ML19331D595
| ML19331D595 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 08/15/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Goodwin C PORTLAND GENERAL ELECTRIC CO. |
| References | |
| NUDOCS 8009030290 | |
| Download: ML19331D595 (1) | |
Text
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UNITED STATES
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s.h).f, f)f',g NUCLEAR REGULATORY COMMISSION
-V t C REGION V 8
1990 N. CALIFORNIA BOULEVARD e.4
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,d SUITE 202, WALNUT CREEK PLAZA e,,,*
WALNUT CREE K, CALIFORNIA 94596 August 15, 1980 Docket tio. 50-344 Portland General Electric Company 121 S.W. Salnon Street Portland, Oregon 97204 Attention: Mr. Charles Goodwin Assistant Vice President Gentlemen:
SUBJECT:
IE BULLETI!! fl0. 80-19, REVISI0fl 1 - FAILURES OF MERCURY-WETTED MATRIX RELAYS Irl REACTOR PROTECTIVE SYSTEMS OF OPERATIfiG fiUCLEAR P01!ER PLAflTS DESIGilED BY COMBUSTI0ft EflGIfiEERIfiG Enclosed is Revision 1 to IE Bulletin tio. 80-19. The revision merely clarifies the areas of concern; therefore, the actions including dates of reports required by you with respect to your nuclear power facility are not changed.
In order to assist the flRC in evaluating the value/ impact of each Bulletin on licensees, it would be helpful if you would provide an estimate of the nanpower expended in conduct of the review and preparation of the report (s) reouired 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 the revised Bulletin or actions required by you, please contact this office.
Sincerely,
/Q
- h. h' gelken.((N8 !
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Jirector
Enclosures:
i 1.
IE Bulletin tio. 80-19 Revision 1 2.
List of Recently Issued IE Bulletins cc w/ enclosures:
F. C. Gaidos, PGE J.11. Lentsch, PGE C. P. Yundt, PGE 8000030 % @
o SSIflS tio. : 6820 UflITED STATES Accession flo.:
flVCLEAR REGULATORY COMMISSI0ff 8006190052 0FFICE OF IflSPECTI0ft AflD ErlFORCEMEllT
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UASHINGT0ft, D.C.
20555 August 15, 1980 IE Bulletin fio. 80-19 Revision 1 FAILURES OF MERCURY-WETTED MATRIX RELAYS IN REACTOR PP.0TECTIVE SYSTEMS OF OPERATIflG flVCLEAR POWER PLAflTS DESIGf!ED BY COMBUSTI0fl ENGIflEERIllG BACKGROUfID:
This bulletin addresses the failures of mercury-wetted relays used in the logic matrix of the reactor protective system (RPS) of nuclear power plants designed by Combustion Engineering (C-E).
Except for Arkansas fluclear One Unit 2 and Palisades, both of which use dry-contact matrix relays, the flRC undet stands that all other operating C-E plants use C.P. Clare Model HG2X-1011 mercury-wetted matrix relays in the RPS.
Mercury-we'ed matrix relays manufactured by the Adams and Westlake Company were init ally used in the Palisades plant; however, because of repeated failures 4 t"~: relays, they were subsequently replaced with relays having dry-contacts. GTE, the manufacturer of these dry-contact relays, however, has since discontinued their production. Thus, although the dry-contact relays used at Palisades have performed without a failure since they were installed, they are not available for the other operating nuclear power plants designed by C-E.
OPERATIllG EXPERIEflCES AflD EVALUATI0ft:
To date, operating nuclear power plants designed by C-E have reported thirty-one (31) failures of mercury-wetted relays used in the logic matrix of the RPS.
Most of the reported failures were " failed-closed" type (i.e., the type that could inhibit a reactor trip), and four of the reported events involved multi-pie failures (i.e., three relay failures were detected during two tests; two other failures were detected during two different tests).
Because of the re-dundancy within the RPS, no reported event would have prevented a reactor trip; however, the build-up of coincident " failed-closed" failures of certain sets of relays could result in trip failures for off-normal events.
