ML19338D406
| ML19338D406 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 08/15/1980 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Pilant J NEBRASKA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 8009230116 | |
| Download: ML19338D406 (1) | |
Text
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i UNITED STATES CENTRAL' FILES gY)W/r g NUCLEAR REGULATORY. COMMISSION.
PDR:HQ
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" /. c REGION IV
, kAlu '[ I t
all RYAN TLAZA oRIVE, SUITE 1000
- I ARLINGTON, TEXAS 76012 August 15, 1980 Docket No.
50-298 Nebraska Public Power-District ATTN:
J. M. P11 ant, Director Licensing & Quality Assurance Post Office Sox 499 Columbus, Nebraska 68601 Gentle =en:
SUBJECT:
IE BULLETIN NO. 80-19, REVISION 1 - FAILURES OF MERCURY-WETTED MATRIX RELAYS IN REACTOR PROTECTIVE SYSTEMS OF CPERATING NUCLEAR POWER PLANTS DESIGNED 3Y CCMBUSTION ENGINEERING Enclosed is Revision 1 to IE Sulletin No. 80- 19.
The revision cerely 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 NRC in evaluating the value/ impact of each Bulletin on licensees, it would be helpful if you would provide an estinate of the nanpower expended in conduct of the review and preparation of the report (s) required by the Bulletin.
Please estinate separately the nanpower associated with correc-tive actions necessary following identification of problens through the Bulletin.
Should you have any questions regarding the revised Bulletin or act. ions required by you, please contact this office.
Sincerel,
./
f K. V.
Seyfrit /
Director f
Enclosures:
1.
II Bulletin No. 80-19, Revision 1 2.
List of Recently Issued II Bulletins cc:
L. C. Lessor, Superistandent Cooper Nuclear Station Post Office Box 98-Brownv111e, Nebraska 68321 o
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he SNUCLEARtREGULATORYiCOMMISSIONJ 80061900521 f
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1DateFAugust'15, 1980 Page;1 of 2-(FAILURES.0F MERCURY-WETTED MATRIX RELAYS IN REACTOR PROTECTIVE SYSTEMS'.0F:
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- 0PERATING~NUCLEARiPOWER PLANTS' DESIGNED BY1 COMBUSTION ENGINEERING
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- BACKGROUND
.This bulletisiaddresses:theJfailures of mercury-wetted. relays used in the logic' matrix of :the reactorcprotsetive system.(RPS) of-nuclear power-plants :
designed by' Combustion 1 Engineering'(C-E). Exceptlfor! Arkansas-Nuclear One Unit.2;and Palisades ~, bothLof which use; dry-contact matrix relays, the NRC'
~
- understands >that;all-other operating C-E plants use'C.P. Clare Model HG2X-1011-mercury-wetted: matrix relays'in the RPS.
N Mercury-wette' matrix relays manufactured by the Adams and.Westlake Company d
weresinitially used.'in the Palisades plant;' however, because of repeated failures.of;theseirelays, they'were subsequently replaced with relays having dry-contactsj j.GTE,'the manufacturer'of!these dry-contact relays, however, has sinceidiscontinued+ cheir production. Thus, although the' dry-contact relays.
usediat Palisades:have' performed without a-failure since they were installed,.
they are inottavailable ' for 'the other operating. nuclear. power plants designed
.byfC-Ei
-OPERATING [ EXPERIENCES AND EVALUATION:
,i Toidate,foperating. nuclear power plants designed by-C-E have reported. thirty-one1(31) failures of(mercury-wetted relays used in the logic matrix-of-the RPS.
D Most-of,the. reported failures.were:" failed-closed" type ~(i.e.,
the type that
- could;inhibitLa reactor trip),-~andcfour of the reported events involved multi-
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- ple; failures (iie.,jthree relay failures were detected during two tests; two other failuresLwere detected during two different tests).
Because of the-re-2 dun _dancy,within the;RPS, no! reported event would have: prevented a reactor trip;;;however,f;the build-up"of coincident " failed-closed" failures of certain ssets.of selays [could. result in trip failures.for dff-normal events.
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[The $umberl ofi single 'and: multiple relay failures. reported gives rise to two k
' concerns: (1)ithe total" number.of failures yields a-.much higher random failure rate than: that used iniotherirelayf failure -estimates *, and -(2). the number of
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- ~ Other relay; failure : estimates; include (1) WASH-1400, Reactor Safety Study",
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~0NRC kOctober'1975;~'(2)lIEEE:Stdl50.0-1977.,"IEEE Guide to the' Collection and R.
