ML20129B423
| ML20129B423 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 05/29/1985 |
| From: | Dixon O SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| GL-81-12, GL-83-33, GL-85-01, GL-85-1, NUDOCS 8506050222 | |
| Download: ML20129B423 (24) | |
Text
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SOUTH CAROLINA ELECTRIC & GAS COMPANY POST OFFICE 764 CotupolA. SOUTH CARouNA 29218 O. W. Dinow. Ja.
d*,'J"o'l,7',"1,
May 29, 1985 Mr. Harold R. Denton
-Director, Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory.Comnission Washington, D.C.
20555
Subject:
Virgil C. Sunmer Nuclear Station Docket No. 50/395 Operating License Ib. NPF-12 APPEbOIX R REANILLYSIS
Dear Mr. Denton:
On May 4,1984, South Carolina Electric & Gas Cmpany (SCEEG) representatives attended the IWC Regional Apryrvlix R Workshop in Atlanta, Georgia. As a result of infonnation obtained at that Worksing, T4E&G initiated an Appendix R
- reanalysis to assure continued coupliance with the NRC clarifications /interpre-tations of that docment.
SCE&G notified the Staff of its intent to conduct this reanalysis and has kept the Staff informed of progress made during the course of this effort.
j Generic Letters 81-12, 83-33, and draf t 85-01, and other applicable interpretive documents were used~as guidance for the Appendix R reanalysis effort. Enclo-sures to this letter document interim results of that reanalysis.
Any questions you may have concerning this infonnation should ba directed to P;r.
Hal Donnelly or Dr. James Barker at (803) 748-3892.
Very truly yours,
[$
O. W. Dixon, Jr.
HID/OW/mec Enclosure cc:
V. C. Sumner C. A. Price T. C. Nichols, Jr./O. W. Dixon, Jr.
C. L. Ligon (!ERC)
E. H. Crews, Jr.
K. E. Nodland E. C. Roberts R. A. Stough W. A. Williams, Jr.
G. O. Percival J. Nelson Grace C. W. Hehl D. A. Natanan J. B. Knota,,Tr.
O. S. Bradhan NPCF fL'*
Group Managers File 15.1360 8506050222 8505EPP PDR ADOCK 05000395 F
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'b Report on Appendix R 1
Reanalysis'for. Virgil C. Summer: Nuclear Station May128, 1985
,o k,
f Enclosure to Letter From:
Mr. O. W.
Dixo n Vice President Nuclear Operations, SCE&G TO:
Mr. Harold R.
De nton Director, Office of Nuclear Reactor Regulation
!sar s:
s, IR;portz onTAppendix R for, May 28, 1985 DVirgil C. Summer < Nuclear Station
' INTRODUCTION f
Thefrecent NRC. int'erpretations on acceptable criteria, assump-ttions,'and methodologies to be utilized in the course of.a
~10CFR50,-Appendix R fire hazards-analysis have caused SCE&G to
- conduct-a. reanalysis for virgil C. Smmmer Nuclear Station.
The original analysis method was-to assess the relative probability of specific types of: fire damage,.e.g., cable to cable hot shorts and dismiss cn a generic basis those types deemed to be of an insignificant hazard.
The new-analysis, as suggested by NRC Staff
' guidance, expands the realm of-credible. fire failures and defends individual system or equipment impacts for fires in all areas of
- the plant,fparticularly in the area of " Associated Circuits".
.This new approach has several consequences.
First, it requires significantly greater resources to complete.an analysis of much greater complexity'and sophistication.
Secondly, the number of systems, pieces of. equipment, and cables which must be analyzed,
- physically located 'in the plant and verified to possess adequate
- fire protection separation is greatly increased.
SCE&G has attempted to counteract this large increase in the safe shutdown
~
equipment / cable lists by the careful and proper use of post fire operator actions as a substitute for intrusive plant backfits.
4 Thisihas not been achievable in'all cases.- The third consequence of this new.ap' roach is the inevitable increase in deviations and p
- plant modifications.
MODIFICATIONS As a result of the SCEEG reanalysis in progress which documents lthe extent of compliance with Sections G, J, and O of Appendix R, s
soveral' cases were identified where modifications are proposed to resolve Associated Circuits of Concern issues and enhance compli-
- ance to Appendix R, requirements.
'The proposed modifications fall intofroughly three categories.
The first category consists of modifications that.are proposed to prevent' and/or mitigate spurious equipment operation caused by fireYinduced conductor *to~ conductor or' cable to cable faults.
