ML20207S627

Summary of 870210 Meeting W/Util Re Emergency Diesel Generator Electrical Independence.List of Attendees Encl

ML20207S627
Person / Time
Site:	Fort Saint Vrain
Issue date:	03/12/1987
From:	Heitner K Office of Nuclear Reactor Regulation
To:	Berkow H Office of Nuclear Reactor Regulation
References
TAC-59801, TAC-65517, NUDOCS 8703200109
Download: ML20207S627 (8)

Text

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3 j  % UNITED STATES 4 3 -k NUCLEAR REGULATORY COMMlSSION l

3,'#' } W ASHINGTON. D. C. 20555 i

• s  ! March 12, 1987

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Docket No. 50-267 MEMORANDUM FOR: Herbert N. Berkow,' Director Standardization and Special Projects Directorate Division of PWR Licensing-P THRU: 0. D. T. Lynch, Jr., Section Leader

. Standardization and Special Projects Directorate Division of PWR Licensing-B l

FROM: Kenneth L. Heitner, Project Manager Standardization and Special 1 Projects Directorate E Division of PWR Licensing-B

SUMMARY

OF FEBRUARY 10, 1987 MEETING WITH PUBLIC SERVICE COMPANY OF COLORADO (PSC).TO DISCUSS FORT ST. VRAIN EMERGENCY DIESEL GENERATOR (EDG) ELECTRICAL INDEPENDENCE Introduction The purpose of this meeting was to discuss in detail the PSC submittal, dated January 9,1987 (P-87008),on EDG electrical independence. The staff's

objective during this meeting was to establish that no single failure of the

automatic control system would

!= - Lead to accidental paralleling of the EDGs, or j

- Prevent manual operation of the EDGs.

In addition, the staff wished to discuss PSC's program for testing the circuit breakers (CBs) which protected the circuits containing the automatic throwover i (ATO) for the 480 volt switchgear de control power supplies. Attendees at this meeting are listed in the enclosure.

At the onset of the meeting, PSC stated that each of the three switchgear sets discussed'during the meeting is designed to have its control power provided from either of the two redundant de buses through an ATO scheme.

PSC stated that there were four levels of automatic undervoltage protection provided on each of the three 480 volt ac emergency buses. These were:

1) Loss of primary power source on any one of the three buses -

Automatic throwover of the affected bus to the alternate off-site

! power source.

2) Degraded voltage for 120 seconds on any two of the three buses -

Trip all three off-site source CEs, start both EDGs, and load shed.

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3) Loss of voltage on any two of the three buses - Start EDGs and Icad shed.

4) Loss of voltage for 30 seconds on any one of three buses - Scrarr the reactor.

EDG Operation The staff and PSC personnel reviewed the operation of the EDGs in detail, including the steps required for the EDGs to energize their respective buses.

Separate examinations were made for:

- EDG output CBs,

- Emergency bus off-site pcwer source CBs, and

- Emergency bus tie CBs.

0>eration of the CBs Tie EDG output CBs can be closed ranually from the control room or locally at the EDGs. Synchronizing equipment is at both locations. There are protective circuits for over-current and reverse power associated with the CB. The local panels also have controls for the individual engines. If both engines associated with an EDG do not start, the output CB will not close automatically and can be manually closed.

The bus tie CBs have protective circuitry to prevent them f:om closing on a faulted bus. Additional contacts were being utilized to assure the EDGs could not accidentally be paralleled through the bus ties, even if a single failure occurred. In a loss-of-bus-voltage, the ccnnection preference for the swing-bus (No. 2) was preselected. Powever, when the EDGs were called to start, the swing-bus will be tied to the first bus energized by its associated EDG.

Operation of the off-site power source CBs was also examined.

The staff concluded from their examination of the CBs that manual capability )

of the EDG CBs has civisional independence, and was not affected by any identified single failure. Furthermore, there was no possibility cf accidentally paralleling the EDGs as a result of a single failure.

CB Testing PSC stated that to assure that the ATO for the 480 volt switchgear control power supply would not lead to the loss of all de power, the ATO CBs, along with the ATO contractors, would be tested before plant restart from the present outage.

