ML20117M214

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Documents Actions Taken in Response to Safe Shutdown Analysis.Detailed Explanation of Newly Identified Discrepancies for Fire Zones Presented in Attachment a
ML20117M214
Person / Time
Site: Byron  Constellation icon.png
Issue date: 06/12/1996
From: Graesser K
COMMONWEALTH EDISON CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BYRON-96-0175, BYRON-96-175, NUDOCS 9606180269
Download: ML20117M214 (15)
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  • '- Commonw ealth lithon Company

- *- It)ron Generatmg station 4150 North German Church Road II) ton. !!. 610149794 Tel

  • Hli-231516 I June 12,1996 i

1 LTR: Byron 96-0175 FILE: 1.10.0101 i

U.S. Nuclear Regulatory Commission '

Washington, D.C. 20555 ATTENTION: Document Control Desk

SUBJECT:

Byron Station Units 1 & 2 Actions taken in Response to Safe Shutdown Analysis Deficiencies NRC Docket Nos. 50-454 and 50-455

REFERENCE:

6/4/96 Emergency Notification System call regarding identified deficiencies in the Safe Shutdown Analysis

. On 6/4/96, Byron Site Engineering concluded the existing Byron Fire Protection Report (FPR) Safe Shutdown Analysis (SSA) conclusions regarding the availability of Control Room Ventilation (VC) System after a fire in the fire zones 2.1-0,3.28-1, 11.4-0,11.4C-0,11.5-0 and 11.6-0 are incorrect. Detailed reviews performed at

. Byron Station identified that redundant safe shutdown cables from both trains of VC are currently located within the fire zones identified above and are not protected in accordance with the separation requirements of Section Ill.G of 10CFR50 Appendix

! R.

It was determined that the cxisting configuration was not in compliance with the 1,.

requirements of Section Ill.G of 10CFR50 Appendix R and that this condition was reportable per 10CFR 50.72(b)(1)(ii). The Reference ENS phone notification was

made to the NRC on 6/04/96 for a condition outside the design basis for the plant.

Additional details related to these deficiencies were discussed with NRC staff members in conference calls held on June 6 and 7,1996. The purpose of this letter

- is to document the results of those discussions and the results of reviews completed since June 7.

A detailed explanation of these newly identified discrepancies for each of the six (6)

- fire zones is presented in Attachment A. Also included is an evaluation of the specific fire zones, short term compensatory actions, and the planned resolutions for these discrepancies.

9606180269 960612 PDR ADOCK 05000454

.70049

F PDR_ 4 (pT96byRrsS6-0175.docV)61296) (

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' A l'nicom Company

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  • Byron Ltr. 96-0175 June 12,1996 Page 2 l

Compensatory actions in the form of hourly firewatches, procedure verification, l additional controls over transient combustibles and hot work, attemate cooling capability, and shift briefings have been initiated. These actions are presented in zone-specific manner in the Attachment. Additionally, the long term resolutions are detailed in the Attachment. }

Additional vulnerabilities have been identified in one zone. Compensatory measures for this zone have been adjusted accordingly. The affected zone is Fire Zone 11.4-0.

Please address any questions to D. Brindle, Regulatory Assurance Supervisor, at (815) 234-5441 extension 2280.

Respectfully,

. v h K. L. Gr e , r Site Vice esident Byron Nuclear Power Station KLG/DB/rp cc: H. Miller, Administrator Region 111 G. Dick, Project Manager- NRR H. Peterson, Senior Resident inspector - Byron I

(p:\96byttrs/960175. doc 061296)

FIRE ZONE 2.1-0. MAIN CONTROL ROOM:

DescriDtion of fire zonC:

Fire Zone 2.1-0 is located on Auxiliary Building Elevation 451 and includes the Main Control Room (MCR) between row / columns L and P and 13 and 23 as shown on Figure 2.3-8 of the Fire Protection Report (FPR). The fire zone includes both the Unit I and Unit 2 main control panels. This zone is continuously manned by the control room operators. Also, ionization detectors in the supply and exhaust ductwork for the control pancis alarm in the MCR. The zonc contains ionization detcetors which annunciate and alarm in the Main Control Room (MCR). No automatic suppression systems are present in the zone.

ExistinE safe shutdown analysis discussion:

FPR Sections 2.4.2.4 (Unit 1) and 2.4.2.2 (Unit 2) discuss the are shutdown analysis for this zone. Power and/or control cables for redundant safe shutdown equipment ace routed through this zone.

Instrument cables required to verify safe shutdown are also preseciin the zone. The current analysis describes an evaluation to evacuate the MCR due to the fire and to achieve safe shutdown outside of the MCR.

