ML20210D644

Responds to 860730 Request for Schedule for Submission of Addl Detailed Design Info Re Dedicated Shutdown Sys Independent of 4,160-volt Switchgear Room Bypass Needed to Meet Fire Protection Requirements

ML20210D644
Person / Time
Site:	Point Beach
Issue date:	09/10/1986
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
CON-NRC-86-92 860910, VPNPD-86-408, VPNPOD-86-408, NUDOCS 8609190286
Download: ML20210D644 (5)

Text

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l%sconsin Electnc powca couesur 23 W. MICHIGAN.P.O BOX 2046, MILWAUKEE.Wl53201 (414)277-2345 VPNPD-86-408 NRC-86-92 September 10, 1986 Mr. H. R. Denton Office of Nuclear Reactor Regulations U.S. NUCLEAR REGULATORY COMMISSION Washington, D.C. 20555 Attention: Mr. George Lear, Director PWR Project Directorate

Dear Mr. Denton:

DOCKET NOS. 50-266 AND 50-301 FIRE PROTECTION REQUIREMENTS 4160 VOLT SWITCHGEAR ROOM BYPASS DESIGN SCHEDULE POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 In a letter from Timothy G. Colburn, of your staff, to C. W. Fay, Wisconsin Electric, dated July 30, 1986, the Staff provided acceptance of the conceptual design for a dedicated shutdown system independent of the 4160 volt switchgear room at the Point Beach Nuclear Plant. The conceptual design was provided in our letters of February 7, 1986 and April 23, 1986.

The letter of July 30, 1986 also requested that we provide our schedule for submission of the additional detailed design infor-mation related to the dedicated shutdown system as requested in your letter of March 17, 1986. This letter provides the requested schedule and justification for our anticipated com-pletion of the detailed design by April 1, 1987. This date is based on the. engineering effort made to date and assumes an optimistic schedule where no problems are encountered in the design or other concurrent projects. Our resources are currently involved in other Appendix R design and construction items, Regulatory Guide 1.97 implementations, final design and installation of the new Safety Assessment System and plant process computer system, and support of necessary plant outages j and operational upgrades.

i After submission of our April 23, 1986 letter and in anticipa-tion of receiving NRC approval of the dedicated shutdown system conceptual design, we began a limited engineering effort to l define the major items needed to provide the system. This effort was primarily devoted to determining what changes must be ob 8609190286 860710 PDR i

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. Mr. H. R. D nton September 11, 1986 Page 2 made to the 13.8 KV power system to allow for the supply of the dedicated shutdown system. The 13.8 KV system presently does not include provisions for supply of the additional transformer required for the dedicated shutdown system. Modification of the 13.8 KV system necessary to support the' dedicated shutdown system will require the longest design and installation effort and therefore is being addressed first. In determining what changes should be made to the 13.8 KV system several factors outside the need for supply of the dedicated shutdown system were considered. These include the following:

1. The requirement to provide power for a new building addition as well as possible future plant additions.

2. Concern expressed by the NRC staff in the past regarding the close physical proximity of the low voltage station auxiliary transformers for each unit to each other and to their common 13.8 KV switchgear. Any modifications to the 13.8 KV system must be designed to decrease, to the extent practicable, the possibility of simultaneous transformer outages due to any single physical event.

3. As a result of the concerns described in (2) we are in the process of purchasing a spare low voltage station auxiliary transformer. While the original intention was to have a spare transformer available for replacement, it was deemed desirable to provide for future permanent installation of this transformer and supply from the 13.8 KV system. Such permanent installation would allow for use of this trans-former as an installed spare for either of the two existing low voltage station auxiliary transformers.

4. Several unresolved issues which could have potential effects on the plant power distribution' system adequacy in the future were also considered. These issues include the loss of all AC power and decay heat removal. Modifications to the 13.8 KV system should, to the extent possible, antici-pate any future changes which may be required to resolve these issues.

The consideration of these factors has resulted in the develop-ment of a one-line diagram for modifications to the 13.8 KV system which attempts to address each of the above issues. At the present time we are in the process of evaluating several different methods for implementing changes to the 13.8 KV system based on this one-line diagram. It is anticipated that prepara-tion of equipment specifications will begin.approximately October 1, 1986.

