ML18085A838
| ML18085A838 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 01/23/1981 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Schneider F Public Service Enterprise Group |
| References | |
| NUDOCS 8102190476 | |
| Download: ML18085A838 (6) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION REGION I 631 PARK AVENUE KING OF PRUSSIA, PENNSYLVANIA 19406 JAN 2 3 798J Docket Nos. 50-272 50-311 Public Service Electric and Gas Company ATTN:
Mr. F. W. Schneider Vice President - Production 80 Park Plaza - lSA Newark, New Jersey 07101 Gentlemen:
The enclosed IE Circular No. 81-01, "Design Problems Involving Indicating Pushbutton Switches Manufactured by Honeywell Incorporated," is forwarded to you for information.
No written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely,
'.I/
ii\\
&e:.~
Director
Enclosures:
- 1.
- 2.
List of Recently Issued Circulars CONTACT:
E. G. Greenman,,
(215-337-5267) cc w/encls:
J. T. Boettger, General Manager - Corporate Quality Assurance R. L. Mittl, General Manager - Licensing and Environment H. J. Midura, Manager - Salem Generating Station R. A. Uderitz, General Manager - Nuclear Production 810.! l 90'176
UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D. C. 20555 January 23, 1981 SSINS No.:
6830 Acce.ssfon No.:
8008220280 IEC No. 81-01 IE CIRCULAR NO. 8!-01:* DESIGN PROBLEMS INVOLVING INDICATING PUSHBUTTON SWITCHES MANUFACTURED BY HONEYWELL INCORPORATED
Background:
. By letter dated September 1a: 1980 (J.M. Curran to R.H. Engelken), Southern California Edison Company (SCE) notified NRC of design problems involving certain indicating pushbutton switches. The subject switches are of the type designated as Series 2 inqicating pushbutton switches that are manufactured by the Micro Switch Division of Honeywell Incorporated.
The switches identified by SCE as having design deficiencies are used.on the containment isolation
. panels at San Onofre Unit 1 (Docket No. 50-206).
.SCE identified two problems with the subject, switches, both of which manifest
- themselves during re lamping:
(1) a short circuit may be induced; and (2) the circuit controlled by the switch may inadvertently be actuated.
- Although the
- specificity of this circular is restricted to the previously mentioned Series 2
- switches the deficienties cited may be common to other indicating pushbutton
- . switches..Accordingly, holders of operating licenses and construction permits should scrutinize the design of other indicating pushbutton switches in their facilities for susceptiblity to the above problems..
By letter dated October 10, 1980 (J. G. Haynes to R. H. Engelken), SCE submitted a detailed followup report addressing the defective switches.
Sections of the SCE report containing relevant information have been excerpted and included in the paragraphs that follow.
Sections so excerpted are identified by quotation
- marks.
Discussion:
The SCE report provided the following details of the problems previously mentioned:
111.
- The design of indicating pushbutton switches is such that during insertion of the lamp assembly into the switch housing, shorting could occur between the metallic plunger and the energized indicator lamp connection inside the switch assembly.
Since the metal plunger is connected to the cabinet ground through the switch housing, the control circuit could be short circuited, causing failure of the control circuit if it is energized.
IEC No. 81-01 January 23, 1981 Page 2 of 4
- 2.
The design of the lamp assembly is such that to lock the switch into place after relamping will cause actuation of the switch resulting in operation of the control circuit if it is energized. Since the current containment isolation system operational design requires that the power supply to the containment i so 1 at ion pane*l s remain energized during relamping, the potential exists for operating containment isolation valves during the lampreplaceinent. 11
~.
To circumvent the preceding problems, SCE, in cooperation with Hone}'Well
- Incorporated, is implementing the following corrective actions.
111. The. metallic plunger is being redesigned to solve the short circuit
_problem discussed in Item 1 above.
The de.sign modification involves.
providing a plastic tip.on the.*plunger.
The plastic tip will provide
. isolation between the metallic plunger and energized indicator lamp connectfon inside the switch assembly and this will avoid short circuit problems.
A prototype modified switch assembly was received
. on September 20, 1980 and successfully tested. Accardi ngly, the manufacturer is developing the necessary too1ing for production
. purposes. It is expected that the modified switch assemblies can be delivered and installed prior to return to power operation from the current* outage..
- 2.
The indicating pushbutton lamp assembly system is being redesigned to solve the switch actuation problem discussed in Item 2 above.
The design modification will permit relamping with the power supply energized, without causing switch actuation. It is expected that the system wi 11 be redesigned and the current switches rep 1 aced during
- the next scheduled cold shutdown of sufficient duration following return to power operation from the current outage.
11 In addition, SCE has instructed its station personnel on procedural steps to be followed when changing lamps.
The procedural steps currently in effect at San Onofre Unit l for relamping the indicating push button switches address the potential for shorting or for inadvertently actuating the control circuit *a~
follows:
111. Containment Isolation Valves on Non-essential Systems All automatic containment isolat.ion valves are included in this category.
When replacement of a burned out lamp is necessary, the power supply of the circuit of the valve wil1 be opened *and the associated valve will close if open or will be de-energized in the closed position if already closed.
