ML20004D723

Responds to Generic Ltr 81-04.Util Will Develop plant- Specific Procedures & Training Based on Westinghouse Owners Group Loss of All Ac Power Guideline as Reviewed by NRC

ML20004D723
Person / Time
Site:	Summer
Issue date:	06/03/1981
From:	Nichols T SOUTH CAROLINA ELECTRIC & GAS CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
GL-81-04, GL-81-4, NUDOCS 8106090687
Download: ML20004D723 (3)

Text

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%o Mr. Harold R. Denton, Director Page 1 of 3 Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

Virgil C. Summer Nuclear Station Docket No. 50/395 NRC Generic Letter 81-04

Dear Mr. Denton:

In regards to the NRC requirement for Station Blackout events to be addressed in plant emergency procedures and training programs, as, delineated in NRC Generic Letter 81-04, dated February 25, 1981 from Darrell G. Eisenhut of the NRC to all Licensees of Operating Nuclear Power Reactors and Applicants for Operating Licenses (except for St. Lucie Unit Nos. 1 and 2), South Carolina Electric and Gas Company'(SCE&G), acting for itself and agent for South Carolina Public Service Authority, provides the following response.

Items a, b, e, and g are being addressed by the Westinghouse Owners Group (WOG) as delineated in WOG letter 0G-56, dated April 9, 1981, from Robert W.

Jurgensen, Chairman, Westinghouse Owners Group to Mr. Darrell G. Eisenhut.

As a participating member of the WOG, SCE&G will develop plant specific pro-cedures and training based on the WGG Loss Of All AC Power Guideline as reviewed by the NRC.

Schedule of implementation should be within 60 days of receipt of the approved guidelines.

Item c: Actions for restoring offsite AC power in the event of a loss of the grid. The Virgil C. Summer Nuclear Station receives off-site AC power from two independent sources. One source is a direct 115KV line from the company's Parr Plant located approximately 2 miles southwest of the Nuclear Station. This 115KV line ties directly into the Nuclear Station's ESF buses via a 115KV/7.2KV stepdown transformer. The Parr Plant has a 14MW hydro unit, a 60MW gas turbine, and a 28MW steam plant. The Parr Plant can be isolated from the grid by its local switchyard and still provide AC power to the Nuclear Station. This action can be accomplished rapidly and easily without resorting to any transmission line modifications. The other source partially independent of the transmission grid is the Fairfield Pump Storage Plant located one mile west of the Nuclear Station. This plant has 8 hydro units with a combined output of 512MW which is routed through two transmission lines to the 230KV switchyard adjacent to the Nuclear Station for connection to the transmission grid. Switching in the 230KV switchyard is via hydraulic closed / spring opened oil circuit breakers (OCB) which can be operated from the Nuclear Station's main control room, from a substation house in the switchyard, or locally at the breaker. The breakers have a hydraulic reservoir capacity of 5. closures after loss of hydraulic pump power and can be manually Boc/

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Mr. Harold R. Denton Page 2 of 3 NRC Generic Letter 81-04 recharged. The 230KV system supplies the Nuclear Station ESF and non safety-related distribution systems through.two OCB's.

In the event of the loss of the grid, the plant can be isolated from the grid by opening the switchyard OCB's, a Fairfield Pump Storage Plant hydro started, and the OCB's from the Fairfield Plant and to the Nuclear Station closed. This action can be accomplished rapidly and easily without resorting to any trans-mission line modifications.

Item d: Actions for restoring offsite AC power when its loss is due to postu-lated onsite equipment failures. The Virgil C. Summer Nuclear Station re-ceives offsite AC power from two independent sources as described in the re-sponse to item e of this letter. A loss of all offsite AC due to onsite equip-ment failures would require simultaneous failures of five (5) transformers (1 main transformer, 2 emergency auxiliary transformers, 2 ESF transformers) or similar multiple equipment failures.

In our -judgement, the possibility of this happening is quite remote. The actions necessary to restore offsite AC power in this event would be to restore any single transformer to an operable status.

Item f: Consideration of the availability of emergency lighting, and any actions required to provide such lighting, in equipment areas where operator or maintenance actions may be necessary. The V.C. Summer Nuclear Station essential lighting operates in conjunction with normal lighting where a more reliable source of illumination is required. Essential lighting power is supplied from the ESF buses and divided into Train A and Train B in accordance with the

-designation of the respective ESF source bus. Train A and Train B are separated from each other. The ESF buses are supplied by their respective diesel gener-ators in the event of a loss of all offsite AC power. Fused circuit breakers at the ESF source bus provide isolation, thereby eliminating separation criteria problems. Essential lighting is provided in the following areas:

1) Turbine Bldg.