The
- originalJfire hazards analysis did not consider these types of low
- probability; fire damage as credible in the context of safe
' shutdown equipment / cable' selection.
Category two contains modifications that are proposed to facilitate or enhance local i
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. R port on' Appendix RLfor' May 28,L 1985'
! Virgil-C.fSummer Nuclear Station J
. operator, actions.
In order to-isolate potential fire-damage, so that plant. operators can manipulate equipment-' locally,
- modifications;are proposed to reduce the need for post fire repairs-orsjumper. procedures 1to. cold shutdown iquipment.
The third category of; modifications resolve additional Associated
' Circuits'of Concern issues which were~ identified during the course
'of.the fire hazards analysis.
These. proposed modifications have been identified' as follows:-
l '.
' Auxiliary Spray l Cable.
f 2..
Steam: Generator. Power-Operated Relief Valves
,3.
.~ Excess Letdown ' Isolation Valves:
4 '. - Main SteamcIsolati~on'and Bypass Valves-5.
- Pressurizer' Power. Operated Relief. Valves Diesel Generator Control 1 Transfer Switch ^
6.
J
- 7.-
- Control-TransfertSwitches >
c
(.
8.-
CurrentlTransformer: Protection 9.
-Reacto'rJCoolant Temperature 1 Instruments 110. Power-Cable Tray Separation
- 11. SourceLRange Nuclear Instruments 12.JEmergency. Lighting They are described in. detail:in Section-I.
1The modifications-have been reviewed with respect to.a schedule of implementation.
Several of the modifications require that the plant be-off-line and therefore need to be scheduled.during outage periods.- The first suchToutage is the second. refueling. outage, scheduled'for the fall'of-1985.
The short lead Ltime to this outage'along with;the.need for.a' controlled approach _to assure-plant reliability and safe operation'have placed engineering-and'
' procurement. constraints'that preclude completion of most off-line Lrelated work during_this' refueling outage.
SCE&G therefore will-s s
attempt-to' complete all' work'by the end of the third refueling i
outage,. scheduled for the spring of 19_87.
Non-outage work will.be
. scheduled in a timely fashion.between now and the third ~ refueling outage._ Outage:related work will progress as far as possible
-subject _to constraints imposed by adherence to technical
.i specifications and will be.-completed as'quickly as possible taking
/ advantage of any-forced: outages of sufficient duration.'
+
-SCE&G believes thatLthe actions described.in Section I will Eprovide a high. degree of confidence that no adverseTeffects will occur.during the_ implementation period.
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MRepdrtion Appendix.R for.
May 28, 1985 Virgil lC.' Summer Nuclear Station Kh LDEVIATIONS F
~As"a resultf of the SCEEG reanalysis: currently in progress documentingithe degree'of compliance with Sections-G, J, and O of h.
- Appendix-R,'as recently clarified, three deviations were
' identified relating; to Associated Circuits of Concer n.
- .They are' identified as-follows
11., cFire Area AB-1, Deviation to III.G.2 Separation and Automatic Suppression Requirements
' 2... Fire Area IB-25,' Deviation to III.G.2 Separation Requirements 3.
LFireEArea~MH-2, Deviation to III.G.2: Separation = Requirements-L They-are described in detail in Section II.
NOTIFICAT* 1S.
'Iffsigni__
nt changes, occur during ' completion of the fire hazards
-; analysis,JSCEEG'will submit a revised list of plant modifications-and deviations along with a schedule for completion of 'all the.
proposed backfits... Additional modifications may be identified'or L
- changes to
- the' present proposed modification list. may be made as
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more effective alternatives are. identified.
Any problems which would ~ inpact. completion of the proposed modifications by - the end Lof ;thef third refueling outage will be communicated.to the
' Staff.
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y SECTION I MODIFICATIONS b
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import on-Appendix R for-ley 28, -1985
? Virgil C. Sunener mclear Station
Title:
. Auxiliary @ ray' Cable.
==
Description:==
1 Spurious operation of the Auxiliary Spray Valve (XVf-8145-CS) could occur for-several fire areas due to a hot short to the valve solenoid control cable.
- Opening of this valve with a charging punp operating would result in inadvertent '
primary plant de-prescurization.
Proposed Modification:-
A) It is proposed that the control cables for the' Auxiliary spray valve be provided with cable which includes.a grounded shield (with sufficient short circuit capacity) from the Control Roczn to the valve,.thereby preventing the
+ possibility of an external hot short.
B)1'Do prevent spurious aperation from a Control Room fire, a second control power disconnect, downstream from the Control Room disconnect is proposed.
