ML20006E328

Special Rept 90-02:on 900126,electrical Cables to Ensure RCS Letdown Path Exists Did Not Meet Separation Requirements in Two Plant Locations.Caused by Deficiencies in Development of App R Sketch Drawings.Roving Fire Watches Established

ML20006E328
Person / Time
Site:	Sequoyah
Issue date:	02/09/1990
From:	Michael Ray TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
90-02, 90-2, NUDOCS 9002220665
Download: ML20006E328 (4)

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' TENNESSEE VALLEY AUTHORITY -

CH ATTANOOGA. TENNESSEE 37401 -

p SN 1578 Lookout Place l L FEB 091990 I, U.S.= Nuclear, Regulatory Commission-ATIN:- Document Control Desk- -

Washington, D.C. 20555 Gentlemen:

TENNESSEE VALLEY AUTHORITY - SEQUO)AH, NUCLEAR PLANT UNITS l'AND 2 - DOCKET NOS. 50-327 AND-50-328 - FACILITY OPERATING LICENSES DPR-77 AND 79 - SPECIAL-REPORT 90 APPENDIX R i The enclosed special report provides details concerning noncompliance with requirements of Unit 2 License Condition, Section 2.C.13.c, of'the Unit 2 ,

facility Operating License. This issue was initially reported by telephone notifications on January 26 and 29, 1990,- and by facsimile dated ,

January 29, 1990. The noncompliance conditions are applicable to both Units 1 and 2. These conditions are reported in accordance with Unit 2 License Condition 2.H.  !

If you h' ave any questions concerning this submittal, please telephone M. A. Cooper at (615) 843-6651. -

Very truly yours, -

TENNESSEE VAL! EY AUTHORITY -

I nf Manager,NuclehdLicensingand ~j Regulatory Affairs Enclosure cc.(Enclosure):

Ms. S. C. Black, Assistant Director ,

for Projects TVA Projects Division

.U.S. Nuclear Regulatory Commission 1 One White Flint, North- c

-11555 Rockville Pike )

Rockville, Maryland 20d52  :

Mr. B. A' Wilson, Assistent Director e for Inspection Programs TVA Projects Division U.S. Nuclear Regulatory Commission Region II _

101 Marietta Street, NW, Suite 2900 i Atlanta, Georgia 30323 NRC Resident Inspector Sequoyah Nuclear Plant

~~2600 Igou Ferry Road ,

Soddy Daisy, Tennessee 37379 ggg22ggobk-00b327 An Equal Opportunity Employer I / g'  ;

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_Sequoyah Nuclear Plant n '.

Units:1 and 2-h 14-Day follow-Up Report

. , Special Report 90 i Description of Condition 3, This special report addresses the requirements of Unit 2

License Condition E Section 2.C.13.c, of the Unit 2 Facility Operating License regarding 10 CFR 50, Appendix R. These conditions'are reported in accordance with Unit 2 License Condition 2.H and are applicable to both Units 1 and 2.

A noncompliance with 10 CFR 50, Appendix R, Section III.G.2, requirements was 2 documented o'n Condition Adverse to Quality Report SQP900040 on f January 26, 1990.

.Section III,G.2 requires redundant safety shutdown components to be separated from each other by one of the following methods. ]

1. Separation of cables and equipment and associated nonsafety circuits of redundant trains by a fire barrier having a 3-hour rating. ,

2. Separation of cables and equipment and associated nonsafety circuits of. "

I redundant trains by a horizontal distance of more than 20 feet with no intervening combustible or fire hazards In addition, fire detectors and-an automatic fire suppression system shall be installed in the fire area.  ;

3. Enclosure of cable and equipment and associated nonsafety circuits of one

, redundant train in a fire barrior having a 1-hour rating. In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area.

Contrary to Section III.G.2, electrical cables required to ensure a reactor coolant system (RCS) letdown path exists do not meet the separation Lrequirements in two plant locations. These interactions are located in the auxillary building Units 1 and 2 Mechanical Equipment Rooms A8 and A9,

respectively, at Elevation 749. Currently the cables involved are separated by a distance of.20 feet; however,'there are intervening combustibles '

. pre s en t~. As a result of.a further review of this condition, an additional interaction on Unit 2 was identifled on. January 28, 1990,-in the mechanical equipment room. This interaction involves the electrical cables for the 125-volt, direct-current power supply to Valve 2-PCV-68-334 (RCS pressurizer

power operated relief valve (PORV]) and its associated block valve (2-FCV-68-333). These cables do not meet the 20-foot separation requirements. Fire induced damage to these cables could result in the spurious-opening of the PORV and the inability to close the associated block valve.

