W3P85-0322, Provides Addl Info Re Associated Circuits Analysis of Control Room/Cable Vault Damage Prior to Transfer Isolation, in Response to NRC 841226 Request.Analysis Extended to Include Single Spurious Actuation

Provides Addl Info Re Associated Circuits Analysis of Control Room/Cable Vault Damage Prior to Transfer Isolation, in Response to NRC 841226 Request.Analysis Extended to Include Single Spurious Actuation

ML20106C254
Person / Time
Site:	Waterford
Issue date:	02/07/1985
From:	Cook K LOUISIANA POWER & LIGHT CO.
To:	Knighton G Office of Nuclear Reactor Regulation
References
W3P85-0322, W3P85-322, NUDOCS 8502120198
Download: ML20106C254 (6)

Text

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P O W E R & L i G H T / N.W o%.ANS LouGANA 701744000 . (504)388-934S

$lUTN0Y M February 7, 1985 W3P85-0322 3-A1.01.04 Q-3-P43 A4.05 Director of Nuclear Reactor Regulation s Attention: Mr. G.W. Knighton, Chief Licensing Branch No. 3 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555

SUBJECT:

Waterford SES Unit 3 Docket No. 50-382 Associated Circuits Analysis Analysis of Damage Prior to Transfer /

Isolation of Control Room Circuit

REFERENCES:

1) Letter from G.W. Knighton (NRC) to R.S. Leddick (LP&L),

" Request for Additional Information - Spurious Signal Analysis", dated December 26, 1984

2) Letter W3P85-0062 from K.W. Cook (LP&L) to G.W. Knighton (NRC),

" Associated Circuits Analysis", dated January 10, 1985

3) Letter W3P84-3325 from K.W. Cook (LP&L) to G.W. Knighton (NRC),

" Associated Circuits Analysis" dated November 30, 1984

Dear Sir:

The purpose of this letter is to provide information requested by Reference 1 on the effects of Control Room / Cable Vault (CR/CV) circuit damage prior to transfer / isolation. It is submitted within the 30 day extension of the Reference 1 deadline as requ'sted e by Reference 2.

Our previous analysis of the CR/CV in Reference 3 assumed no damage from a postulated fire occurred prior to transfer / isolation of circuits essential for achieving and maintaining safe shutdown. This analysis has now been extended to include a single spurious actuation prior to transfer / isolation.

Table 1 (attached) lists the hot standby components where the provided alter-nate shutdown control is interrupted due to loss of common power supply from one electrical fault occurring prior to manual isolation of the affected (CR/CV) portion of the circuit. Note that only three essential circuits are susceptible to the blown fused power supplies concern of Reference 1. Damage to the remaining ten alternate shutdown circuits is limited to tripped circuit breakers which can be reset by the operator. Damage prior to transfer / isolation of all other essential control circuits originating from the CR/CV, is not a concern for the remaining components or circuits as they fall into one of the following categories:

8502120198 850207 PDR ADOCK 05000302 P PDR g s

- - _ . . . . . _ . . _ _. .. _- -_ - _ ._.._-.__ _ ___ _m -

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~Mr. G.W. Kn'ghtsu i W3P85-0322 -

i Page ' 2.-

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1.: 1,oss of ' power does not degrade shutdown capability since the desired effect. af ter isolation from the CR/CV is de-energization of the control

circuit..

' 2.; Safe l shutdown capability is not adversely affected by any one spurious '

y actuation (i.e. loss of control power) because redundant circuits exist which are transferred / isolated from CR/CV to continue the safe shutdown process affectively.

3'. -Equipment is' accessible for manual operation.

4. Equipment is required for cold shutdown. Although the power source may

, ;be lost initially, it can be restored before the equipment is required' ,

for service.

E l5. The control power for the piece of equipment is either an ungrounded 120V vital AC-source or an ungrounded 125V DC source. Since only the positive ,

or negative leg of the power source is exposed to the hazards of fire in i a cable, no one electrical fault (i.e. hot short, open circuit..or short

.tol ground) will result in the flow of current intensity capable of

?O interrupting the power supply.

6,. The' power source is entirely.outside of the fire zone, that portion of the circuitry that may be exposed to fire cannot disable the power source

._because it contains either isolation--(electronic logic) or current limiting

• -(dropping; resistor) properties.

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'7. The circuit is normally de-energised with.the power breaker locked in the

open position. '

Proposed hardware changes for the three fused control circuits affected by the concerns of Reference;1 are listed in Table 1.: These changes'are recommended

,in conjunction with modifications resulting from the previously: submitted

~

t: , spurious signal analysis (Reference 3). They'are considered'only preliminary-pending comprehensive review of all architect engineer recommendations by our

' project engineering group.andLanticipated further guidance from the NRC. 'It is

.our understanding based on previous discussions with Auxiliary Systems Branch 4, reviewers, that'an;IE Bulletin addressing the concerns of Reference I will be forthcoming in the near future. ~ Upon issuance of this guidance, we will direct our architect engineer to provide detailed design recommendations consistent'with our schedule for installing station modifications resulting 1from the spurious' signal analysis (i.e' prior to startup following the first refueling outage).-

+

4 We trust that the information provided will-enable you to satisfactorily complete your review of our Associated Circuits Analysis. Should you have

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, .'Mr. G.W. K2ighton

.- 'W3P85-0322

..Page 3 t ,.

further questions regarding this analysis please contact R.J. Murillo, Safety

' and Environmental Licensing Coordinator, at (504) 595-2838.