The staff stated that this would be acceptable. However, it was agreed that the CB testino will be an interim measure to avoid a single fault causing loss of both sources of de control power due to the ATO scheme. A permanent solution of the problems associated with the existing ATO scheme is to adc a third dc source of power. PSC is actively evaluating this modification and will submit their proposal to the NRC by June 1, 1987, per the commitment in Attachment 3 of the PSC submittal of January 9,1987, noted above.

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v 3-Automatic Controls Staff review of the autorietic control of the EDG output CBs, the off-site power source CBs, and the bus tie CBs led to the conclusion that this syster' was also acceptable. That is, the automatic centrol system met the single failure criteria, and the PSC separation criteria for divisicnal independence appeared to be adequate. However, the staff stated thst they would reouest a confirmatory review of the separation criteria by Region IV inspection personnel. Reference would also be made to the staff's acceptance of the Alternate Cooling Method diesel as the power source should a single fire damage the 480 volt switchgear.

Based on the above findings, the staff cencludes that all majcr concerns abcut the electrical independence of the EDG's and their manual and automatic control systems have been resolved. The staff concludes that the licensee's actions to resolve these issues to date fom an adecuate basis for safe plert operation.

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fMd.3 Kenneth L. Heitner, Project Manager -

Standardization and Special Projects Directorate Division of PWP. Licensing-B

Enclosure:

As stated cc w/ enclosure:

See next page

Mr. R. O. Williams 4- Public Service Company of Colorado Fort St. Vrain cc:

Mr. D. W. Warembourg, Manager Albert J. Hazle, Director Nuclear Engineering Division Radiation Control Division Public Service Conpany Department of Health of Colorado 4210 East lith Avenue P. O. Box 840 Denver, Colorado 80220 Denver, Colorado 80201 Mr. David Alberstein, 14/159A Mr. J. W. Gahm, Manager GA Technologies, Inc. Nuclear Production Division Post Office Box 65608 Public Service Company of Colerado San Diego, California 92138 16805 Weld County Road 19-1/2 Platteville, Colorado 80651 Mr. H. L. Brey, Manager Nuclear Licensing and Fuel Division Mr. P. F. Tomlinson, Manager Public Service Company of Colorado Quality Assurance Division P. O. Box 840 Public Service Company of Colorado Denver, Colorado 80201 16805 Weld County Road 19-1/2 Platteville, Colorado 80651 Senior Resident Inspector U.S. Nuclear Regulatory Commission Mr. R. F. Walker P. 0. Box 840 Public Service Company of Colorado Platteville, Colorado 80651 Post Office Ecx 840 Denver, Colorado 80201-0840 Kelley, Stansfield ti O'Donnell Public Service Company Building Commitment Control Program Room 900 Coordinator 550 15th Street Public Service Company of Colorado Denver, Colorado 80202 2420 W. 26th Ave. Suite 100-D Denver, Colorado 80211 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000

-Arlington, Texas 76011 i

Chairman, Board of County Commissioners of Weld County, Colorado Greeley, Colorado 80631 Regional Representative

Radiation Programs Environmental Protection Agency 1 Denver Place 999 18th Street, Suite 1300 Denver. Colorado 80202-2413 1

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Enclosure 1

t Attendees at PSC - NPC Meetino February 10', 1987 Name Oroanization Ken Feitner NRC/NRR/DPWRL-B J. R. Reesy Public Service Company of Colorado J. R. Johns Public Service Company of Colorado Howard Parkhunst Proto Power Corp.

Robert A. Schenderlein Public Service Company of Colorado James Selan PSC/ Licensing Paul Michaud NRC/ Resident Inspector Charles Miller NRC/NRR/PEICSB-SL

1. Ahmed NRC/NRR/PEICSB J. Calvo NRC/NRR/PEICSB l

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.- T March'12, 1987 Automatic Controls Staff review of the automatic control of the EDG output CBs, the off-site power source CBs, and the bus tie CBs led to the conclusion that this system was also acceptable. That is, the automatic control system met the single

-failure criteria, and the PSC separation criteria for divisional independence appeared to be adequate. However, the staff stated that they would request a confirmatory review of the separation criteria by Region IV inspection personnel. Reference would also be made to the staff's acceptance of the Alternate Cooling Method diesel as the power source should a single fire damage the 480 volt switchgear.

