the Action Statements appropriate for the inoperable equipment.

ItEOUESTED CilANGE Change Technical Specincation 3.8.2.1 for Unit Nos. I and 2 as shown on the marked-up pages attached to this transmittal (Attachments 2 and 3).

sal'IslY ANAINSIS/.lUSTIFICATION The proposed change will add additional requirements to the electrical distribution Technical Specification for the 480-volt emergency busses so that all emergency 480-volt busses must be operable in hiodes 1,2,3, and 4. It will also add the safety-related h1CCs (104R and 114R for Unit 1 and 204R and 214R for Unit 2) to the list of AC busses which must be operable.

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The 480-volt emergency busses and the safety-related hiCCs supply redundant engineered safety features equipment. Design criteria for Calvert Cliffs requires that two independent and redundant systems be maintained for continuous operation and to mitigate a design basia accident. If any of these busses are inoperable, the reliability of the engineered safety features system is significantly reduced and the plant may no longer meet the single failure criteria. By revising the Technical Specifications as described above, two independent and redundant power source trains supplying the engineered safety systems will be required during power operation.

Dl?rEllMINATION OF SIGNIFICANT ll AZAllDS The proposed change has been evaluated against the standards in 10 CFR 50.92 and has been determined to not involve a significant hazards consideration, in that operation of the facility in accordance with the proposed amendment:

1. Would not involve a significant increase in the probability or consequences of an accident previously evaluated.

Adding the additional operating requirements to the Alternating Current (AC) Electrical Distribution System will have no effect on the pro' bility of an accident as more busses will be required to be in service. He proposed i m iing Condition for Operation (LCO) specifies that all four 4S(Wolt Emergency Busses and the two safety.related hiotor Control Centers (htCCs) are required to be operable during power operation. These changes ensee that there are two 'adependent and redundant power sources to the engineered safety features systems as assumed in the Chapter 14 accident analyses and that the plant will be able to meet the single-failure criteria.

Adding the additional operating requirements to the AC Electrical Distribution System will decrease the consequences of an accident as electrical redundancy to Engineered Safety Features Actuation System (ESFAS) is required. Herefore, changing the operating bus

7 Document Contro! Desk ey, , - ! september 1,1992 gJ Page 3 p

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..'... T "y3 requircrr.cna will not involve a significer t increase in the probability or corv.yuences of an accident previously evaluated.

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&- Would not create the possibiilt;' of a new or different type of accident from any accident

%R previously evaluated.

.k ' He preposed changes to the AC Electrical Distribution System operatint bus requirements do not represent a significant change in the configuration of the plant. 5pecifically, no new hardware is being added to the plant as part of the proposed changes. Esuring edSt ioral d C- cricrgency busses are o[mable does not create the possibility of a new or diffs of g accident. Therefore, this change would not create the poss'.bihty of a nr je of u f ident from those previously evaluated. -

3 wuld not intoh e a significant reduction in the margin ofsafety.

i The proposed changes to the AC Electrical Distnbut!.m System operating bus requirements 4 will ensure that the margin of safety is inaintained c 2.. ased. Increasing the number of .

tresses that are required for operation ensurc, . hat th:en we two independent and redundant L swer sorces to the engineered safety features .faems r.d that the plant will be able to

. -t singl-failure criteria. Therefore, the proposeJ &nges do not involve a significant red'. a i U ii, margin of safety.

1;: <ed on the atxm, we have concluded that these changes do not constitute a significant hazard. >

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SCllEDULE E This change is equested to be approved and usued by February 28,1993. However, issuance of this amendrnent does not have an itapact on continued plant operation. We will continue to comply with the Administrative controls and esperating procedures described above until the amendment is =

approved.

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Document Control Desk September 1,1992 Page 4

. sal'isTY COMMI'ITEE RINilM The proposed changes to the Technical Specifications and our determination of significant hazards were reviewed by our Plant Operations and Safety Review Committee and our Off-Site Safety Review Committee. They c<meluded that implementation of these c' ,es will not result in an undue risk to the health and safety of the public.

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Very truly 'ours, ) /

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{ i STATE OF MARYLAND

TO WIT :

COUNTY OF CALVERT  : j I hereby certify that on the /* day of b'al2M2cr' .,1992, before me, the subscriber, a Notary Public of the State of Maryland in'and for (_b kert Ibn-h!

personally appeared George C. Creel, being duly sworn, and states that he is Vice President of the Baltimore Gas and Electric Company, a corporation of the State of Marylanct; the he prevides the 5 foregoing response for the purposes therein set forth; that the statements mr.de are true and correct to the best of his knowledge, information, and belief; and that he was authorized to provide the response on behalf of said Corporation.

WITNESS my lland and Notarial Scal: b .(

Notary Public' '

M' My Commission Expires: j va4 2, N9

/Date '

GCC/LMD/Imd/ din.

Attachments cc: D. A. Brune, Esquire J. E. Silberg, Esquire R. A. Capr'. NRC D. G. McIhmalJ, Jr., NRC T. T. Martin, NRC P. R. Wilson, NRC R. I. McLean, DNR J. H. Walter, PSC

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