ML17329A637

Informs That Util Will Continue to Implement primary-to- Secondary Leak Rate Monitoring Program Described in 880331 Response to NRC Bulletin 88-002,w/one Exception,In Response to NRC

ML17329A637
Person / Time
Site:	Cook
Issue date:	10/16/1992
From:	Fitzpatrick E INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
AEP:NRC:1056D, IEB-88-002, IEB-88-2, NUDOCS 9210200012
Download: ML17329A637 (6)

Text

Acczr.m~rz rsvruaurror ozvr sraxnor'vsrzM REGULA ORY INFORMATION DISTRIBUTIO SYSTEM (RIDS)

ACCESSION NBR:9210200012 DOC.DATE: 92/10/16 NOTARIZED: NO

'OCKET ¹ FACX :50-'315 Donald C.

Cook Nuclear Power Plant, Unit 1, Indiana M

05000315 AUTH.NAME AUTHOR AFFILIATION FITZPATRICK,E.E Indiana Michigan Power Co. (formerly Indiana

& Michigan Ele RECIP.NAME RECIPIENT AFFILIATION MURLEY,T.E.

Document Control Branch (Document Control Desk)

SUBJECT:

Informs that util will continue to implement primary-to-secondary leak rate monitoring program described in 880331 response to NRC Bulletin 88-002,w/one exception, in response to NRC 920810 ltr.

DISTRIBDTION CODE:

IE13D COPIES RECEIVED:LTR

(

ENCL g SIZE:

TITLE: Bulletin Response, 88-02 Rapidly Propagating Fatigue Cracks in Steam S

NOTES:

RECIPIENT ID CODE/NAME PD3-1 LA STANGFJ INTERNAL: NRR MURPHY,E NRR/DOEA/OGCB11 NRR/DST 8E2

~EG FIMgQ 02 RGN3 FILE 01

'I EXTERNAL: NRC PDR, COPIES LTTR ENCL RECIPIENT ID CODE/NAME PD3-1 PD NRR WILLIAMS,F.

NRR/DREP/PEPB9D NRR/PMAS/ILRB12 RES/DSIR/EIB NSIC I

COPIES LTTR ENCL NOTE TO ALL RIDS RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK.

ROOM Pl-S7 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED:

LTTR 14 ENCL

Indiana Michigan Power Company P.O. Box 16631 Columbus, OH 43216 Z

INDIANA NICHIGiAN POWER AEP:NRC:1056D Donald C.

Cook Nuclear Plant Unit 1 Docket Nos.

50-315 License Nos.

DPR-58 NRC BULLETIN 88-02, "RAPIDLY PROPAGATING FATIGUE CRACKS IN STEAM GENERATOR TUBES" U. S. Nuclear Regulatory Commission Attn:

Document Control Desk Washington, D.

C.

20555 Attn:

T.

E. Murley October l6, l992

Reference:

Letter, J.

F.

Stang (NRC) to E.

E. Fitzpatrick (AEP),

"Donald C. Cook Nuclear Plant, Unit 1, NRC Bulletin 88-02, Rapidly Propagating Fatigue Cracks in Steam Generator Tubes," August 10, 1992 This letter responds to a request from the NRC staff for Indiana Michigan Power Company (I&M) to provide details of its program to ensure that Cook Nuclear Plant Unit 1 is in compliance with paragraph C of the "Actions Requested" section of NRC Bulletin 88-02.

The following provides the response to this request.

Response

to Action C.l Primary-to-Secondary Leak Rate Monitoring Program Indiana

& Michigan will continue to implement the primary-to-secondary leak rate monitoring program previously described in the original response to the

bulletin, which was provided in AEP:NRC:1056 dated March 31, 1988, with one exception.

The maximum steam generator leak rate given in the Unit 1

Technical Specifications has been recently revised from 500 to 150 gallons per day per steam generator, equivalent to 0.347 gpm and 0.1 gpm,-

respectively, (Amendment 166).

Administrative limits are being revised to reflect the lower limit.

Increase in blowdown sampling frequency to every eight hours will be initiated if primary-to-secondary leak rates exceed 0.01 gpm.

TAA>a~

7210200052

'921036 P DR ADOCK 0500031 5 G

PDR

Dr. T. E.. Murley 2

AEP:NRC:1056D Alarm setpoints are being evaluated and actions to be taken will be determined by December 31, 1992.

Procedural changes for leak rate determination 'are complete.

The monitoring program has also been reviewed against NRC Information Notice 91-43, "Recent Incidents Involving Rapid Increases In Primary to Secondary Leak Rate."

It was determined that the program established at the Cook Nuclear Plant provides a

comprehensive means to monitor, trend and react to steam generator tube leaks.

4

Response

to Action C.2 Minimize The Probability of a Fatigue Failure A program will be implemented to minimize the probability of a

rapidly propagating fatigue failure.

The program will be based on analysis performed by Westinghouse Electric Corporation.

This analysis will include the assessment of stability ratios and flow peaking effects 'for the most limiting tube locations as well as an assessment of the depth of penetration of each anti-vibration bar.

The Westinghouse effort will also take into account thermal/hydraulic

analysis, unit - operating

history, and tube vibration effects to identify those unsupported U-bend tubes.with denting at the top support plate that may develop fatigue failure similar to North Anna Unit l.

Results from the analysis will establish Cook Nuclear Plant s long-term preventive action to preclude such failures.

Tub'e plugging and the installation of dampeners are considered the most likely preventative actions for those tubes not meeting acceptance criteria.

The detailed analysis, will require 12 to 20 weeks.

Release of a purchase order to Westinghouse is scheduled in the last quarter of this year,.

Implementation of preventive actions, if required, will be scheduled for the next Unit 1 refueling outage, currently estimated to commence in the first quarter of 1994.

Tube conditions on the cold leg and hot leg sides at the top support plate have remained constant since the original submittal.

Eddy current inspection results for the Unit 1 1992 refueling outage were compared to the reported dents identified in the past examinations.

No changes were found.

Based on the stable tube conditions, at the top support plate, continued operation until the 1994 refueling outage is considered acceptable.

Sincerely, eeu..<

E.

E. Fi patrick Vice President

l

Dr. T.

E. Murley 3

AEP:NRC:1056D tjw CC:

D.

H. Williams, Jr.,

A. A. Blind - Bridgman J.

R. Padgett.

G. Charnoff NRC Resident Inspector

- Bridgman NFEM Section Chief

0 I

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