ML20134K313

Forwards RAI Re Revised SG Tube Rupture Analysis for Mentioned Plants

ML20134K313
Person / Time
Site:	Byron, Braidwood
Issue date:	02/11/1997
From:	Dick G NRC (Affiliation Not Assigned)
To:	Johnson I COMMONWEALTH EDISON CO.
References
TAC-M97315, TAC-M97316, TAC-M97317, TAC-M97318, NUDOCS 9702130238
Download: ML20134K313 (4)

Text

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=, February 11, 1997 Ms. Irene M. Johnson, Acting Manager ,

Nuclear Regulatory Services l Commonwealth Edison Company Executive Towers West III 1400 Opus Place, Suite 500 Downers Grove, IL 60515

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION REGARDING THE REVISED STEAM GENERATOR TUBE RUPTURE ANALYSIS - BYRON STATION AND BRAIDWOOD STATION (TAC NOS. M97315, M97316, M97317 AND M97318)  !

Dear Ms. Johnson:

1 On November 13, 1996, Commonwealth Edison Company (Comed) submitted its revised steam generator tube rupture analysis for Byron, Units I and 2, and Braidwood, Units I and 2. During the course of our review, we have identified l the need for further information as discussed in the enclosed request for additional information (RAI). Please provide your response to the request so that we may maintain our schedule for review'of your submittal.

Sincerely, ,

. '; z l

/s/, .

' ' ,i ' -

George F.- Dick, Jr., Project' Manager Project Directorate III-2. ,

Division'of Reactor Projects III/IV Office of Nuclear, Reactor Regulation ,

Docket Nos. STN 50-454, STN 50-455,~ .

STN 50-456, STN 50-457 ', ,

Enclosure:

RAI ,

cc w/ encl: see next page /

[b 30042 9702130238 970211 ,

PDR ADOCK 05000454 p PDR DISTRIBUTION: Docket F to PUBLIC PDIll-2 r/f J. Roe, JWR R.Capra C. Moore G. Dick OGC, 015B18 ACRS, T2E26 S. Bailey C. Jackson, CPJ R. Assa J. Lyons R. Lanksbury, RDL C. Thomes J. Arildsen, JAA G. West, GXW E. Adensam, EGA1 Document Names Gr\CNNTJR\ BRAID-BY\BB9 15.RAI t 77 receive a copy of this document, i cate in the boa: "C" = copy without enclosures "E" = Copy with enclosures "W" = No copy 0FC PM:PDIll-2 A h fLAfPelli-2 b HHFB E SRXB D:PDill 2 I i IMIE GDICK CM00RE [ftT S sh JL ONS RCAPRA DATE 02/ @ /97 02/[,/97 02//M/97 02/ll /97 02/ // /97 0FFICIAL RECORD COPY

1. Johnson Byron /Braidwood Power Stations commonwealth Edison Company cc:

Mr. William P. Poirier, Director George L. Edgar i 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 Office of Nuclear Facility Safety 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 4 Byron, Illinois 61010 U.S. Nuclear Regulatory Commission Byron Resident Inspectors Office Kenneth Graesser, Site Vice President

! 4448 North German Church Road Byron Station 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 4

Ms. Lorraine Creek Braceville, Illinois 60407 Rt. 1, Box 182 Manteno, Illinois 60950 Mr. Ron Stephens Illinois Emergency Services Chairman, Ogle County Board and Disaster Agency Post Office Box 357 110 East Adams Street Oregon, Illinois 61061 Springfield, Illinois 62706 Mrs. Phillip B. Johnson Chainian 1907 Stratford Lane Will County Board of Supervisors Rockford, Illinois 61107 Will County Board Courthouse Joliet, Illinois 60434 l

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.. Cosmonwealth Edison Company Braidwood Station Manager Rt. 1, Box 84 Braceville, Illinois 60407 Ms. Bridget Little Rorem

