05000400/LER-2002-004

LER-2002-004, Unanalyzed Condition Due to Inadequate Separation of Associated Circuits

Harris Nuclear Plant - Unit 1
Event date:	09-15-2004
Report date:	11-15-2004
Reporting criterion:	10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition
4002002004R05 - NRC Website

I. DESCRIPTION OF EVENT /

The Harris Nuclear Plant (HNP) discovered that a condition exists with the lack of separation of cables for redundant components credited by the Safe Shutdown Analysis (SSA). This condition was discovered on December 20, 2002 and reported in LER 2002-004-00, dated February 18, 2003. Revision 1 to this LER describes another condition, which was discovered on January 29, 2003. Revision 2 to this LER describes another condition, which was discovered on July 23, 2003. Revision 3 to this LER describes another condition, which was discovered on February 13, 2004. Revision 4 to this LER describes additional conditions, which were discovered on August 13, September 14, and September 15, 2004. Revision 5 to this LER describes additional conditions, which were discovered on September 15 and October 4, 2004.

On December 20, 2002, with the Unit in Mode 1 at 100% power, inspection of the Harris Nuclear Plant (HNP) Safe Shutdown Analysis (SSA) in Case of Fire identified that for postulated fires in three SSA fire areas, the design and compensatory actions credited by the SSA would not ensure a protected train of equipment would remain available. Specifically, the inspection identified that postulated fires could cause spurious actuation of components potentially resulting in loss of the Charging/Safety Injection Pump (CSIP) [CB-P] or loss of Reactor Coolant Pump (RCP) [AB-P] seal cooling credited by the SSA. The fires were postulated to cause spurious closure of valves in the flowpaths for the protected CSIP, prior to implementation of the preplanned actions designed to preserve these flowpaths, resulting in loss of the protected CSIP if it was in service at the time of the postulated fire. Similarly, the fires were postulated to cause spurious closure of valves in the flowpath of Component Cooling Water (CCW) [CC] to the RCP thermal barrier heat exchangers, resulting in loss of flow to RCP thermal barrier heat exchangers credited by the SSA for RCP protection.

On January 29, 2003, with the Unit in Mode 1 at 100% power, HNP identified that simultaneous spurious opening of multiple valves could result in transferring of Refueling Water Storage Tank (RWST) [BE-, BP-, & BQ-TK] inventory to the containment recirculation sump. A roving fire watch has been posted in fire areas of concern.

On July 23, 2003, with the Unit in Mode 1 at 100% power, HNP identified that spurious opening of certain valves could result in transferring of RWST inventory to the containment recirculation sump. A roving fire watch was already posted in fire areas of concern as interim compensatory actions for other safe shutdown related issues, and the fire watch remains posted. This discovery of an old design issue was made during validation of the HNP safe shutdown analysis. This validation was being performed as a corrective action to the previously reported conditions.

On February 13, 2004, with the Unit in Mode 1 at 100% power, HNP identified four additional fire areas where spurious actuation of multiple valves could result in loss of the CSIP in service at the time of the postulated fire and in transferring of RWST inventory to the containment recirculation sump. The fire areas of concern are protected by detection and suppression systems, and they are on the path of a roving fire watch already posted as interim compensatory actions for other safe shutdown related issues. The fire watch remains posted. These additional fire areas were inadvertently missed during the investigation for the previously reported conditions (reference December 20, 2002 and July 23, 2003 discoveries). Similar to the previous discoveries, the discovery on February 13, 2004, is an old design issue that was identified during a review of the HNP safe shutdown program. This review and other validations are being performed as corrective actions to the previously reported conditions.

I. DESCRIPTION OF EVENT (Continued) On August 13, September 14, and September 15, 2004, with the Unit in Mode 1 at 100% power, HNP identified that spurious opening of multiple valves could potentially result in the loss of the CSIP in service at the time of the postulated fire. A roving fire watch was already posted in fire areas of concern as interim compensatory actions for other safe shutdown related issues, and the fire watch remains posted. These discoveries are old design issues that were identified during a review of the HNP safe shutdown program.