FPR resisions reauired to address current Control Room Ventilation (VC) system evaluations: 1 I

FPR Sections 2.4.2.4 and 2.4.2.2 do not list VC cables. Neither unit discusses the potential loss of both l trains of the VC system due to a fire in this zone. In this zone, new evaluations indicate that both VC Return Fans OA and OB would be disabled, along with redundant dampers such as both VC Supply Fan discharge dampers (0VC033Y, OVC172Y). When these recently identified additional VC safe shutdown components and cables are added to the analysis, both trains of VC become vulnerable to a fire in this l zone. The redundant safe shutdown VC cables are routed to a MCR panel where control switches for l

both VC trains are located. The existing safe shutdown analysis for a fire in this zonc assumes all control

and instrumentation functions are lost and the evacuation of the MCR is required. This evaluation bounds a loss of ventilation in the MCR, except that the loss of VC results in the loss of cooling in the Aux L

Electric Equipment Rooms. This could alTect instrumentation equipment in these rooms which could disable instrumentation indication at the Remote Shutdown Panel. If this should occur, instrumentation

will still be available at the Fire llazards Panels. Existing procedure BOA PRI-5 " Control Room

! Inaccessibility" incorporates utilization of the Fire llazards Panel. FPR Sections 2.4.2.4 (Unit 1) and 2.4.2.2 (Unit 2) require a minor resision to discuss this alternate shutdown capability.

ComDeusatorY actions and lone term resolutions:

The capability to safely shutdown following a fire in zone 2.1-0 is established by the existing evaluations for this zone. The loss of ventilation in the Aux Electric Equipment Rooms does not impact the current procedure (BOA PRI 5) for shutting down outside the MCR. Therefore, no compensatory actions or long term fixes are required.

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FIRE ZONE 3.2B-1. LOWER CABLE SPREADING AREA:

D_gscription of fire zant n

Fire Zone 3.2D-1 is located on Auxiliary Building Elevation 439 and includes a portion of the lower cable spreading area between row / columns L and Q and 10 and 13 as shown on Figure 2.3-9 of the Fire Protection Report (FPR). The fire zone is located in the Unit I area of the Aux Building. The zone contains thermal ionization detectors which annunciate and alarm in the Main Control Room (MCR). j Automatic suppression (total flooding CO2 system) is present in this zone.

Existinn safe shutdown analysis discussion: j 1

FPR Section 2.4.2.8 (Unit 1) discusses the safe shutdown analysis for this zone. The existing analysis states power and/or control cables for only Division 12 are routed through this zone. Instrument cables for both channels of source range neutron monitoring ar. also present in the zone. The existing analysis takes credit for alternate source range monitoring at the Fire Hazards Panel. j l

FPR revisigns required to address current Control Room Ventilation (VC) system evaluations:

FPR Section 2.4.2.8 does not list VC cables. It also does not discuss the potential loss of both trains of the VC system due to a fire in this zone. In this zone, new evaluations indicate that both VC Return Fans OA and OB would be disabled, along with redundant dampers such as both VC Supply Fan discharge dampers (OVC033Y,0VC172Y). When these recently identified additional VC safe shutdown components and cables are added to the analysis, both trains of VC become vulnerable to a fire in this zone. The redundant safe shutdown VC cables are routed in trays / conduits which are separated by a distance of 4 horizontal feet. This occurs at a single point of c'.osest approach near column rows 10 and M where conduits containing Division iI VC cables cross over cable trays containing redundant VC cables. The conclusion that both trains of VC are vulnerable to a fire in this zone will be added to the safe shutdown analyses for this zone. Although fire zone 3.2B 1 contains Division 12 cables, Division 12 power will be available to power the Fire Hazard Panel. Also, the alternate safe shutdown capability discussed below will be added to the FPR sections.

Alternate safe shutdqujLg_apability with the loss of the entire VC system:

Existing safe shutdown analyses for fires in the MCR and the Aux Electric Equipment Rooms bound the consequences of the loss of ventilation in these rooms. FPR Unit 1 Sections 2.4.2.4 & 2.4.2.21 and Unit 2 Sections 2.4.2.2 & 2.4.2.20 currently evaluate the capability to achieve and maintain safe shutdown following a fire occurring in the Main Control Room Fire Zone 2.1-0 and the Aux Electric Equipment Rooms (lire zones 5.5-i&2). The fire in the MCR is assumed to disable control and instrumentation functions and force the evacuation of the MCR. The fire in the Aux Electric Equipment Rooms are assumed to disable redundant control and instrumentation functions. These existing evaluations for fire bound the consequences of the loss of ventilation to the MCR and the Aux Electric Equipment Rooms.

These evaluations assume that instrumentation provided at the Fire Hazards Panel, IPL10J, is available.

The existing criteria for achicsing safe shutdown following a fire in these zones are:

1. Reactor is tripped and control rods inserted is verified prior to evacuation.
2. Pressurizer safety valves provide over-pressure protection for hot standby and the PORV controls can be repaired and restored for later controlled depressurization. PORV block valves can be operated from their respective MCCs.
3. Main Steam Relief valves will be operated locally using the hand hydraulic pumps.