4 Presentation?of. Electrical 2 Electronic! and Sensing Component < Reliability y
WData LforlNuclearjPoweriGenerating Stations", IEEE,1New York;1and -(3) NUREG/
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' # lCR-0942,i Nuclear? Plants Reliability: Data: System, J1978 Annual' Reports of m
LCumulative SystemfandTComponentfReliability":,"NRC.-
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multipleLfailures(detected' suggests 3the'; presence;of'a common-mode; failure.
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-g N mechanismi 3Suchla common-mode failure mechanism could result'in the build-up-Jof:specifice"faile'd-closed"ifailures which,.in turn, could result in antici ;
- ? pated transients"without? scram {ATWS)'. 1Thus',Jthe relatively/high randomD failure : rate;and the suggesud common-modei failure mechanism, l indicate.: that Jplants usingimercury-wetted; matrix relays.in:the RPS-are more susceptible.to-7 iseram failures:than predicted in other studies..
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CACTIONS TO.BE TAKEN;BY HOLDERS OF CONSTRUCTION PERMIIS OR OPERATING LICENSES FOR NUCLEAR POWER 1 FACILITIES:
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. Review lyour facility toidetermine whetheriC.P. Clare Model HG2X-1011
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mercury-wetted relays!are use'd in the logic matrix ofLthe RPS.
If R1 no suchirelays are used, you'shouldcsubmit a. negative-declaration-to this.effecciand you need not respond t'o the remaining l items' in this bulletin. ? Your negativeideclaration shall be submitted to-the. appropriate a
FRCTregional.o'ffice within thirty'(30)idays of the date of this-bulletin
- and a. copy forwarded to the Director, Division of. Reactor Operations-Inspection,! Office'o'f Inspectiorcand Enforcement, NRC,1 Washington, D.!C.;20555.
2.
Licensees lof operating facilities using:the.aboveirelays in the logic.
R1 3' matrix of the RPS.should' increase the; frequency.of<their surveillance- -
R1
. tests. :Until further notice, or until-the mercury-wette'd relays have been jeplaced with qualified relayslof a different design,. surveillance.
W
. testing.of the relaysishall be? initiated withinLten (10) days of:the-date-
~ of this-bulletin'and repeated at-intervals not' exceeding ten (10):dsys'.
. thereafter. _ TheLadditional surveillance.: testing applies.when iop'erability R1 g
ofithe.RPS isirequired by' th'e, Technical Specification. - Upon ; detecting ' ~a R1-
-failed: relay;!:the. failed unit shall1be' replaced with a. qualified dry ~
contact-relay.oria;new mercury-wetted relay.? (The removed. relay shall not T
belreus'edlintthe!RPS.)~
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.3.
Nuclearfpower facilities;which are using or-whose design' includes the use "offthe aboveirelaysfin the logi'c matrix'of:the RPS shall submit either
.R1' 1.their plans;and schedules 1for1 replacing the: mercury-wetted relays with
- qualified lrelaysiofia; different tdesign, or justification for using the mercury-wettedirelays. LResponsesito this item shall.-be' submitted to'the offices flisted' in Item?l,-labove,; within -ninety (90) days of the date of
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- the Loriginaliversion of this bulletin, ' July 30,-1980.~
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~ ;Approvedby[GAO[Bl80225L(R0072)hclearanceexpiresJuly 31, 19.80..
(Application
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- given under a blanket-clearance
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f 1.specificallyffor identified; generic l problems '
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'IE Bulletin No'. 80 19:
~ July _31,;1980
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RECENTLY5ISSUEDLIE! BULLETINS.
(Bulletin: ?SubjectL Date Issuec-
-Issued'To
- No.
180-17; Failure of 76 of 185 7/3/80 All BWR power reactor
- Control Rods to Fully-facilities holding H
Insert lDuring'a' Scram Operating l Licenses (OLs) at~a BWR-or Construction Permit (CP):
Sup. 1 (Failure'of Control Rods 7/18/80
'All~-BWR. power reactor-to 80-17. -to Insert During a Scram facilities holding Operating
.at a'BWR^
Licenses (OLs) or Con-struction Permits (cps)
Sup. 2 Failures Revealed by 7/22/80 All BWR power reactor l-Lto 80-17 : Testing Subsequent to-facilities holding Failure of Control Rods Operating LicensesL(OLs) to' Insert-During a Scram or Construction Permits atia BWR-(cps) 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 b
Line Rupture-80-19
' Failures of-. Mercury-Wettcd 7/31/80 All nuclear power Matrix ~ Relays in Reactor facilities-having-
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Psotective Systems of either an Operating
- l Operating' Nuclear Power License (OL) or a Plants-Designad..by Combus-Construction Permit (CP) tion ~ Engineering 180-20i Failures?of_ Westinghouse 7/31/80 To each nuclear
-Type'W-2 Spring Return power _ facility in
-to Neutral' Control your region having-l' Switches' an Operating' License (OL) or a Construction Permit (CP)
Enclosure t
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