This review and other validations are being performed as corrective actions to the previously reported conditions.

On September 15, with the Unit in Mode 1 at 100% power, HNP identified that spurious actuation of multiple valves could potentially result in the loss of the CSIP in service at the time of the postulated fire. Additionally, HNP identified that spurious valve opening concurrent with spurious start of a Containment Spray (CT) pump [BE-P] could potentially result in the transfer of the RWST inventory to containment. On October 4, 2004, with the Unit in Mode 1 at 100% power, HNP identified that spurious closure of a certain valve could potentially result in the loss of RCP seal cooling credited by the SSA. Additionally, HNP identified that a postulated fire could result in a loss of indication of both Reactor Coolant System (RCS) wide range pressure transmitters [AB-PT] credited to monitor RCS pressure and level. A roving fire watch was already posted in these fire areas of concern as interim compensatory actions for other safe shutdown related issues, and the fire watch remains posted. These discoveries are old design issues that were identified during a review of the HNP safe shutdown program. This detailed review and other validations are being performed as corrective actions to the previously reported conditions.

These findings of unanalyzed conditions are being reported pursuant to 10 CFR 50.73(a)(2)(ii)(B). No systems, structures, or components were inoperable at the time of discovery that significantly contributed to the event.

The previous four SSA fire areas identified included:

1. 1-A-BAL-B, located in the Reactor Auxiliary Building (RAB) Elevations 261' and 286' 2. 1-A-BAL-C, located in the RAB Elevation 286' 3. 1-A-EPA, located in the RAB Electrical Penetration Room "A" Elevation 261' 4. 1-A-EPB, located in the RAB Electrical Penetration Room "B" Elevation 261' The discdvery on February 13, 2004 identified the following four additional SSA fire areas:

5. 1-A-CSRA, located in the RAB Elevation 286' 6. 1-A-CSRB, located in the RAB Elevation 286' 7. 12-A-CR, located in the RAB Elevation 305' 8. 12-A-CRC1, located in the RAB Elevation 305' I. DESCRIPTION OF EVENT (Continued) The discoveries on August 13, September 14, and September 15, 2004 included new valves in the following five previously identified SSA fire areas:

1. 1-A-BAL-B, located in the Reactor Auxiliary Building (RAB) Elevations 261' and 286' 2. 1-A-BAL-C, located in the RAB Elevation 286' 3. 1-A-EPA, located in the RAB Electrical Penetration Room "A" Elevation 261' 4. 1-A-CSRA, located in the RAB Elevation 286' 5. 1-A-CSRB, located in the RAB Elevation 286' The discoveries on September 15 and October 4, 2004 included new components in the previously identified SSA fire areas 1-A-CSRB, located in the RAB Elevation 286'; and 1-A-BAL-B, located in the RAB Elevations 261' and 286'.

The specific conditions for each of the fire areas identified above or for a combination of the fire areas identified above, as applicable based on the routing of cables for the various components are detailed below.

For a postulated fire in SSA fire areas 1-A-BAL-B or 1-A-EPA (261' elevation), certain cabling [CBL3] for the two outlet valves (1CS-165 or 1CS-166) of the Volume Control Tank (VCT), the CCW supply valve to RCP thermal barriers (1CC-207), the outlet isolation valve (1SI-4) of the Boron Injection Tank (BIT), and the safety injection to the Reactor Coolant System (RCS) isolation valves (1SI-52 and 1SI-107) are not protected from spurious actuation in accordance with the requirements of NUREG 0800, Attachment 1 (Branch Technical Position CMEB 9.5-1) Section C.5.b. Specifically, the control power cables for charging system Motor Operated Valve (MOV) [20] 1CS-165 and CCW system MOV 1CC-207 are routed through SSA fire areas 1- A-BAL-B and 1-A-EPA with no fire barrier. Similarly, the control power cables for safety injection system MOVs 1SI-4, 1SI-52, and 1SI-107 are routed through SSA fire areas 1-A-BAL-B and 1-A-EPA with no fire barrier. In addition, the control power cable for charging system MOV 1CS-166 is unprotected for about one foot above its Motor Control Center (MCC) [MCC] and inside its MCC in SSA fire area 1-A-BAL-B.