Mr. H. R. Denton September 11, 1986 Page 3 In addition, investigations have begun into two additional aspects of the dedicated shutdown system. First, several loca-tions have been proposed for the 480 volt switchgear and these locations are presently under investigation. Second, we are in the process of determining whether it is appropriate to provide an alternate source of power to additional equipment other than those which were shown in Figure 1 attached to our February 7, 1986 letter.

Our overall schedule for detailed engineering calls for com-pletion by April 1, 1987. This design process is divided into three separate but related efforts. The following provides milestones which have been established to provide for completion of design by April 1, 1987:

1. 13.8 KV modification effort

a. Develop initial one-line diagram for 13.8 KV modifica-tions. (Complete)

b. Develop design requirements for 13.8 KV system _modifi-cations which will assure the ability to align breakers

necessary for use of the dedicated shutdown system.

These design requirements will be based on the .

assumption that all equipment in the 4160 volt switch-gear room or dependent upon equipment in that room are not operable. (Anticipated completion date 12/1/86)

2. Modifications to gas turbine control

a. Investigate the physical location of components and

cables necessary for starting and loading of the gas turbine, including control of the gas turbine output breaker. Determine what effect a fire in the 4160 volt switchgear room may have upon these components and the ability to start and load the gas turbine. (Antici-pated completion date 12/15/86)

b. Based on the findings of 2.a. determine what changes are required to the gas turbine and gas turbine output breaker control circuits, including isolation of any local control from the effects of a switchgear room fire. (Anticipated completion date 2/1/87) a

e-Mr. H. R. Denton September.ll, 1986 Page 4

c. Complete elementary _(schematic) diagrams for revised gas turbine and gas turbine output breaker control and determine locations of any additional required com-ponents. (Anticipated completion date 3/1/87)

d. Complete the determination of cable routing for any additional cables required and complete the analysis necessary to verify their independence from the 4160 volt switchgear room. (Anticipated completion date 4/1/87)

3. Dedicated shutdown switchgear and alternate supply to selected equipment

a. Finalize the one-line diagram for the dedicated shut-down system including final determination of which loads should be supplied. (Anticipated completion date 11/1/86)

b. Determine the initial requirements for the dedicated shutdown switchgear and transformer including approxi-mate physical size and weight. (Anticipated completion date 12/15/86)

c. Determine the initial requirements for local switching devices necessary to allow for selection of normal or dedicated shutdown ,ource at each piece of equipment to be supplied. (An ;ipated completion date 12/15/86)

d. Complete elemen'.ary (schematic) wiring diagrams for control of each dedicated shutdown switchgear breaker.

(Anticipated completion date 1/15/87)

e. Determine final locati on of dedicated shutdown switch-gear and local switching devices. This analysis must include analysis of the effects of added floor loading on seismic structures and verification of adequate access for equipment installation 'Tnticipated completion date 2/1/87)

f. Complete the determination of cab]: rcuting for tional required cables including ar alysis of r > i equipment independance from the 4160 volt swi .

room. (Anticipated completion date 4/1/87)

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o Mr..H. R. Denton September 11, 1986 Page 5 Based on the above schedule it is anticipated that we will be able to provide the additional design information requested in your March 17, 1986 and July 30, 1986. letters by April 15, 1987.

Please note that we do not intend on providing documents such as equipment specifications or detailed installation documents such as connection diagrams. It is anticipated that these will be ,

developed as part of an orderly design process leading to ,

installation of the dedicated shutdown system. Any subsequent i changes to the design after initial NRC approval will be l submitted to the NRC in a timely manner for your concurrence.

Please note that only limited resources are available for completion of the dedicated shutdown detailed design effort until after completion of the Fall 1986 Unit 2 outage at Point Beach. This is due to prior ded,tcation of resources to outage ,

related design and installation tasks, including several modifications required by Appendix R. We trust that the

• schedule and justification provided above is a. satisfactory response to your request contained in your July 30, 1986 letter. '

i Should you have any further questions please contact us and we ,

will attempt to answer your concerns.

i Very truly yours, e

r

/ ,J AA G ,

C. W. Fay Vice President Nuclear Power Copy to NRC Resident Inspector t

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