The number of single and multiple relay failures reported gives rise to two concerns: (1) the total number of failures yields a much higher random failure rate than that used in other relay failure estimates *, and (2) the number of Other relay failure estimates include (1) WASH-1400, " Reactor Safety Study",
fRC, October 1975; (2) IEEE Std 500-1977,"IEEE Guide to the Collection and Presentation of Electrical, Electronic, and Sensing Component Reliability Data for fluclear Power Generating Stations", IEEE, flew York; and (3) flVREG/
CR-0942, "fluclear Plant Reliability Data System,1978 Annual Reports of Cumulative System and Component Reliability", flRC.
IE Bulletin f:o. 80-19, Revision 1 August 15, 1980 Page 2 of 2 multiole failures detected suggests the presence of a common-mode failure mechanism.
Such a common-mode failure mechanism could result in the build-up of specific " failed-closed" failures which, in turn, could result in antici-pated transients without scram ( ATUS). Thus, the relatively high random failure rate and the suggested common-mode failure mechanism, indicate that plants using mercury-wetted matrix relays in the RPS are more susceptible to scram failures than predicted in other studies.
ACTIOlS TO SE TAKEft BY HOLDERS OF C0flSTRUCTION PERMITS OR OPERATIllG LICE llSES FOR flUCLEAR POWER FACILITIES:
1.
Review your facility to determine whether C.P. Clare Model HG2X-1011 R1 mercury-wetted relays are used in the logic matrix of the RPS.
If R1 no such relays are used, you should submit a negative declaration to this effect and you need not respond to the remaining items in this bulletin. Your negative declaration shall be submitted to the appropriate flRC regional office within thirty (30) days of the date of this bulletin and a copy forwarded to the Director, Division of Reactor Operations Inspection, Office of Inspection and Enforcement, flRC, Washington, D. C. 20555.
2.
Licensees of operating facilities using the above relays in the logic R1 matrix of the RPS should increase the frequency of their surveillance R1 tests. Until further notice, or until the mercury-wetted relays have been replaced with oualified relays of a different design, surveillance testing of the relays shall be initiated within ten (10) days of the date of this bulletin and repeated at intervals not exceeding ten (10) days thereafter. The additional surveillance testing applies when operability R1 of the RPS is required by the Technical Specification.
Upon detecting a R1 failed relay, the failed unit shall be replaced with a qualified dry-contact relay or a new mercury-wetted relay.
(The removed relay shall not be reused in the RPS.)
3.
fluclear power facilities which are using or whose design includes the use of the above relays in the logic matrix of the RPS shall submit either R1 their plans and schedules for replacing the mercury-wetted relays with qualified relays of a different design, or justification for using the mercury-wetted relays.
Responses to this item shall be submitted to the offices listed in Item 1, above, within ninety (90) days of the date of j
the original version of this bulletin, July 30, 1980.
R1 Approved by GAO, B180225 (R0072); clearance expires July 31, 1980.
(Application for renewal pending befnre GA0.) Approval was given under a blanket clearance specifically for identified generic problems.
i
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IE Bulletin flo. 80-19, Revision 1 Enclosure August 15 1980 RECEllTLY ISSUED IE BULLETIf1S Bulletin Subject Date Issued Issued To flo.
80-20 Failures of Westinghouse 7/31/80 To each nuclear Type W-2 Spring Return power facility in to fleutral Control Switches your region having an OL or a CP 80-19 Failures of !!ercury-7/31/80 All nuclear power Wetted Matrix Relays in facilities having Reactor Protective Systems either an OL or a CP of Operating fluclear 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 BUR 80-17 Failure of Control Rods 7/3/80 All BWR power reactor to Ir. sert During a Scram facilities holding OLs at a BWR 80-16 Potential Misapplication of 6/27/80 All Power Reactor Rosemount Inc., Models 1151 Facilities with an anc 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 (I