ML19330A389
| ML19330A389 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 06/18/1980 |
| From: | Anderson T WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| To: | |
| References | |
| REF-PT21-80-233-001 NS-TMA-2264, NUDOCS 8007170230 | |
| Download: ML19330A389 (5) | |
Text
ATTAGED IS A PART 21 REPORT FROM IE PAIL lilIT - R021359 E/W PART21IDENTIFICATIONNO.
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COMPANY roe 2d d l l ~ d DAE OF EITER 6//t /P o DOCKET NO.
50 MTE DISTRIBUTED 6[47/7 d ORIGINAL PEPORT SUPPLDEiTARY X DISTRIBUTION:
REACTOR (R)
FUEL CYCE &
SAFEGUARDS (S)
PATERIALS (F0 IE FIES IE FIES AD/ROI (2)
IE FIES AD / SG AD/RCI AD / FFFBI AD / ROI REGIONS PEGIONS REGIONS VENDOR BR R IV VENDOR BR R IV VENDOR BR. R IV,
LDEB / FPA FIB 5715 ttBS / FCFS NR / DDR AE0D fib 7602 L0EB / MPA FIG 5715 M SS / SG SS-881 NRR / DDR (2)
AEOD M8 7602 m / p MB 57E NRR / DPM (2)
CENTRAL FIES 016 AE0D M B 7602 CENTRAL FIES 016 CENTPAL FIES (GRON)
CBURAL FIES 016 CENTPAL FIES (CHR000 PDR CBERAL FIE (GRE PDR LPDR CENTPAL FILES SS -I g
- gpg, LPDR EM ACTION:
PRELIMINARY EVALUATION OF THE ATTACHED REPORT INDICATES LEAD RESPONSIBILITY FOR FOLLOW-UP AS SH0hN BELOW:
-FFMSI THIS DOCUMENT CONTAINS POOR QUAllTY PAGES REV. 6/L3/;
80071702,30 g
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a Westinghouse Water Reactor ww' *w > $5 Electric Corporation Divisions
. gm33 rr., tan F:nsniaxa *523; NS-TMA-2254 June 19, 1980
- m. ' lictor Steilo, Jr.
70 M 3-ooI Cirectcr Office of Insoecti * ' and Enforcement U.S. *iuclear Regul Conn 1ission Washington, D.C.
Dear Mr. Stallo:
In its June 14, 1980 notification to Region III of the NRC Directorate of Regulatory Goerations, the Oc=cnwealth Ediscn Company recorted on
.the T,alfunctioning of a switch important to safety at its Zicn Unit 1
. generating station.
- n conjunction with Commonwealth Ediscn and
'Westinghcuse Switchgear Division, the canufacturer of the switch, the Water React:rs Division of 'Jestinghouse has investigated the nature of the preolem and assessed its safety impact as follows.
i On May 15, 1980, during cerformance of safeguards testing at Zicn 1, a Westinghouse Type W-2 switch was observed to be the cause of the 1A Service Water Pump's f ailure to automatically start on co=and from the Saf4 guards Actuation System.
Although the switch was croperly in the Autcmatic Start (Neutral) position, its contacts, series-connected to safeguards actuation relay contacts, did not provide electrical con-tinuity and thus prevented autcmatic start of the pump.
The pump was s:arted successfully when the switch was positioned to the 1 o' clock Start oosition, a manual coeration.
Scosecuent test's by Commonwealth E' discn on the malfunctioning switch i
identified intermittert contact closure with the switch in the Automatic 5 tart position, ~and resulted in notification to Westinghouse of the problem on June 12, 1980.
Tests on icentical switches frcm spares and i
Mniti ecuicment disclosed two additional. switches with a tendency for -
q internittent contact closure.
All tests were inconclusive however, sirce interT.ittent operation was reither controllable nor eprocucible over an.cxtended period.
In conjunc'.icn with :he Cc=cnwealth Edison Co. 's notification to the NRC on June 14,_.1980 Westinghouse alerted the utility owners of ali Westinghouse operating.olants -hat Zion had exoerienced switch ma:func-tiens and recc= ended i.T. mediate testing of V-2 switches in systems toc *i. ant to safety.
There is a cossioility that the ype W-2 switch is Osed in.safsouards and qco-safecuards a:c;icaticns in other than Westingnouse nucles. facilities, but we are anable to specificai'y identi'y'them.
t l'
k On J ne '.7,1930 the Westingneuse 'WR0 Safety Review Ccmmittee assessed the ceneric imcact Of the current oroblem.