2) Auxiliary Bldg.

3) Diesel Generator Bldg.

4) Water Treatment Bldg.

5) Intermediate Bldg.

6) Control Complex:

a.

Control Room b.

Controlled Access Area c.

Safe Shutdown Areas

7) Critical Electrical Distribution Areas:

a.

DC Distribution Panels b.

Inverter c.

Charger d.

ESF Switchgear e.

ESF Motor Control Centers As a backup to essential lighting, emergency lighting supplied from the station 125 Volt DC power system is provided in the Diesel Generator Bldg., Reactor Bldg.,

-Mr. Harold R. Denton Page 3 of 3 NRC Generic Letter 81-04 Control Room Operating floor, and Relay Room. The illumination level is adequate for the performance of critical tasks and access to these areas.

Upon loss of AC voltage to these lighting panel boards, the hold-out relay in the 125 Volt DC emergency panel closes, thereby energizing the emergency lighting system. Restoration of AC voltage to the lighting panelboard.

automatically de-energizes the DC contactor, re-establishing the normal mode of operation.

In addition to the 125 Volt DC system, fixed emergency lighting consisting of sealed beam units with individual 8-hour minimum battery power supplies is provided in the following areas:

1) Control Room

2) Control Room Evacuation Panel Rooms

3) ESF Switchgear Rooms (Intermediate Building)

4) Diesel Generator Building

5) ESF Switchgear and Motor Control Center Rooms (Auxiliary Building)

6) and along access and egress routes to the areas listed above.

The Cold License Operator Training Program includes training on all Emergency Operating Procedures (EOP's).

E0P-4, " Station Blackout Operation",

will be revised based on the WOG Loss Of All AC Power Guidelines. Once this revision has been completed, training will be held to ensure that all cold license trainees are familiarized with the procedural revisions.

In addition, annual requalification training will include instruction in the use of all E0P's.

Should you require further information in this regard concerning the schedule or scope of our planned actions on this topic, please let me know.

Very truly yours, T.C. Nichols, Jr.

KWW/RMF/TCN/bsg cc:

V.C. Summer G.H. Fischer T.C. Nichols, Jr.

H.N. Cyrus D.A. Nauman W.A. Williams, Jr.

R.B. Clary 0.S. Bradham A.R. Koon M.N. Broome B.A. Bursey Dr. J. Ruoff J.L. Skolds J.B. Knotts, Jr.

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tenu.aam T Mr. Narold R. Denton, Director Page 1 of 3 Office of Nuclear Reactor Regulatica U.S. Nucisar Regulatory (*hsaion Washington, D.C.

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Subject:

Virgil C. Summer Nuclear S' ation t

Docket No. 50/395 NRC Generic Letter 81-04 Deer Mr. Dentons I

.In regarda to the NRC requirement for Station-Blackout events to be addressed -

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in plant emergcucy procedures and training programs, es delineated in NRC i

generic letter 81-04, dated February 25, 1981 froen Darrell G. Eisenhut of ha NRC to all Licensees of Operating Muc1 car Power Reactors and Applicants or Operating Licenses (except for St. Lucie Unit Nos. I ar.4 2), South j

Carolina Electrica and Caa n==pany (SCE&G) a et-ing for itself and agent for South Carolina Public Service Authority provides the following response..

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_It ems a, b e. and _g are being addressed by the Westinghouse owners Croup (WOG) as delineated in WOC letter OG-56, dated April 9,1981, from Robert W.

J JurgensenyChairman, Wes.tinghouse owners Group to Mr. Darrell C. Eisenhut.

l As a participating member of the WOC, SCE&C will develop plant specific pro-l

'cedurestbased on the WOG Loss of All AC Power Guideline as reviewed by the j

NRC. Schedule of implesmentation should be within 60 days of receipt of the i

approved guidelines.

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Iten c: Actions for restoring offsite AC power in the event of a loss of l

the grid. The Virgil C. Susumer Nuc1 car Station receives off-site AC power j

4-from two indegendent sources. One source is a direct 115KV line fro:s the company's Parr Plant located approximately 2 elles southwest of the Nuc1 car

$.A Station. Thia 115KV line ties directly into the Nuclear Station's ESF buscs.