. Appleseed Coordinator 117 North Linden Street l Essex, Illinois 60935 1 ,

I Document Control Desk-Licensing

Commonwealth Edison Company 4

1400 Opus Place, Suite 400 Downers Grove, Illinois 60515 Mr. H. G. Stanley Site Vice President Braidwood Station Commonwealth Edison Company RR 1, Box 84 Braceville, IL 60407 i

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. i 5*. REQUEST FOR ADDITIONAL INFORMATION i*

I REVISED STEAN GENERATOR TUBE RUPTURE ANALYSIS i 4

i COMONWEALTH EDISON COMPANY l BYRON STATION. UNITS 1 AND 2: BRAIDWOOD STATION. UNITS 1 AND 2 4

f W KET NDS. STN 50-454. STN 50-455. STN 50-456. AND STN 50-457 l r

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! A. Questions Reaardina Marain to Overfill calculations i

l. The submittal states that as part of the T-HOT reduction program Byron  ;

4 and Braidwood have been analyzed for a T window of 569.1 degrees  :

Fahrenheit tc 588.4 degrees Fahrenheit. The analysis submitted assumes t 1 567.1 degrees Fahrenheit, 2 degrees Fahrenheit lower than the low end of the T window. The Updated Final Safety Analysis Report states

! (pg.15.E9) that the average reactor coolant system temperature j uncertainty is 14.7 degrees Fahrenheit. Please explain why the choice i of 567 degrees Fahrenheit bounds the operational range with instrument

uncertainty included.

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i 2. The analysis concluded that the limiting margin to overfill is 60 cubic feet. Given that this is probably less than a half a foot of water l 1evel, less than 30 seconds of auxiliary feedwater flow, less than a

! few seconds of main feedwater flow and less than two percent of the '

J total steam generator volume, please provide greater justification that

this very small margin gives reasonable assurance that the steam

! generators will not fill. An evaluation of the sensitivity of key  ;

! parameters to the margin available or an estimation of the j calculational uncertainty may be helpful in determining if the margin  :

is adequate.

! 3. The original staff approved analysis was performed using RETRAN-02 l MOD 3. The current analysis uses RETRAN-02 MOD 5.1. Please provide 4

a reference for both the generic and site specific staff approval of MOD 5.1 for the application of steam generator tube rupture analysis.

j 4. Provide additional discussion of why the amount of turbine runback is

now assumed to be 70 percent rather than 60 percent in the previous

, analysis. Describe the effect of a turbine runback on the results of the analysis. Additionally, why is an immediate manual reactor trip not assumed if this provides more conservative results?

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! 5. Provide greater detail explaining why the assumption of 102 percent j initial reactor power before the steam generator tube rupture (SGTR)

is more conservative than the previously assumed value of 100 percent

Power.

! ENCLOSURE

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,. B. Questions Recardina Goerator Actions 4

. 1. As noted in Question A.2, the margin to overfill is small. What assurance will the licensee provide to the staff that demonstration j runs on the overfill scenario discussed in the submittal dated November 13, 1996, will be completed for 100 percent of Byron an_

i Braidwood operators?

i 2. The licensee committed to evaluate a minimum of 80 percent of the Byron and Braidwood licensed operator crews in the design basis SGTR overfill scenario, and in fact evaluated all 12 similar crews at each site.

Please discuss the rationale for selecting the two licensed reactor operator crews from Byron and Braidwood for the revised SGTR overfill scenario.

3. Provide the results of a sensitivity study that would evaluate the significance of observed average response times that exceed the revised analysis response times discussed in Tables 3 and 4 of the November 13, 1996, submittal.

! 4. Provide the actual times for the Byron and Braidwood licensed operator crews that participated in demonstration runs for the overfill scenario discussed in the November 13, 1996, submittal.

5. Provide information regarding the time anticipated to obtain steam generator sample results. Include discussion of the effect on performance of subsequent E0P steps and any resultant effect regarding the SGTR event.

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