~pustification for Continued Operation:
Hot shorts, while extremely unlikely, must be considered during a fire hazards-analysis per'leC Staff guidance.. Autcnatic fire detection is provided for all.
. fire areas of concern; automatic s@pression is provided in areas with higher fire loading. Fires will'be detected during their early. stage and automatically or manually s@ pre ned before the postulated hot shorts can occur. Wese features provide an adequate level of protection until the proposed modification can be ccupleted.
- continued plant operation until coupletion of the proposed modification presents no additional hazards because:
A. : he purpose of the second electrical disconnect is to provide a means 'of-achieving valve solenoid electrical isolation should the control room isola-Ltion point not be available..We only way in which this could occur is to have a major fire start in the continuously manned control room and develop with such rapidity that physical' access was inpossible. Such a fire in the intervening period is not credible..
B.
A post fire control wire cutting procedure is being develcped which-is functionally equivalent to the proposed second electrical disconnect.
C.
We purpose of the ground shield is to prevent very low probability fire
, induced faults from occurring, namely contact of one control conductor with a hot conductor in a second cable plus a second contact or ground for a' current return path.
D.. Neither of.the above modifications are required unless a CVCS punp is running and post-fire punp~ trip capability presently exists.
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. Report on 4pendix.R for May 28, 1985 Virgil C. Summer Itx: lear Station Titlet:. Steam Generator Pom Cperated Relief Valves
==
Description:==
= Spurious opening of the steam generator power operated relief valves
~
(IPV-2000-es, IPV-2010-46, IPV-2020-M5) via a postulated hot short to the control cables for either of two control solenoids for each valve causes excessive cooldown and_RCS shrinkage.
PrW Modification:
- A) ~ It is proposed that the control cables for the critical solenoids of the steam'PORVs.be provided with cable which includes a grounded shield (with sufficient short circuit capacity) from the Control Room to the valve, and
. control power disconnects are to be identified within the Control Ibom.
B) To prevent spurious operation from a Control Room fire which would preclude access to the control room disconnect, a second power disconnect,. downstream
- fram the Control Rom disconnect is proposed.
@sti_ffcati_gifor__ Continued Operation _:
Automatic fire detection is provided for all fire areas of concern, automatic sgpression is provided 'in areas with higher fire loading. Fires coule be detected during their early stage and automatically or manually stppressed before the postulated hot shorts can occur.
Continued plant operation 'until the above modifications are completed presents
-no undue risk because:
A. - We purpose of the second electrical disecin:sct is to provide a means of achieving valve solenoid electrical isolation should the control room isola-tion point not be available. We only way in which this could occur is to have a major fire start in the continuously manned control room and develop
.with such rqidity that physical access was inpossible. Such a fire in the
~
intervening period is not credible'.
' A post fire control wire cutting procedure has been developed which is B.
functionally equivalent to the pragmed second ~ electrical disconnect.
-C.
We purpose of the ground shield is.to prevent very low probability fire
-induced faults from occurring, namely contact of one control conductor with a hot conductor. in a second cable plus.a second contact or ground for a
_ current return path..
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y Jo' my 28,1985 Report on Appendix R for Virgil C. Summer Wclear Station i'
Ti,tle: Eress Letdown Isolation Valves
==
Description:==
For a fire in the Control Rom, or Relay Room or Spreading Roms, it is postulated that a hot short could spuriously operate both of the emess letdown isolation valves (XVT-8153-CS, XVT-8154-CS) causing loss of primary inventory.
Outside of the Control Room, Relay Room, and Spreading Booms, two independent hot shorts are required to be postulated for both valves to open. Since these wives are not pressure boundary valves this is considered incredible.
Proposed _ Modification:
A) It is proposed to idet.tify control power disconnects in the Control Bom and to install control power disconnects in the Cable Spreading Room. This will ensure that the valves can be closed such that the two independent hot shorts would be required to open both valves.
Justification for Continued Operations:
Hot' shorts, while ext renely unlikely, must be considered during a fire hazards analysis per EC Staff guidance. Automatic fire detection is provided for all fire areas of concern; automatic suppression is provided in areas with higher i
fire loading. Fires will be detected during their early stage and automatically or manually suppressed before the postulated hot shorts can occur.
In addition, an interim post-fire operating procedure has been developed which will cut selected control wiring equivalent to the electrical disconnects to be
-installed. The need for this wire cutting is only for a major fire in the Control Rom, as the existing Control Boom fuses provide an acceptable means of electrical isolation. Plant operation in the interim presents no additional risk due to the very low probability of a major fire in the Control Rom in the time rennining prior to installation of the plant modification, combined with the low probability of any fire causing the precise type of damage necessary to cause this type of spurious operation.
