ML19256E551
| ML19256E551 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 10/16/1979 |
| From: | Ippolito T Office of Nuclear Reactor Regulation |
| To: | Groce R YANKEE ATOMIC ELECTRIC CO. |
| References | |
| NUDOCS 7911080024 | |
| Download: ML19256E551 (3) | |
Text
.
s
/'pa ascg%
UNITED STATES y1 NUCLEAR REGULATO3Y COMMISSION
{'
j WASHINGTON, O. C. 20556 o%, v /
October 16, 1979 Docket No. 50-271 Mr. Robert H. Grace Licensing Engineer Yankee Atomic Electric Company 20 Turnpike Road Westboro, Massachusetts 01581
Dear Mr. Groce:
We have been reviewing your submittal of July 18, 1977 dealing with degraded grid voltage at Vermont Yankee Nuclear Power Station. As a result of our review, additional information is required. This infomation, which we discussed with your representatives by telephone on September 18, 1979, is identified in Enclosure 1.
Your response to this letter is requested within 45 days of its receipt.
Sincerely, G
7 As; +p. ]Hs L L C-TFfomas'A.dppolito, Chief Operating Reactors Branch #3 Division of Operating Reactors
Enclosure:
Request for Additional Information 4
1294 065 791108002-S
Y Mr. Robert H. Groce.
cc: Ms. J. M. Abbey John R. Stanton, Ofrector Ver:nont Yankee Nuclear Power Radiation Control Agency Corporation Hazen Drive 77 Grove Street Concord, New Hampshire 03301 Rutland, Vermont 05701 John W. Stevens Mr. Donald E. Vandenburgh, Conservation Society of Vice President Southern Vermont Vermont Yankee Nuclear Power P. O. Box 256 Corporation Townshend, Vermont 05353 Turnpike Road, Route 9 Westboro, Massachusetts 01581 Dr. Mars Langley, Director Div. Occupational Health John A. Ritsher, Esquire 32 Spaulding Street Ropes & Gray Barre, Vemont 05641 225 Franklin Street Boston, Massachusetts 02110 New England Coalition on Nuclear Pollution Laurie Burt Hill and Dale Farm Assistant Attorney, General West Hill-Faraway Road Environmental Protection Division Putney, Vermont 05346 Attorney General's Office One Ashburton Place,19th Floor Public Service Board Boston, Massachusetts 02108 State of Vermont Ricnard E. Ayres, Esquire 120 State Street Natural Resources Defense Counsel Montpelier, Vermont 05602 917 15th Street, N. W.
Washington, D. C.
20005 W. F. Conway, Plant Superintendent Vermont Yankee Nuclear P0wer Honorable M. Jerome Diamond Corporation P. O. Box 157 Attorney General Vernon, Vermont 05354 State of Vermont 109 State Streat Pavilion Office Building Mr. Charles Sheketoff Montpelier, Vermont 05602 Assistant Director Vermont Public Interest John A. Calhoun Research Group, Inc.
Assistant Attorney General 25 State Street State of Vermont "ontoelier, Vermont 05602 109 State Street Pavilion Office Building Brooks vemorial Library Montpelier, Vermont 05602 224 Main Street Brattleboro, Vermont 05301 Anthony Z. Roisman Natural. Resources Defense Council 917 15th Street, N. W.
Washington, D. C.
20005 1294 066
REQUEST FO? %DDITIONAL INFORMATION
'2 RMONT YANKFE DEGkADED GRID ' CTAGE By your letter dated September IC,1976, you proposed to instal' 2n additional undsrvoltage relay with a time delay of several seconds on each 4160 volt emergency bus. On initiation of these relays, an annunciator will be activated in the control room and then the operator will have instructions to manually trip the offsite supply breaker.
Based on our review of your information, manual action to trip the offsite supply breaker is not acceptable.
Your basis does nct meet the requirements of the IEEE Std. 279-1971, Section 4.1, "The nuclear power generating station protection shall, with precision and reliability, automatically initiate appropriate protection action whenever a condition monitored by the system reaches a preset level."
On your submittal of July 18, 1977, you stated that NRC had failed to acknow-ledge GDC 17 and that the automatic disconnection of high reliability source would appear irresponsible and short-sighted, and violate GCC 17 Our position is that an adequately designed undervoltage relaying with optimum time delay protects the safety equipment against sustained degraded power suoply by means of automatic disconnection of degraded power. This relaying system does not disconnect high reliability power source and, therefore, does not reduce an availability of offsite power source and de,
not increase the probability of loosing good quality electric power from offsite power. This relaying system disconnects automatically the unreliable power supply which is not capable of starting and operating all required loads on the emergency buses.
In addition to the. protection for the
~
safety related equipment from sustained degraded pcwer supply, this protection system improves the capability of the offsite power supply.
In view of the above, we request that you provide your proposed design modification and changes in the Technical Specifications based on the guidance contained in the Staff Positions sent to you by our letter of June 3, 1977.
I294 067