ML20086G072

Responds to Generic Ltr 91-11, Resolution of Generic Issues 48, 'Limiting Conditions for Operation for Class 1E Vital Instrument Buses' & 49, 'Interlocks & Limiting Conditions for Operation for Class 1E Tie Breakers.'

ML20086G072
Person / Time
Site:	Grand Gulf
Issue date:	11/22/1991
From:	Cottle W ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-GTECI-048, REF-GTECI-049, REF-GTECI-NI, TASK-048, TASK-049, TASK-48, TASK-49, TASK-OR GL-91-11, GNRO-91-00182, GNRO-91-182, NUDOCS 9112040160
Download: ML20086G072 (5)

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===~ ENTERGY W.1 C ot tle Ncvember 22, 1991 li.S. Nuclent Regulatory Commission 11a ll St nt ion P1-137 Washinigt on, D.C. 20555 At tent lon: Document Control llenk Subjecti 01atul Gn f Nui1ent f' t a t ion linit 1 Docket No. 50-416 License Po. N p F- 2 9 Response to Generin het t e r 91-11 Resolut (on of Generit isnues 48, "ICOs fot Class 11; Vit a l Inst rument itunes," and 49, " Int e r loc k *. ntni hCOs fot Class lE Tie lire d e t s" GN RO- 91/ 00 l ft2 Gentlemen:

On July 18, 1991, the NkC issued Genet in 1.et ter (GL) 91-11, Resolut ion of Get.e r i c 1rnuen 48, "hCOs for Class 11. V i t a l inst t ornent Isoses " atul 49,

" int erlock s and LCOs for Clnsr. lE Tie li r e n k e r s" (GNKi-91/001"m). Geneiic Issues (GIs) 48 and 49 nddressed vital AC buses nini tle brnnhets t ha t.

r.onnect redundant sa f ety-t elat ed luises. In t he Gh, the NKC St a f (

cotteluded that unless 1itensecs provide ndequate ]nst i f icalion t hat such prov18 f ons are not needed at thelr specifit faci!itles, 1i<ensees shouhl havn appropr int e procedures to fulfill the following requiremen's:

l (1) 1. i m i t the time thqt a plant is in poulble vloint ion of t he single-fallute et it erion wit h regard to the Glass lE vital

• i inst rument huses a nd 1. l e b r r- n k e t s ,

(2) Kequ i r e nurveillances of t hose c omponent s , and (3) Ensure that, except for t he times cov e red fu 1 tem (1), the plant is operat ing in nn elect rical configuint ion consistent with the reguintions and its design bases.

Entergy Operations has concluded that the desigt and operat lon of the Grant Gulf Nuclear Flation (GGNS) 125 VDC Engineered Sa f et y rent ot e (ESF) liiv islon 1, 1 I , a nel i!I electr(cal huses 1imit n the time that t hes, ,uses may opeint e nn dev r ibed in i t em ( 1). GGNS Technical Specif icat inn 3/4.8.2, D.C Sources-Oper nt inn, cont n ins acceptable <uitveillance requ irement s , including mu imum t ime limit s and hat tery conf igurat ions that s a t i s f y l t rm s ( 1 ) , (2), and (3).

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9 r-November _22, 1991 GNRO-91/00182 Page 2 of 3 Justification for these conclusions is provided in the Attachment, and we plan no l'urther action in response to GL 91-11.

If you require additional information, please advise.

Yours truly, c p C Cot % C WTC/JDG/mte-attachments: Response to GL 91-11, GGNS Position cci Mr. D. C.-llintz (w/a)

Mr. J. L. Mathis (w/a)

Mr. R. B. McGehoe (wls)

Mr. N. S. Reynolds (w/a)

Mr.11. L. Thomas (w/o)

Mr. Stewart D. Ebneter (w/a)

Reglonal Administrator U.S.. Nuclear Regulatory Commission

. Region 11 101 Marietta St., N.W., Suite 2900 Atlanta, Georgia 30323 Mr. P. W. O'Connor Project Manager (w/a)

Office of Nuclear Reactor Regulation 11.S. Nuclear Regulatory Commission

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Mail Stop 13113 Washington. D.C. 20555 G9110161/SNLICFLR

)

. BEFORE THE l

UNITED STATES NUCLEAR REGULATORY COMMISSION 1 LICENSE NO. NPF-29 i

DOCKET NO. 50-416 i

IN Ti!E MATTER OF MISSISSIPPI POWER & LIGilT COMPANY i

and SYSTEM ENERGY RESOURCES. INC. i and  !

