ML20151U523

Discusses Proposed Sys of Fire Protection Requirements,Per 850821 Denial of 820630 Request for Exemption from App R Requirements for Separation of Redundant Trains of Safe Shutdown Equipment by 1-h-rated Barriers

ML20151U523
Person / Time
Site:	Point Beach
Issue date:	02/07/1986
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	Harold Denton, Lear G Office of Nuclear Reactor Regulation
References
CON-NRC-86-12 VPNPD-86-54, NUDOCS 8602110040
Download: ML20151U523 (7)

Text

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O Msconsin Electnc m coumr 231 W. MICHIGAN, P.O. BOX 2046. MILWAUKEE, WI S3201 VPNPD-86-54 NRC-86-12 February 7, 1986 Mr. H. R. Denton, Director Office of Nuclear Reactor Regulation U. S. NUCLEAR REGULATORY COMMISSION Washington, D. C. 20555 Attention: Mr. G. Lear, Project Director PWR Project Directorate No. 1.

Gentlemen:

DOCKET NOS. 50-266 AND 50-301 FIRE PROTECTION REQUIREMENTS 4160-VOLT SWITCHGEAR ROOM POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 By-letter dated June 30, 1982 we requested exemptions from Appendix R requirements for separation of redundant trains of safe shutdown equipment by one-hour-rated barriers or by 20 feet of horizontal separation for the 4160-volt switchgear room at Point Beach Nuclear Plant, Units 1 and 2. By letter dated August 21, 1985, the NRC denied our requested exemption. Our October 4, 1985 letter in response to your denial advised you that we were evaluating alternatives to provide alternate capability for the room.

We have completed our preliminary evaluation and propose a dedicated system, as described below, which will enable safe plant shutdown independent of the 4160-volt switchgear room.

This system is proposed in accordance with 10 CFR 50.48 paragraph (d) (4) for a dedicated shutdown system. We expect to be able to design, procure, and install this system within 30 months following NRC approval.

The proposed system is shown on Figure 1. Electric power for the system will be provided by the existing on-site gas turbine. The following new equipment will be installed to bypass the switchgear room:

1. One 13.8 KV power supply breaker. 00 l

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2. One 480-volt load center which includes:

a. One 13.8 KV/480-volt transformer.

b. One 480-volt transformer input breaker,

c. Eight 480-volt power supply breakers.

3. Six power supply switcher.

4. Sixteen Class lE 480-volt breaker panels with interlocked breakers.

The new 480-volt load center will contain sufficient power supply breakers to provide electric power to the following pumps:

1. Either of two Chemical and Volume Control System (CVCS) charging pumps for each unit (only one per unit is required for safe shutdown).

2. Either residual heat removal (RHR) pump for each unit (only one per unit is required for safe shutdown) .

3. Two of four component cooling water (CCW) pumps (only one is required for safe shutdown) .

4. Two of four service water -(SW) pumps (only one is required for safe shutdown).

In addition to the above, one turbine-driven auxiliary feedwater (AFW) pump which does not require electrical power is provided for each unit. The proposed system, therefore, will provide more than the required minimum safe shutdown capability independent of the existing trains.

Figure 2 shows a typical configuration for supplying electric power to the pumps. A power supply switch (Item 3 on Figure 2) is included such that alternate power can be made available to the pumps. Each pump is equipped with a Class lE breaker panel (Item 4 on Figure 2) . Each panel contains mechanically interlocked breakers and provides an interface between the new 480-volt load center and the existing plant system in accordance with Appendix R Section III.L.6 which states:

" Shutdown systems installed to ensure post fire shutdown capability need not be designed to meet seismic Category I criteria, single failure criteria, or other design basis accident criteria, except where required for other reasons, e.g., because of interface with or impact on existing safety systems or because of adverse valve actions due to fire."

Mr. H. R. Denton February 7, 1986

.Page 3 Because the Class lE breaker panels will provide a suitable interface with the existing safe shutdown systems, alternate power supply components installed upstream of the panels will be commercial grade equipment.

Cables which will provide the new alternate power to the CVCS charging pumps, SW pumps, and RHR pumps will be permanently installed between the 480-volt load center and the Class lE breaker panels. Breaker operation will be the only manual action required to provide alternate power to these components.

Cables for the CCW pumps cannot be installed permanently in strict accordance with Appendix R since the pumps for both units are located in a single fire zone with less than 20 feet horizontal separation between the pumps. Therefore, cables will be permanently installed between the 480-volt load center and terminal boxes located outside the CCW pump fire zone. Dedicated cables with plug end connectors will be provided for manual installation between the terminal boxes and the CCW pumps in accordance with Appendix R Section III.L.5.

The following fire protection provisions currently exist at Point Beach and constitute interim protection for the 4160-volt switchgear room until completion of the dedicated alternate shutdown system:

1. A single-failure-proof Halon automatic fire suppression system.

2. A diverse means of fire detection and Halon system actuation by:

a. Cross-zoned photoelectric smoke detectors,

b. Rate-compensated heat detectors.

These measures, together with the existing physical separation of alternate switchgear within the room, stringent administrative control of access to the 4160-volt switcngear room, and stringent control of transient combustibles constitute significant and adequate measures of fire protection until installation of the dedicated shutdown system is complettd. Therefore, no additional interim fire protection measures are considered to be necessary.

Mr. H. R. Denton February 7, 1986 Page 4 As a result of our ccmmitment to provide the dedicated alternate shutdown capability described in this letter, the following previous commitments will be modified or not installed:

1. In our " Response to 10 CFR 50 Appendix R Alternate Shutdown. Capability" report dated October 26, 1983, we proposed to provide dedicated cables for the RHR pumps which could be manually connected in order to achieve cold shutdown. Since the proposed alternate power supply will now be permanently installed for these pumps, the dedicated cable provisions will no longer be required or provided.

2. In the same report we committed to installing a power supply cross-tie for the CVCS charging pumps for each unit. This modification is being installed to provide alternate shutdown capability for the cable spreading room. Once the proposed dedicated system is installed and operable, the cross-tie provision will no longer be required.

3. Our January 3, 1985 letter proposed additional fire protection measures for the 4160-volt switchgear room as follows:

a. Provision of an independent Halon automatic fire suppression system actuated by smoke detectors for all safeguards switchgear cabinets.

b. Provision of conduit wrapping for one division of incoming power cable from one dieFal generator.

c. Provision of conduit wrapping for one division of outgoing power to required safu shutdown equipment.

d. Provision of cable tray wrapping and pullbox enclosure for cables to two SW pumps.

e. Provision of cable wrapping for incoming and outgoing power from one alternate set cf non-safeguards switchgear.

Since the dedicated system will provide safe shutdown capability independent of the switchgear room, these modifications in the room and cabinets are no longer required and will not be installed.

1.

A Mr. H. R. Denton February 7,~1986 Page'5' We request'your approval of the proposed system as soon as possible.

Please call us-if you'have any questions regarding this proposal.

-Very truly yours,-

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