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t Report on Appendix ~ R for May 28, 1985 Virgil C. Stener Naclear Station
Title:
Main Steam Isolation and Bypass Valves l
Descqiptig1:
. Spurious operation of the main steam isolation and bypass valves (XVM-2801A,B,C and XVI-2869A,B,C-M) via fire induced hot shorts in various areas could cause loss of secondary inventory.
P_qoposed__Mi_f_i_ca_tipn:
A). It is proposed that-electrical disconnects be identified within the Main Q)ntrol Room and that a seconchry electrical disconnect be installed
.. downstream of the Main Control Room disconnects in a separate fire area.
Once either set of disoonnects is opened two independent hot shorts would have to occur before the valves could spurio2 sly open and this type of fire failure is incredible.
Justification _for_ Continued operations:
Hot shorts, while extranely unlikely, nust be considered during a fire hazards analysis per tRC Staff guidance. Automatic fire detection is provided for all fire areas of concern and automatic suppression is provided in areas with higher fire loading. Fires will be detected during their early stage and automatically.
or manually sippressed before the postulated hot shorts can occur. % ese features provide an adequate level of protection until the proposed modification can be conpleted. In addition, a procedure is in place for cutting wiring which is equivalent to the disconnects which are to be installed. W e need for this wire cutting is only for a major fire in the Control Roan, as the existing Control Room fuses provide an acceptable mans of electrical isolation. Plant operation in the interim presents no additional hazard due to the very low probability of a major fire in the Cbntrol Room in the time remining prior to installation of the plant modification cmbined with the low probability of any fire causing the precise damage necessary to cause this type of spurious operation.
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Report on Appendix R for May 28,1985 Virgil C. Stmner Nuclear Station
Title:
Pressurizer Power Operated Relief Valves Qescqiggon:
Spurious operation of pressurizer power operated relief valves (IPV-444B, IPV-445A, IPV-445B) could occur based on MC guidance which requires consideration of a hot short to the control cable for each valve. m is results in a loss of Primary Inventory.
Proposed Modification _:
A) It is proposed that the cortrol cables for all pressurizer PORVs are to be prcvided with cable which include a grcunded shield (with sufficient short circuit capacity) from the Control Room to the valve, and control power disconnects are to be identified within the Control Rxxn.
B) To prevent spurious operation due to a Control Roan fire which wculd preclude access to the Control Room power disconnect, downstre4un from the Control Room a second control power disconnect is proposed.
qus,Qfi,ca,Qqn,fqq_Qo_n_Qnued _Opeqagon:
Hot shorts, whilr. extremely unlikely, uust be considered during a fire hacards analysis per EC 3taff guidance. Autanatic fire detection is provided for all fire-areas of concern; automatic stppression is provided in areas with higher fire loading. FiresLshN1d be detected during their early stage and attomati-cally or manually suppressed before the postulated hot shorts can occur.
'Iwo of the three valves already have a second control power disconnect point outside of the Control Room located at the Control Roan Evacuation Panel. An interim procedure is in place for post fire wire cutting on the third valve which will be equivalent to the second disconnect point on the other two valves.
We need for this wire cutting is only for a major fire in the Control Room, as the existing Control Room fuses provide an acceptable means of electrical isolation. We lack of contiguous cable shielding during interim plant operation is not significant as the purpose of the cable shielding is to prevent an extremely low probability fire induced fault from occurring, nanely contact of one control conductor with a hot conductor in a second cable plus a second contact or ground for a current return path.
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r Report 'on 4pendix R for m y'28, 1985
)
Virgil C. Sumser teaclear Station
.r
. Title, Diesel Generator Control Transfer Switch Description
. A postulated fire in the Cable spreading Room CB-15 could result in hot shorts-
'Ihis
~ to cables for the Train "B" Diesel Generator-(DCM 29B, DGM 21B, DGM 22B). ~
. prevents' the usef of "B" Train Diesel Generator which 'is the intended power train
'for a fire in the Cable $ reading Room.
Proposed Modification:
A)11t is proposed to relocate two cables (DCM 21B and 22B) outside the fire area.to preclude damages from the postulated fire. Cable DGM 29B is to be isolated by additional contacts fra the existing control transfer switch.