Therefore, the unprotected cables for these MOVs are vulnerable to fire-induced hot shorts. The charging system valves are required to remain open to provide CSIP suction from the VCT during a postulated fire in these fire areas. As a result, a fire in any of these areas could result in spurious closure of one of the VCT outlet valves, loss of suction flow to the running CSIP, and subsequent damage to the running CSIP credited by the SSA for charging flow and RCP seal cooling. The CCW system valve is required to remain open to provide CCW flow to RCP thermal barrier heat exchangers. As a result, a postulated fire in this area could result in spurious closure of this valve and loss of flow to RCP thermal barrier heat exchangers credited by the SSA for RCP seal protection. The safety injection system valves are normally closed, so a postulated fire in this area resulting in spurious opening of multiple valves could result in damage to the running CSIP due to run out conditions. Simultaneous spurious actuation of multiple valves in the charging system and the component cooling water system could result in degradation of the RCP seals, possibly leading to an RCP seal loss of coolant accident (LOCA) without credited CSIPs.

I. DESCRIPTION OF EVENT (Continued) For a postulated fire in SSA fire area 1-A-BAL-C (286' elevation), the control power cables for the CCW return valve from RCP thermal barriers (1CC-251) and the CCW supply valve to RCP seals and motor coolers (1CC-208) are not protected from spurious actuation in accordance with the requirements of NUREG 0800, Attachment 1 (Branch Technical Position CMEB 9.5-1) Section C.5.b. Specifically, the control power cables for the CCW system MOVs 1CC-251 and 1CC-208 are routed through SSA fire area 1-A-BAL-C and into their MCC in this area with no fire barrier. Therefore, the unprotected cables for these MOVs are vulnerable to fire-induced hot shorts. The CCW system valves are required to remain open to provide CCW flow to RCP thermal barrier heat exchangers. As a result, a postulated fire in this area could result in spurious closure of these valves and loss of flow to RCP thermal barrier heat exchangers credited by the SSA for RCP seal protection. However, RCP seals would still be protected by the normal seal injection function of the redundant charging/safety injection trains.

For a postulated fire in SSA fire area 1-A-BAL-B (261' elevation), the control power cables for the CSIP suction cross-connect valves (1CS-168 and 1CS-169), the CSIP mini-flow isolation valve (1CS-214), and the CSIP discharge cross-connect valves (1CS-217, 1CS-218, and 1CS-219) are not protected from spurious actuation in accordance with the requirements of NUREG 0800, Attachment 1 (Branch Technical Position CMEB 9.5-1) Section C.5.b. Specifically, the control power cable for charging system MOVs 1CS-168 and 1CS-217 are unprotected inside their MCC in SSA fire area 1-A-BAL-B. The control power cables for charging system MOVs 1CS-169, 1CS-214, 1CS-218, and 1CS-219 are unprotected for about one foot above their MCC and inside their MCC in the same fire area. Therefore, the unprotected cables for these MOVs are vulnerable to fire-induced hot shorts.

MOVS 1CS-168 and 1CS-169 valves are required to remain open to provide CSIP suction during a postulated fire in these fire areas. As a result, a fire in th!s area (1-A-BAL-B, 261' elevation) could result in spurious closure of one of the CSIP suction valves, loss of suction flow to the running CSIP, and subsequent damage to the running CSIP credited by the SSA for charging flow and RCP seal cooling.

