ML18033B085

Rev 3 to Electrical Cable Separations Rept, Clarifying Pages 4 & 35a of Rept

ML18033B085
Person / Time
Site:	Browns Ferry
Issue date:	11/30/1989
From:	Jay Collins, Hollingsworth, Williams B TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML18033B084	List: ML18033B083 ML18033B085
References
NUDOCS 8912200227
Download: ML18033B085 (6)

Text

BROWNS FERRY NUCLEAR PLANT ELECTRICAL CABLE SEPARATIONS REPORT (Revision 3)

Prepared by Date Reviewed by Tlirt Ca/f 5' ec o Date // P8-Reviewed by Sod Z ]N 8'c'ate f QZ cP$

Reviewed by Date /I 2 / 8/

Approved by Date Approved by Date l/X+ ~f 0425e/5/BFN 8912200227 891214 PDR ADOCK 05000260 P PNU

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Nondivisional V3 cables which originate from nonsafety-related power supplies (Subsection 4.5).

Nondivisional Vl and V2 cables which originate from both safety-related and nonsafety-related power supplies (Subsection 4.6).

Divisional and nondivisional cables designated with an "IE" suffix (Subsection 4.7).

Nondivisional V4 and V5 cables contained in the project Q-List (Subsection 4.8).

Nondivisional V3 cables contained in the project Q-List (Subsection 4.9).

Nondivisional Vl and V2 cables contained in the project Q-List (Subsection 4.10).

Divisional Vl and V2 cables (Subsection 4.11)

Evaluation of cables contained in divisional and nondivisional cable trays that physically connect (Subsection 4.12).

Other than potential discrepancies in the "IE" cable population and those nondivisional V3 cables in the project Q-list, no known design separation discrepancies existed for V3 divisional cables. Therefore, these cables were not chosen as a separate population to review. However, during the course of the Appendix R and ampacity reviews, a total of 168 safety-related V3 cables were field verified and their routing evaluated. The results of those evaluations did not reveal any problems which would indicate any further review was required. These evaluations were performed using the present separations criteria (BFN-50-728 Rl).

TVA recently issued Design Input Memorandum (DIM) BFN-50-728-1 which is an advance revision notice to design criteria BFN-50-728. This DIM allows exceptions for nonsafety-related power cables to share a power supply and enclosure with one safety-related division and an enclosure or raceway with the other safety-related division if the circuit is provided with protection consisting of two safety-related electrical protection devices to prevent it from degrading safety-related circuitry. A safety-related protection device may consist of a qualified Class lE breaker or a qualified or non-qualified fuse because of its operation (fails safe).

Exceptions are also allowed for nonsafety-related instrumentation and low voltage control circuitry to be routed with both safety-related divisions when an analysis demonstrates the absence of adverse interactions between safety-related circuitry and associated nonsafety-related circuits.

Each of the specific cable population evaluations considered this DIM to be either an acceptable method for satisfying the separation criteria or an acceptable corrective action for any discrepancies that might be identified. The methodology used in these evaluations and the results are contained in Section 4.0 of this report.

0425e/1/BFN

1 The only potential source of damage to divisional V1/V2 cables is from an external source such as jet impingement, pipe whip,missle, seismic event, or fire. TVA's pipe rupture evaluations have confirmed that safety is not compromised as a result of jet impingement, (both inside and outside containment), pipe whip (both inside and outside containment), and externally generated missles inside containment because safety related raceways are not affected as a result of these events. This evaluation is documented in Civil Engineering Branch Report CEB 88-06-C, entitled "Pipe Rupture Evaluation Program for Inside and Outside Pr'imary Containment for Browns Ferry Nuclear Plant Unit 2" (B41881114005). TVA has evaluated the Vl/V2 cables for potential damage from missles outside containment and concluded that cables of redundant functions are not affected in any area susceptible to externally generated missles.

This review is documented by QIR BFEBFN89086 (B22890928009).

All raceway in Category I structures are seismically supported and documented in QIRCEBBFN88155 (B22881018021).

All piping in a Category I structure is seismically supported at a minimum position retention. This evaluation is documented in EQE Report Number 51001.02-R-001 Revision 0 dated July 11, 1989 "Evaluation of Seismic-Induced Spray Hazards at BFNP" attached to TVA calculation CD-Q0999-894853 (B22 890930 101) and NUREG-1232, Volume 3, supplement 1 "Safety Evaluation Report on Tennessee Valley Authority:

Browns Ferry Nuclear Performance Plan." The only remaining source of damages is from an external fire. TVA has field verified the 62 Vl/V2 Appendix R required cables identified in QIR TEPBFN89038. No corrective actions are required.

This field verification is documented by QIR BFEBFN89055.

4.12 Evaluation of Cables Contained in Divisional and Nondivisional Cable Tra s that Ph sicall Connect While performing the evaluation of field verified cable data in section 4.1, drawing discrepancies for unit 3 cables were identified where divisional cable was routed on nondivisional cable tray. The reason for this is that in some instances divisional trays and nondivisional trays are physically attached as shown in Figure 4.12 with a common intersection node point in the Unit 3 computer cable routing program.

Since the Unit 3 computer cable routing program automatically routes cables, it was possible for nondivisional cables to route undetected through these divisional/nondivisional intersections and then route in an opposite division tray.

The purpose of this evaluation was to identify these situations and evaluate the cables common to these intersections to determine conformance to the separations

'riteria.

0304e/38

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