ML20012C419

LER 90-003-00:on 900206,found That Several Minor Deficiencies Existed in thermo-lag Fire Barrier Envelopes Redundant Safe Shutdown Circuits.Util Currently Working W/ Vendor to Resolve Identified discrepancies.W/900308 Ltr

ML20012C419
Person / Time
Site:	River Bend
Issue date:	03/08/1990
From:	England L, Odell W GULF STATES UTILITIES CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-90-003, LER-90-3, RBG-32467, NUDOCS 9003210261
Download: ML20012C419 (5)

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GULF STATES UTILITIES COMPANY HivtR BE ND ST Ah0N POST OFFICE BOK 220 $f FRANCISVILLL LOUISlANA 70775 ARE A CODE $04 63b 6094 346 8661 March 8', 1990 RBG- 32467 File Nos. G9.5, G9.25.1.3 ,

U. S. Nuclear Regulatory Comission sDocument Control Desk

-Washington, D. C. 20555 Gentlemen:

River Bend' Station - Unit l' Docket No. 50-458 Please find -enclosed Licensee Event Report No.90-003 for River Bend

. Station - Unit 1. This report is being submitted pursuant to 10CFR50.73.

P Sincerely, I

W. H. Odell L Manager-River Bend Oversight L River Bend Nuclear Group .

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cc: U.'S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 100 Arlington, TX 76011 l

NRC Resident Inspector P. O. Box 1051 St. Francisville, LA 70775.

INP0 Records Center 1100 Circle 75 Parkway Atlanta, GA 30339-3064 9003210261 900o08 gDR ADOCK0500g}.8 7/

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.,,,.- n . ,nei 01 7 11 5 91 0 During the performance of Surveillance Test Procedure STP-000-3602 on 02/06/90 through 02/08/90 with the unit in Operational Condition 1 (full power), it was found that several minor deficiencies existed in the Thermo-Lag fire barrier envelopes redundant safe shutdown circuits. These deficiencies consisted of small holes, cracks and unfilled seams in the Thermo-Lag material. A fire watch had already ocan established in areas utilizing Thermo-Lag as a fire barrier.

GSU is currently working with the vendor to resolve the identified discrepancies which occurred during construction and the deficient Thermo-Lag barriers.

A supplemental response to this LER and the information report dated 01/09/90 will be submitted to the NRC by 07/15/90.

The combination of the cable jacket properties, the control of transient combustibles, the use of suppression systems in the plant, and the minor nature of the defects in the barriers provides assurance that plant safety and the health and safety of the public has not been jeopardized.

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0 l0 0l2 0F 0k ve u . s mar = answim REPORTED CONDITION During the performance of Surveillance Test Proceaure STP-000-3602 on 02/06/90 through 02/08/90 with the unit in Operational Condition 1 (full power), it was found that several minor deficiencies existed in the Thermo-Lag fire barrier . envelopes redundant safe shutdown circuits. These deficiencies consisted of small holes, cracks and unfilled seams in the Thermo-Lag material. Condition reports (CR) 90-0094, 90-0095, 90-0101, and 90-0106 were initiated to evaluate the conditions according to 10CFR50, Appendix R, fi re barrier requirements. Since these deficiencies rendered the fire barrier inoperable and the unfilled seams existed since construction, this event is reportable pursuant to 10CFR50.73(a)(2)(1)(B) as a condition prohibited by Technical Specifications. A fire watch had already been established in areas utilizing Thermo-Lag as a fire barrier, thus Technical Specification Section 3/4.7.7 action statement requirements had already been fulfilled.

l INVESTIGATION Thermo-Lag fire barriers have been under review at River Bend Station since late 1989. Potential discrepancies between the installation manual of Thermal Science Incorporated (TSI) (a GSU subcontractor during construction) and the actual site installation practices, and

. discrepancies between TSI installation manual and the qualification fire test results were discovered at that time. Due to these issues, the fire barriers were indeterminate for operability and firewatches were established for all areas utilizing Thermo-Lag as a fire barrier.

An i nformation report was submitted to the NRC 01/09/90 cnncerning this subject.

! The performance of STP-000-3602 was intended to identify conditions in l fire barriers where normal wear and tear had caused damage to the barriers. The small holes and miscellaneous cracks that were identified during the performance of the STP fall into this category.