MOV 1CS-214 provides mini-flow for the CSIPs. As a result, a fire in this area could result in spurious closure of the mini-flow isolation valve and subsequent loss of mini-flow to the CSIPs. However, this loss of function would be recoverable since the CSIPs would not be damaged. MOVs 1CS-217, 1CS-218, and 1CS-219 are required to remain open to provide charging flow from the running CSIP. As a result, a postulated fire in this area could result in spurious closure of one of the CSIP discharge valves, and subsequent loss of flow to charging or high head safety injection credited by the SSA. However, this loss of function would be recoverable since the CSIPs would not be damaged.

Simultaneous spurious actuation of multiple valves in the charging system (i.e., MOVs 1CS-214, 1CS- 217, 1CS-218, and 1CS-219) could result in loss of mini-flow to the CSIPs and loss of flow to charging or high head safety injection, and subsequent damage to the running CSIP.

Upon discovery, interim compensatory actions were implemented to minimize the impact of the postulated fires. These measures included de-energizing the CSIP suction cross-connect valves to minimize susceptibility to mal-operation of components, and posting a roving fire watch in fire areas of concern.

I. DESCRIPTION OF EVENT (Continued) For a postulated fire in SSA fire areas 1-A-BAL-B or 1-A-BAL-C (286' elevation), certain cabling for eight safety injection MOVs, three MOVs in each area, (1SI-300, 1SI-310, and 1S1-322; or 1S1-301, 1S1-311, and 1SI-323, respectively); and two MOV's in both areas, the outlet isolation valve (1S1-3) of the Boron Injection

• Tank (BIT) and the safety injection to the RCS isolation valve (1S1-86), are not protected from spurious actuation in accordance with the requirements of NUREG 0800, Attachment 1 (Branch Technical Position CMEB 9.5-1) Section C.5.b. Specifically, the control power cables for MOVs 1SI-300, 1SI-310, and 1St-322 are unprotected inside their MCCs in SSA fire area 1-A-BAL-B. Similarly, the control power cables for MOVs 1S1-301, 1S1-311, and 1SI-323 are routed through SSA fire area 1-A-BAL-C and into their MCCs in this area with no fire barrier. In addition, the control power cables for safety injection system MOVs 1S1-3 and 1S1-86 are routed through SSA fire areas 1-A-BAL-B and 1-A-BAL-C with no fire barrier. Therefore, the unprotected cables for these MOVs are vulnerable to fire-induced hot shorts. These valves are required to shut to prevent transfer of inventory from the RWST to the containment recirculation sump. Simultaneous spurious opening of these multiple valves from a fire in either of these areas could result in inadvertently transferring inventory from the RWST to the containment recirculation sump. If this transfer of inventory were to occur, the water normally used for inventory makeup to the Reactor Coolant System (RCS) would not be available from a suction source (i.e., the RWST) credited by the SSA. The safety injection system MOVs 1SI-3 and 1SI-86 are normally closed, so a postulated fire in these areas resulting in spurious opening of these multiple valves could result in damage to the running CSIP due to run out conditions.

For a postulated fire in SSA fire areas 1-A-EPA, 1A-EPB, or 1-A-BAL-B (261' elevation), certain cabling for two containment spray MOVs (1CT-102 and 1CT-105) are not protected from spurious actuation in accordance with the requirements of NUREG 0800, Attachment 1 (Branch Technical Position CMEB 9.5-1) Section C.5.b.

Specifically, the control power cables for MOV 1CT-102 are routed in SSA fire area 1-A-EPB with no fire barrier.

Similarly, the control power cables for MOVs 1CT-105 are routed through SSA fire areas 1-A-EPA and 1-A-BAL- B with no fire barrier. Therefore, the unprotected cables for these MOVs are vulnerable to fire-induced hot shorts. These valves are required to remain shut to prevent transfer of inventory from the RWST to the containment recirculation sump. Spurious opening of either of these valves from a fire in any of these fire areas could result in inadvertently transferring inventory from the RWST to the containment recirculation sump. If this transfer of inventory were to occur, the water normally used for inventory makeup to the Reactor Coolant System (RCS) would not be available from a suction source (i.e., the RWST) credited by the SSA. However, back-up sources would be available, and the ability to achieve and maintain cold shutdown would not be affected.

