05000482/LER-1985-057, Responds to NRC 850809 Request for Addl Info Re Cutler- Hammer Type E30 Pushbutton Switches,Per LER 85-057-00 Re 850712 Control Room Ventilation Isolation Signal.Util, Cutler-Hammer,Inc & Bechtel Investigations in Progress

Responds to NRC 850809 Request for Addl Info Re Cutler- Hammer Type E30 Pushbutton Switches,Per LER 85-057-00 Re 850712 Control Room Ventilation Isolation Signal.Util, Cutler-Hammer,Inc & Bechtel Investigations in Progress

ML20137F710
Person / Time
Site:	Wolf Creek
Issue date:	08/12/1985
From:	Koester G KANSAS GAS & ELECTRIC CO.
To:	Denise R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
KMLNRC-85-196, NUDOCS 8508270059
Download: ML20137F710 (5)

LER-2085-057, Responds to NRC 850809 Request for Addl Info Re Cutler- Hammer Type E30 Pushbutton Switches,Per LER 85-057-00 Re 850712 Control Room Ventilation Isolation Signal.Util, Cutler-Hammer,Inc & Bechtel Investigations in Progress

Event date:
Report date:
4822085057R00 - NRC Website

text

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/ KANSAS GAS AND ELECTRIC COMPANY T>4 ELECTRIC CON *PANY l

l i

August 12, 1985 ooa~~t oa=v<a

..c.-.......~ca..

l Mr. R.P. Denise, Director Division of Reactor Safety and Projects p ,apg r, U.S. Nuclear Regulatory Comnission '

t (o L i Region IV ')

611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011 AUG l 61985 -

~~

KMLNRC 85-196 Re: Docket No. 50-482 Ref: KMLNRC 85-195 dated 08/09/85 from Gmoester, KG&E, to RPDenise, NRC Subj: Cutler-Hammer Type E30 Pushbutton Switches

Dear Mr. Denise:

The prpose of this letter is to provide additional information concerning Cutler-Ham er Type E30 pushbutton Pursuantswitches to your request installedofat tblf Creek Generating Station (PEGS) . E August 9, 1985, ainvestigations description of the operational concern regarding and analyses thatand have been or are these switches, plans regarding being performed, interim conpensatory actions, resolution of this concern are herewith provided.

On July 12, 1985, at 1246 hours0.0144 days <br />0.346 hours <br />0.00206 weeks <br />4.74103e-4 months <br /> Central occurred Daylight Time a Control Room as a result of an Vent ilation Isolatbn Signal (CRVIS) electrical " spike" on Control Room intakeequipment radiation monitor G-RE-04.

responded properly All required 4 gineered Safety Features B, and C with the excytion of Control Building dampers G-HZ123 A, Redundant Control which failed to close on the isolation signal.

Building danptrs G-HZ13 A, B, and C did close on the isolation signal, thereby isolating air flow to and from the affected areas.

This event was fully described in Licensee Event Report 85-057-00 transnitted by the reference.

ce A work request was innediately written to investigate The theelectrician failure of Jg these dampers to reposition during the CRVIS.

- o n.

88 investigating this matter determined that monentary contact pshbutton The handswitch G-HIS 123 was not in its normal operating position.

8g pshbutton plunger which is normally flush with The the rearadjusted electrician of the contact blocks was in an extended position.

$$ the alignment of the associated contact blocks at which time the 88 plunger retracted and the affected dampers repositioned since the M

$ isolation signal was still present.

05 The Cutler-Hanmer Type E30 pushbutton switches are conprised of a coa.tn spring return pushbutton with an upper and lower stack operating nl plunger. Up to four (4) single circuit contact blocks (Types KIAland KIA4, and KIA2) or two (2) two circuit contact blocks (Types KIA3, [#{

KIA5) can be stacked behind both the upper and lower stack operating i 1

( Code (316) 261-64:1 201 N. Market ~ Wichita, Kansas - Mail Address: Po. Box 208 i Wichita, Kansas 67201 - Telephone

plungers. Each single circuit contact block contains a pair of contact terminals and rectangular spring return plunger /contactor which is noved by the stack operating plunger in the pshbutton switch (See Attachment). Two circuit contact blocks are identical to the single circuit contact blocks except a longer contact block and two pairs of contact terminals are providM . Two single circuit contact blocks can be utilized in place of a single two circuit contact block. The contact blocks are secured to the pushbutton switch with screws.

Alignment pins are also provided to insure good contact block alignment with virtually no alignment " free play".

While gathering information for Licensee Event Report 85-057-00 further investigation of this matter was deemed warranted. An Engineering Evaluation Request was prepared on July 25, 1985 in order to fully investigate this concern. Two additional switches (GG-HIS 44, AC-HS 181B) were observed by Engineering. Hand !

indicating switch GG-HIS 44, associated with the Fuel Building Heating, Ventilation and Air Conditioning System (HVAC) , was observed to have its plunger /contactor extended beyond the back of the contact block.

