ML20083H529

Suppl 2 to Third-Party Review of TMI-1 Steam Generator Repair. Js Wetmore 830822 & 0909 Ltrs Encl

ML20083H529
Person / Time
Site:	Three Mile Island
Issue date:	12/03/1983
From:	Brown S, Holland S, Kalnins W CINCINNATI GAS & ELECTRIC CO.
To:
Shared Package
ML20083H525	List: ML20083H523 ML20083H529
References
NUDOCS 8401090315
Download: ML20083H529 (7)

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REPORT OF THE THIRD PARTY REVIEW OF THREE MILE ISLAND, UNIT 1, STEAM GENERATOR REPAIR SUPPLEMENT 2

' y To R. F. Wilson - Vice President, Technical Functions l - GPU Nuclear, t Prepared by

. THIRD PARTY-' REVIEW GROUP:

Stephen D.-Brown Stanley A. Holland Arturs Kalnins William H.' Layman David J. Morgan Richard W.-Weeks Edwin J. Wagner - Chairman I

i Submitted for the Review Group By:

401090315 B40103 . Wagn6#

DR ADOCK 05000

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Date: ' 3's 3 / 8 I

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PURPOSE This report is Supplement 2 of the report of the Third Party Review of the TMI-l steam generator repair dated February 18, 1983. It evaluates a revision to the Safety Evaluation Repor;t (SER) mado cince the Review Group issuc,d.its conclusions in-Sup-plement 1 of May 16, 1983.

BACKGROUND The establishment and operation of-the Third Party Review Group of the TMI-l steam generator repair was previously dis-cussed in the Review Group's Report of-February 18, 1983. The report contained a conclusion concerning the adequacy of the steam generator repairs for safe operation of the TMI plant and findings, comments, and recommendations about the steam genera-tor repair and return of the plant to operation.

In Supplement 1, of May 16, 1983, the Review Group evalu-ated the GPU Nuclear responses to the Review Group's Report and concluded that

"...upon satisfactory completion of the entire program as defined in the safety evaluations and as augmented by GPU Nuclear comments during and subse-quent to the April 12 and 13 neeting, the TMI-l -

plant can be operated safely with the repaired steam generators." .

GPU Nuclear subsequently revised their SER and issued " Assess-ment of TMI-l Plant Safety for Return to Service After Steam Gen-erator Repair, Topical Report 008, Revision 3, August 19, 1983."

The Review Group was requested by GPU Nuclear letters of August 22 and September 9, 1983, to review the revised SER. The GPU Nuclear letters are attached as Appendix A and B to provide explicit identity to those documents supplied for review.

- Revision 3 of the SER and related documents were distributed to the specialist members of the Review Group who_had~ interest in design analysis, which was the principal content of the revision.

The reviewers were Mr. Layman, Mr. Kalnins, and Mr. Wagner. They performed the review and discussed the conclusion by telephone. .

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The conclusion was provided to Mr. Wetmore, of GPU Nuclear, by.the Chairman on October 6, 1983. This supplement 2 reports the Review Group's conclusion.

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CONCLUSION

'The1 Review Group reiterates.the conclusion of our Supplement-1 :as : quoted; above. - Revision 3-of the SER included actions to

. resolve prior Review Group-comments as GPU Nuclear ~ indicated

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,']our review of3the revisions of the SER.

COMMENTS

, [ ' The: Review Group was specifically interested in the revised 77y0 actions'taken by GPU-Nuclear.on topics upon which the Review n  : Group commented-inLSupplement.l. Those topics follow and are C.,..<> -

.. referred:to the same numbered section of Supplement 1.

,+y j{7,. :E. Stiress ' Analysis of Steam Generators,

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gp: The' Review Group:had-commented:

"For this' reason, the-Review' Group recom-i .a mended that a detailed ctress analysis of the transition zone be made including the loading of- the main steam line break.

+- Subsequent to-the Review Group meeting, e~- s~; 'GPU Nuclear l advised that they-had completed the stress analysis of the' transition zone, and the' revising the'-stress report to include

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this. analysis and that~the analysis shows an o s , acceptable.: stress condition. This resolves

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the' Review' Group's comment."

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-[? The. Review Group;found Revision 3 of the SER to reflect

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• the revised stress analysis of the transition and that the

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'P.f:' Steam. Generator-Leak Tightness After Repair p

The Review Group had commented:

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..~Because of these uncertainties in the

. analyses, the' Review Group questioned whether

the results'of the GPU Nuclear analysis of~

leak before break had sufficient margin for 4

the-limiting ~ case ofja main steam line break.

g . Subsequent-to the meeting GPU Nuclear has

" ' pursued.thiscissue and advised they have come A to the following conclusions:

-o '- The GPU Naclear study'on crack preparation

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their interpretation of the draft analy-L / @r' ' .a y sis done by others' suggests that cracks will

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not grow or not grow rapidly as a result of flow induced vibration. Although growth rate is a function of the assumed threshold stress intensity, even the extreme case of no thres-hold revealed long time periods for crack growth to a critical size and therefore ample

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time for operator action to shut down the re-actor prior to a tube failure either at power or during shutdown.