. These areas are provided with fire detection and an automatic fire suppression system. Additionally, these areas are included in the existing hourly roving fire watches, This condition was identified during a review of the Appendix R drawings.

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A Cause The root cause of this event has been attributed to deficiencies in the-development of the Appendix R sketch (ARSK) drawings. The ARSK drawings-were developed from more detailed conduit and grounding cable tray drawings (45N880 series). The ARSK drawings contained insufficient details regarding

'the. routing of the cable trays at the locations identified.

m Development of the " base" ARSK drawings for Elevations 734 and 749 has been r identified as the source of this Appendix R deficiency. The base ARSK drawings are a checked transfer of information (depicting a plan view of cable trays) from the 45N880 series, as-constructed cable tray drawings.

Drawings were made for-each elevation in the auvillary building. The base

.ARSK drawings were then used to generate the " final" ARSK drawings by showing the cable routings for Appendix R required equipment in a color-coded method, f

-The base drawings did not provide adequate clarity with respect to the location at which certain cable trays penetrate the U-line wall. This wall i separates the emergency gas treatment system room or reverse osmosis room l from the mechanical equipment rooms for each unit.

.In particular, the floor elevations east of the U-line wall are j Elevations 734 and 759. The corresponding floor elevations on the opposite j side (west side) of this wall are 734 and 749. f At the time the base ARSK drawings were developed from the as-constructed l

.45N880 series drawings, the cable trays were correctly shown on the ARSKs. l

~However, because the ARSK drawings are plan views only and do not contain~or j reference details.or section views, insufficient information pertaining to 1 the U-line wall resulted. Thus, when the cables were plotted and color-coded ,

on the initial issue of the final ARSK drawings, errors were introduced in the plotting of certain cables in cable trays located on Elevation 749.

Analysis of Condition ,

As a result of the identified interactions, there are no plant systems or- l components considered inoperable or incapable of performing their function. j Roving (one-hour) fire watches had already been established for the auxiliary  ;

building areas as a result of previously identified Appendix R deficiencies, i The roving fire watches, coupled with the existing fire detection and  ;

suppression system, provide assurance that a fire in these areas will bc )

identified and appropriate corrective action will be taken to ensure safe ,

operation, j Corrective Actions i l

In1 accordance with limiting Condition for Operation.3.7.12 on fire barriers l and an NRC letter to TVA dated August 10, 1984, roving fire watches are in [

effect for the affected areas. These fire watches will continue until the i subject interactions are resolved.

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f-Q>rrective Actions (Continued) b A. fire hazard analysis will be performed on the interactions identified on the Unit 1= and Unit. 2 letdown paths in accordance with Generic Letter d6-10.

This' analysis will be evaluated in accordance with TVA's deviation request L h regarding intervening combustibles approved by NRC in a letter. dated May 29, 1986. Based on the results.of the analysis, the appropriate corrective actions will be determined. This analysis will be completed by June 22, 1990. The results of the analysis will be provided to NRC after-completion. The-interaction involving the Unit 2 electrical cables for the RCS PORV (2-PCV-68-334) and its associated block valve (2-FCV-68-333) will be corrected to meet the Appendix R requirements by the end of the Unit 2 o Cycle-4 refueling outage.

~As.'a result of further review, other ARSK drawings were identified as having similar problems regarding the level of detail. These drawing' deficiencies i were reviewed for hardware implications and no other interactions were -

i identified. The ARSK drawings w111 be corrected by June 22, 1990.

Additional Information- _

Additional Appendix R interactions have been reported in Docket Nos. 50-327 j and 50-328, facility Operating Licenses DPR-77 and DPR-79, Special  ;

Reports 89-11, 88-14, and 84-08. The root cause of the above interactions j did not relate to the cause of the Interactions identified in this report, ,

therefore, the corrective actions could not have been expected to have t prevented this' problem.

Comm1tments

1. The documentation problems associated with the ARSK drawings will be corrected by June 22, 1990. j

2. 'TVA will perform a fire hazard analysis in accordance with Generic Letter 86-10 for the Unit 1 and Unit 2 letdown path. As a result of the -!

analysis, appropriate corrective actions will be determined. This j analysis will be coupleted by June 22, 1990. '

3. TVA will notify NRC.of the results/ corrective actions determined from the 1 fire hazard analysis by July 23, 1990. -!

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4. The interaction involving the Unit _2 electrical cables for RCS PORV 2-PCV-68-334 and its associated Block Valve 2-FCV-68-333 will be j corrected;to meet the Appendix R requirements by the end of the Unit 2 q Cycle 4 refueling outage. .;

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