ML20002C334
| ML20002C334 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 10/20/1980 |
| From: | Curtis N PENNSYLVANIA POWER & LIGHT CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20002C331 | List: |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, ER-100450, ER-100508, PLA-560, NUDOCS 8101100076 | |
| Download: ML20002C334 (2) | |
Text
,.,~ e PPat TWO N o tf H NIN TH STR E E T, AL L E N f oWN, PA.18101 PH oNEs (213) 8215131 O
No7. MAN W. f. *1713 vics Frosident.Engineenng & Construction.Nucteef October 20, 1980 Mr. Boyce H. Grier Director, Region I U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406 SUSQUEHANNA STEAM ELECTRIC STATION INTERIM REPORT OF A DEFICIENCY ON EXCESSIVE VOLTAGE DROPS IN AC MOTOR OPERATED VALVE CONTROL CIRCUITS ERs 100450/100508 FILE 840-4 PLA-560
Dear Mr. Grier:
This letter serves to confirm information provided by telephone to NBC Region I Inspector Mr. J. Durr by Mr. R. A. Schwan of PP&L on September 18, 1980. During that conversation Mr. Curr was advised that the subject con-dition was under evaldation for reportability under the provisions of 10CFR50.55(e).
The deficiency involves excessive voltage drops in the control circuitry of the motor starters for some motor operated valves (MOVs).
(Motor starters are devices which provide the control of power to motors-)
For AC powered MOVs, the motor starter operating coils are supplied via a control' transformer tapped off the MOV power supply. Multiple switches and relay contacts are wired in this control circuit to make up the control logic for the MOV.
At Susquehanna SES, excessive voltage drops occur in motor starter control l
cables when size 2, or larger, starters for motor operat'ed valves are energized.
These voltage drops, which are severe enough to prevent motor starter operation, are caused by the sizeable resistance (several ohms) of long lengths (several thousand Jeetl of small (#14 cu) control cable.
Twenty-two (22) size 2 or larger motor starters are located in Class lE safety systems such as Reactor Recirculation and Residual Heat Removal and must be checked to determine if excessive voltage drops occur.
Since these valves are required to operate to mitigate a design basis event, the aforementioned failure to operate represents a significant deficiency in design. Therefore, the deficiency is deemed reportable under 10CFR50.55(e).
Further, since the details of this report provide.. information relevant to the reporting requirements of 10CFR21, this correspondence is considered to also discharge any formal responsibility PP&L may have for reporting in compliance thereto.
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Mr. Boyce H. Grier October 20, 1980 PP&L Engineering is in the process of evaluating several alternatives la order to determine an optimum course of action. We currently estimate that a final report of the deficiency and the corrective action taken will be transmitted to you in January, 1981.
Very truly yours, O
s.
r
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N. W. Curtis
(
Vice President-Engineering & Construction-Nuclear FLW:mcb cc Mr. Victor Stello (15)
Director-office of Inspection & Enforcement U. S. Nuclear Regulatory Consnission Washington, D.C.
20555 Mr. G. Mcdonald, Director Office of Management Information & Program Control U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Mr. Robert M. Gallo U. S. Nuclear Regulatory Conunission P. O. Box 52 Shickshinny, Pennsylvania 18655 1
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