ML20024J452
| ML20024J452 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 10/06/1994 |
| From: | Dan Dorman Office of Nuclear Reactor Regulation |
| To: | Tremblay L VERMONT YANKEE NUCLEAR POWER CORP. |
| References | |
| TAC-M88768, NUDOCS 9410180215 | |
| Download: ML20024J452 (4) | |
Text
October 6, 1994
^Mr. L. A. Triblay Senior Licensing Engineer Vermont Yankee Nuclear Power Corporation 580 Main Street Bolton, Massachusetts 01740-1398
SUBJECT:
ALTERNATE R0D INSERTION (ARI) MODIFICATIONS - VERMONT YANKEE NUCLEAR POWER STATION (TAC NO. M88768)
Dear Mr. Tremblay:
By letter dated April 15, 1994, you documented an April 1, 1994, telecon between Yankee Atomic Electric Company and the NRC staff regarding planned modifications to the ARI system at the Vermont Yankee Nuclear Power Station (VYNPS) to meet the instrument diversity requirements of the Anticipated Transient Without Scram (ATWS) Rule (10 CFR 50.62). As noted in your letter, the modifications are planned for implementation during the planned 1995 refueling outage of VYMPS.
Your letter described the planned modifications as follows. The new ARI/Recirculathn Pump Trip (ARI/RPT) System to be implemented at VYNPS will consist of redundant safety class and seismic instrument loops.
New dedicated Rosemount Model 1152 transmitters with Acromag trip modules are to be installed in-order to diversify from the Rosemount 710 trip cards presently used for the reactor trip system (RTS).
Power feeds to the loops will be provided by the station safety class 120 vac Vital and Instrument Busses which are independent from RTS power supplies. This arrangement will provide reliable power sources to the instruments for all conditions.
Following a loss of normal power the instrumentation powered from the 120 vac Instrument Bus would be unavailable for the approximately 13 seconds required for the emergency diesel generators to start and come up to power. However, the ARI instrument loop fed from Vital Instrument power would be available during any loss of normal power event.
The modifications described above are consistent with the staff's understanding from the April 1, 1994, telecon. As stated during that telecon, the staff finds that modifications as described above are adequate to provide j
the instrument diversity required by the ATWS Rule and are, the.*efore, acceptable to the staff.
If the planned modifications or the associated schedules change, you are requested to notify the NRC staff as soon as practicable.
If you have any questions, please contact me at (301) 504-1429.
Sincerely, l
Original sinned by Ronald Eaton for Daniel H. Dorman, Project Manager Project Directorate I-3 9410180215 941006 Division of Reactor Projects - I/II DR ADOCK0500g1 Office of Nuclear Reactor Regulation Docket No. 50-271 cc:
See next page DOCUMENT NAME: A:VYM88768.LTR
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October 6, 1994 Mr. L. A. Tremblay Senior Licensing Engineer Vermont Yankee Nuclear Power Corporation 580 Main Street Bolton, MA 01740-1398
SUBJECT:
ALTERNATE R0D INSERTION (ARI) MODIFICATIONS - VERMONT YANKEE NUCLEAR POWER STATION (TAC NO.:M88768)
Dear Mr. Tremblay:
By letter dated Ap'ril 15, 1994, you documented an April 1, 1994, telecon between Yankee Atomic Electric Company and the NRC staff regarding planned modifications to the ARI system at the Vermont _ Yankee Nuclear Power Station (VYNPS) to meet the instrument diversity requirements of the Anticipated Transient Without Scram (ATWS) Rule (10 CFR 50.62). As noted in your letter, the modifications are planned for implementation during the planned 1995.
refueling outage of VYNPS.
Your letter described the planned modifications as follows. The new ARI/ Recirculation Pump Trip (ARI/RPT) System to be implemented at VYNPS will consist of redundant safety class and seismic instrument loops. New dedicated Rosemovat Model 1152 transmitters with Acromag trip modules are to be installed in order to diversify from the Rosemount 710 trip cards presently used for the reactor trip system (RTS).
Power feeds to the loops will be provided by the station safety class 120 vac Vital and Instrument Busses which are independent from RTS power supplies. This arrangement will provide reliable power sources to the instruments for all conditions. Following a loss of normal power the instrumentation powered from the 120 vac Instrument Bus would be unavailable for the approximately 13 seconds required for the emergency diesel generators to start and come up to power. However, the ARI instrument loop fed from Vital Instrument power would be available during any loss of normal power event.
The modifications described above are consistent with the staff's understanding from the April 1, 1994, telecon. As stated during-that telecon, the staff finds that modifications as described above are adequate to provide the instrument diversity required by the ATWS Rule and are, therefore, acceptable to the staff.
If the planned modifications or the associated schedules change, you are requested to notify the NRC staff as soon as 1
practicaole.
If you-have any questions, please contact me at (301) 504-1429.
j l
Sincerely, i
l/
/
L I
u:... e H. Do an, Project Manager Project Direc orate I-3 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket No. 50-271 1
cc:
See next page
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l Mr. L. A. Tremblay Vermont Yankee Nuclear Power Station 4
cc:
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 i
U. S. Nuclear Regulatory Commission i
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 Roper & 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 l
120 State Street Framingham, Massachusetts 01701-0317 Montpelier, Vermont 05602 ATTN: James Muckerheide Chairman, Board of Selectmen Mr. Raymond N. McCandless Town of Vernon Vermont Division of Occupational 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. Donald A. Reid, Vice President Corporation Operations Ferry Road Vermont Yankee Nuclear Power Brattleboro, Vermont 05301 Corporation Ferry Road Brattleboro, Vermont 05301 Mr. Robert J. Wanczyk, Plant Manager Vermont Yankee Nuclear Power Plant P. O. Box 157, Governor Hunt Road Vernon, VT 05354 i
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