ML20248A785
| ML20248A785 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 07/31/1989 |
| From: | Fogarty E PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 8908090028 | |
| Download: ML20248A785 (2) | |
Text
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e PHILADELPHIA ELECTRIC COMPANY NUCLEAR GROUP HEADQUARTERS 955-65 CHESTERBROOK BLVD.
WAYNE, PA 19087-5691 E "10,jhRTY (2I5) 640 6000 July 31, 1989 NUCLE AR SUPPORT DIVISION Docket No.
50-353 License No. NPF-84 U.S. Nuclear Regulatory Commission Attn:
Doccment Control Desk Washington, D.C.
20555
Subject:
Limetick Generating Station, Unit 2 Independent Design and Construction Assessment
Reference:
Letter from J.
S.
Kemper to U.S.
Nuclear Regulatory Commission, dated May 16, 1989, same subject Gentlemen:
In the referenced letter, Philadelphia Electric Company (PECo) identified specific actions to be taken to address open action items from responses to the Independent Design and Construction Assessment (IDCA) Design Observation Reports (DORS).
In that letter, PECo addressed the issue of minimum service life of Class IE Agastat relays located in a mild environment (DOR-114).
PECo performed thermal aging calculations using the Arrhenius methodology to determine a predicted service lifa for Agastat relays.
A minimum of 40 years for normally deenergized applications and a minimum of 8 years for normally energized applications were calculated.
PECo indicated that we would place the subject relays into our Preventative Maintenance (PM) Program by August 1, 1989 to identify the required re placement dates of these relays.
The August 1,
1989 schedule date was established to support an anticipated need to begin replacement of relays in early 1990.
The replacement year of 1990 was based on a determination that there are no relays in Limerick Generating Station (LGS) Unit 2 which have a date of manufacture prior to 1982.
8908090028 890731 BOO ppR ADOCK0500gg3 P
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l 0, S. Nuclear Regulatory Commission Page 2 1
Through additional investigation and review of the standard l
industry practice, we have concluded that the use of the date of I
manufacture as the baseline for determining the end of life / replacement date of relays is overly conservative.
Our intent is to use the LGS Unit 2 fuel load date (i.e.
June 23, 1989) as the baseline for determining the earliest relay replacement date for Unit 2 relays.
In light of our modified approach, the earliest that Unit 2 relays would need to be changed is June 1997.
On this basis /the Unit 2 mild environment relays need not be input into the PM Program by August 1, 1989.
i We plan to continue to analyze the service life and reliability of Agastat relays and this information will be included in our PM program in sufficient time to ensure that any required replacements will be appropriately accomplished.
Very truly yours, "3
k c~ %.
cc:
W.
T.
Russell, Administrator, Region I, USNRC T.
J. Kenny, USNRC Senior Resident Inspector, LGS
)
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