For a postulated fire in SSA fire areas 1-A-CSRA (286' elevation), 1-A-CSRB (286' elevation), 12-A-CR (305' elevation) or 12-A-CRC1 (305' elevation), certain cabling for the two outlet MOVs (1CS-165 or 1CS-166) of the Volume Control Tank (VCT) and for two containment spray MOVs (1CT-102 and 1CT-105) are not protected from spurious actuation in accordance with the requirements of NUREG 0800, Attachment 1 (Branch Technical Position CMEB 9.5-1) Section C.5.b. Specifically, the control power cables for charging system MOVs 1CS-165 and 1CS-166 are routed through SSA fire areas 1-A-CSRA, 1-A-CSRB, 12-A-CR, and 12-A-CRC1 with no fire barrier. Therefore, the unprotected cables for these MOVs are vulnerable to fire- induced hot shorts. The charging system valves are required to remain open to provide CSIP suction from the VCT during a postulated fire in these fire areas. As a result, a fire in any of these areas could result in spurious closure of one of the VCT outlet valves, loss of suction flow to the running CSIP, and subsequent damage to the running CSIP credited by the SSA for charging flow and RCP seal cooling.

I. DESCRIPTION OF EVENT (Continued) In addition, the control power cables for MOVs 1CT-102 and 1CT-105 are routed through SSA fire areas 1-A- CSRA, 1-A-CSRB, 12-A-CR, and 12-A-CRC1 with no fire barrier. Therefore, the unprotected cables for these MOVs are vulnerable to fire-induced hot shorts. These valves are required to remain shut to prevent transfer of inventory from the RWST to the containment recirculation sump. Spurious opening of either of these valves from a fire in any of these fire areas could result in inadvertently transferring inventory from the RWST to the containment recirculation sump. If this transfer of inventory were to occur, the water normally used for inventory makeup to the Reactor Coolant System (RCS) would not be available from a suction source (i.e., the RWST) credited by the SSA. However, back-up sources would be available, and the ability to achieve and maintain cold shutdown would not be affected.

For a postulated fire in SSA fire areas 1-A-CSRA (286' elevation) or 1-A-CSRB (286' elevation), certain cabling for the four safety injection MOVs (1SI-3, 1SI-4, 1SI-86, and 1SI-107) are not protected from spurious actuation in accordance with the requirements of NUREG 0800, Attachment 1 (Branch Technical Position CMEB 9.5-1) Section C.5.b. Specifically, the control power cables for safety injection MOVs 1SI-4, 1SI-86, and 1SI-107 are routed through SSA fire area 1-A-CSRA with no fire barrier, and the control power cables for safety injection MOVs 1S1-3 and 1SI-86 are routed through SSA fire area 1-A-CSRB with no fire barrier and therefore, are vulnerable to fire-induced hot shorts. These safety injection system valves are normally closed, so a postulated fire in either of these areas resulting in spurious opening of these multiple valves could result in damage to the running CSIP due to run out conditions.

For a postulated fire in SSA fire area 1-A-CSRB (286' elevation) certain cabling is not protected in accordance with the requirements of NUREG 0800, Attachment 1 (Branch Technical Position CMEB 9.5-1) Section C.5.b and therefore is vulnerable to fire-induced hot shorts.

The C CSIP suction cross-connect valve with the A CSIP (1CS-168) is required to remain open to ensure the credited A CSIP is aligned to its suction source. Therefore, a postulated fire resulting in a spurious closure of this valve could result in damage to the running CSIP.

