ML20046D314
| ML20046D314 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 07/27/1993 |
| From: | Dan Dorman Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9308170258 | |
| Download: ML20046D314 (10) | |
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'o UNITED STATES g
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NUCLEAR REGULATORY COMMISSION-o r,
p WASHINGTON, D. C. 20555 k..... /
July 27, 1993 l
Docket No. 50-271 LICENSEE: Vermont Yankee Nuclear Power Corporation UTILITY:
Vermont Yankee Nuclear Power Station i
SUBJECT:
SUMMARY
OF JULY 22, 1993, MEETING WITH REPRESENTATIVES OF VERMONT YANKEE NUCLEAR POWER CORPORATION j
i On July 22, 1993, pursuant to notice, the NRC staff met with representatives.-
of Vermont Yankee Nuclear Power Corporation (the licensee) at Rockville, 1
Maryland, to discuss the licensee's plans for compliance with the Station Blackout (SBO) Rule,10 CFR 50.61, for the Vermont Yankee Nuclear Power Station. A list of attendees is provided as Enclosure 1.
The licensee's handout is provided as Enclosure 2.
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On June 18, 1993, the staff issued a supplemental safety evaluation (SSE) regarding the licensee's plans to demonstrate of the ability of the _ alternate
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.AC (AAC) source, the Vernon Hydro tie-line, to provide power to a safety bus during a SB0 event. Specifically, the staff found the licensee's proposal-j unacceptable in that it did not include load testing of the tie-line. ~
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-i During the meeting, the licensee stated _that it plans to test the upgraded f
tie-line under load-during the 1993 refueling outage. The licensee. indicated-i that the test load will be the greatest that it "can readily, accommodate" during the outage. The licensee is " evaluating the basis for performing this test every refueling outage" and " believes that the intent of the [NUMARC]
l recommendation to' perform a rated load capacity test is met by enveloping the i
required SB0 load."
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The staff was concerned about a portion of the tie-line on the Vernon Hydro property which remains exposed to the weather. The staff's original: approval of the tie-line as an AAC source was based in part on the assumption that the q
tie-line would be completely buried'during the upgrade.
The modification.now includes a short line between the Hydro plant' and the switchgear 'on the Hydro.
i plant property. Specifically, the staff asked the licensee to provide on the
'l docket, its' justification that'this exposed portion of the tie-line does not.
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present a significant weather-related common mode. failure relative to the j
Vermont Yankee (VY) switchgear.
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The staff stated that the licensee should place on the docket its -
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justification for any desired relief from testing the tie-line at rated load,-
from testing the line.every refueling' outage, or from the licensee's' commitment to comply with the SB0 Rule'by September 1994.
In addition, the staff' requested that the. licensee address the staff's concerns regarding the-weather vulnerability of the new configuration of the tie-line, and include one-line diagram.
The staff also asked the licensee to provide information' j$0**lEEN0hh?2 NPtP, HE CMTER COPY b i
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l July 27,1993 regarding time required to manually load the safety buses from the tie-line.
Finally, the staff requested a copy of the agreement between VY and. the i
operator of the Vernon Hydro plant which states that VY is the Hydro plant's l
top priority load.
i Original signed by Daniel H. Dorman, Project Manager Project Directorate I-3 Division of Reactor Projects - I/II
Enclosures:
1.
List of Attendees 2.
Licensee's Handout cc w/ enclosures:
- i-See next page b
OFFICE LA:PDI-3 PM:PDI4,.
D:PDI-3
$[ihe DDorman mW WButler NAME 9 /[7/93 1 /23/93 7 T17/93
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DATE OFFICIAL RECORD COPY FILENAME: A:\\VYMTGSUM.722
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. July 27, 1993 i
regarding time required to manually load the safety buses-from the tie-line.
Finally, the staff requested a copy of the agreement between VY and the
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operator of the Vernon Hydro plant which states that VY is the Hydro plant's top priority load.
Daniel H. Dorman, Project Manager Project Directorate I-3 Division of Reactor Projects - I/II
Enclosures:
i 1.
List of Attendees 2.
Licensee's Handout cc w/ enclosures:
See next page l
i
4 Vermont Yankee Nuclear Power Station Operations
'cc:
i Mr. Jay Thayer, Vice President G. Dana Bisbee, Esq.
Yankee Atomic Electric Company Office of the Attorney General 580 Main Street Environmental Protection Bureau Bolton, Massachusetts 01740-1398 State House Annex 25 Capitol Street' Regional Administrator, Region I Concord, New Hampshire 03301-6937 U. S. Nuclear Regulatory Commission 475 Allendale Road Resident Inspector King of Prussia, Pennsylvania 19406 Vermont Yankee Nuclear Power Station U.S. Nuclear Regulatory Commission R. K. Gad, III P. O. Box.176 Ropes & Gray Vernon, Vermont 05354 One International Place Boston, Massachusetts 02110-2624 Chief, Safety Unit Office of the Attorney General Mr. Richard P. Sedano, Commissioner One Ashburton Place,19th Floor Vermont Department of Public Service Boston, Massachusetts 02108 120 State Street, 3rd Floor Montpelier, Vermont 05602 Mr. David Rodham, Director Massachusetts Civil Defense Agency Public Service Board 400 Worcester Rd.
State of Vermont P.O. Box 1496 120 State Street Framingham, Massachusetts 01701-0317 Montpelier, Vermont 0560?