- The tube loads associated with the steam main line break case were calculated using a gener-ic analysis for B&W plants. The assumptions

• used in this analysis are very conservative with respect to the particular plant para-meters for TMI-l and results in calculated tube loads substantially greater than would

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actually. occur. When more-realistic tube loads are taken into account, the critical crack size is estimated to be significantly larger and the corresponding leak rate is in-creased by approximately a factor of two.

Thus GPU Nuclear concludes that because sig-

nificant margin exists in the tube loading used-to determine critical crack size, no further conservatisms need be added in desig-nating administrative limits which take credit for leak before break...

In addition, in response to Review Group e suggestions, GPU Nuclear will record the conden-ser offgas activity data during cooldown and evaluate the feasibility of using this data for determining primary-to secondary leak rates dur-ing conditions of higher tube-to-shell dolta T.

GPU Nuclear also plans to use secondary-to-primary bubble testing tube as one technique for locating leaking tubes whenever the plant is shut down in response to an increase to a leak rate 0.1 gpm or more. The high sensitivity of this measurement technique provides additional assurance that flaws that could become unstable before the next eddy current inspection will be detected."

The Review Group found Revision 3 of the SER contains the following items which respond satisfactorily to our pre-vious comments:

a) The leak befcre break critical crack analysis was per-formed for the TMI-1 specific main steam line break in addition to the generic analysis. The leak before break analysis was also further supported by improved analysis of leakage rates through cracks.

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. r b) Monitoring primary-to-secondary leakage rate indications during operational cooldowns was included.

c) Secondary-to-primary bubble. testing for tube leak detec-tion was included whenever the plant is shutdown in response to an increase in leak rate of 6 gph (0.1 gpm) or more.

APPENDIX 1 - GPU Nuclear letter dated August 22, 1983 to Mr. Edward Wagner from Mr. J.S. Wetmore, Manager, PWR Licens-ing.

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-APPENDIX 2 - GPU Nuclear letter dated September 9, 1983 to I Mr. Edward Wagner from Mr. J.S. Wetmore, Manager, PWR Licensing.

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APPENDIX 1 GPU Nuclear Corporation UCIMr 100 lnterpace Parkway Parsippany New Jersey 07054 201 263 6500 TELEX 136-482 Writer's Direct Dial Number:

August 22, 1983 REcy;ygg ,,7,0 Mr. IMward Wagner ~ -

Cincinnati Gas & Electric  %

Zirmer Nuclear Power Station RR$1 Box 2023 QI MO2. dim 3 U.S. Ibute 52 Moscow, 01 45153 g -

Dear Ed:

Per our telephone conversation today, I am forwarding the below listed documents for review by the Third Party Review Group for 'IMI-l OPSG Repair:

1. An SER entitled " Assessment of 'IMI-l Plant Safety for Return to Service After Steam Generator Repair,"

2. TDR-417 Rev.1 entitled "'IMI-l OPSG Tutn Axial Ioads and Leakage Bbntoring."

3. 'IDR-417 Rev. O entitled "OrSG Leakage and Operating Limits," and

4. Report entitled "The Residual Crack Opening Displacements in Tubes and Pipes."

Item 1 consists of changes made to Topical Report 008 (changes indicated by marginal change bars) to reflect results of OrSG cold testing and updated assessment of tube axial loads and their effects on leakage rate monitoring. Items 2 through 4 provide additional information to support the changes reflected in Item 1.

We expect to have further data to support the validity of estimates of residual crack opening displacements in the near future. A final revision to 'Ibpical Report 008 will be completed at that time.

Per your request, I have forwarded copies of the enclosed to A. Kalnins an.3 W. Layman.

Sincerel

. S. Wetmore Manager PWR Licensing dis:0079f Enclosures GPU Nuclear Corporatior;is a subsidiary of the General Pubhc Utihties Corporation /

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. . . . APPENDIX 2 .

l GPU Nuclear Corporation piUGE nep 100 Interpace Parkway s

l w Parsippany. New Jersey 07054 j

201 263-6500 1 TELEX 136-482 Writer's Direct Dial Number:

E&L: 5066 September 9,1983 arrn RECEIVED NOTED E.J. WAGNER Mr. Edward Wagner Cincinnati Gas S Electric Zimmer Nuclear Power Station E\' To-R.R. #1 Box 2023 U.S. Route 52 Moscow, 011. 45153

Dear Ed:

Enclosed for Third Party Review Group review is Revision 3 to spical Report 008, " Assessment of TMI-1 Plant Safety for Return to Serv' ice After Steam Generator Repair."

To minimize unnecessary delays, I have also forwarded copies directly to A. Kalnins and W. Layman.

Very tr 1 urs, i

J S. Wetmore anager, PWR Licensing 1r Enclosure GPU Nuclear Corporation is a subs diary of the General Public Utilities Corporation