ML19338C551
| ML19338C551 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 07/31/1980 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Gerstner W ILLINOIS POWER CO. |
| References | |
| NUDOCS 8008180120 | |
| Download: ML19338C551 (1) | |
Text
b UNITED STATES
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NUCLEAR REGULATORY COMMISSION
,e n
E REGION lil
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799 ROOSEVELT ROAD P
GLEN ELLYN. ILLINOIS 6o137 g*****
o WL 31 880 Docket No. 50-461 Docket No. 50-462 Illinois Power Company ATTN:
Mr. W. C. Gerstner Executive Vice President 500 South 27th Street Decatur, IL 62525 Gentlemen:
Enclosed is IE Bulletin No. 80-20 which requires action by you with regard to your nuclear power facility.
In order to assist the NRC in evaluating the value/ impact of each bulletin on licensees, it would be helpful if you would provide an estimate of the manpower expended in conduct of the review and preparation of the reports required by the bulletin. Please estimate separately the manpower associated with corrective actions necessary following identification of problems through the bulletin.
Should you have any questions regarding this bulletin or the actions required by you, please contact this office.
Sincerely, w b+
ames G. Keppler Director
Enclosure:
IE Bulletin No. 80-20 cc w/ encl:
Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Mr. Dean Hansell, Office of Assistant Attorney General Mr. Gary N. Wright, Chief Division of Nuclear Safety I
SSINS No.: 6820 UNITED STATES Accession No.:
NUCLEAR REGULATORY COMMISSION 8006190023 0FFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 July 31,1980 IE Bulletin No. 80-20 FAILURES OF WESTINGHOUSE TYPE W-2 SPRING RETURN TO NEUTRAL CONTROL SWITCHES By letter dated June 18, 1980, Commonwealth Edison Company submitted Licensee Event Report No. LER 50-295/80-24 to the NRC describing a malfunction of a Westinghouse Type W-2 control switch at the Zion Generating Station, Unit 1.
The malfunctioning switch is a three position spring return to neutral switch.
Although the switch was in its proper neutral position when it malfunctioned, its neutral contacts failed to close properly thereby preventing the automatic start of 1A Service Water Pump.
Subsequent tests conducted on the malfunctioning switch revealed that contact closure was intermittent with the switch in the neutral (or " Auto Start")
position.
Other tests conducted on identical switches from spares and from Unit 2 equipment disclosed two adoitional switches with a tendency for inter-mittent contact closure.
A review of this matter by Westinghouse led to the issuance of NSD Technical Bulletin No. NSD-TB-80-9 to the utility owners of all Westinghouse ooerating plants. The recommendations contained in the Westinghouse technical bulletin include: (i) testing the neutral position contacts of the subject W-2 switches for continuity, and (ii) rewiring of the indicating light circuit to permit the early detection of a neutral contact failure as shown in Figure 1.
Depending on how the indicating light circuit is wired, loss of continuity thru the neutral position contact of a W-2 switch could remain undetected until the equipment associated with the switch were called upon to operate.
Since such a failure would be equiv.nlent to by passing the system associated with the switch, consideration sh9uld ta given to rewiring the switches used in safety-related applications as shown ir. Figure 1.
Such rewiring would provide an acceptable means for detecting contact failure, provided the indicating light is in the control room and readily visible by the operator.
If the indicating light is not so located, consid; ration should be given to annunciating the neut*31 position cont:ct failures at the control room toIn alert the operator of the inoperable rtatus of a safety-related system.
addition, consideration should be given to adding redundant contacts to the W-2 switches or to replacing the W-2 hitches with others having a more posi-tive contact wiping action.
ACTIONS TO BE TAKEN BY LICENSEES AND HOLDERS OF CONSTRUCTION PERMITS:
1.
Determine whether Westinghouse Type W-2 control switches with spring return to neutral pcsition are used in safety-related applications at your facility.
If so, identify the safety-related systems using these
IE Bulletin No. 80-20 July 31, 3"'s0 Page 2 o' ?