The following were taken
~
intc acccunc durinc tne -eview; (1) switch maifuncticn wouic not have crevented nanual sifeguaros actuation by the ocerators (switen to Star ocsiticn), (2) desicn redundancy allows for a single f ailure, howe',er,
- 2ilure to establish continuity is undetectable until the ecuipment i s called upon to coerate, (2) failure of safeguards ecuicment to actuate is discernable to the coeratcrs, (d) the probien is '4mited to only i
these'W-2 switcnes with spring return to neutral (Auto) cosition.
%estiqcheuse performance recuirements for safeguards systems call for reliable, autcaatic operation anc since it was unable to preclude a grneri: problem sithout a clear uncerstanding of the 'ailure mechanism, tae WR0 Safety.?.eview Committee cenc:cded that the naifunctions consti-Uted a potential substantial safety hazard recortable to the NRC under 10 CFR Par: 21 for coerating olants and a cotential signi'icant defi-ciency under 10 C.:R 50.55f e) for piants under construction.
It also recomnenced (~.) #amec' ate implementation of status tests ecommended on June 14, 1930 of W-2' switches (with spring return to neutral) in systems imoortant c safety at ocerating plants to confirm proper contact closure, (2) continuity tests of these switch contacts immediately
'0'icwing any switch coeration with return to the Automatic Start
).
(neutral) cositi:n from either the Stop cr Start positions.
These
'recemcendatiens are contained in the Westin'chouse Technical Sulletin attached.
This informaticn 's being provided to the uti'ity owners of ali Westinghouse clants.
Power Systems Engineering in the Westinghousc Nuclear Technology Division, in. conjunction with the Westinghcuse Switchgear Division have initiated a program aimed at ident4fying t ni exact nature of the inter-mittent contact operation of the Type W-2 rwitch.
All #indings 2
resulting in either additional or alternate recommendaticns will be forwarded to the NRC and Westinghouse custcr.ars.
?! ease refer any cuestions to Mr. O. H. Rawlins, Manager of Standards and Electrical Systems Evaluation in the Nuclear Safety Decartment.
f6,
T. M. Anderson
~
. Manager _
Nuclear ~ 5af e ty ~ Dep~artment
- WM/TMA/wpc Attachment t
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No.:
NSD-T3-50-9 Jate:
5/13/S0 NSO TECHNICAL BULLETIN I
I(Preliminary infornat co only.
i An iter m advis ry notice of a recent e
- significant echnical development.reouiring irr adiate consideration by Westinghcuse Nuclear Service 6ersonnel.
'Sucplemental 'nstructions and i formation, as accreoriate, to foilcw through normal div'sion and n
decartment crocedures.)
Seriect W-2 Switches (wita sorino return te neutrai)
System's)
Electrical Control S.O.(si 385 Affe::ec 31 ants Ali Sites 1-References Technical Bulle:in NSD-TB-73-Zo '
t i
information:
f
'Ouring monthly ocerational testing cf the safeguarcs system at an opera-ing nuclear plant, intermittent. W-2 switch oceration was dis-coverec in the. neutral (auto) position.
Investigaticns revealed that c
~the intermittent coerition resulted when the switch is returned from
' the eleven or cne o' clock cositions to the neutral (autol ocsition.
l This ~ natter was -recorted to the Nuclear Regulatory Ccamission.
The sw'tch manufacturer (Westinghouse Switchgear Division, Eas:
Pittsburgh, Pa.) is currently. investigating the situation in detail.
Information frcm this investigation will be suoplied to you as soon as it is available.
In the interim, the following action should be taken.
3 i
Recommendeo Action:
i l
Ali piants should tes; all safety-related contacts of the W-2 switches
-(with soring return to neutral position) in-the neutral position.
curthermore, these tests should he repeated folicwing each subsecuent use (removal feca the. neutral cosition) of the switch.
Testing should be done_either at_ normal operating voltage at the centacts, or at least 24 volts OC.
As an alternative to recetitive continuity checks after switch operation, wiring to the existing bre'ker " green light" indicatcr mav be- ~out in series with the neutral cosition
' ~ ~
~
safety-relate'd switch contacts.- (See sketch).
Plant coerators snould
~
toen be aware that " green light" indication may no loncer exist during.
- he 'ack-out (cull-our) position.
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C-reen l'ch; indication will row conf 4 a c:csure of the safety-related switch :50 tacts in the net;;ra: ocsitica.
This " green I'cnt" ndica-i tion srcL'O be chec'<ed af ter saca swi".ch OCeraticn.
~ Jr".nsr Wes-'nghouse recommendations. vill be t=ansmit:id 25 Soon as Urr int inves t# gat ions are cOOD !ere.
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