Handswitch AC-US 181 B, associated with the Main Turbine System, was also inspected, however, its plunger /contactor was observed to be in  ;

the normal position. All inspected switches utilized two circuit l contact blocks. l GG-HIS 44 was removed to facilitate in-depth examination and was replaced with a pushbutton switch assenbly conposed of single circuit l contact blocks. Although not easily reproducible, the plunger /contactor of a tw circuit contact block did at times remain j in the extended position after its associated pushbutton was released.

The affected contact block was removed from the pushbutton switch assenbly and shipped to Cutler-Haniner for further evaluation.

Preliminary investigation by Cutler-Hanner identified a piece of foreign material near the contacts which may have " bound" the l

plunger /contactor.

{

Subsequently G-HIS 123 was renoved and replaced with a pushbutton switch assenbly conposed of single circuit contact blocks. The

" bound" plunger /contactor condition was repetitively duplicated on l this hand indicating switch. The entire p shbutton switch assenbly l has been shipped to Cutler-Hammer for further evaluation.

As a result of these events and the fact that all observed problems had occurred on switches utilizing the two circuit contact blocks Engineering requested that all safety-related momentary contact Cutler-Hanmer Type E30 pushbuttons switches, including those recently replaced, be inspected to determine the type of contact block assenblies and the "as found" plunger /contactor position. These inspections, which involved approximately 478 switches, were conpleted on August 9, 1985. The information obtained from these inspections is going through a final reconcilation effort to assure overall accuracy. The finalized inspecticn results will be transmitted by separate cover. During the inspections three safety-related pushbutton switches were observed with their plunger /contactors in an extended position (BM-HIS 4A, Steam Generator Blowdown System; GI'-HIS 28,

( .

r i

Containment Air Purification and Cleanup System; EG-HIS 102, Conponent Cooling mter System).

Due to evidence suggesting a possible generic problem and the

potential consequences of a pushbutton switch plunger /contactor failing to return to its normal position Kansas Gas and Electric Company (KG&E) instituted several coupensatory measures, which are described below, to give added assurance that the identified operational concern with these switches would not affect the safe i

operation of 2 1f Creek Generating Station.

i i All safety-related switches of this type will be identified with a small label. Any Operator using one of these switches will

, 11mnediately verify that the plunger /contactor is not extended from the back of the switch. If the Operator cannot practically verify the plunger /contactor position, an electrician will be notified to promptly perform this surveillance. Any switch observed with its plunger /contactor in the extended postion will be identified cc a work request and the Superintendent of Operations will be notified.

In the event of a plant emergency, an electrician shall be notified to report to the Control Room to observe and verify normal switch operation and, with Operator consent, reset any plunger /contactors observed to remain in the extended position. Resetting a switch plunger /contactor involves applying pressure to the end of the plunger /contactor, this restores the switch to normal operation.

,l Additionally a weekly independent inspection of all identified switches will be performed to confirm that all plunger /contactors are in their normal position. The frequency of this independent verification may be adjusted on the basis of information gathered on switch performance. Any pushbuttion switch identified as having a

, plunger /contactor in a " bound" condition will be replaced contingent upon the availability of replacement pushbutton switch assenblies an#or single circuit contact blocks, and appropriate plant conditionc.'

A review of all NCGS Emergency Operating Procedures has identified references to approximately 157 of the potentially affected switches.

An initial review of switch function by Shift Supervisors revealed no

• situation where there would not be adequate time to verify the j plunger /contactor position prior to subsequent usage.

A separate Engineering analysis identified that the preponderance of applications for the affected safety-related switches are valves and HVAC dangers. This engineering analysis has identified all situations where an individual stack plunger /contactor in the " bound" condition

could inhibit an automatic Engineered Safety Features Actuation; whether this would or would not be obvious to the Operator; and whether manual switch actuation resulting in a " bound" l plunger /contactor condition could inhibit subsequent omg=sent -

actuation. The detailed results of this analysis are being verified and will be transmitted by separate cover.

Cutler-Hanmer, KG&E and Bechtel are continuing to investigate this j matter in order to coupletely resolve the operational concerns 1

associated with these switches. However, it is KG&E's position that the coupensatory actions initiated are both thorough and conservative. The aforementioned actions assure the continued safe operation of Wolf Creek Generating Station.

If you have any additional questions concerning this matter, please contact me or Mr. Otto L. Maynard of my staff.

Yours very truly, lenn L. Koester Vice President, NL1 clear GE:olm xc: PO'Connor (2)

JCunnins l

l l

l

Attachment to KMLNRC 85-196 l

i SINGLE CIRCUIT CONTACT BLOCKS (NORMAL POSITION)

FREE FLOATING OPERATING STACK PAIR OF

^

PUSHBUTTONS SPRING LOADED PLUNGER /CONTACTOR AN =c u

J $  ; e N

W.

PUSHBUTTON TWO CIRCUIT <

SWITCH - CONTACT BLOCK (NORMAL POSITION)

• g TWO CIRCUIT CONTACT BLOCK (PLUNGER /CONTACTOR EXTENDED)

1. . .

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