@hstif_i_catipn for_ Continued Operat, ions:
The Cable spreading Rom is protected by an existing full area fire detection system and fixed autmatic stppression' system. : The fire induced, external cable 1 hot shorts which.are required in order to fail the "B" Diesel Generator in this fire area are very unlikely, but nust be~oonsidered during a fire hazards analysis per tsC Staff guidance. An interim operational procedure has been developed which will lift ' control leads in order to isolate this ' postulated fire damage and operate the Diesel Generator locally.. Plant operation until
-installation of the proposed modification presents no additional risk 'as the -
operational procedure is functionally equivalent to the proposed modification.
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1 J'3 Report on appendix R for May 28, 1985 Virgil C. Sunner Nuclear Station
Title:
Control Transfer Switches
==
Description:==
The following equipment is necessary for safe shutdown and is subject to spurious operation due to hot shorts caused by fire dunage.
1 Wis equipment will be modified or junper procedures developed to facilitiate local manual operator action. The decission to junper or nodify this equipnent will be made based on operator safety, system conplexity, and manpower resource limitations.
Prcposed Modification:
A) It is proposed to add control transfer switches and local controls or junper procedures for the following equipment.
Equipment Tag #
Description XPP-43B-CS Charging Punp "B" XPP-45B-SW S.W. Booster Pung "B" XPP-1B-CC
. Couponent Cooling Punp "B" XPP-48B-VU Chilled Miter Punp "B" MFN-97B-AH and Reactor Building Train "B" MFN-97D-AH Cooling Fans XSW-lDB-ES, U4 Switchgear, XSW-lEB Feeder XSW-lDB-ES, U7 Switchgear, XSW-lDBl and XSW-lDB2 Feeder XSW-lEB-ES, U3 Switchgear, XSW-lEB1 Feeder XSW-lDBl-ES 480V Main Breaker XSW-LIB 2-ES.
480V Main Breaker XSW-lEBl-ES 480V Main Breaker XFN-45A-AH Diesel Generator "B" Cooling Fans XFN-45B-AH Diesel Generator "B" Cooling Fans B) It is proposed to nodify the following transfer switches.
Equipment Tag #
Description XPP-39B-SW S.W. Punp "B" XEG-lB-DG Diesel Generator "B" XHX-1B-VU Chiller Unit "B" Justification for Continued Operations:
Because of the inherent design of Virgil C. Suniner Nuclear Sta lon, hot shorts are very unlikely but must be considered during a fire hazards analysis per NRC Staff guidance. Automatic fire detection is provided for all fire areas of concern; suppression is provided in areas with higher fire loading. Fires will be detected during their early stage and autmatically or manually stppressed before the postulated hot shorts can occur. In addition, tenporary Junper Procedures are being develcped for interim action. These junper procedures are functionally equivalent to the proposed nodification. The nodifications are considered desirable as a long term solution since they provide for rapid and safe operation of the equipment when tine or marpower constraints are of concern. These features provide an adequate level of protection until the proposed nodification can be conpleted.
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Report on Appendix R for' May 28, 1985 Virgil C. Stamer Nuclear Station
Title:
Current Transformer Protection
==
Description:==
A postillated fire.in the Control Rom or Cable Spreading Ibm co11d damage a current transformer -(CT) circuit. One possible consequence could be an open
- circuit which in turn could possibly result in a secondary fire at the current transformer (inside switchgear). %is could result in chmage to Train "B" switchgear which is the intended shutdown equipment for a fire in the Control Room or Cable $ reading Roam.
- Prcposed' Modification:
A).It is proposed to protect the Train "B" switchgear equipnent with surge suppressors (thyrite) installed in parallel with the current transformer to
- prevent the over voltage surge which would occur in the event of an open circuit.
Justification for Continued Operations:
.We probability of. a fire causing Train "B" switchgear damage. due to Cr open.
< circuit prior to thyrite instaliation is extranely low because:
A.
We only fire areas where these cables are a problem (i.e., causes failure of redundant equipment) are in the Control acom and Cable Spreading acom.
We likelihood of a significant fire in either of these areas is low because the Control Room is continually manned and the Cable Spreading Rom has full.
area autmatic detection and suppression coverage.
i B.
%is damage will occur only.if one of the two conductors open circuits 1
C
.'without shorting together or to ground..
i C.
Even if an open circuit were to occur, the two conductors are always contained within a single. cable. We resulting voltage surge between the conductors would most likely cause insulation breakdown, arcing and re-welding the conductors prior to causing Cr chmage.
l lD., he plant cts are conservatively designed and most likely could tolerate an open circuit without causing a secondary fire..
E.
