ML20129H237

Forwards RAI Re Proposed Deletion of Plant,Unit 1 mid-cycle SG Tube Insp That Licensee Committed to Conduct No Later than 961015.Advisement Requested Re Whether or Not Licensee Wishes for Review to Be Continued Beyond 961011

ML20129H237
Person / Time
Site:	Braidwood
Issue date:	10/03/1996
From:	Lynch M NRC (Affiliation Not Assigned)
To:	Johnson I COMMONWEALTH EDISON CO.
References
NUDOCS 9610080060
Download: ML20129H237 (6)

Text

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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20666-0001 l

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,o8 October 3, 1996 l

Ms. Irene Johnson, Acting Manager Nuclear Regulatory Services Commor.wcalth Edison Company  ;

Executive Towers West III l 1400 Opus Place, Suite 500 i Downers Grove, IL 60515

SUBJECT:

PROPOSED DELETION OF THE BRAIDWOOD, UNIT 1 MID-CYCLE STEAM GENERATOR TUBE INSPECTION

Dear Ms. Johnson:

In your letter dated August 2,1996, you proposed to omit the Braidwood 1 mid- j cycle steam generator (SG) tube inspection which you committed to conduct no l later than October 15, 1996. The purpose of this inspection is to determine j whether there are circumferential indications in the SG tubes at the top of '

the tubesheet in the roll transition zone. During the course of our review, we identified a need for additional information (an RAI) which we sent to you in our letter dated September 9,1996. You responded to this RAI in three parts with the last response submitted on September 24, 1996.

While we have not completed our review of your responses, we have identified a need for further information before we can reach a decision on your proposal of August 2, 1996, cited above. We informed members of your staff by telephone on September 30, 1996, that we would need a few weeks to complete a thorough review of your extensive responses to our RAI. In light of that determination, we also stated in this telephone conference that we believed it ,

was premature to meet with you on October 1,1996, to discuss those portions )

of your responses which need further clarification and/or justification. We ,

further stated that you should continue with your plans and preparations for  !

the Braidwood 1 SG tube inspection presently scheduled to begin on October 11, 1996, in that we believed the effort required to complete our review and for you to resolve all outstanding issues would not allow us to each a decision on ,

your pending proposal until well after your present schedule for conducting  !

the Braidwood 1 mid-cycle SG tube inspection.

In response to your request for a meeting with the staff in order to provide further clarification and/or justification for your responses, we have scheduled a meeting for October 4,1996. To assist you in this regard, the attachment to this letter contains a list of items that need additional effort on your part. We note that these items represent only those issues we have identified to date in our review.

However, the staff continues to believe that there is a low likelihood that its review of your pending proposal can be completed successfully before the inspection schedule date. To this end, we believe it is still ap te 9610000060 961003 PDR ADOCK 05000456 G PDR u

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Ms. Irene Johnson that you continue your plans and preparations for the scheduled Braidwood 1 1 i

inspection outage, In that it is highly unlikely that your proposal to delete the Braidwood 1 mid-cycle SG inspection will be granted in the required time frame, we request that you inform us whether you want the staff to continue its review past October 11, 1996. Such a request, if submitted, should include the specific objectives and the required completion schedule of this staff review.

If you have any questions on these matters, please contact M. David Lynch at (301) 415-3023.

Sincerely, US _

M. David Lynch, Senior Project Manager Projact Directorate III-2 Division of Reactor frojects - III/IV Office of Nuclear Reactor Regulation I

Docket No. STN 50-456 j

Enclosure:

As stated cc w/ enc 1: See next page

Ms. Irene Johnson l that you continue your plans and preparations for the scheduled Braidwood 1 inspection outage.

l In that it is highly unlikely that your proposal to delete the Braidwood 1 mid-cycle SG inspection will be granted in the required time frame, we request that you inform us whether you want the staff to continue its review past October 11, 1996. Such a request, if submitted, should include the specific objectives and the required completion schedule of this staff review.

If you have any questions on these matters, please contact M. David Lynch at (301) 415-3023.

Sincerely, Orioinal signed by:

M. David Lynch, Senior Project Manager Project Directorate III-2 Divisitan of Reactor Projects - III/IV Office of Nuclear Reactor Regulation Docket No. STN 50-456

Enclosure:

As stated cc w/ enc 1: See next page Distribution: B. Sheron

-Docket File J. Strosnider PUBLIC K. Wichman PDIII-2 R/F E. Sullivan J. Roe, JWR P. Rurh E. Adensam, EGAl K. Karwoski R. Capra G. Dick M.D. Lynch R. Assa C. Moore L. Miller, RIII OGC, 015B18 ACRS, T2E26 DOCUMENT NAME: BRAID \ DEFERRAL.LTR Ts receive a copy of this document. Indicate in the box: "C" - Copy without enclos_ures *E" = Copy with enclosures *N* = No copy 0FFICE Pguu A l L@_4%l C Q ll D:PDIII-2 lC l NAME 4DtTM6h J AS46tT8fW _fw,#!If<N RCAPRA Acre-DATE 10/og/9 F ' ' 10/ /96 V~

1042/96 10/a3/96 10/ /96 0FFICIAL RECORD COPY

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I. Johnson Braidwood Station Commonwealth Edison Company Unit Nos. 1 and 2 cc:

! Michael Miller, Esquire Mr. Ron Stephens

, Sidley and Austin Illinois Emergency Services One First National Plaza and Disaster Agency Chicago, Illinois 60603 110 East Adams Street Springfield, Illinois 62706 Regional Administrator U.S. NRC, Region III Chairman I 801 Warrenville Road Will County Board of Supervisors '

Lisle, Illinois 60532-4351 Will County Board Courthouse Joliet, Illinois 60434 Illinois Department of Nuclear Safety Ms. !orraine Creek Office of Nuclear Facility Safety Rt. 1, Box 182 1035 Outer Park Drive Manteno, Illinois 60950

Springfield, Illinois 62704 Attorney General 1 Document Control Desk-Licensing 500 South Second Street i Commonwealth Edison Company Springfield, Illinois 62701 1 1400 Opus Place, Suite 400 Downers Grove, Illinois 60515 George L. Edgar Morgan, Lewis and Bochius

. Mr. William P. Poirier 1800 M Street, N.W.

Westinghouse Electric Corporation Washington, DC 20036 Energy Systems Business Unit Post Office Box 355, Bay 236 West Commo.: wealth Edison Company Pittsburgh, Pennsylvania 15230 Braidwood Station Manager Rt. 1, Box 84 Joseph Gallo Braceville, Illinois 60407 Gallo & Ross 1250 Eye St., N.W., Suite 302 EIS Review Coordinator Washington, DC 20005 U.S. Environmental Protection Agency i 77 W. Jackson Blvd.

Ms. Bridget Little Rorem Chicago, Illinois 60604-3590 Appleseed Coordinator 117 North Linden Street Mr. H. G. Stanley Essex, Illinois 60935 Site Vice President Braidwood Station Howard A. Learner Commonwealth Edison Company Environmental Law and Policy RR #1, Box 84 Center of the Midwest Braceville, IL 60407 203 North LaSalle Street Suite 1390 Chicago, Illinois 60601 U.S. Nuclear Regulatory Commission Braidwood Resident Inspectors Office Rural Route #1, Box 79 Braceville, Illinois 60407 "

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(. RE0 VEST FOR ADDITIONAL INFORMATION

[ RELATED TO THE PROPOSED DELETION OF THE BRAIDWOOD. UNIT 1 MID-CYCLE STEAM GENERATOR TUBE INSPECTION DOCKET NO. STN 50-456 i

L I 1. The data provided in Table 5 in the' submittal dated September 24, 1996,

indicate that a number of steam generator (SG) tubes burst axially

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during testing and several exhibited mixed mode cracking. Explain the basis for including these data in the burst correlations. Since both

' axial and circumferential flaws were identified in a number of the 4

pulled tubes, discuss the uncertainty involved in using other data obtained from in-situ tests when the morphology of the cracking could not be definitively determined.

l l 2. The staff has evaluated the data supplied by the licensee in Table 19b

' to verify the validity of the licensee's proposed correction factors of ,

j 0.58 and 0.76. Based on this evaluation, the staff has conc':uded that i i using fixed values to convert voltage data could result in significant i i errors in the analysis. This conclusion is based on the level of l scatter observed in a sample of data provided in this table. The staff l also assessed the correction factor used by the. licensee to adjust d i

l 0.115-inch coil probe voltages to equivalent 0.080-inch coil probe  ;

voltages. The results of this staff assessment do not support the l

! licensee's proposed correction factor of 0.78. Specifically,  !

L the staff's assessment indicates that the use of fixed values of correction factors to adjust voltages for different calibration

! procedures and probes can lead to significant errors in the adjusted voltages. In addition, the normalization values used by the licensee i were non-conservative based on values determined in the staff's i independent assessment. Accordingly, due to the high degree'of scatter in the data, discuss whether it is more appropriate to bound the normalization factors at an elevated confidence level when adjusting 4

voltages.

! 3. The correction factor for converting voltages from 0.115-inch coils to 0.080-inch coils varies significantly based on in;inpendent staff ,

calculations using the data supplied in Table 19b as discussed in Item 4 4

below. This conclusion introduces uncertainty into the proposed voltage threshold for SG tube leakage. Discuss the fffects of this uncertainly on your conclusions.

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. 4. Clarify the normalization of voltage data. For example, in your response to Item 5 of the staff's request for additional information (RAI) dated September 9,1996, and in the submittal dated August 2, 1996, it is stated that no calibration corrections were applied to measurements recorded when the probe voltage was set at 10 volts on the 100-percent through-wall hole. However, the values listed in Table 5 of the response to the previous RAI do not appear to correlate with data provided elsewhere in the submittal. For example, one of the six leakage datum has a reported average voltage of 1.66 volts. Applying a correction factor of 0.75 to adjust for probe coil differences rt:sults in a voltage greater than any of the data in Figure 14a. Clarify this apparent discrepancy.

5. Several values important in assessing the end-of-cycle (E0C) structural and leakage integrity of Braidwood 1 SG tubes have been modified since the submittal dated August 2, 1996. For example, the burst and leakage correlations in response to the prior RAI have been adjusted to account for industry material property data and revised values for analyst error. Accordingly, re-evaluate the Braidwood 1 E0C assessment considering all changes to the proposed methodology. Address the use of bounding voltage correction values as discussed in Item 3 above and the limiting growth rate distribution in light of the responses to Items 2 and 3 of the prior RAI.

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