The B CT pump and its associated discharge valve (1CT-88) are required to remain off and shut, respectively, to ensure that the RWST inventory is not discharged to the containment via the containment spray ring header. Therefore, a postulated fire in this area resulting in spurious actuation of these multiple components could result in the water normally used for inventory makeup to the RCS not being available from a suction source (i.e., the RWST) credited by the SSA.

The RCP Thermal Barrier Flow Control Valve (1CC-252) is required to remain open to provide CCW flow to the RCP seals. As a result, a postulated fire in this area could result in spurious closure of this valve and loss of RCP seal cooling credited by the SSA.

The RCS wide range pressure transmitters (PT-402 and PT-403) provide the Operator with an indication of RCS pressure and level. Therefore, a postulated fire in this area could result in the loss of RCS pressure and level indication credited by the SSA.

I. DESCRIPTION OF EVENT (Continued) For a postulated fire in SSA fire area 1-A-BAL-B (261' and 286' elevations) certain cabling is not protected in accordance with the requirements of NUREG 0800, Attachment 1 (Branch Technical Position CMEB 9.5-1) Section C.5.b and therefore is vulnerable to fire-induced hot shorts. The A CT pump is required to remain off and its associated discharge valve (1CT-50) is required to remain shut to ensure that the RWST inventory is not discharged to the containment via the containment spray ring header. Therefore, a postulated fire in this area resulting in spurious actuation of these multiple components could result in the water normally used for inventory makeup to the RCS not being available from a suction source (i.e., the RWST) credited by the SSA.

Energy Industry Identification System (EIIS) codes are identified in the text within brackets [ ].

II. CAUSE OF EVENT

The cause of these conditions is inadequate original Safe Shutdown Analysis. Specifically, certain conductor-to-conductor interactions (i.e., hot shorts) were not adequately evaluated in the initial Safe Shutdown Analysis.

III. SAFETY SIGNIFICANCE

All of the findings are based on scenarios that have not actually occurred. Therefore, there are no actual adverse safety consequences.

Potential safety consequences for postulated fires in fire areas 1-A-BAL-B and 1-A-EPA (261' elevation) that also result in spurious closure of certain SSA MOVs may include:

• Loss of suction flow and subsequent damage to the running CSIP credited by the SSA for charging flow and RCP seal cooling,

• Loss of flow to RCP thermal barrier heat exchangers credited by the SSA for RCP seal protection,

• Loss of charging or high head safety injection flow credited by the SSA,

• Simultaneous spurious actuation of multiple valves in the charging system could result in loss of mini- flow to the CSIPs and loss of flow to charging or high head safety injection, and subsequent damage to the running CSIP,

• Simultaneous spurious actuation of multiple valves in the charging system and the component cooling water system could result in degradation of the RCP seals, possibly leading to a RCP seal LOCA without credited CSIPs.

Potential safety consequences for postulated fires in fire areas 1-A-BAL-B and 1-A-EPA (261' elevation) that also result in spurious opening of certain SSA MOVs may include:

• Spurious opening of valves in the containment spray system could result in transfer of RWST inventory to the containment recirculation sump. However, this water inventory would still be available for use, if needed, from the containment recirculation sump.

• Simultaneous spurious opening of multiple valves in the safety injection system could result in damage to the CSIP in service due to run out conditions.

• III. SAFETY SIGNIFICANCE (Continued) Potential safety consequence for a postulated fire in fire area 1-A-BAL-B (286' elevation) that also results in spurious opening of certain SSA MOVs may include:

• Simultaneous spurious opening of multiple valves in the safety injection system could result in transfer of RWST inventory to the containment recirculation sump. However, this water inventory would still be available for use, if needed, from the containment recirculation sump.

• Simultaneous spurious opening of multiple valves in the safety injection system could result in damage to the CSIP in service due to run out conditions.