Even if'the CT were to became damaged, it would not in all likelihood cause l
l-damage to.the adjacent bus bars to the point where the switchgear would no longer be functional'.
Given the above arguments it has been concluded that continued operation until
. Installation of the Cr overcurrent protective devices presents no additional hazard.~
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%y asport on Appendix R for May 28, 1985 Virgil C. Sumner Nuclear Station
~.
Title:
Reactor Coolant Temperature Instruments naar'ription:
For fires which could potentially disable Train "B" it is' intended to shutdown with control from the Control Room using steam generator ~ "B".
Ioss of Train "B" power presently results in the ultimate loss of the instruments which indicate.
~f Icop "B" TC (ITE-420-BC, ITE-420A-RC).
P_rg2ceed Modification:
A); It is proposed to change Icop "B" Tcold Instrument frcm electrical-Train 'B" to electrical Train "A".
Justification for continued operations: -
' Automatic. fire detection is provided for all fire areas of concern, automatic suppression is provided in areas with higher fire loading. Fires will be Edetected during their early stage and automatically or manually suppressed before the postulated total loss of Train "B" power can occur.
- It'is SCE&G's position that the specific Tcold instrument is not' required in order to verify adequate natural circulation' flow conditions. The -
Steam Generator Pressure Instrument is a much more accurate instrument for this purpose due to the large relative parameter changes of saturated pressure versus
- saturated temperature at hot standby. The NRC Staff has, in published guidance, indicated a strong preference for both T ot and Teold and this capability will h
be achieved via plant backfit. Plant operation in the interim presents no additional risk as there is an operational procedure that~uses Steam Generator Pressure in lieu of Cold Leg Tenperature, is L
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. v os aeport on Appendix R for my 28,1985 Virgil C. Sumner mclear Station
Title:
' Power Cable Tray Separation
==
Description:==
For a postulated fire in the south west corner of elevation 412'-0" of the internediate building, Fire Area IB-25, (near column line intersection 7.5/G.4) cables for required sluipnent of both "A" and "B" Trains could be damaged.
P_ reposed _ Modification:
A) ~It is proposed to wrap the one Train "A" tray (number 3088) throughout this fire area with a fire barrier material which has been tested in a one hour rated configuration.
Justification for Continued Operation:
We fire area has autanatic detection and partial area suppression. An em:eption from providing full area suppression has been previously granted, based tpon the low fire loading. We existing protection, together with the
_ proposed modification, provides reasonable assurance that a fire would be detected and automatically or manually extinguished in its initial stage before significant damage or propagation occurred. We area is open, well lighted, and easily accessible.
In addition this location has been added as a check point for the roving fire watch. This conpensatory action will continue until the modification is canplete.
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- I s Report on 7ppendix R for May 28, 1985 I
' Virgil C. Summer 1ticlear Station
'.Ti,tle: _ - Source Range Nuclear Instrimnents
==
Description:==
For a postulated fire in the north cable chase of the Control Building at the -
L 436'-0" elevation, all three of the available source range nuclear instrtments could be disabled.
Pr@osed_ _ML2dif_ication_:
It is proposed to make one of the following two modifications:
A) Wap the conduit for the cable of one of the nuclear instruments with a fire barrier material which has been tested in a one hour rated configuration.
i B) Install a power source selector switch for one nuclear instrtment (which presently could be disabled by damage to its existing power source cable which passes through the. area).
Justification for Continued Operation:
j The area of concern has automatic detection and stppression. Fires'should be
. detected during their early stage and automatically or manually stppressed before the postulated cable damage can occur.
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In addition this location has been aided as a check point for the roving fire l
watch. This will continue until the modification is ccmplete.
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Report on Appendix R for May 28, 1985
~ Virgil C. Sununer Nuclear Station
Title:
Bnergency Lighting-
==
Description:==
%e explicit consideration of spurious operation has greatly increased the number of pieces of equipment-that are considered necessary for safe shutdown.
We SCE&G approach of. utilizing direct manual operation by personnel in order to reduce modifications to control circuits requires increased plant lighting to provide for access'and adequate operating conditions.
Proposed Modification:
Based upon a plant walkdown of all areas required for operation under the new guidelines, it is proposed to stpplement the existing emergency lighting system with additional eight hour burn time battery operated lights. Wese lights will be of the same character and subject to the same surveillance and control as existing energency lights.