The burned out lamp will be replaced and the power supply to the circuit will be closed permitting the valve to be reopened or re-energi'zed in the closed position.
- 2.
Remote Manual Containment Isolation.Valves on Essential Systems The systems in this category include.the Chemical Volume and Control Letdown System, Reactor Coolant Pump Seal Water Return System, Turbin.e Pl ant Coo 1 ing Water Supply and Return System, and Press.uri zer Re 1 i ef
IEC No. 81-01
. January 23, 1981 Page 3 of 4 Tank Nitrogen Supply System.
The containment isolation valves on these systems are normally open during operation and may be required to.be open during acc.i dent conditions. *
- If it ;s* necessary to rep 1 ace burned out 1 amps after the meta 11 i c, plunger has.been redesigned as described in corrective action 1 above, the following. steps wi 11 be taken:
- 1. *.
The touch p 1 ate with the burned out lamp wi 11 be removed and 1 amps replaced.
- 2.
The g*.lass cover on the. HFA relay (panels behi~dnorth veritical.
. board) associated with the va 1 ve in question wn 1 be removed and
- the relay held in place by depressing the insulated portion of the spring loaded relay plunger.
- 3.
- The touch plate* with the replaced lamps will be inserted into the switch chassis.
- 4.
The 11open 11 switch of the valve in question will be depressed to
. assure that the circuit has been reset and the glass cover
. replaced on the HFA relay. II
. "If it is necessary to rep lace burned out 1 amps before the meta 11 i c p 1 un-ger is redesigned, the replacement will be performed during an outage of sufficient duration when the affected system and valve can be removed from
. service *. *At that time, the procedural steps to be.followed are identical to those established for the automatic containment isolation valves on non..
essential systems discussed above.
Until such time as the lamp* can be re-
. placed,. the position of the affected valve can be* determined by examining the system flow, pressure and temperature process instrumentation."
Recommended Actions for Holders of Construction Permits or Operating Licenses:
I
- 1. ! Determine whether your facility uses the subject Series 2 indicating push-button switches in any safety-related function.
If there are no indicating pushbutton switches of this type in your facility, you need not pursue this matter further.
- 2.
If the subject switches are used* to perform safety-related functions at your facilityt either replace them with qualified units or modify them to
- eliminate the deficiencies. Holders of operating licenses should take the appropriate action as soon as practical;. construction permit holders should take the appropriate *action prior to startup. (If the switches are to be modified, contact Honeywell Incorporated for assistance.)
- 3.
Until the appropriate corrective action is completed, the following interim measures should be taken:
...lEC No. 81-01 January 23, 1981 Page 4 of 4.
- a.
lf the desi-gn of the affected equipment permits its.switch assembly to *
- be deenergi zed for rel amping, verify that.the procedures
- speti fy that power is to. be removed from the switch assembly during rel amping.
If the procedures do not so specify, revise them to include: such a provision.
- b. *
- If the design of *the affected equipotent does. not permit its* switch assembly to be deenerg.ized for relamping, verify that the operator can determine the status of the affected equipment by alternate means.
Towards this end, implement*procedures to enable the operator to* determine the status of the affected equipment by alternate means
= (e. g~.; acceptable method for inferring the position of a valve could include system flow, pressure, or temperature measurements). If alternate status indication methods are not availab.le, relamping should be deferred until the next outage during which time the affected equipment can be removed from service. However, during the resulting blind time, rigid *administrative controls should be
. implemented to provide the operator with reliable status information.
No written response to this circular is required. If you require additional information with regard to this subject, please *contact the. appropriate NRC Regional Office.
1-
.. - IE Circular 81-01 January 23, 1981 RECENTLY ISSUED IE CIRCULARS Circular No.
Subject 80-25*
Case Histories of Radiography Events 80~24 AECL Teletherapy Unit Malfunctions 80-23 Potential Defects in Beloit Power Systems Emergency Generators 80-22 Confirmation of Employee Qualifications 80-21 Regulation of Refueling Crews 80-20 Changes in Safe-Slab Tank Dimensions 80-19
-Noncompliance with Licensee Requirements 80-18 10 CFR 50.59 Safety Evaluations for Changes to Radioactive Waste Treatment Systems 80-17 Fuel Pin Damage Due to Water Jet from Baffle Plate Corner 80-16 Operational Deficiencies In Rosemount Model 510DU Trip Units And Model 1152 Pressure Transmitters 80-15 Loss of Reactor Coolant Pump Cooling and Natural Circula-tion Cooldown Date of Issue 12/5/80 12/2/80 10/31/80 10/2/80 9/10/80 8/21/80 8/26/80 8/22/80 7/23/80 6/27/80 6/20/80 Issued to All holders of a radiography license All holders of a teletherapy license All holders of a power reactor OL or CP All holders of a power reactor OL or CP All holders of a power reactor OL or CP All holders of a Part 50 or Part 70 Fuel
-Facility License All holders of a medical license All holders of a power reactor OL or CP All holders of a PWR.
power reactor OL or CP All holders of a power reactor OL or CP All holders of a power reactor OL or CP