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. via a 115KV/7.2XV stepdown transformer. - The Parr Plant has a.~14 MW hydro unit, a 60MW gas turbine, and a 28HW steam plant. ne Parr Plant can be isolated from the. grid by its local switchyard and still provide AC power to the Nuclear Station. nis action can be accomplished rapidly and casily without resorting to any transmission line weilificatione. De other source

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I partially independent of the transmission grid is the Fairfield Puesp Storage Plant located one mile west of the Nacicar Station.: This plant has 8 hydro ur.ite with a combined output of 512MW which is routed through two trans-

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mission-lines to the 230KV switchyard adjacent to the Nuclear Station for connection to the transmission grid. Switching in the 230KV switchyard in via hydraulic closed / spring opened oil circuit breakers (OCB) which can be operated froes the Nuclear Station's main control room, from,a substation f

house in the switchyard, or locally at the breaker. The breakers have a hydrau-i 11e reservoir capacity of 5 closures after loss of hydraullc pump power and can be f

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manually recharged. The 230KV system' supplies the Nucicar Station ESF' and _

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non safety-related distribution systems through two oCB's.

In the event of Oi the loss of the grid, the plant can be isolated from the grid by opening the

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switchyard OCB's, a Fairfield Pump Storage Plant hydro started, a1d the OC3o 1

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from the Fairfield Plant and to the Nuclear Station closed. This action can be accomplished rapidly and easily without resorting to any transmission line modifications.

l Itesd: Actions for restoring offsite AC power when its loss is due-to postu-lated onsite equipment failures. The Virgil C. Summer Nuclear Station re-ceives offsite AC power from two independent sources as described in the re-sponse to item e of this letter. A loss of all offsite AC due to onsito equip -

ment. failures would require sinntitaneous failures of five (5) transformers (1 mein transfosser, 2 caerzency auxiliary transformers. 2 ESF transformers) a.

or:similar multiple equipment failures.

In cur judgement,. the possibility of-this happening is quite remote. The actions necessary to restore offsite AC power in this event would be t'o restore any singla transformer to an operable status.

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P en f: Consideration of the availability of emergency lighting, and any actions required to provide.such lighting, in equipment arcas where operator or main-tenance actions-mey be accessary. The V.C. Summer Nuclear Station essential ~

lighting operates in conjunction with normal lighting where a more reliable 2

source of illumination is required. Essential lighting power is supplied from the ESP buses and divided into Train A and Train B in accordance with the designation of the respective ESP source bos.

Train A and Train B are separated

~ 4h from-each other. The ESP buses are supplied by their respective diesel. gener-ators-in the event of a loss of all.offsite AC power. Fused circuit breakers at

@the ESF source bum provide isolation, thereby eliminating separatiou criteria Hfi ~ den' problems. Essential lighting is provided in. the following areas:

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1) Turbine Bldg.

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'2) Auxiliary Bldg.

3) Diesel Gcucrator Bldg.

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4) Water Treatment Bldg.

5) Intermediate Bldg.

6) Control Comp 3cx:

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c. Safe Shutdown Arcas

7) Critical Electrical Distribution Areas:

a. DC Distribution Panels 1

b. Inverter i

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d. ESF Switchgear

e. ESF Hotor Control Centers

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125 \\olt DC power system is provided in the Diesci Cenerator Bldg.. Reactor Bldg.,

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Mr. Harold R. Denton Page 1,of 3 MRC Generic Letter 81-04

-f Cont:o1 Room Operating f3oor, and Relay Room. The illumination Icvol is

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4 4 adequate for the performance of critical tasks and accces to these areas.

Upon loss of AC voltage to these lighting panel boards, the hold-out relay l

p.g in the 125 Volt DC caer8ency " panel closes, thereby energizing t,hc emergency

,y 11theing system. Restoration of AC voltage to the lighting panelboards automatically de-energizes the DC contactor, re-establishing the normal mode

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' E of operation.

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! ji aik In addition to the 125 Volt DC system, fixed emergency lighting consisting

.~ of sealed beam units with individual 8-hour minimum bactery pcwer supplies E is provided in the following areas:

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1) Control Roon l

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2) Control Room Evacuation Panel Rooms l

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ESF Switchgear' Roome (Intermediate Builaing)-

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4) Diesel Genrerato-Building

5) ESF Switchgear and Motor Control Center Rooms

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6) and along access and egress routes to the areas

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listed above.

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[2 or acope of our planned actions on this topic, please let me know.

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J. C. Ruoff D. A. Nauman V. A. Williams, Jr.

R. B. Clary l

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A. A. Smith-I H. N. Cyrus l

J. B. Knotts, Jr.

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