ML17329A181
| ML17329A181 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 09/10/1991 |
| From: | Colburn T Office of Nuclear Reactor Regulation |
| To: | Fitzpatrick G INDIANA MICHIGAN POWER CO. |
| References | |
| IEB-89-001, IEB-89-1, TAC-73164, NUDOCS 9109200088 | |
| Download: ML17329A181 (4) | |
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Docket No. 50-315 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 September 10, 1991 Mr. Gene Fitzpatrick, Vice President Indiana Michigan Power Company c/o American Electric Power Service Corporation I Riverside Plaza
- Columbus, Ohio 43216
Dear Hr. Fitzpatrick:
SUBJECT:
RESPONSE
TO NRC BULLETIN 89-01 AND SUPPLEMENTS 1
AND 2:
FAILURE OF WESTINGHOUSE STEAM GENERATOR MECHANICAL PLUGS-D. C.
COOK UNIT 1 (TAC NO. 73164)
Your June 20, 1989, response to the subject NRC Bulletin dated Hay 15, 1989, indicated that 538 mechanical plugs installed in Unit 1 steam generators were of the suspect heat which may be susceptible to stress corrosion cracking.
These plugs were equally divided between the hot and cold legs.
The attachment to your June 20 letter indicated a calculated lifetime of 353 effective full power days (EFPDs) for the hot leg plugs and 9,099 EFPDs for the cold leg plugs.
You comIitted to replacing the hot leg plugs at the next refueling outage scheduled to occur in late 1990.
You further confirmed that the conditions necessary for the one-time deferment of remedial actions until the next refueling outage (as allowed by the bulletin) were met for your facility.
By letter dated June 4, 1991, the staff indicated that its review of this item was complete for D.C. Cook Unit 2 based upon your certification that Unit 2 had newly installed steam generators and had no mechanical plugs installed.
The staff also requested that you confirm in writing that the actions comitted to in your June 20, 1989, letter had been completed.
This request had been discussed with your staff by telephone in May 1991.
By letter dated IIay 30 1991, you confirmed that all hot leg mechanica'I plugs from the suspect heats 269 p1ugs) had been replaced during the refueling outage for Unit 1 which occurred between October 20, 1990, and January 26, 1991.
On Novemeber 14, 1990 and June 28, 1991 the staff issued Supplements I and 2, respectively, to NRC Bulletin 89-01.
These supplements identified further instances of cracking in Westinghouse mechanical plugs fabricated from thermally treated inconel 600.
Supplement 2 additionally requested of all licensees that actions similar to those requested in the original bulletin be extended to include all Westinghouse plugs fabricated from thermally treated inconel 600.
By letter dated July 29, 1991, you responded to NRC Bulletin 89-01 Supplement 2.
In your letter, you provided a corrected table concerning Westinghouse Alloy 600 mechanical plugs.
Further, you committed to replace all affected mechanical plugs prior to exceeding their effective full power day (EFPD) limits listed in the table or provide an alternative plan for insuring plug integrity at least 30 days prior to the end of the refueling outage that 69I10'3I200088 5000gi5 23I 10 3I10 PDR ADOCK 0 PDR II Q
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Mr. Gene Fitzpatrick Indiana Michigan Power Company Donald C.
Cook Nuclear Plant CC:
Regional Adrrinistrator, Region III U.S. Nuclear Regulatory Corrrrission 799 Roosevelt Road Glen Ellyn, Illinois 60137 Attorney General Departrrent of Attorney General 525 West Ottawa Street Lansing, Michigan 48913 Township Supervisor Lake Township Hall Post Office Box 818 Bridge'an, Michigan 49106 Al Blind, Plant Manager Donald C.
Cook Nuclear Plant Post Office Box 458 Bridgn an, Michigan 49106 U.S. Nuclear Regulatory Corrrrission Resident Inspectors Office 7700 Red Arrow Highway Stevensville, Michigan 49127 Gerald Charnoff, Esquire Shaw, Pitto an, Potts and Trowbridge 2300 N Street, N.W.
Washington, DC 20037 Mayor, City of Bridgvan Post Office Box 366 Bridgnan, Michigan 49106 Special Assistant to the Governor Root 1 - State Capitol Lansing, Michigan 48909 Nuclear Facilities and Environs'ental Monitoring Section Office Division of Radiological Health Departrrent of Public Health 3500 N. Logan Street Post Office Box 30035 Lansing, Michigan 48909 Mr. S. Brewer Awerican Electric Power Service Corporation 1 Riverside Plaza
- Columbus, Ohio 43216
occurs before the date of the EFPD limit listed in the table.
Based on your commitment we consider this item closed for D.C.
Cook Unit 1.
Please keep us informed of your replacement efforts until all affected plugs have been replaced.
Rough calculations, based upon your estimate of EFPDs for your last operating cycle, indicate that the remaining life of the cold leg plugs may extend to the end of your current operating license for Unit 1.
Please keep us informed if it becomes necessary to replace those mechanical plugs.
The reporting requirements in this letter affect fewer than ten respondants,
Sincerely, cc:
See next page DISTRIBUTION:
Original signed by Timothy G. Colburn, Sr. Project Manager Project Directorate III-I Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation PD31 r/f TColburn BBoger OGC PD31 Gray NRC 5 LPDRs JZwolinski E Jordan PShuttleworth ACRS (10)
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NAME:PShuttl eworth: TColburn/dy:CYCheng: LBMarsh
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DATE:f/Q/91:f/B/91:
/f/91:
9//0/91 Document Name:
GENE FITZPATRICK LETTER
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