Justification for Continued Operation:
We existing emergency lights. provide adequate coverage for access to most areas of concern including the Control Room, Control Room Evacuation Panels, major switchgear roans and access to the radiation control areas. %e proposed 1stpplemental lighting will enhance the ability to utilize alternate access routes and to provide lighting for valve gallaries which contain ntunerous valves which will be manually verifed or respositioned. SCE&G is confident that in the interim the existing emergency lighting,. supplemented by hand held lighting and
- an existing Central DC Powered Energency Lighting System, will provide adequate -
coverage. We proposed enhancement provides a desirable increase in personnel protection and operational flexibility, but their absence does not preclude the -
safe shutdown of the plant.
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i SECTION II DEVIATIONS
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Report on Appendix R for May 28,1985 Virgil C. ~ Sununer Nuclear Station
Title:
. Fire Area AB-1, Deviation to III.G.2 Separation and Automatic Sippression Area
Description:
Fire Area AB-1 is the entire Auxiliary Building and is ccmprised of 31 separate
-fire zones. m e Auxiliary Building is a multi-level structure with three levels below grade and three above grade. We Auxiliary Building is bound on the north and west by exterior walls; on the east by Fuel Handling, Reactor and Inter-mediate Buildings; and on the south by the Intermediate and Control Buildings.
Tetils are of reinforced concrete except for the top level which is netal siding on steel framing. We walls.which separate-this fire area from other fire areas satisfy the requirements for three hour rated fire tarriers. % e floors are also of reinforced concrete and except for urprotected openings would satisfy the requirements for three hour rated fire attriers. A nore. detailed descrip-tion of this fire area is contained in sect'.on 4.2 of the Fire Protection Evaluation Report.
Affected Safe Shutdown Capability:
Redundant trains for the Chmical Volume Control Systs functions are located in
-this area.
LFire Area Analysis:
Fire Area AB-1 contains redundant trains for the Chmical Volume Control Systs function. Train "B" cables and raceways are located in Fire Zone AB-1.9 on elevation 397'. Redundant Train "A" cables and raceways are located in Fire Zones AB-1.10, AB-1.18 and AB-1.21 on elevations ' 412', 436 ' and 463', respec-tively.. Although redundant trains are s@arated by a vertical distance ranging from 25 to 70 feet, a horizontal separation of 20 feet is not present. A fire detection system is installed throughout the area. Fire stppression is provided by interior manual hose stations and portable extinguishers.
Deviation:
Fire Area AB-1 does not conply with the requirenents in Fection III.G.2 of Appendix R to 10CFR50, in that cable and equipment of one redundant train 'is not enclosed in a fire barrier having a one hour rating and there is no automatic fire stppression system installed in the entire area.
Justification for the Deviation:
he "B" train cable in Fire Zone AB-1.9 is separated from redundant "A" train cables and raceways in Fire Zones AB-1.10,1.18 and 1.19 by one to three
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Report on Appendix R for May 28, 1985 Virgil C. Stamer Nuclear Station
[
l reinforced concrete floors which would satisfy the requirements for three hour rated barriers if not for unprotected openings. Cable trays are provided with f
-fire stops where they penetrate the flooc. Other openings are of a size and location which would not present a significant pathway for the propagation of a fire from one zone to another. In addition to this passive protection, active fire protection is provided by an automatic fire detection system located in each affected fire zone. tJpon actuation, these systems alarm in'the Control Room. This provides a reasonable assurance that a fire would be detected in its initial stage before significant damage or propagation occtr: red. W e fire would then be extinguished using mantal suppression equipment located throughout the fire area.. An exenption from providing automatic fire suppression in these zones was previously granted based upon the low fire loading.
In conclusion, it is SCFAG's position that the existing fire protection features, both active and passive in nature for Fire Area AB-1, provide a level of fire protection consistent with the hazards identified and provide a high level of assurance that at least one train of safe shutdown equipment will i
ranain free of fire damage. We existing fire protection features provide a level of fire protection equivalent to that of III.G.2.
Modifications required to meet III.G.2 would not enhance fire protection safety above that currently l
provided.-
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uw Report on Appendix R for May 28, 1985 Virgil C. Sumer Nuclear Station
Title:
. Fire Area Mif-2, Deviation to III.G.2 Separation Area'_
Description:
' Fire Area Mii-2 is electrical manhole nunber 2 located in the yard approximately 100 feet east of the power block. Manhole 2 is a two conpartment manhole; each conpartment is designated as a separate Fire Zone (MEl-2.1 and Mif-2.2). We Fire Zoms are separated by a 6" concrate wall with a single 4" pipe opening at the base for drainage. Access to the manhole is made by removing a 2' thick con-crete manhole cover.