SOUTil MISSISSIPPI ELF,CTRIC POWER ASSOCIATION i and ENTERGY OPERATIONS, INC.

AFFIRMATION I, W. T. Cottle, being duly sworn, state that I am Vice President, Operations GGNS of Entergy Operations, Inc.: that on behalf of Entergy  ;

Operations Inc., System Energy Resources, Inc., and South Mississippi Electric Power Association I am authorized by Entergy Operations,-Inc. to sign and file with the Nuclear Regulatory Commission, this response to Generic Letter 91-11 for the Grand Gulf Nucicar Station; that I signed this response =to Generic Letter 91-11 as Vice President, operations GGNS _;

of Entergy Operations, Inc. and that the statements made and the matters

- set forth therein are true and correct to the best of my knowledge, l

Information and belief. i (J ) ~C.Stu:

W. T. Cottle

- STATE OF MISSISSIPPI COUNTY OF CLAIDORNE SUBSCRIBED AND SWORN To before me, a Notary Public, in and for the County l and Stato above named, this afL day of Y%nskn,Vuor , 1991. ,

(SEAL) htfGu.1 O tn A ncm Notary (}51(c)

My commission expires:

O 09110161/SNLICFLR

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Attachment to GNRO-91/00182 RESPONSE TO GENERIC LETTER 91-11, GGNS POSITION P

• ACKGROLTND:

In Generic Letter (GL) 91-11. the term " vital instrument bus" refers to a buw that provides power for the Instrumentation and controls of the engineered safety features (ESP) systems and/or the reactor protection system (RPS), it is designed to provide continuous power during postulated events including loss of normal offsite power.

At Grand Gulf Nuclear Station (GGNS), the 125 VDC ESF buses are designed to provide power to the ESF vital instrument buses (UFSAR 8.1.4.2 Safety Design Bases-Onsite Power). There are no AC offsite power sources

- normally utilir.cd as an alternate source for the ESF vital Justrument buses. The minimum equipment operability, surveillance requirements, and limiting conditions for operations for the three independent 125 VDC batteries and associated chargers are administratively controlled per Technical Specification 3/4.8.2 D.C. Sources.

The RPS system is designed to fall safn such that it perfoims its safety function on loss of power. Therefore, the RPS is not. requ! red to be powered by a " vital Instrument bus" as described in GL 91-11.

The 43F buses are three separate, independent, and redundant bui.es with complete divisional separat. ion. No tie breakern, as der.cribed in GL 91-11. are used between any redundant GGNS ESF buses.

DISCUSSION / JUSTIFICATION:

CL 91-11 ITEM (1):

(1) Limit the time that a plant is in possibic violation of the single-failure criterion with regard t o the Class IE vital instrument buses and tio breakers.

l GGNS JUSTIFICATION:

l The term " vital instrument bus" as defined by GL 91-11 refers to the 125 VDC ESF t>us at GGh1. This bus supplies Emergency Core Cooling System (ECCS) control voltages which requiro continuous power during a postulated event including loss of power. The ./inimum alignment of battery chargers and hatteries is administt atively contrel. led per Technical Specification 3/4.8.2. D.C. Sources. The design of the j ESF bus and the adnanW rative limits set fo ta in the Technical i

Specifications concerning equipment availability limit the time that these buses may operate as outlined in Item (li.

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. A'tachment to GNRO-91/00182 r

. I GL 91-11 ITEM (2):

(2) Require surveillances of these components, and ,

GGNS JUSTIFICATION:

Surveillance requirernents and equipment operability requirements ior the GGNS 12$ VDC ESF divisional buses are provided in Technical Specification 1/4.8.2. D.C. Sources.

GL 91-11 ITEM (3):

(3) Ensure that, except for the times covered ir. Item (1), the plant is operating in an electrical configuration consistent with the regulations and its design bases.

GGNS JUSTIFICATION:

The three ESF buses are independent and redundant buses with complete divisional separation. No tie-breakers, as described in GL 91*11. are used between any redundant. GGNS ESF buses.

CON /" USION: i The GGNS design and operation af the " vital instrument buses" are acceptable por GL 91-11 and no tie-breakers, as described in GL 91-11 are used between any redundant GGNS ESF buses. Therefore no further ,

action is required by GGNS for resolution of concerns raised by GL 91-11.

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