ML20077G735

Special Rept 91-09 on 910612,breach Discovered from Main Control Room to Cable Spreading Room in Bottom of Panel 2-M-13 Cabinet Iii.Caused by Craftsman Error.Operability of Fire Detection Sys Verified & Fire Watch Established

ML20077G735
Person / Time
Site:	Sequoyah
Issue date:	06/26/1991
From:	Wallace E TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
91-09, 91-9, NUDOCS 9107020216
Download: ML20077G735 (5)

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e i e- g IUA l Tennessee Va' ley Authony 110t Market Speet. Chattanooga, Tennessee 37G JUN 261991 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:

In the Matter of ) Docket Nos. 50-327 Tennessee Valloy Authority ) 50-328 SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 - FACILITY.0PERATING LICENSES DPR-77 AND DPR SPECIAL REPORT 91 FIRE PROTECTION PLAN The enclosed special report provides details concerning a noncompliance with the requirements of Unit 2 License Condition 2.C.13.a. This issue was initially reported by telephone notification at 1138-Eastern daylight-time on June 13, 1991,- and by facsimile dated June 13. 1991. Details of the noncompliance are provided in the enclosure - Ths, noncompi.iance condition is applicable to Units 1 and 2. This scport is being_made in accordance with Unit 2 License Condition-2.H.

If you have any questions concerning this submittal, please telephone Russell R. Thompson at (615) 843-7470.

Very truly yours.

TENNESSEE VALLEY AUTHORITY E. G. allace Nuclea Licensing and Regulatory. Affairs Enclosure cc: See page 2

' I 9107020216-910626 PDR-- ADOCK 05000327

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U.S. Nuclear Regulatory Commission-JUN 261991  :

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Ms. S. C. Black, Deputy Director Project Directorate 11-4 U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. D. E. LaBarge, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 NRC Resident Inspector Sequoyah Nuc1 car Plant.

2600 Igou Ferry Road-Soddy Daisy, Tennessee 37379 Mr. B. A. Wilson, Project. Chief U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323-

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ENCLOSURE 14 Day Follow-Up Report Specini Report 91-09 Description of Condittom This special report addrooses the requirements of Unit 2 License Condition 2.C.13.a requiring TVA to maintain and impleront all provisions of the approved fire protection plan, which, in part, commits to barriers of specified fire-rated durations in certain plant locations. A noncompliance with the above-cited licence condition was identified during the periodic performance of surveillance 0-SI-MIN-302-001.0, " Visual Inspection of Electrical penetration Fire Barriers - System 302," on June 12, 1991, at approximately 1250 Eastern dEylight time (EDT).

Two Modifications insulators performing the surve' -

locovered a breach from the main control room (MCR) to the cab] m below in the bottom of MCR panel 2-M-13 Cabinet III. Th. -

nir foreman and he immediately contacted Fire Operations and roqs a _.. aching permit. Fire Operations determined the breach had to be evaluated under 0-TI-SXX-000-016.0,

" Breach of Emergency Control Room pressurization Boundary (ECRpB)." At this time, Fire Operations notified the shift operations supervisor (SOS) of the breach. At 1331 EDT on June 12, 1991, both units entered Limiting Condition for Operation (LCO) 3.7.12. Systems Engineering was contacted by the SOS to assist in calculating the size of the breach.

A work request was initiated to correct the problem and at approximately 1600 EDT on June 12, 1991, steps were taken to seal the breach. On June 13, 1991, at approximately 1327 EDT, documentation confirming that the breach had been scaled properly was reviewed by the SOS, and LCO 3.7.12 was exited.

Subsequent investigation determined that the breach occurred on September 8, 1990, during the implementation of a work plan installing the Unit 2 Cycle 4 (U2CA) nuclear instrumentation Gamma Metrics modification.

Modifications' craf tsmen were instructed to install a now 1-1/2 inch conduit in the bottom of panel 2-M-13 Cabinet II. This installation required the fire barrier foam in the bottom of the panel to be breached and a hole cut in a steel plate for the installation of the conduit. The proper pernits were obtained, including a physical Security Instruction (PHYS 1) 13. " Breaching permit Fire Barrier Breach," breach permit, and an ECRpB breach permit.

The craftsmen inadvertently proceeded to breach the foam insulation in the bottom of Cabinet III to support the conduit installation. While removing the foam insulation, the subject breach (hole in foam insulation to spreading room) was made. A simplified sketch of the breach is attached. It appears that the craftsmen were not aware that they had inadvertently breached the ECRPB through the foam insulation. The ersftsmen proceeded to install the conduit in the bottom of Cabinet III through the steel plate and prepared to install the cable.

On September 9, 1990, the cable installation was started. The cable was pulled from the other termination point to the condulet just below panel 2-M-13, Cabinet III in the spreading room. At this time, it was discovered that the conduit had been installed in the wrong cabinet. Craft and engineering supervistor were notified of the incorrect installation, but J

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were unaware of_the inadvertant ECRpB breach. The original PHYSI-13 permit was still open for the conduit installation, and was considered still applicable for the breach in Cabinet II (instead of obtaining a second breach permit). The craft removed the conduit from the bottom of'2-M-13 Cabinet III, lugged the conduit in Cabinet III, and rerouted the conduit to Cabinet II.

..e cable installation was then completed.

paper work for resealing Cabinet II was given to the oncoming shift.

Cabinet II was resealed and the PHYSI-13 permit was closed as part of the work plan. The conduit in Cabinet III was plugged; howevcc, no actions were-initiated to reinsulate the-bottom of Cabinet III until-it was discovered on-June 12, 1991,-during the performance of the scheduled surveillance.

Cause of the condition The breach discovered from the MCR to the cable spreading room resulted from inadvertent installation of a conduit in panel 2-M-13, Cabinet III instead of.

Cabinet II. A failure to initiate appropriate dacumentation and tracking paper for the inadvertent Cabinet III breach also appears to have contributed to failure to correct this condition. Investigation into the cause_of the condition is ongoing. The results will be provided in Licensco Event Report (LER) 50-327/91012.

Analysis of Condition The breach penetrated the fire barrier between the MCR and the cable spreading room. The continuous presence of personnel in the MCR in. conjunction with existing fire detection and suppression systems in both the MCR and cable j spreading room, provide assurance that a fire in these areas would be

identified in order to initiate appropriate response actions.

Because the breach _also penetrated the ECRPB,_the operability;of the control room emergency ventilation system (CREVS) was evaluated. At the time of discovery, no other breaches were open in the pressurization boundary. The

! size of the discovered breach was calculated.to be within limits such that I operability of CREVS was not impacted. An evaluation of potential CREVS operability impacts since the breach was initially opened is ongoing. The results will be included in LER 50-327/91012.

Corrective Action

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Upon discovery of the breach, the operability of-fire detection systems.in the affected areas was verified, and the breach included in fire watch. patrols, in accordance with LCO 3.7.12. A work request was initiated to repair the breach. At approximately 1600 EDT on June 12, 1991, the breach was sealed.

Documentation for sealing the breach was completed, and LCO 3.7.12' exited at 1327 EDT on June 13, 1991.

Corrective actions to prevent recurrence are_being developed, and will be included in LER 50-327/91012.

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