Very truly yours.

K.W. Cook'

< Nuclear Support & Licensing Manager KWC/KNC/pel Attachment cc: E.L. Blake, W.M. Stevenson, D.M. Crutchfield, J. Wilson, J. Weirmiel, R.D. Martin, G.L. Constable i

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. LOUICIANA PONER & LIGRT CofDANY Tcble 1 MATERFORD SES UNIT NO. 3 Page 1 of 3 ASSOCINFED CIRCUITS ANALYSIS .

CONTROL ROOM /CASLE VAULT ,

, DAMAGE PRIOR TO TRANSFER /ISOLATICII

- MODIFICATIONS-PROPOSED PROPOSED HARDNARE OPERATOR REF., WO/CIS CO N DESCRIPTICNE DK)DIFICATION ' ACTION REMARKS 1/295 Pressuriser Auriliary Spray 120V Vital AC PDP391-SB. Control Station is available CKT #31 on Panel LCP-43 Reset the Circuit Breaker -

2/799, Dry Tower B Isolation Valve 3CC-52033 1207 vital AC PDP391-SB. Isolation Switch will direct CKT #17 Isolation Valve to an open and Bypese valve 3CC-5262B Reset the Circuit position and the bypass Breaker valve to a closed position 3/826 Chillers coolaet Selective 120V Fmergency AC Isolation Switch will Velves - Systema B PDP361-98. CKT #11 automatically select dry 3CC-F273B, 3CC-F2758 Reset the Circuit tower or wet tower as a 3CC-F2775, 3CC-F279B I'*aker source for chiller collant, function of Auxiliary CCW Pump B operation 4/1058 unter Chiller B Bacirculation Install standby Fuey F-1 (33-53) fuse and selector 480V MCC 38311-S. Control Station is available Compt SM on Chiller Control Local switch Select the Standby Panel Fuse with the Selector Switch 5/1079 Switchgear Area A-H Unit Install standby AR-25 (35-53) fuse and selector 480V MCC 35313-S.

Compt SH A local control station is available to start /stop the.

Select the Standby switch unit

, . Fuse with the Selector Switch O

. _ . . _ ~ _ . _ _

IANIISIAMk POWER G LIGBT C00DANY Tcble 1 MATERFORD SES UNIT NO. 3 Pega 2 of 3

• ASSOCIATED CIRCUITS ANALYSIS CONTROL ROOM /CARLE VAULT DAMAGE PRIOR TO TRANSFER / ISOLATION -

.... ..a. MODIFICATIONS I

~

PROPOSED PROPOSED

' HARDWARE OPERATOR ACTION REMARKS REF. WO/CND C00Dnarutas? DESCRIPTION SODIFICATION i

i 6/495 Refueling Water Storage Pool 120V Emergency PDP395-SB. Control Station is available i j Outlet Va. 2SI-L104B CKT #3 on Panel LCP-43

. Reset the Circuit ,

i Breaker i

j - .

7/702 CCW Pump A Beader Isolation 120V Vital AC PDF391-SB. Isolation Switch will j Valves: 3CC-F110&B and CKT #15 direct valves to a closed i 3CC-F114AB Reset the Circuit position j Breaker

)

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l 8/703 CCW Pump B Beader Isolation 120V Vital AC PDP391-SB. Isolation Switch will l Valves: 3CC-F111AR and CKT #15 direct valves to a closed '

i 3CC-F115AB , Reset the Circuit position Breaker j

9/1646 Steam Line 1 Isolation valve 125V DC PDP-3Al-DC-S. -A local control station 2NS-V602A CKT #8 is available for one time  !

Reset the Circuit valve closure operatfaa 'f j Breaker 1

i l

! 10/1661 Steam Line 2 Isolation valve 125V DC PDP-381-DC-S, A local control station 2NS-V6043 CKT #10 is available for one time i

, Reset the Circuit valve closure operation

{ Breaker I

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. IDUISIANA PONE 3 & LIGHT. COMPANY Table 1-WATERFORD SES UNIT NO. 3 Page 3 of 3 ASSOCIATED CIRCUITS ANALYSIS CONTROL ROOM / CABLE VAULT ,

DAMAGE PRIOR TO TRANSFER / ISOLATION RECOfetENDED MODIFICATIONS PROPOSED PROPOSED HARDWARE OPERATOR s

REF. NO/CND COMPONENT DESCRIPTION MODIFICATION ACTION REMARKS 11/2367 Diesel-Generator B Voltage Two 2 Amp fuses No operator's action will Indicator ' proposed for be required in this case installation in series with the -

existing 6 Amp ,

fuses in the blue and red-black wires of Cable 32367A-SB.

The 2 Amp fuses will provide automatic protec-tion for the.6 Amp ,

fuses in case of a short circuit.

12/2388 4kV and 480V Safety Bus B 125V DC PDP-3B-DC-S. Circuit will resume its 2390 Undervoltage Monitoring CKT #28 function automatically Circuit Reset the Circuit by virtue of its cesign Breaker .

13/2409 4kV and 480V Safety Bus AB 125V DC PDP-3AB-DC-S. Circuit will resume its 2411 Undervoltage Monitoring cKT #23 function automatically Circuit Reset the Circuit by virtue of its design Breaker O

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