• l Normally a fire watch would be established and the holes and cracks would be repaired. unfilled seams in the Thermo-Lag However, the installations that we.re identified during the performance of the STP are a condition that must have ' existed from the time of initial

, construction and are not in accordance with either the vendors l installation manual or normal site practices. In accordance with the vendor manual, the seams between boards of a Thermo-Lag were to be prebuttered with a trowel grade material and then joined; or i

alternatively dry fitted together with trowel grade material then applied to the joint. In either case, the seams were to have been grouted with the trowel grade material and they were not. The l preexisting firewatches satisfy the action statement of section 3/4.7.7 of the Technical Specifications. Eight fire areas were identified by the condition reports as having Thermo-Lag barriers exhibiting the unfilled seams. A brief description of each area follows.

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0l0 0l3 oF 0 l4 mn. .. mac=mmwnn Fire area C2A is the southeast cable chase at elevation 70 feet of the control building (*NA*). Fire area C2C is in the same cable chase but located at elevation 115 feet. These areas have safety related.

cabling feeding through up to the termination cabinets in the main control room. The areas have sprinkler suppression systems (*KP*) on the cable trays, which comprise the exposed fixed combustible in the areas. Area C6 is adjacent to area C2A on the west side. The area contains safety related air accumulators as well as safety related cabling. The exposed cables in cable trays comprising the exposed fixed combustible in the area, are protected by a sprinkler suppression system.

Fire area AB2/Z2 is located in the auxiliary building (*NF*) at elevation 95 feet in the sout' east corner of the building. The- area contains safety related instra.onts, piping and safety related cables.

The cabling, which makes up the fixed combustible in the area, represents a fire loading of 1.0 hour0 days <br />0 hours <br />0 weeks <br />0 months <br />. Fire area AB7 is the "D" tunnel located at elevation 70 feet on the south end of the auxiliary building. Safety related piping and motcr operated valves (MOV)

(*FCV*) are located in the area in addition to the safety related cabling. The cable tra sprinkler system (*KP*)ys and the MOVs are protected by a water deluge Fire FB1/Z1 is located at elevation 70 feet of the fuel building

(*ND*). The area contains fuel pool cooling equipment, reactor plant component cooling water piping piping (*(*DA*) CC*) and and MOVs as well as safety related cabling. The crescent area, near the reactor building shield wall (*NH*), contains the major portion of the cable trays in the area. The cable trays represent a fire. loading of 21 minutes and are the fixed combustible in the area. Fire areas FB3 and F84 are the charcoal filter rooms located et elevation 148 feet of the fuel building. The ventilation system charcoal filters and fans are contained in the area. All cabling is routed in conduit in these areas. The charcoal filters are the fixed combustible for this area.

They are protected by manually actuated water spray systems. Th'e~

charcoal in each area is a fire loading of 45 and 46 minutes respectively for areas FB3 and FB4, Fire area PT1 is the pipe tunnel at elevat1on 70 feet which extends

'from the standby cooling tower (*CTW*) to the fuel building. The area contains- piping, MOVs, and instrumentation in addition to the safety related cabling. The cable trays are the on1.y fixed combustible in l

the area and are protected by a sprinkler suppression system. The i

cable trays represent a fire loading of 29 minutes.

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In addition to the informational report submitted on 01/09/90, LERs87-005 and 89-009 were reviewed for similarity. This is the first time unfilled seams have been identified.

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_ CORRECTIVE ACTION GSU is currently working with the vendor to resolve the identified discrepancies which occurred during construction and the deficient Thermo-Lag barriers.

The corrective action to be taken to repair deficiencies identified by the STP in the Thermo-Lag barriers will be dependent on the extent of the overall Thermo-Lag problems identified (and yet to be identified) at River Bend and the resolution of those problems. A supplemental response to this LER and the information report dated 01/09/90 will-be submitted to the NRC by 07/15/90.

SAFETY ASSESSMENT The primary fixed combustible at River Bend in the safety related areas is cable jacketing on the electrical cables. The type of cable j used at River Bend has been shown through testing to resist ignition i and when the ignition / heat source is removed, the cable self

! extinguishes. Transient combustibles are controlled throu'h g administrative means to limit the amounts brought into any given crea of the plant. The charcoal filter rooms of the fuel building are the only areas that require any appreciable amount of combustibles to be brought into the area. This happens infrequently during changing of the charcoal in the filters.

1 The combination of the cable jacket properties, the control of transient combustibles, the use of suppression systems in the plant, and the minor nature of the defects in the barriers provides assurance that plant safety and the health and safety of the public has not been jeopardized, l

NOTE: Energy Industry Identification System Codes are identified in the text as (*XX*).

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