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, 4. Control of essential hot shutdown equipment can be achieve at the Remote Shutdown Panel and locally using DOA PRI-5 " Control Room Inaccessibility"and BOA ELECT-5 " Local Emergency Control of Safe Shutdown Equipment"

5. Essential instrumentation indication is available at the Remote Shutdown and/or Fire llazards Panels.
6. Controls for Rif can be repaired to achieve cold shutdown within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

Safe shutdown in fire zone 3.28-1, if the loss of all VC should occur, will be demonstrated by applying the above criteria with the following verifications:

1. Reactor is tripped and control rods inserted, the consequences of the loss of VC does not occur so fast that this verification cannot be made for a fire in this zone.
2. Pressurizer safety valve function and capability to repair / operate the pressurizer PORVs or its block valves are not impaired as a result of a fire in this zone.
3. Local manual operation of the main steam relief valves using the hand hydraulic pumps .is not impaired as a result of a fire in this zone.
4. Operation of the essential hot shutdown equipment utilizing BOA PRI-5 and DOA ELECT-5 is not impaired as a result of a fire in this zone.
5. Essential instrumentation on the Unit 1 Fire llazard Pancis is available for a fire in this zone since the installation of Thermo-Lag resolution cable re-route modification in May 1996.
6. Capability to repair / operate equipment necessary for residual heat removal is not impaired as j a result of a fire in this zone. j i

Criteria 5 is met since the installation of recent Thermo-lag resolution modifications and due to operating i policies which establish that control of Division 12 switchgcar and miscellaneous equipment room l ventilation systems will be maintained in a " local" control mode. Operation in this mode will prevent fire induced faults from affecting the Division 12 ventilation train.

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Comnensatory actions and lonn term resolutions:

The capability to safely shutdown following a fire in zonc 3.2B-1 that results in the loss of ventilation in the MCR and Aux Electric Equipment Room is established by the bounding evaluations for fire in these rooms. Therefore, no long term fixes are required in this zone.

l This Unit 1 Lower Cable Spreading Area has been made a transient combustible and hot work exclusion I

area. In the event that either transient combustibles must be present or hot work must be performed, a continuous fire watch will be established.

i in this zone, control cables associated with the Unit 1 Division 12 swithgear and miscellaneous equipment room ventilation systems can be damaged by the fire. Byron Ma operates these systems in the " local" control mode which will isolate the cables of concern. Operation will be available at the local panel. Caution cards are placed at the appropriate locations to assure this operating configuration is maintained. The completion of the long term action for this zone discussed below will allow the removal of the caution cards and the reliance on this mode of operation.

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, FIRE ZONE 11.4-0. AUXILIARY BUILDING ELEVATION 3N3 FEET:

Rqsg_iptigo i of fire zone:

Fire Zone L l-0 is located on Auxiliary Building Elevation 383 and includes all of the general open-access arcas between row / columns L and W and 10 and 25 as shi wn on Figure 2.3-13 of the Fire Protection Report (FPR). The fire zonc includes both Unit I and Unit 2 areas of the Aux Building. This zone secs normal foot traffic by site personnel performing activitics in the Auxiliary Building. The zone contains ionization detectors which annunciate and alarm in the Main Control Room (MCR). No automatic suppression systems are present except for automatic sprinklers provided around a stairway at coordinates P-18.

Existinn safe shutdon analysis discussion:

FPR Sections 2.4.2.43 (Unit 1) and 2.4.2.42 (Unit 2) discuss the safe shutdown analysis for this zone.

Power and/or control cables for redundant safe shutdown equipment are routed through this zone.

Instrument cables required to verify safe shutdown are also present in the zone. The existing analysis states Division i1 (Unit 1) and Division 21 (Unit 2) cables will be protected as necessary with fire rated barriers. The existing analysis is currently being resised to reflect re-routing of cables out of the zone to accomplish equivalent protection presiously provided by the Thermo-Lag fire barriers.

FPR revisions reauired to address currgpt Control Room Ventilation (VC) system evaluations:

FPR Section 2.4.2.42 (Unit 2) currently lists the routing unme redundant VC safe shutdown cables in zonc 11.4-0. Unit I does not list VC cables. Neither unit discusses the potential loss of both trains of the VC system due to a fire in this zone. In this zone, new cvaluations indicate that both VC Return Fans OA and OB would be disabled, along with redundant dampers such as both VC Supply Fan discharge dampers (0VC033Y, OVC172Y). When these recotly identified additional VC safe shutdown components and cables are added to the analysis, both trains of VC become vulnerable to a fire in this zone. The redundant safe shutdown VC cables are routed in trays which are separated by a distance of approximately 10 feet.

This occurs at a single point of closest approach near column rows 17 and P. The conclusion that both trains of VC are vulnerable to a fire in this zone will be added to the safe shutdown analyses for this zone.

Also the alternate safe shutdown capability discussed below will be added to the FPR sections.

