ML20148A582

Requests Addl Info Re Effect of Dynamic Component Uncertainties on Byron & Braidwood UFSAR Accident Analyses, Per Licensee 961112 Response to NRC 960522 Request

ML20148A582
Person / Time
Site:	Byron, Braidwood
Issue date:	05/05/1997
From:	Dick G NRC (Affiliation Not Assigned)
To:	Johnson I COMMONWEALTH EDISON CO.
References
TAC-M95340, TAC-M95341, NUDOCS 9705090084
Download: ML20148A582 (4)

Text

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't NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001

\...../ May 5, 1997 Ms. Irene Johnson, Acting Manager Nuclear Regulatory Services Commonwealth Edison Company Executive Towers West III 1400 Opus Place, Suite 500 Downers Grove, IL 60515

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION - DETERMINATION OF DYNAMIC COMPONENT SETPOINT UNCERTAINTIES AT BYRON, UNIT 1 AND BRAIDWOOD, UNIT 1 (TAC NOS. M95340 AND M95341)

Dear Ms. Johnson:

By letter dated May 22, 1996, the NRC requested information related to dynamic testing of instrument channels using the liESAC system at Commonwealth Edison Company (Comed). This letter was in response to issues raised by a concerned member of the NRC staff. The NRC staff has reviewed the concerns, the instrument setpoint analyses and the use of the MESAC system at Braidwood Station. As a result of this review, the NRC staff concluded that the health and safety of the public was not effected by the use of the MESAC system and that Comed is in compliance with its licensing bases and technical specifications (TS). Nevertheless, the concerned NRC staff member requested that Comed review the NRC staff analysis and conclusions and confirm that ,

Byron and Braidwood stations are being operated within their licensing bases l and TS requirements. 1 l

By letter dated No/ ember 12, 1996, Comed responded to the request. Comed stated that the Ot ertemperature Delta-T (OTAT) calibration setpoint at Byron  ;

and Braidwood inc~.udes an additional delay function to account for unknowns i such as uncertainty in other lead / lag modules. Therefore, even though the I Updated Final Safety Analysis Report (UFSAR), Chapter 15, accident analyses do i not explicitly include a 13% (Braidwood) or a t10% (Byron) time constant deviation for the OTAT trip function, the additional 6 second delay function l

(lag function to measured T in the analyses bounds this deviation. Thus, i the actual performance of thy) e Reactor Protection System in the field results in a trip of the reactor. earlier than the Final Safety Analysis Report (FSAR) accident analyses. Comed stated this methodology is consistent with ,

Westinghouse accident analysis methodology. Comed believes that Byron and i Braidwood are being operated within their licensing bases and TSs.

The NRC staff requests the following additional information concerning the effect of dynamic component uncertainties on the Byron and Braidwood UFSAR accident analyses, TSs, and setpoint methodology. Dynamic components consist of lead / lag, lead, and signal filtering components. Specifically: p 080063 g g]g$@Y 9705090084 970505 PDR ADOCK 05000454 P PDR .

I I. Johnson 1. For both Byron and Braidwood, list all safety related protection channels that use dynamic components (e.g., Overtemperature Delta-T (OTAT), Overpower Delta-T (0 PAT) and low pressurizer pressure). For each channel credited in the UFSAR, Chapter 15, or other accident l analyses, if a trip function associated with dynamic components is credited as the primary trip, discuss whether another channel trip i

function without dynamic components could provide the same protection l (e.g., low pressurizer pressure is credited; however, low pressurizer i level would also be expected to actuate).

2. Describe the process used to account for dynamic component setpoint i uncertainties in the Braidwood UFSAR accident analyses. Include in this

discussion, dynamic components in channels other than the OPAT. This l information should be sufficient for the staff to verify that the use of dynamic testing and the acceptance criteria are bounded by the FSAR accident analyses.

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3. Describe the process used to combine dynamic component setpoint l uncertainties with static component setpoint uncertainties to establish  !

TS acceptance criteria. If the dynamic component setpoint uncertainties  ;

are not included in the TS acceptance criteria, describe the process by which these uncertainties are included in the Braidwood trip setpoints.

l 4. For both Byron and Braidwood, describe the process used to account for the effect of dynamic component uncertainties on channel total uncertainty determinations during periodic surveillances.