Potential safety consequence for a postulated fire in fire area 1-A-EPB (261' elevation) that also results in spurious opening of certain SSA MOVs may include:

• Spurious opening of valves in the containment spray system could result in transfer of RWST inventory to the containment recirculation sump. However, this water inventory would still be available for use, if

• needed, from the containment recirculation sump.

Potential safety consequences for a postulated fire in fire area 1-A-BAL-C (286' elevation) that also results in spurious actuation of certain SSA MOVs may include:

• Loss of flow to RCP thermal barrier heat exchangers credited by the SSA for RCP seal protection.

However, RCP seals would still be protected by the normal seal injection function of the redundant charging/safety injection trains.

• Simultaneous spurious opening of multiple valves in the safety injection system could result in transfer of RWST inventory to the containment recirculation sump. However, this water inventory would still be available for use, if needed, from the containment recirculation sump.

• Simultaneous spurious opening of multiple valves in the safety injection system could result in damage to the CSIP in service due to run out conditions.

Potential safety consequences fora postulated fire in fire areas 1-A-CSRA (286' elevation), 1-A-CSRB (286' elevation), 12-A-CR (305' elevation) and 12-A-CRC1 (305' elevation) that also results in spurious actuation of certain SSA MOVs may include:

• Losi of suction flow and subsequent damage to the running CSIP credited by the SSA for charging flow and RCP seal cooling.

• Spurious opening of valves in the containment spray system could result in transfer of RWST inventory to the containment recirculation sump. However, this water inventory would still be available for use, if needed, from the containment recirculation sump.

Potential safety consequences for a postulated fire in fire areas 1-A-CSRA (286' elevation) and 1-A-CSRB (286' elevation) that also results in spurious opening of certain SSA MOVs may include:

• Simultaneous spurious opening of multiple valves in the safety injection system could result in damage to the CSIP in service due to run out conditions.

SAFETY SIGNIFICANCE (Continued) Potential safety consequence for a postulated fire in fire area 1-A-CSRB (286' elevation) that also results in spurious actuation of certain components include:

• Subsequent damage to the running CSIP credited by the SSA for charging flow and RCP seal cooling.

• Discharge of RWST inventory to the containment via the containment spray ring header, resulting in the water normally used for inventory makeup to the RCS not available from a suction source (i.e., the RWST) credited by the SSA.

• Loss of CCW flow, the SSA credited source, to the RCP seals which could potentially result in degradation of the RCP seals, possibly leading to a RCP seal LOCA.

• Loss of RCS pressure and level indication credited by the SSA which could potentially impact pressure and level monitoring.

Potential safety consequence for a postulated fire in fire area 1-A-BAL-B (261' and 286' elevations) that also results in spurious actuation of certain components include:

• Discharge of RWST inventory to the containment via the containment spray ring header, resulting in the water normally used for inventory makeup to the RCS not being available from a suction source (i.e., the RWST) credited by the SSA.

The defense-in-depth provided by the fire protection program mitigates some of these potential safety consequences by:

• Prevention of fire initiation,

• Prompt detection of fires or incipient fire conditions by installed automatic detection systems,

• Effective suppression of fires by installed automatic fire suppression systems with fire brigade backup.

Opening and de-energizing the CSIP suction cross-connect valves (1CS-168 and 1CS-169) also mitigates the potential safety consequences of a postulated fire in fire area 1-A-BAL-B.

IV. CORRECTIVE ACTIONS

Upon discovery, interim compensatory actions were implemented to minimize the impact of the postulated fires. These measures included de-energizing the CSIP suction cross-connect valves (1CS-168 and 1CS- 169) to minimize susceptibility to mal-operation of components, and posting a roving fire watch in fire areas of concern.

The additional fire areas have been added to the roving fire watch as interim compensatory action for the condition identified on February 13, 2004.

Complete a validation of the HNP safe shutdown analysis.

Restore the identified conditions of this LER to compliance by design changes or other methods approved by the NRC.

These actions are scheduled to be completed by refueling outage (RFO) 13 (Currently scheduled for May 13, 2006).