Alternate safe shutdown capability with the loss of the entire VC system:

Existing safe shutdown analyses for fires in the MCR and the Aux Electric Equipment Rooms bound the consequences of the loss of ventilation in these rooms. FPR Unit 1 Sections 2.4.2.4 & 2.4.2.21 and Unit 2 Sections 2.47.1 & 2.42 20 currently evaluate the npability to achieve and maintain safe shutdown following a i ic (curring it the Main Control Room Firc Zone 2.1-0 and the Aux Electric Equipment Rooms (fire zo; 4 3.5-t&2). The fire in the MCR is assumed to disable control and instrumentation functions and fuce the evacuate.: f the MCR. The fire in the Aux Electric Equipment Rooms are assumed to disable redundant controi Ad instrumentation functions. These existing evaluations for fire bound the consequences of the loss of nntilation to the MCR and the Aux Electric Equipment Rooms. ,

However, these evaluations assume %t instrumentation provided at the Fire Hazards Pancis,1/2PL10J, is (

available. For a fire in this zone, Unit 1 Fire Hazard Panel will be powered from Division 12 as a result of I a Thermo-Lag resolution cable re-route modification installed in May 1996. For a fire in this zonc, Unit 2 Fire Hazard Panel will nu be available because of damage to the Division 22 power systems.

The existing criteria for achiesing safe shutdown following a fire in these zones are:

1 Reactor is tripped and control rods inserted is verified prior to evacuation.

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. 2. Pressurizer safety valves proside over-pressure pretection for hot standby and the PORV l controls can be repaired and restored for later controlled depressurization. PORV block )

valves can be operated from their respective MCCs. I

3. Main 5tcam Relief valves will be operated locally using the hand hydraulic pumps. l
4. Control of essential hot shutdown equipment can be achieve at the Remote Shutdown Panel I and locally using BOA PRI-5 " Control Room inaccessibility"and BOA ELECT-5 "imal j Emergency Control of Safe Shutdown Equipment" j
5. Essential instrumentation indication is available at the Remote Shutdown and/or Fire  !

Hazards Panels.  !

6. Controls for RH can be repaired to achieve cold shutdown within '12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. l Safe sMtdown in fire zone 11.4-0, if the loss of all VC should occur, will be demonstrated by applying the above criteria with the following verifications:
1. Reactor is tripped and control rods inserted; the consequences of the loss of VC does not occur so fast that this verification cannot be made for a fire n this zone.

Pressurizer safety valve function and capability to repair / operate the pressurizer PORVs or  !

2.

its block valves are not impaired as a result of a fire in this zone. l

3. Local manual operation of the main steam relief valves using the hand hydraulic pumps is not impaired as a result of a fire in this zone.
4. Oncration of the essential hot shutdown equipment utilizing BOA T"' 5 and BOA ELECT-5 is not impaired as a result of a fire in this zone.
5. Essential instrumentation on the Unit 1 Fire Hazard Panel is now available for a fire in this ne. For Unit 2, the Division 22 power supply for the Fire Hazard Panel will not bc l available, and therefore the panel will not be available.  !
6. Capability to repair / operate equipment necessary for residual heat removal is not impaired as a result of a fire in this zone.

The ability to safely shut down Unit 1 is demonstrated. However, Criteria 5 would not be met for Unit 2, and the capability to safety shut down that Unit cannot be demonstrated.

Compensatory actions and lone term resolutions:

The capability to safely shut down Unit I following a fire in this zone that results in loss of ventilation in the MCR and AEER is established by the bounding evaluations for fire in these rooms. Therefore, no compensatory actions nor long term fixes are required.

The capability to safely shutdown Unit 2 following a fire in zone 11.4-0 that results in the loss of ventilation in the MCR and Anx Electric Equipment Room, and loss of power to the Fire Hazards Panel will be assured by the following interim compensatory actions, and long term resolutions.

The following interim compensatory actions have been instituted to ensure that a fire severe enough to threaten safe shutdown equipment from both divisions will not occur, and to ensure that the capability to restore safe shutdown functions is available even if such a fire did occur:

1. In the event that the detection system is disabled, a continuous fire watch will be established.
2. Temporary procedures and a temporary alteration are being prepared and materials ordered to allow restoration of one train of the control room ventilation system in a once through purge mode using 100% outside air. These procedures involve opening two dampers in the supply air flowpath, and manually operating a supply fan at the switchgear bus breaker, and opening control room envelope doors to establish a relief flowpath to the turbine building operating deck.

It is estin'ated that these actions can be implemented within 30 minutes of receiving a control 5

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. room ventilation airflow alarm. These actions will restore adequate air flow through the control l

room envelope using outside air. The temporary alteration will be installed no later than 6/21/96.

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i. 3. Training will be provided for all scheduled shifts prior to ass sming their shift responsibilities.
All training of scheduled shifts will occur within one week of the installation of the measures discussed in #2 above.