V' svitches and the total number of switches so used.
If no such switches are used in your facility, you should indicate that this is the case and ignore the remaining questions.
2.
Licensees of operating plants using Type W-2 spring return to neutral control switches in safety-related applications shall perform continuity tests on all such switches. These tests shall be performed with the switch operator in the neutral position and completed within ten (10) days of the date of this bulletin.
In addition, this continuity test shall be repeated at least every thirty-one (31) days after the initial test and after each manipulation of the switch from its neutral position.
These continuity tests may be discontinued subsequent to implementing the longer term corrective measures described below.
3.
Licensees of operating plants and holders of construction permits shall describe the longer term corrective measures planned and the date by which such measures will be implemented by actual installation or by design cnange, as appropriate.
As a minimum, the longer term corrective measures should include rewiring the indicating light as shown in Figure If 1 provided the light is readily visible to the control room operator.
not, failures of the neutral position contacts should be annunicated in the control room.
A report addressing the above matters, including the number of failures detected during the first series of tests and the safety-related systems involved, shall be submitted to the director of the appropriate NRC regional office within forty-five (45) days of the date of this bulletin.
A copy of the report shall be forwarded to the Director, Division of Reactor Operations Inspection, Office of Inspection and Enforcement, Nuclear Regulatory Commission, Washington, D. C. 20555.
Approved by GAO, B180225 (R0072); clearance expires 7/31/80.
Approval was given under a blanket clearance specifically for identified generic problems.
Enclosure:
Figure 1
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ee, a
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m
EXISTING INDICATING L2GHT C2RCUIT (TYPICAL) i NEUTRAL 4
SWITCH Nf CONTACT INDICATING LIGHT m,
I
/
SAFETY
(->
SIGNAL
(+)
PROPOSED REWIRING OF INDICATING LIGHT CIRCUIT ("!YPICAL)
NEUTRAL-SWITCH
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CONTACT. 7 INDICATING LIGHT up' SAFETY
= = SIGNAL
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(-)
I FIGURE 1:
REWIRING OF INDICATING LIGHT CIRCUIT OF W-2 SWITCHES AS ' REC 0". MENDED BY WESTINGHOUSE TECHNICAL BULLETIN NSD-TB-50
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I' IE Bulletin No. 80-20 Enclosure July 31, 1980 RECENTLY ISSUED IE BULLETINS Belletin Subject Date Issued Issued To No.
80-19 Failures of Mercury-7/31/80 All nuclear power Wetted Matrix Relays in facilities having Reactor Protective Systems either an OL or a CP of Operating Nuclear Power Plants Designed by Combus-tion Engineering 80-18 Maintenance of Adequate 7/24/80 All PWR power reactor Minimum Flow Thru Centrifugal facilities holding OLs Charging Pumps Following and to those PWRs Secondary Side High Energy nearing licensing Line Rupture Supplement 2 Failures Revealed by 7/22/80 All BWR power reactor to 80-17 Testing Subsequent to facilities holding OLs Failure of Control Rods to Insert During a Scram at a BWR Supplement 1 Failure of Control Rods 7/18/80 All BWR power reactor to 80-17 to Insert During a Scram facilities holding OLs at a BWR 80-17 Failure of Control Rods 7/3/80 All BWR power reactor to Insert During a Scram facilities holding OLs at a BWR l
80-16 Potential Misapplication of 6/27/80 All Power Reactor l
Rosemount Inc., Models 1151 Facilities with an and 1152 Pressure Transmitters OL or a CP with Either "A" or "D" Output Codes 80-15 Possible Loss Of Hotline 6/18/80 All nuclear facilities With Loss Of Off-Site Power holding OLs 80-14 Degradation of Scram 6/12/80 All BWR's with an Discharge Volume Capability OL 80-13 Crackin:, In Core Spray 5/12/80 All BWR's with an Spargers OL 80-12 Decay Heat Removal System 5/9/80 Each PWR with an OL Operability
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