ATTN: James Muckerheide Chairman, Board of Selectmen Mr. Raymond N. McCandless Town of Vernon Vermont Division of 0ccupational Post Office Box 116 and Radiological Health-Vernon, Vermont 05354-0116 Administration Building Montpelier, Vermont 05602 Mr. J. P. Pelletier, Vice President Vermont Yankee Nuclear Power Mr. L. A. Tremblay Corporation Senior Licensing Engineer Ferry Road Vermont Yankee Nuclear Power Brattleboro, Vermont 05301 Corporation 580 Main Street Mr.. Donald A. Reid, Vice President Bolton, Massachusetts 01740-1398 Operations Vermont Yankee Nuclear Power Corporation Ferry Road Brattleboro, Vermont 05301
t DISTRIBUTION: (w/ enclosures)
= Docket: File NRC & Local PDRs PDI-3 Reading File J. Linville, RI D. Dorman DISTRIBUTION: (w/o enclosure 2)
T. Murley/F.Miraglia J. Partlow S. Varga J. Calvo W. Butler S. Little l
C. Berlinger P. Gill A. Pal OGC E. Jordan ACRS (10)
V. McCree, EDO R. Cooper, RI J. Linville, RI 1
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F LIST OF ATTENDEES LICENSEE PRESENTATION ON STATION BLACK 0UT FOR VERMONT YANKEE NUCLEAR POWER STATION ROCKVILLE. MARYLAND JULY 22. 1993 HAME AFFILIATION TITLE
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Carl Berlinger NRC/NRR/DE/EELB Branch Chief Paul Gill NRC/NRR/DE/EELB Section Chief Amar Pal NRC/NRR/DE/EELB Electrical Engineer Dan Dorman NRC/NRR/PD I-3 Project Manager Frank Helin Vermont Yankee Project Engineer Paul Johnson Yankee Atomic Electric Co.
Lead Electrical Engineer i
' Enclosure 2 NUMARC 87-00 APPENDIX B.10 GUIDANCE The AAC source should be started and brought to operating conditions at intervals not longer than three months, following manufacturer's recommendations or in accordance with plant developed procedures.
VERMONT YANKEE APPROACH o Vermont Yankee's AAC source is the adjacent Vernon Hydroelectric station.
1 o Continuously operating AAC Source o Availability to Vermont Yankee has exceeded 99.9% over the last 20 years.
o Vermont Yankee has committed to monitor the availability of the station to assure that it exceeds the SBO target availability for a continuously running AAC source of 95%.
The intention of this recommendation is met.
.e NUMARC 87-00 APPENDIX B.10 GUIDANCE Once every refueling outage a timed start (within the time Period specified under blackout conditions) and rated 1oad capacity test shall be performed.
VERMONT YANKEE APPROACH o Vermont Yankee considers its AAC source to be continuously available and capable of being connected within 10 minutes of the onset of a station blackout.
o Vermont Yankee will perform a timed test during the 1993 refueling outage to demonstrate the ability to repower the emergency bus within 10 minutes of the start of the test.
o Vermont Yankee has conservatively designed the new tie line to provide margin and reduce voltage drop.
Vermont Yankee will test to demonstrate the ability to supply the required SBO load, o Vermont Yankee will perform a load test, to the highest load we can readily accomodate, on the existing line or the upgraded line (if available) during the 1993 outage.
o Vermont Yankee is still evaluating the basis for j
performing this test every refueling outage as well as i
investigating alternative testing methods to demonstrate the capability of the Vernon Tie Line.
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Vermont Yankee believes that the intent of the i
recommendation to perform a rated load capacity test is met by enveloping the required SBO load.
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VERMONT YANKEE STATION BLACKOUT LOAD BASIS.
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t o Vermont Yankee's SBO approach was to size the AAC source to be equivalent to one emergency-DG j
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o Operators would use existing loss of offsite operating procedures for SBO o VY has indicated that the maximum SBO load is 2300 kW.
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o The maximum load, based on the FSAR diesel loading table, is very conservative and contains many loads f
included as possible diesel generator loads in the procedure for loss of offsite power but not required for the SBO design basis.
These include:
l Control Rod Drive Pump l
Standby Liquid Pump l
t Turbine Building Cooling Water Pump Station Battery Charger o Vermont Yankee may choose to redefine the required SBO
'l load and develop a specific' procedure for shutdown in i
the event of a SBO i
t o Vermont Yankee will test to demonstrate the ability to supply the required SBO loads.
If it can be reasonably i
accomodated, this testing will be accomplished during the upcoming 1993 refueling outage.
In any event, the required testing will occur no later than the spring.
1995 refueling outage.
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4' OBSTACLES TO PERFORMING RATED CAPACITY' TEST o Vermont Yankee intends to demonstrate the ability to
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supply the required'SBO loads.
The new Vernon: tie was designed with margin to minimize voltage drop.
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the new cable and transformer are oversized.
Testing to rated capacity of the equipment is unnecessarily; burdensome to Vermont Yankee.
o Paralleling Vernon Hydro and Vermont Yankee may be theoretically possible but the short circuit duty of Verment Yankee's switchgear would be exceeded.
A fault l
during testing could severely jeopardize safety equipment and personnel at Vermont Yankee.
o If paralleled, power flow on the line between Vernon Hydro and Vermont Yankee would be a function of the impedance of the transformer and line,:the impedance of other sources (VY main generator and-unit transformer)',
and the relative voltage of both sources.
Our-assesment of the impedances indicates that controling power flow on the line is impractical.
t o The addition of dummy loads at Vermont Yankee in order
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to facilitate testing would likely require the addition of a cubicle to the existing 4kV safety related switchgear.
Vermont Yankee believes intention of'SBO.
- i rule is met by testing to the required SBO load and that the addition of special test equipment is not.
justified.
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