4, The common area surrounding the cables of concern (redundant VC cables, cables powering Unit 2 Fire Hazards Panc!) has been designated a transient combustible exclusion area with no .

hot work allowed. If transient combustibles are brought in the area or hot work is performed, a continuous fire watch in the zone will be established.

i The following long term actions will be implemented as a long term solution to this problem:

1. A Thermo-lag resolutien cable re-route modification being installed in the upcoming Unit 2
refuel outage (B2R06) in September,1996, will restore this zone to compliance with j Appendix it Upon completion of this modification, the interim compensatory measures will bc discontinued.

i l 2. Also, to insure consistency with Braidwood Unit 2, a modification will be installed to provide l an alternate power source for the Unit 2 Fire Hazards Panel by the Unit 2 refueling outage l B2R07.

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l FIRE 7.ONE 11.4C-0. RADWASTE AND REMOTE SIIUTDOWN CONTROI, ROOM-

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l Rggpiption of fire zone: )

Fire Zone 11.4C-0 is located on Auxiliary Building Elevation 383 and includes the radwaste and the Unit i and 2 remote shutdown control rooms located between row / columns L and P and 23 and 28 as shown on Figure 2.3 13 of the Fire Protection Report (FPR). The fire zone is located in the Unit 2 area of the Aux Building. This zone is normally occupied by an operator who is present at the radwaste control panel. i The zone contains ionization detectors which annunciate and alarm in the Main Control Room (MCR).

No automatic suppression systems are present.

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[ixistinn safe shutdown analysis discusl_og FPR Sections 2.4.2.46 (Unit 1) and 2.4.2.45 (Unit 2) discuss the safe shutdown analysis for this zone.

Control cables for redundant safe shutdown equipment are routed through this zone. Instrument cables required to verify safe shutdown are also present in the zone. The existing analysis states a fire in this zone will render inoperabic controls on the remote shutdown panel and the corresponding controls in the MCR, however, alternate shutdown capability is provided for all controls located on the panel. The existing analysis states that instrumentation located on the remote shutdown panel is isolated from instrumentation at tl.e MCR. It is stated that all instrumentation lost at the remote shutdown panel has either redundant channels of the same instrument or diverse instruments of equivalent information in the MCR or ciscwhere.

EPR revisionU.92nired to add _rgss current Control Room Ventilation (VC) system evaluations:

FPR Section 2.4.2.46 (Unit 1) currently does not list the routing of redundant VC safe shutdown cables brought to the Unit I remote shutdown panel in zone 11.4C-0. The Unit 2 remote shutdown panel does not contain any VC controls or instrumentation. Unit I does not discuss the potential loss of both trains of the VC system due to a fire in this zone. In this zone, new cvaluations indicate that both VC Return Fans OA and OB would be disabled, along with redundant dampers such as both VC Supply Fan discharge dampers (OVC033Y, OVC172Y). When these recently identified additional VC safe shutdown components and cables are added to the analysis, both trains of VC become vulnerable to a nre in this zone. The redundant safe shutdown VC cables are routed in trays / conduits which enter the Unit I remote shutdown panel from the ceiling and floor separated by a metal barrier between train pancis. If the modification discussed below under compensatory actions and long term resolution is installed, loss of redundant VC trains is not possible and no FPR resisions will be required. If the modification is not installed, the conclusion that both trains of VC are vulnerable to a fire in this zone will be added to the safe shutdown analyses for Unit 1. Also the alternate safe shutdown capability discussed in Section 2.4.2.46 will be revised to take credit for the fire hazards panel instead of the MCR instrumentation. The revised alternate safe shutdown capability is discussed below.

A]tgrnate safe shutdown capability with the loss of the entire VC system:

Existing safe shutdown analyses for fires in the MCR and the Aux Electric Equipment Rooms bound the consequences of the loss of ventilation in these rooms. FPR Unit 1 Sections 2.4.2.4 & 2.4.2.21 and Unit 2 Sections 2.4.2.2 & 2.4.2.20 currently evaluate the capability to achieve and maintain safe shutdown following a fire occurring in the Main Control Room Fire Zone 2.1-0 and the Aux Electric Equipment Rooms (fire zones 5.5-l&2). The fire in the MCR is assumed to disable control and instrumentation functions and force the evact.alion of the MCR. The fire in the Aux Electric Equipment Rooms are assumed to disable redemdant control and instrumentation functions. These existing evaluations for fire bound the consequences of the loss of ventilation to the MCR and the Aux Electric Equipment Rooms.

