ML20043E428

Requests That Util Recommit to Enhanced primary-to-secondary Leak Rate Monitoring Program of Bulletin 88-002, Rapidly Propagating Fatigue Cracks in Steam Generator Tubes Pending Completion of Westinghouse Reassessment

ML20043E428
Person / Time
Site:	Zion File:ZionSolutions icon.png
Issue date:	06/06/1990
From:	Chandu Patel Office of Nuclear Reactor Regulation
To:	Kovach T COMMONWEALTH EDISON CO.
References
IEB-88-002, IEB-88-2, TAC-67332, NUDOCS 9006120430
Download: ML20043E428 (5)

Text

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c June 6, 1990'-

Docket No. 50-295

-DISTRIBUTION:

pp"tRiESTTTTIE NRC & Local PDRs PD111-2 Sf JZwolinski Mr. Thomas J. Kovach RDudley-CPatel j

Nuclear Licensing Manager CMoore OGC-WF1 J

Commonwealth Edison Company-Suite 300 EJordan ACRS(10)

OPUS West III PDill-2 Gray-1400 OPUS Place Downers Grove, Illinois 60515

SUBJECT:

WESTINGHOUSE REASSESSMENT OF BULLETIN 88-02 FOR ZION STATION,

-UNIT 1-(TACNO.67332)

A number of PWR licensees contracted Westinghouse to perform the analyses requested by NRC Bulletin 88-02, " Rapidly Propagating Fatigue Cracks in Steam Generator Tubes." During this review of these analyses, the staff noted a pattern of deficiencies affecting a number of these analyses and requested Westinghouse to review its analyses to identify and address these deficiencies.

In response, Westinghouse informed the NRC staff of.its plans to reassess and update these analyses:(Enclosure 1).

You are requested to submit the Westinghouse reassessment to the NRC when you receive it so that the staff can finally resolve this issue.

Your plant is-among six of.the nine plants being reassessed by Westinghouse for which the staff has.previously issued safety evaluations concluding that the Bulletin 88-02 issues have been satisfactorily resolved. Accordingly, p

your plant is no longer subject to Item C.1 of the Bulletin which required L

- an " enhanced primary-to-secondary leak rate monitoring program" for the interim period pending staff review and approval of'the Bulletin resolution.

Now that adequacy of your resolution of the Bulletin has been called into question, we request that you recommit.to11 tem C.1 of the Bulletin pending completion of the Westinghouse reassessment and staff review of-that reassessment.

Please respond within thirty days informing us of your commitment to an enhanced primary-to-secondary leak rate monitoring program.

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Chandu P. Patel, Project Manager o

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Enclosure:

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.s June 6, 1990 i

a Docket No. 50-295 f

Mr. Thomas J.'Kovach:

. Nuclear; Licensing Manager Connonwealth' Edison Company-Suite 300

OPUS West 1111 11400 OPUS Place Downers Grove, Illinois 60515

Dear,

Mr. fovach:

SUBJECT:

- WESTINGHOUSE REASSESSMENT OF BULLETIN 88-02 FOR ZION STATION, UNIT 1 (TAC NO. 67332) a

' A. number of PWR licensees contracted Westinghouse to perform the analyses requested by NRC Bulletin 88-02, " Rapidly Propagating Fatigue. Cracks in Steam Generator Tubes." During this review of these analyses, the staff noted a pattern of deficiencies affecting a number of these analyses and requested Westinghouse to_ review its analyses to identify and address

- these deficiencies...~In response, Westinghouse-informed the NRC staff of its L

plans to reassess and update these analyses (Enclosure 1).

l You_are requested to submit the Westinghouse reassessment to the NRC when i

- you receive it so that: the staff can finally resolve this-issue, p-

__Your 11 ant-is among six of the nine plants being reassessed by Westinghouse for w11ch the staff has previously issued safety evaluations concluding that the Bulletin 88-02' issues have'been satisfactorily resolved. -.Accordingly,

..your; plant is no longer subject to Item C.I.of the Bulletin which required an " enhanced primary-to-secondary leak rate monitoring program" for the D

-interim period pending staff review and approval of the Bulletin resolution.

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Now that adequacy of your, resolution of. the Bulletin has been' called into question, we request that you recommit to Item C.1 of the Bulletin pending completion-of the Westinghouse reassessment and staff review of that.

- reassessment.

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.Please respond within thirty days informing us of your commitment to an H

enhanced primary-to-secondary leak rate monitoring program.

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'The reporting and/or recordkeeping requirements contained in this letter.

affect fewer than ten respondents; therefore, OMB clearance is not required ~

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Chandu P. Patel, Project Manager Project. Directorate 111-2 Division of Reactor Projects - III.

-IV, Y and Special Projects Office of Nuclear Reactor Regulation

Enclosure:

As stated cc: See_next page p

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.-. Mr. Thomas'J. Kovach Zion Nuclear Power Station

' Commonwealth Edison: Company-Unit Nos. I and 2 4-cc:

Robert JhVollen Esquit 109 North.Dearborn Street Chicago,_ Illinois 6060?

Dr. Cecil Lue-Hing-Director of Research and Di.;;elopment Metropolitan Sanitary District -

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.of Greater Chicago 100: East Erie Street Chicago, Illinois 60611 Phillip'Steptoe, Esq.

