ML20215M676
| ML20215M676 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 08/04/1986 |
| From: | Carey J DUQUESNE LIGHT CO. |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 2NRC-6-077, 2NRC-6-77, 86-09, 86-9, NUDOCS 8611030158 | |
| Download: ML20215M676 (2) | |
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'Af 2NRC-6-077 Beaver Valley No. 2 Unit Project Organization Telecopy 5 00 Ext.160 S.E.G. Building P.o. Box 328 August 4, 1986 Shippingport, PA 15077 United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 ATTENTION:
Dr. Thomas E. Murley Administrator
SUBJECT:
Beaver Valley Power Station - Unit No. 2 Docket No. 50-412 Actuation Problem of Masoneilan Valve Limit Switches Potential Significant Deficiercy Report 86-09
Dear Sir:
This Potentially Reportable Significant Deficiency Report is being submitted pursuant to the requirements of 10CFR50.55(e).
It is anticipated that no additional reports will be required.
DUQUESNE LIGHT COMPANY By J VJ. Warey Vice President LMR/ijr Attachment NR/S /DEF/8609 AR/1A cc: Mr. P. Tam, Project Manager
- w/ attachment Mr. J. M. Taylor, Director (3)
- w/ attachment Mr. W. Troskoski, Sr. Resident Inspector - w/ attachment Mr. L. Prividy, NRC Resident Inspector
- w/ attachment INP0 Records Center
- w/ attachment NRC Document Control Desk
- w/ attachment hojlO 58 860804 S
CK 05000412 PDR
/ /
ATTACHMENT o
1.
Summary During the testing of a Masoneilan QA Category I valve it was noted that the NAMCO limit switches mounted on the valve would not consistently actuate.
Further investigation revealed that this problem could occur on a total of twenty-eight (28) valves:
twenty-three (23) installed and five (5) spares.
2.
Immediate Action Taken A Nonconformance and Disposition Report was issued for the tested QA Category I valve regarding the potential for improper actuation of the limit switches.
Mr. R. J. Wallauer, Lead Compliance Engineer - Beaver Vcliey Unit 2, notified Mr. L. Tripp, NRC Region I of this concern on July 7,1986.
3.
Description of Deficiency Twenty-eight (28) QA Category I valves have been identified as having the potential for this actuator switch problem.
Tolerances in the actuator linkage allow movement of the valve stem in an axial direction sufficient to permit the switch take-off arm, which connects to the stem connector, to rotate and thus fail to engage the switch actuating l ev er.
The lack of adjustment between the switches and the valve stem intensifies the alignment problem.
4.
Analysis of Safety Implication The faulty actuation of the limit switches could affect the valve position indication only.
No conditions were identified that could adversely affect the safety function of the valve itself to operate on demand.
The f aulty actuation of these limit switches could preclude the capability of post accident monitoring of actual valve position.
Loss of valve position indication required for post accident monitoring could confuse and/or delay proper operator actions subsequent to an accident.
5.
Corrective Action To Resolve the Deficiency Masoneil an is redesigning the limit switch bracket to include slotted mounting holes which allow proper switch alignment.
The new bracket will also incorporate a slotted plate to guide the take-off arm and prevent its rotation tiiroughout the valve stroke.
Masoneilan anticipates that the new mounting bracket assemblies will be available for installation by August 1986.
The modified assemblies, when av ail able, will be installed on the twenty-eight (28) affected v alve s.
6.
Additional Report N3 additional reports are anticipated.
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