The existing criteria for achicsing safe shutdown following a fire in these zones are:

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1. Reactor is tripped and control rods inserted is verified prior to evacustion.
2. Pressurizer safety valves proside over-pressure protection for hot standby and the PORV controls can be repaired and restored for later controlled depressurization. PORV block valves can be operated from their respective MCCs.
3. Main Steam Relief valves will be operated locally using the hand hydraulic pumps.
4. Control of essential hot shutdown equipment can be achieve at the Remote Shutdown Panel and locally using DOA PRI-5 " Control Room inaccessibility"and BOA ELECT-5 " Local Emergency Control of Safe Shutdown Equipment"
5. Essential instrumentation indication is available at the Remote Shutdown and/or Fire llazards Pancis.
6. Controls for Ril can be repaired to achieve cold shutdown within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

Safe shutdown in fire zonc 11.4C-0, if the loss of all VC should occur, will be demonstrated by applying the above criteria with the following verifications:

1. Reactor is tripped and control rods inserted, the consequences of the loss of VC does not occur so fast that this verification cannot be made for a fire in this zone.
2. Pressurizer safety valve function and capability to repair / operate the pressurizer PORVs or its block valves are not impaired as a result of a fire in this zone.
3. Local manual operation of the main steam relief valves using the hand hydraulic pumps is not impaired as a result of a fire in this zone.
4. Operation of the essential hot shutdown equipment utilizing BOA PRI-5 and BOA ELECT-5 is not impaired as a result of a fire in this zone.
5. Essential instrumentation on the Unit 1&2 Fire llazard Pancis are availabic for a fire in this zonC.
6. Capability to repair / operate equipment necessary for residual heat removal is riot impaired as a result of a fire in this zone.

CpmEn._ sal.ory actions and lonn term resolylip_n.g:

The following interim compensatory actions are being instituted to ensure that the capability to restore safe shutdown functions are available even if a fire should occur.

1. There is currently a set of equipment for local safe shutdown actions in the remote shutdown control room. One additional set of equipment for local safe shutdown actions will be prosided in the Shill Engineers Office by 6/21/96.

! 2. Operating procedure BOA PRI-5 " Control Room inaccessibility," has been resiewed for use at the Fire llazards Panel under the conditions postulated as a result of a fire at the Unit I remote shutdown panel.

No fundamental changes to the procedure were identified. As an enhancement to BOA PRI-5, compensatory measurc #3 below will be implemented to provide a means to make the MCR habitable and to have MCR instrumentation available.

3. Temporary procedures and a temporary alteration are being prepared and materials ordered to allow restoration of one train of the control room ventilation system in a once through purge mode using 100%

outside air, opening two dampers in the supply air flowpath, and manually operating a supply fan at the switchgear bus breaker, and opening contrcl room envelope doors to establish a relief flowpath to the turbine building operating deck. It is estimated that these actions can be implemented within 30 minutes of receiving a control room ventilation airflow alarm. These actions will restore adequate air flow using outside air through the control room envelope. The temporary alteration will be installed at Byron by no later than 6/21/96.

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. ,4. Training will be provided for all scheduled shifts prior to assuming their shift responsibilities. All training of scheduled shifts will occur within one week of the installation of the measures discussed in #3

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For fire zone ll.4C-0, the long term corrective actions have not been determined at this time, and are still ;

being evaluated. Actions being considered include a plant modification to remove one train (as a minimum) of VC from the remote shutdown pancis. Details of this long term action will be provided in the LER associated with this issue.

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FIRE ZONE 11.5-0 AUXII IARY BUII DING El EVATION 401 FEET:

Description of fLrglong.;

Fire Zot.c 11.5-0 is located on Auxiliary Building Elevation 401 and includes all of the general open-access a2cas between row / columns L and W and 10 and 26 as shown on Figure 2.3-12 of the Fire Protection Report (FPR). The fire zone includes both Unit I and Unit 2 areas of the Aux Building. This zonc secs normal foot traffic by site personnel performing activitics in the Auxiliary Building. The zone contains ionization detectors which annunciate and alarm in the Main Control Room (MCR). No automatic suppression systems are present except for automatic sprinklers provided around a stairway at coordinates P-18 and over the waste oil tank at coordinates M-11.

J1xistinn safe shutdown analysis discussion:

FPR Sections 2.4.2.47 (Unit 1) and Section 2.4.2.48 (Unit 2) discuss the safe shutdown analysis for this zone. Power and/or control cables for redundant safe shutdown equipment are routed through this zone.

Instrument cabics required to verify safe shutdown are also present in the zone. The existing analysis states Division i1 (Unit 1) and Division 22 (Unit 2) cables will be protected as necessary with fire rated barriers. The existing analysis takes credit for the Fire llazards Panel for selected instrumentation. The existing analysis is currently being revised to reficct re-routing of cables out of the zonc to accornplish equivalent protection previously provided by the Thermo-Lag fire barriers.