Sidley and Austin One First National Plaza!

a Chicago, Illinois 60603

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Mayor of Zion Zion,' Illinois 60099 tl Illinois Department of Nuclear Safety Office:of_ Nuclear Facility Safety-

-1035 Outer Park-Drive Springfield,. Illinois 62704 I

U.S. NuclearfRegulatory Commission

Resident Inspectors Office.

t 105:Shiloh= Blvd.

' Zion. Illinois 60099 a

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Regional Administrator,-Region III

.U.S.~ Nuclear Regulatory Commission

.799. Roosevelt Road,-Bldg. #4 Glen Ellyn,! Illinois 60137 i,

Robert Neumann Office'of.Public' Counsel 1

L State of_ Illinois Center 100 W.iRandolph Suite 11-300 E

Chicago,il111nois 60601 1

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ENCLOSURE 1 m

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W9Efingh0USS Intrgy Systems

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am 355 Pmsugh Pemsrvma 15230 03!5 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk NS NRC 90 3498 Washington, D.C. 20555 March 27, 1990 ATTENT!DN:

Mr. J.E. Richardson Director, Division of Engineering Technology

Subject:

Steam Generator Tube Fatigue Evaluations Update

Dear Mr. Richardson:

This letter outlines a plan and the basis for this plan to update steam l

generator tube fatigue evaluations performed by Westinghouse in response-to NRC Bulletin 88 02. As these evaluations progressed from late 1987 to -in particular, late 1988, metho'ds for defining AVB position unce,rtainties improved and a larger flow peaking test data base showed increased sensitivity to AV8 positions.. On this basis, it is l

prudent.to review some of the earlier completed analyses.

To date, reevaluations of earlier reports have been completed for six plants and a reevaluation partially completed for, a s6venth plant. These efforts have led to the identification of a total of two tubes requiring corrective action that-were not included in the original assessment.

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one case Diablo Canyon Unit 1 a tube was identified for corrective p

action as a consequence of an error in transposing graphical AVB data l

that was supplied by another vendor.

Following:this occurrence all p

other plants that used graphical input to prepare AVB maps were, reviewed E

and no other case of a transposition error was identified.

For plants having the edd p

Westinghouse, y current review for AVB positions performed byAVB depth AVB positions which further minimizes the potential for an AV8 mapping error.

For Salem Unit 1, the reassessment completed to.date has identified ~one additional' tube requiring corrective action.

In this case, increased adjustments of AVB positions further away from the best estimate i

positions to account for position uncertainties resulted in a higher flow peaking factor than the original evaluation. The larger data base on flow peaking factors permits identification of more limiting AVB positions than possible for the earlier assessments.

This situation forms the basis for the planned review of the tube fatigue evaluations completed prior to November 1988.

Evaluations completed since this date have included increased efforts to establish AVB positions to maximize flow peaking based on extensive flow peaking tests.

Consequently, these later evaluations do not require a reevaluation.

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4 The existing e"aluations completed prior to November 1988 have identified I

The later assi.s.tients and planned reevaluations more ext incorporate lovev probabtitty AVB positions in the evaluation to increase the confidence that all potentially affected tubes have been identified.

t A total of 3 to 4 months are necessary to complete the reevaluation.

the identified plants.the interim, Westinghouse is not recomending that any ac In To identify the tube fatipe analyses requiring review, the plants for which Westinghouse has completed the evaluations have been grouped into six categories. These categories are identified in Table 1 i

Categories 1 to 4 do not require reevaluation for the reasons (attached).

noted in the table; therefore, the associated plant names are not listed.

The reevaluations have been completed for the Categor results transmitted to the respective utilities. y 5 plants and the As noted above, one tube in Diablo Can corrective action. yon Unit I for the Category 5 plants was identified for 1

There are 9 plants in Category 4 for which reevaluation will be performed.

To date in this Unit 1 has been identified for corrective action. group, one tube in Salem i

Westinghouse intends to complete the reevaluation for the Category 6 plants over the next 3 to 4 months.

A letter sumariting the results of these assessments will be transmitted to the plant owners upon completion of these activities.

If there are any questions on this transmittal, please contact T.A. Lordi (412 374 4311) of my staff.

Si cerely, u_v~

W ohn n, Manager Ne ar S fety Department i

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TABLE 1 PLANT CATEGORIES FOR TUBE FATIGUE EVALVATION j

CATEGORY PLANTS 1.

Plants with AV8 Modifications o Performed with projections

$ mall uncertainty on AV8 positions o

Negligible flow Peaking effects o

0 Reeva untion not required l

2.

Plants with large margins o Reevaluation not required 3.

Plants with round bars Round bars do not show high o

peaking factors or sensitivity as found for square bars o Reevaluation not requ' red 4.

Evaluation performed since late 1988 sensitivity to AV8s fully recognized o

Conservative evaluations performed o

l o Reevaluation not required 5.

Reevaluation already completed o Sensitivity analysis performed Diablo Canyon 1 and 2 Sequoyah 1 and 2 Trojan Point Beach 2 6.

Reevaluation should be performed Indian Point 2 Evaluatier. performed prior to 11/88 Kewaunee o

Sensitivity analysis-to be performed Zion 1 o

o g plants McGuire 2 Beaver Valley 1 and 2 Salem 1 and 2 Ginna l

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