1 This information is needed promptly in order to resolve the differing  ;

l professional view of the concerned NRC staff member. l l Sincerely, i

1

/s/

George F. Dick, Senior Project Manager Project Directorate III-2 Division of Reactor Projects - III/IV Office' of Nuclear Reactor Regulation l Docket Nos. STN 50-454, STN 50-455, Distribution: _

PUBLIC STN 50-456, STN 50-457  : Docket File, TSC3 PDIII-2 r/f J. Roe, JWR E. Adensam, EGAl :

cc: see next page R. Capra C. Moore f

G. Dick S. Bailey l R. Assa 0GC, 015818

, R. Lanksbury, RIII ACRS, T2E26 DOCUMENT NAME: G:\CMNTJR\ BRAID-BY\BB95340.RAI

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To rsezive a copy of thle document,indicateAthe box: "C" = Copy without enclosures *E" = Copy with enclosures "N" = No copy i 0FFICE PM:PDIII-2 , _f LA:$flI-2 2_ - PM:PDIII-2 , D:PDIII-2 l6 l 2

NAME G. Dick Mf C J dre S. Bailey.ef g y R. Capra A>- l

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DATE 05/0f/97 " "~ 05///97 05/al/97 05/o6/97 0FFICIAL RECORD COPY 1 j

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.- l Commonwealth Edison Company l Braidwood Station Manager

, Rt. 1, Box 84

( Braceville, Illinois 60407 Ms. Bridget Little Rorem i

Appleseed Coordinator 117 North Linden Street '

Essex, Illinois 60935 Document Control Desk-Licensing Commonwealth Edison Company 1400 Opus Place, Suite 400 j Downers Grove, Illinois 60515 l

Mr. H. G. Stanley .

Site Vice President Braidwood Station l Commonwealth Edison Company RR 1, Box 84 Braceville, IL 60407 I

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,' I. Johnson Byron /Braidwood Power Stations i Commonwealth Edison Company  ;

cc:

Mr. William P. Poirier, Director George L. Edgar Westinghouse Electric Corporation Morgan, Lewis and Bochius Energy Systems Business Unit 1800 M Street, N.W.

Post Office Box 355, Bay 236 West Washington, DC 20036 Pittsburgh, Pennsylvania 15230 Attorney General Joseph Gallo 500 South Second Street Gallo & Ross Springfield, Illinois 62701 1250 Eye St., N.W.

Suite 302 EIS Review Coordinator Washington, DC 20005 U.S. Environmental Protection Agency 77 W. Jackson Blvd.

Michael I. Miller, Esquire Chicago, Illinois 60604-3590 Sidley and Austin One First National Plaza Illinois Department of Chicago, Illinois 60603 Nuclear Safety l Office of Nuclear Facility Safety l Howard A. Learner 1035 Outer Park Drive Environmental law and Policy Springfield, Illinois 62704 Center of the Midwest 203 North LaSalle Street Commonwealth Edison Company Suite 1390 Byron Station Manager Chicago, Illinois 60601 4450 North German Church Road Byron, Illinois 61010 U.S. Nuclear Regulatory Commission Byron Resident Inspectors Office Kenneth Graesser, Site Vice President 4448 North German Church Road Byron Station l Byron, Illinois 61010-9750 Commonwealth Edison Station  !

4450 N. German Church Road Regional Administrator, Region III Byron, Illinois 61010 U.S. Nuclear Regulatory Commission 801 Warrenville Road U.S. Nuclear Regulatory Commission Lisle, Illinois 60532-4351 Braidwood Resident Inspectors Office Rural Route #1, Box 79 Ms. Lorraine Creek Braceville, Illinois 60407 Rt. 1, Box 182 i Manteno, Illinois 60950 Mr. Ron Stephens Illinois Emergency Services Chairman, Ogle County Boaid and Disaster Agency Post Office Box 357 110 East Adams Street Oregon, Illinois 61061 Springfield, Illinois 62706 l

Mrs. Phillip.B. Johnson Chairman 1907 Stratford Lane Will County Board of Supervisors Rockford, Illinois 61107 Will County Board Courthouse Joliet, Illinois 60434 l

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