EE.R. resisions Ignuired to address current Control Room Ventilation (VC) ss stem evaluatic:g:

FPR Section 2.4.2.48 (Unit 2) currently lists the routing of some redund;mt VC safe shu'.down cables in zonc 11.5-0 and concludes the Division 11 VC train will be availabic, operated locally. Unit I does not list VC cables. In this zone, new cvaluations indicate that both VC Return Fans OA and OB would be disabled, along with redundant dampers such as both VC Supply Fan discharge dampers (OVC033Y, OVC172Y). When these recently identified additional VC safe shutdown components and cables are added to the analysis, both trains of VC become vulnerable to a fire in this zone. The redundant safe shutdown VC cables are routed in trays / conduits which are separated by a distance of approximately 10 feet. This occurs at a single point of closest approach near column rows 15 and Q. The conclusion that both trains of VC are vulnerable to a fire in this zone will be added to the safe shutdown analyses for this zone. The existing conclusion that Division 11 VC train can be operated locally will be removed Also the alternate safe shutdown capability discussed below will be added to the FPR sections.

t AhgtnateJafe shutdown canability with the loss of the entire VC system:

Existing safe shutdown analyses for fires in the MCR and the Aux Electric Equipment Rooms bound the consequences of the loss of ventilation in these rooms. FPR Unit 1 Sections 2.4.2.4 & 2.4.2.21 and Unit 2 Sections 2.4.2.2 & 2.4.2.20 currently evaluate the capability to achieve and maintain safe shutdown following a fire occurring in the Main Control Room Fire Zone 2.1-0 and the Aux Electric Equipment Rooms (firc zones 5.5-l&2). The fire in the MCR is assumed to disable control and instrumentation functions and force the evacuation of the MCR. The fire in the Aux Electric Equipment Rooms are assumed to disable redundant control and instrumentation functions. These existing evaluations for fire bound the consequences of the loss of ventilation to the MCR and the Aux Electric Equipment Rooms.

Ilowever, these evaluations assume that instrumentation provided at the Fire liazards Panels,1/2PL101, is availabic. For a fire in thiuone, Unit 1 Fire Hazard Panel will be powered from Division 12 as a result of a Thermo-Lag resolution cable re-route modification installed in May 1996. For Unit 2, Division 22 is the protected division, and it remains available. Division 22 cables are protected with Thermo-Lag fire barrict. An hourly fire watch is in place. Modifications to climinate Thermo-Lag are designed and will be installed by 12/96.

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. .The existing criteria for achieving safe shutdown following a fire in these zones are:

1. Reactor is tripped and control rods inserted is verified prior to evacuation.
2. Pressurizer safety valves provide over-pressure protection for hot standby and the PORV controls can be repaired and restored for later controlled depressurization. PORV block valves can be operated from their respective MCCs.
3. Main Steam Relief valves will be operated locally using the hand hydraulic pumps.
4. Control of essential hot shutdown equipment can be achieve at the Reinote Shutdown Panel and locally using DOA PRI 5 " Control Room Inaccessibility"and BOA ELECT-5 " Local Emergency Control of Safe Shutdown Equipment"
5. Essential instrumentation indication is available at the Remote Shutdown andor Fire llazards Panels.
6. Controls for Ril can be repaired to achieve cold shutdown within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

Sgfe shutdown in fire zone 11.5-0, if the loss of all VC should occur, will be demonstrated by applying the above criteria with the following verifications:

1. Reactor is tripped and control rods inserted, the consequences of the loss of VC does not occur so fast that this verification cannot be made for a fire in this zone.
2. Pressurizer safety valve function and capability to repair / operate the pressurizer PORVs or its block valves are not impaired as a result of a fire in this zone.
3. Local manual operation of the main steam relief valves using the hand hydraulic pumps is not impaired as a result of a fire in this zone.
4. Operation of the essential hot shutdown equipment utilizing BOA PRI-5 and BOA ELECT-5 is not impaired as a result of a fire in this zone.
5. Essential instrumentation on the Unit 2 Fire Hazard Panel is available for a fire in this zone.

For Unit 1, the Division 12 power supply for the Fire Hazard Panel is available since the installation of Thermo-Lag resolution cabic re-route modifications in May 1996.

6. Capability to repair / operate equipment necessary for residual heat removal is not impaired as a result of a fire in this zone.

Compensatory actions and lona term resolutions:

The capability to safely shutdown following a fire in zone 11.5-0 that results in the loss of ventilation in

the MCR and Aux Electric Equipment Room is established by the bounding evaluations for fire in these rooms. Therefore, no compensatory actions or long term fixes ::re required other than currently ongoing modifications to resolve the Thermo-Lag fire barrier (GL 92-08) issue.

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  • FIRE ZONE 11.6-0. AUXII,IARY BUII, DING EI.EVATION 426 FEET:

Description of fire 7.one-Fire Zonc 11.6-0 is located on Auxiliary Building Elevation 426 and includes all of the general open-access arcas between row / columns L and V and 11 and 26 as shown on Figure 2.3-10 of the Fire Protection Report (FPR). The fire zone includes both Unit I and Unit 2 areas of the Aux Building. This zonc secs normal foot traffic by site personnel performing activities in the Auxiliary Building. The zone contains ionization detectors which annunciate and alarm in the Main Control Room (MCR). No automatic suppression systems are present except for automatic sprinklers prosided around a stairway at coordinates P-18.