Affected Safe Shutdown Capability:
Redundant trains for the Service Water Punp House are located in this' area.
Fire Area Analysis:
Fire Arm MEI-2 contains redundant trains for the Service Water Punp House.
Train "A" and "B" cables are located on opposite sides of the 6" concrete
. dividing wall. Cmbustion loading consists of electrical cables; no other conbustibles are present. We substantial manhole cover precludes the entry of transient conbustibles to this area.
.w iation:
Fire Area MH-2 &es not canply with the requirenents in Section III.G.2 of Appendix R to 10CFR50, in that cables of redundant trains are not separated by a fire barrier having a three hour rating.
Justification for,,the_ Deviation:
Redundant trains are separated by a 6" concrete wall which would satisfy the requirements for a three hour rated barrier if not for the unprotected drainage pipe opening. We opening is of a size which would not present a significant pathway for the propagation of fire from one side to the other. In addition, the in situ cmbustible loading is low and entry of transient conbustibles is precluded.
In conclusion, it is SCE&G's position that the existing fire protection features, both active and passive in nature for Fire Area MH-2, provide a level
.of fire protection consistent with the hazards identified and provide a hiyh level of assurance that at least one train of safe shut &wn equipnent will remain free of fire damage. %e existing fire protection features provide a i-level of fire protection equivalent to that of III.G.2. mdifications required to meet III.G.2 would not enhance fire protection safety above that currently provided.
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Report' on Appendix R for h y 28, 1985
_ Virgil C. Summer Nticlear Station
Title:
. Fire Area IB-25, Deviation to III.G.2 Separation Requirenents
- Area
Description:
=
Fire Area IB-25 is the general floor area of the Intermediate Building on elevation 412' and 436' and the east and west penetration access areas. - his area-is caprised of ten separation fire mones.. Walls surrounding this area are of reinforced concrete and satisfy the requirements for three hour rated barriers where they separate this area from other fire areas. Floors and ceilings are also of reinforced concrete but do not satisfy the requirements for a three hour rated barrier due.to uoprotected or protected steel supports with a one hour fire resistance rating. Floor / ceiling openings between elevation 412'-
and 436' are unsealed in order to provide venting in case of a high energy line rtpture. A more detailed description of this fire area is contained in Section 4.4 of. the Fire Protection Evaluation Report.
Affected_ Safe Shutdown Capability:
- Redundant trains for the Service Water Booster Punps are located in this area.
Fire Area Analysis:
- Fire Area IB-25 contains redundant trains for the Service Water Booster Punps.
Train "A" equipment and cables are located in Fire Zone IB-25.1.
Train "B" power and control cables for the Diesel Generator which could cause loss of power to Service mter Booster Punp "B" are located in Fire Zone IB-25.10. Wis
' Fire Zone is an electric cable chase located 12 feet fran the redundant Train "A" saulpment. We chase is constructed of reinforced concrete which would -
satisfy the requirements for a three hour rated fire barrier if not for urprotected HVAC openings. Automatic detection and stppression systems are lomted in this Fire Zone. Automatic detection is also provided in the cable chase..
Deviation:
Fire Area IB-25 does not conply with the requirenents in Section III.G.2 of
- Appendix R to 10CFR50, in that cable and equipment of one redundant train is not enclosed in a fire barrier having a one hour rating.
' 31stification_, font &Deviatio,n_:
% e "B" train cables in Fire Zone IB-25.10 are separated from redundant "A" train cables and equipment in Fire Zone IB-25.1 by a horizontal distance of 12' and by a reinforced concrete wall which would satisfy the requirenents for three hour rated barriers if not for unprotected openings. Openings are of a size and location which would not present a significant pathway for the propagation of a II-4 P
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R@ ort on Appendix R for May 28, 1985 Virgil C. Sumer Nuclear Station
. fire from one zone to another. In addition to this passive protection, active fire protection is provided by an automatic fire detection and suppression system located in Fire Zone IB-25.1.
Automatic detection is provided in the cable chase. Wese systems provide a reasonable assurance that a fire would be detected and controlled in its initial stage before significant damage or propagation occurred.
In conc 1"sion, it is SCE&G's position that the existing fire protection features, both active and passive in nature for Fire Area IB-25, provide a level of fire protection consistent with the hazards identified and provide a high level of assurance that at least one train of safe shutdown equipment will remain free of fire damage. We existing fire protection features provide a level of fire protection equivalent to that of III.G.2.
Modifications required to meet III.G.2 would not enhance fire protection safety above that currently provided.
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