Based on the above findings, the staff concludes that all major concerns about the electrical independence of the EDG's and their manual and automatic control systems'have been resolved. The staff concludes that the licensee's actions to' resolve these issues to date fonn an adequate basis for safe plant operation.

original signed by Kenneth L. Heitner, Project Manager Standardization and Special

-Projects Directorate Division of PWR Licensing-B

Enclosure:

As stated cc w/ enclosure:

See next page D.lSTRLBUTION:

45 2ReUjJej RIreland, RIV NRC PDR JGagliardo, RIV Local PDR JJaudon,- RIV PBSS Reading DCrutchfield FMiraglia KHeitner 0GC-Bethesda 0 Lynch EJordan HBerkow

, BGrimes IAhmed l JPartlow CMiller l HThompson JCalvo ACRS (10) PNoonan

• See Previous Concurrence Pli PBSS PifsS PR$S S

n XHeitner:cw OL'ydch HBerlkbw 3/n /87 03/12/87 03T4/87 03/lk/87

PEICSB* PEICSB* PEICSB* PBAD*

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IAhmed CMiller JCalvo DCrutchfield l 03/03/87 03/03/87 03/05/87 03/10/87

\

r Automatic Controls Staff review of the automatic control of the EDG output CBs, the off-site power source CBs, and the bus tie CBs led to the conclusion that this system was also acceptable. That is, the automatic control system met the single

- failure criteria and that the PSC separation criteria for divisional 7 independence = appeared- to be adequate.

However, the staff stated that they would request a confirmatory review of I the separation criteria by Region IV inspection personnel. Reference would l .also be made to the staff's acceptance of the Alternate Cooling Method diesel as the power source should a single fire damage the 480 volt switchgear.

Based on the above findings, the staff concludes that all major concerns about

.the electrical independence of the EDG's and their manual and automatic control systems have been resolved. The staff concludes that the licensee's

-actions to resolve these issues to date form an adequate basis for safe plant operation.

Kenneth L. Heitner, Project Manager Standardization and Special Projects Directorate Division of PWR Licensing-B

Enclosure:

As stated cc w/ enclosure:

, See next page DISTRIBUTION:

Docket File RIreland, RIV NRC PDR JGagliardo, RIV Local PDR JJaudon, RIV PBSS Reading DCrutchfield FMiraglia KHeitner 0GC-Bethesda Olynch EJordan HBerkow BGrimes- IAhmed JPartlow CMiller HThompson JCalvo ACRS (10) PNoonan

• See Previous Concurrence (P3 PBSS PBSS PBSS PNoonan KHeitner:cw Olynch HBerkow 03/cl/87 03/3 /87 03/ /87 ,03/ /87 PEICSB* PEICSB* PEICSB* P p IAhmed CMiller JCalvo DC field 03/03/87 03/03/87 03/05/87 03//o /87 ,

, '1

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s However, the staff stated that they would request a confirmatory review of the separation criteria by Region IV inspection personnel. Reference would also be made to the staff's acceptance of the Alternate Cooling Method diesel as the power source should a single fire damage the 480 volt switchgear. '

Basedontheabovefindings,thestaffconcludesthfallmajorconcernsabout the electrical independence of the EDG's and their manual and automatic control systems have been resolved. The staff concludes that the licensee's actions to resolve these issues to date form an adequate basis for safe plant operation.

Kenneth L. Heitner, Project Manager Standardization and Special Projects Directorate Division of PWR Licensing-B

Enclosure:

As stated cc w/ enclosure:

See next page DISTRIBUTION:

Docket File RIreland, RIV NRC PDR JGagliardo, RIV Local PDR JJaudon, RIV PBSS Reading DCrutchfield FMiraglia 0GC-Bethesda EJordan BGrimes JPartlow

, HThompson l ACRS(10)

PNoonan KHeitner Olynch HBerkow IAhmed CMiller j JCalvo PBSS PBSS PBSf, N onan KHeitner:cw Olynch HBe"kow 03/')./87 03/2/87 03/ /87 03/ /87 PEICSB PEICSB G m PEICSB 77 g, Pr;AD IAhmed CMiller JCalvo DCrutchfield 03/3 /87 03/3 /87 03/r/87 03/ /87

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