Existina safe shutdown analysis discussion:

FPR Sections 2.4.2.51 (Unit 1) and 2.4.2.52 (Unit 2) discuss the safe shutdown analysis for this zone.

Power and/or control cables for redundant safe shutdown equipment are routed through this zone.

Instrument cables required to verify safe shutdown are also present in the zone. The existing analysis states Division 12 (Unit 1) and Division 22 (Unit 2) cables will be protected as necessary with fire rated barricts. The existing analysis takes credit for the Fire Hazards Panel for selected instrumentation. The existing analysis is currently being revised to reflect re-routing of cables out of the zone to accomplish equivalent protection presiously provided by the Thermo-Lag fire barriers.

FPR revisions recuired to address current Control Room Ventilation (VC) system evaluations:

FPR Section 2.4.2.52 (Unit 2) currently lists the routing of some redundant VC safe shutdown cables in zonc 11.6-0 and concludes the Division 12 VC train will be availabic, operated locally. Unit I does not list VC cables. In this zone, new cvaluations indicate that both VC Return Fans OA and OB would be disabled, along with redundant dampers such as both VC Supply Fan discharge dampers (0VC033Y, OVC172Y). When these recently identified additional VC safe shutdown components and cables are added to the analysis, both trains of VC become vulnerable to a fire in this zone. The redundant safe shutdown VC cables are routed in trays / conduits which are separated by a maximum distance of approximately 10 fect. This occurs at a single point of closest approach near column rows 16 and P. The conclusion that both trains of VC are vulnerable to a fire in this zone will be added to the safe shutdown analyses for this zone. The existing conclusion that Division 12 VC train can be operated locally will be removed Also the alternate safe shutdown capability discussed below will be added to the FPR sections.

Alternate safe shutdown capability with the loss of the entire VC system:

Existing safe shutdown analyses for fires in the MCR and the Aux Electric Equipment Rooms bound the consequences of the loss of ventilation in these rooms. FPR Unit i Sections 2.4.2.4 & 2.4.2.21 and Unit 2 Sections 2.4.2.2 & 2.4.2.20 currently evaluate the capability to achicyc and maintain safe shutdown follewing a fire occurring in the Main Control Room Fire Zone 2.1-0 and the Aux Electric Equipment Rooms (fire zones 5.5-l&2). The fire in the MCR is assumed to disable control and instrumentation functions and force the evacuation of the MCR. The fire in the Aux Electric Equipment Rooms are assumed to disable redundant control and instrumentation functions. These existing evaluations for fire bound the consequences of the loss of ventilation to the MCR and the Aux Electric Equipment Rooms.

The Fire Hazard Pancis remain available for a fire in this zone because Divisions 12 and 22 are protected divisions. Division 22 is protected with Thermo-lag. An hourly fire watch is in place. Modifications to climinate Thermo-Lag are designed and will be installed by 12/96.

The existing criteria for achieving safe shutdown following a fire in these zones are:

1. Reactor is tripped and control rods inserted is verified prior to evacuation.

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  • 2. Pressurizer safety valves provide over-pressure protection for hot standby and the PORV controls can be repaired and restored for later controlled depressurization. PORV block valves can be operated from their respective MCCs.
3. Main Steam Relief valves will be operated locally using the hand hydraulic pumps.
4. Control of essential hot shutdown equipment can be achieve at the Remote Shutdown Panel .,'

and locally using BOA PRI-5 " Control Room Inaccessibility"and BOA ELECT-5 " Local Emergency Control of Safe Shutdown Equipment".

5. Essential instrumentation indication is available at the Remote Shutdown and/or Fire liazards Pancis.
6. Controls for RH can be repaired to achieve cold shutdown within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

Safe shutdown in fire zone 11.6-0, if the loss of all VC should occur, will be demonstrated by applying the above criteria with the following verifications:

1. Reactor is tripped and control rods inserted; the consequences of the loss of VC does not occur so fast that this verification cannot be made for a fire in this zone.

21 Pressurizer safety valve function and capability to repair / operate the pressurizer PORVs or its block valves are not impaired as a result of a fire in this zone.

3. Local manual operation of the main steam relief valves using the hand hydraulic pumps is i not impaired as a result of a fire in this zone.
4. Operation of the essential hot shutdown equipment utilizing BOA PRI-5 and BOA ELECT-3 is not impaired as a result of a fire in this zone.
5. Essential instrumentation on the Unit l&2 Fire llazard Panels are available for a fire in this -l zone.
6. Capability to repair / operate equipment necessary for residual heat removal is not impaired as a result of a fire in this zone.

Comocnsatory actions and long term resolutions:

The capability to safely shutdown following a fire in zone 11.6-0 that results in the loss of ventilation in the MCR and Aux Electric Equipment Room is established by the bounding evaluations for fire in these rooms. Therefore, no compensatory actions or long term fixes are required other than currently ongoing  !

modifications to resolve the Thermo-Lag fire barrict (GL 92-08) issue.

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