ML19209B984
| ML19209B984 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 10/04/1979 |
| From: | Peoples D COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19209B985 | List: |
| References | |
| NUDOCS 7910110356 | |
| Download: ML19209B984 (2) | |
Text
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Commonwealth Edison One First National Plaza. Chicago, Illinois Address Reply to: Post Office Box 767 Chicago, lilinois 60690 October 4, 1979 Dr. Harold R.
Denton, Director Office of Nuclear Reactor Regulation U.S.
Nuclear Regulatory Commission Washington, D.C.
20555
Subject:
Zion Station Units 1 and 2 Additional Response to IE Bulletin No. 79-01 and Supplement No.79-01A,
" Environmental Qualification of Class lE Equipment" NRC Docket Nos. 50-295 and 50-304 References (a):
February 9, 1970 letter from J.
G.
Keppler to B. Lee, Jr. transmitting IE Bulletin No. 79-01 (b):
June 6, 1979 letter from J.
G. Keppler to B.
Lee, Jr. transmitting IE Bulletin No.79-01A (c):
August 20, 1979 letter from N.
E.
Wandke to J. G. Keppler transmitting Reportable Oc:urrence Report No.
50-295/79-56
Dear Dr. Denton:
References (a) and (b) transmitted IE Bulletin Nos.
79-01 and 79-01A, " Environmental Qualification of Class lE Equipment."
Item 4 of Reference (a) required Commonwealth Edison Company to report any items which are identified as not meeting qualification requirements for service intended directly to the Office of Nuclear Reactor Regulation with a copy to appropriate NRC Regional Office.
However, this requirement was inadvertently overlooked by Commonwealth Edison's Zion Station with regard to Reference (c) which reported switches not environmentally qualified for their application directly to the NRC Regional Office.
This letter corrects that oversight and provides additional information re-garding Commonwealth Edison's justification for continued operation until these switches are replaced with environmentally qualified suitches.
As indicated in Reference ( c), the occurrence was reportcd to the NRC Region III Directorate of Regulatory Operations by telephone on August 6, 1979 and by telegram on August 7, 1979.
This report basically indicated that while performing work associated with Referencd (a), Zion Station personnel discovered
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of
Commonwt:alth Edison NRC Docket Nos. 50-295/304 Dr. Harold R. Denton: October 4, 1979 non-environmentally qualified switches which were apparently overlooked in the initial survey of stem mounted limit switches.
The switches in question are Namco D2400X limit switches which are used on the reactor coolant loop isolation valves in Train B reactor protection circuits.
These Nar co switches, if shorted out, could cause failure of a reactor trip on low-low steam gene _ator level and high steam line delta P safety injection from Train B of reactor protection.
However, as indicated in Reference (c), these switches, if failed, would be backed up by Train A of reactor p::otection which uses gear driven limit switches of the motor operator for the same functions.
Thus, the health and safety of t'he public would not be affected by continued operation until replace-ment with qualified limit switches during the next outages (October anc December 1979 for Zion Units 1 and 2, respectively).
Subsequent to the review associated with Reference (c),
Commonwealth Edison determined that by lifting leads from the valve closed limit switches the protective functions of Train B would not be defeated, i.e.,
the switches, if failed, would cause no problems.
Therefore, until replacement by environmentally qualified switches, one lead will be lifted from each valve closed limit switch of the hot and cold leg isolation valves and the valve open limit switch of the bypass valves.
For your convenience in reviewing this matter the following schematic diagrams are attached:
Drawing Numbers 22E-1-4887, 4888, 4889, 4919 and 4923.
Please address ~any questions that you might have concerning chis matter to this office.
Very truly yours, D.
Louis Peoples Director of Nuclear Licensing WFN:mae attachments cc:
Director, Directorate of Inspection and Enforcement - Region III 1129 306