V. PREVIOUS SIMILAR EVENTS

NRC Inspection Report 50-400/00-09 (dated February 3, 2000) This inspection identified two unresolved items (URIs) concerning adequacy of a Thermo-Lag fire barrier to meet plant licensing basis requirements and the adequacy of the 10 CFR 50.59 for changes made to the FSAR to revise the fire rating of selected Thermo-Lag fire barriers. The identified fire barrier serves as the fire area separation barrier between the "B" Train Switchgear Room/Auxiliary Control Panel (ACP) Room and the "A" Train Cable Spreading Room. Based on Thermo-Lag barrier fire resistance tests conducted in 1994 and 1995, this fire barrier did not have the required three-hour fire resistance rating. Therefore, a single fire in the "B" Train Switchgear Room, of significant intensity and duration, could breach the Thermo-Lag fire barrier assembly and damage certain redundant "A" train cables and their associated functions of safe shutdown systems. The final significance determination for these two items was one notice of violation (White finding). The root cause was inadequate fire testing of the installed fire barrier. The corrective actions included modifications to the affected rooms and establishing review criteria to ensure that future fire barrier modifications do not invalidate test results. The root cause for this previous event is not significant in relation to the subject event, therefore, the previous corrective actions would not be expected to identify or prevent the deficiencies identified by this LER.

HNP LER 97-006-00 (reported 4/17/97) This LER reported that an undocumented breach was identified in the thermo-lag wall while sealing penetrations through the Thermo-Lag Wall in the 286' Cable Spreading Room "A." Follow-up investigation revealed an additional thermo-lag fire barrier deficiency in a floor drain assembly in the cable spread room.

These conditions do not comply with the 3-hour fire-rated barrier requirements specified in the HNP FSAR.

The root cause was identified to be incomplete design, incomplete construction, and incomplete final construction walkdown. The penetration was modified per ESR 95-00715. The root cause investigation (CR 97-01123) stated, "Nothing indicates a common trend to the fact of an area of a Thermo-lag panel being missed both in design and in the final construction walkdown." The root cause for this previous event is not significant in relation to the subject event, therefore, the previous corrective actions would not be expected to identify or prevent the deficiencies identified by this LER.

HNP LER 97-020-00 (reported 9/12/97) This LER reported that design discrepancies were identified during an Engineering review of the Safe Shutdown Analysis in Case of Fire. These discrepancies pertain to safety-related electrical cables in 261' elevation of the RAB for the EDG Fuel Oil Transfer Pumps "A" and "B". These cables did not comply with separation requirements to maintain safe shutdown capability. These deficiencies were caused by engineering oversight and inadequate design verification during initial plant construction. A plant modification was installed to provide the required protection for the cited cables. The root cause investigation (CR 97-03861) stated, "A review of the safe shutdown cables in the unit 2 areas north of column line 43 was performed and no additional cable protection discrepancies were found. Also, an in-depth review of an additional fire area (1-A-EPB) was performed ... and no similar deficiencies were identified." The root cause for this previous event is significant in relation to the subject event. The previous corrective action did not identify or prevent the deficiencies identified by this LER because the valve identified in this fire area (1CT-102) was not included in the SSA. The root cause for the previous event performed a review in the additional fire area only of associated cables credited in the SSA.

VI. COMMITMENTS

of NRC Form 366A) & Light Company doing business as Progress Energy Carolinas, below. Any other actions discussed in this submittal represent are described for the NRC's information and are not regulatory The actions committed to by Carolina Power Inc. (PEC) in this document are identified intended or planned actions by PEC. They commitments.

Commitment(s) .

Scheduled Completion Date 1. Complete a validation of the HNP safe shutdown analysis. June 20, 2005 2. Restore the identified conditions of this LER to compliance by design changes or other methods approved, by the NRC.

Refueling Outage 13 (Current schedule May 13, 2006)