ML17335A319

Informs of Actions Taken Re Crack Discovered in PINGP Part Length Crdm.Ultrasonic Exams of Both Units Part Length CRDMs Identified No in-service Degradation

ML17335A319
Person / Time
Site:	Cook
Issue date:	11/05/1998
From:	Powers R INDIANA MICHIGAN POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
AEP:NRC:1288A, NUDOCS 9811100249
Download: ML17335A319 (6)

Text

CATEGORY 1 t

REGULAT Y INFORMATION DISTRIBUTIO SYSTEM (RIDS)

ACCESSION NBR:9811100249 DOC.DATE: 98/11/05 NOTARIZED: NO DOCKET FACIL:50-315 Donald C. Cook Nuclear Power Plant, Unit 1, Indiana M 05000315 50-"p3.6 Donald C. Cook Nuclear Power Plant, Unit 2, Indiana M 05000316 AUTH. NAME AUTHOR AFFILIATION POWERS,R.P. Indiana Michigan Power Co.

RECIP.NAME RECIPIENT AFFILIATION Records Management Branch (Document Control Desk)

SUBJECT:

Informs of actions taken re crack discovered in PINGP part length CRDM.Ultrasonic exams of both units part length CRDMs identified no in-service degradation. A DISTRIBUTION CODE: A001D COPIES RECEIVED:LTR ENCL SIZE:

TITLE: OR Submittal: General Distribution E

NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD3-3 LA PD3-3 PD STANG, J R

'NTE FILE CE NRR/DE/ECGB/A NRR/DE/EMCB NRR/DRCH/HICB NRR/DSSA/SPLB NRR/DSSA/SRXB NUDOCS-ABSTRACT OGC/HDS3 EXTERNAL: NOAC NRC PDR D

N NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE. TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM DISTRIBUTION LISTS OR REDUCE THE NUMBER OF COPIES RECEIVED BY YOU OR YOUR ORGANIZATION, CONTACT THE DOCUMENT CONTROL DESK (DCD) ON EXTENSION 415-2083 TOTAL NUMBER OF COPIES REQUIRED: LTTR 13 ENCL

Indiana Michigan~

Power Company 500 Circle Drive

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Buchanan, Ml 49107 1373 IItIQIAIlM MCIII6'AN PQWM November 5, 1998 AEP:NRC:1288A Docket Nos. 50-315 50-316 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Stop 0-Pl-17 Washington, D.C. 20555-0001 Donald C. Cook Nuclear Plant Units 1 and 2 PART LENGTH CONTROL ROD DRIVE MECHANISM (CRDM) HOUSING ISSUE Gentlemen:

References:

1. AEP:NRC:1288, "Donald C. Cook Nuclear Plant Units 1 and 2, PART LENGTH CONTROL ROD DRIVE MECHANISM (CRDM) HOUSING ISSUE", dated May 13, 1998.

2. Letter, John A. Grobe to John"Sampson, "NRC INSPECTION REPORT 50-315/98010(DRS); 50-316/98010(DRS)", dated June 18, 1998.

The purpose of this letter is to inform you of the actions we have taken regarding the crack discovered in the Prairie Island Nuclear Plant's part length CRDM.

In reference 1, the plant committed to perform an ultrasonic examination (UT) of the eight unit 1 and eight unit 2 part length CRDMs prior to restarting the units. ABB-Combustion Engineering, who had previously completed sim'ar inspection for several utilities, performed these inspections under contract.

During the inspections performed for other utilities and the analysis of the Prairie Island part length CRDM crack, a concern was raised about the minimum detectable flaw size that the UT procedure was capable of detecting. Consequently, we elected to demonstrate the capability of the UT procedure prior to the gpss inspections of the plant's part length CRDMs. This procedure demonstration, which was conducted with the assistance of the Electric Power Research Institute and witnessed by NRC personnel, indicated that the examination technique was capable of detecting circumferentially oriented indications that were twenty five percent or greater through-wall.

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Page 2 There are eight part length CRDM penetration tubes in each of the plant s units and all of the tubes were inspected. The unit 1 and unit 2 part length CRDM examinations did not identify any indications in excess of twenty-five percent through-wall.

In unit 1, an anomaly was observed during the inspection at location F-12. The reflection was determined to be geometric in origin resulting from beam redirection to the inside diameter other surface. No other reportable indications were observed in any of the fifteen welds examined in unit 1.

For unit 2, one small indichtion plotted at the weld midwa'l at location F-12 is located in the 304 stainless steel base metal side of the weld (not in the area where the Prairie Island flaw was located) and is not surface connected. The indication appears to be a small inclusion, approximately 0.1 inch in length, and is smaller than the maximum permissible flaw as per Westinghouse Owners Group Letter Number OG-98-037. An NRC inspector reviewed the unit 1 and unit 2 results. The unit 2 results are discussed in reference 2.

Because the UT examinations of both units'art length CRDMs identified no in-service degradation, the inspections complete required or anticipated actions, and there are no plans to perform future inspections of the part length CRDMs.

Sincerely, R. P. Powers Vice President

/gmc c: J. A. Abramson J. L. Caldwell MDEQ DW & RPD NRC Resident Inspector J. R. Sampson

U. S. Nuclear Regulatory Commission AEP:NRC:1288A Page 3 bc: T. P. Beilman E. R. Eckstein/D. F. Powell/D. R. Hafer/K. R. Baker J. J. Euto FOLXO B. J. Hickle G. Honma J. B. Kingseed/G. P. Arent/M. J. Gumns T. R. Satyan-Sharma J. F. Stang, Jr., NRC Washington, DC

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