ML19309A752
| ML19309A752 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 03/24/1980 |
| From: | Conway W VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0578, RTR-NUREG-578 WVY-80-50, NUDOCS 8004010256 | |
| Download: ML19309A752 (2) | |
Text
VER$10NT Y AN KME N UCLEAR POWER CORI*OR ATION SEVENTY SEVEN GROVE STRECT KUTI.AND, VI{IO10NT 05701 nE,tv vo; m"I 80-50 ENGINEERING OFFICE TURNPIKE RO AD WEST 00RO. M ASS ACHUSETTS 01581 TELEPHONE 417 366 9011 March 24, 1980 United States Nuclear Regulatory Commission Washington, DC 20555 Attention: Office of Nuclear Reactor Regulation Mr. Harold R. Denton, Director
References:
(a) License No. DPR-28 (Docket No. 50-271)
(b) Letter, D. E. Moody to H. R. Denton dated January 8, 1980
Subject:
Submittal of Additional Information in Response to NUREG-0578 Category A Implementation Review
Dear Sir:
Vermont Yankee Nuclear Power Corporation documented its compliance concerning the Category A items of NUREG-0578 via Reference (b). Subsequent telephone conversations with your staff requested additional information and clarification concerning item 2.1.3A, Direct Position Indication of Safety and Relief Valves. That information is provided below.
The position indication system for the safety / relief valves consists of pressure switches in the valve discharge piping as described in Reference (b). Power to this system is provided from the vital MG set which is driven by either an AC or a DC motor.
The position indicating system for the safety valves consists of acoustic accelerometers on the valve discharge flange and is also described in Reference (b). Power to these devices is provided from the instrument hus.
This is considered an emergency bus and is connected to one emergency ulesel generator with throw-over capability to the second emergency diesel generator.
It can readily be seen that both of these position indicating systems have, in effect, redundant power supplies.
To provide back-up indicating systems, thermocouples are mounted on the discharges of all valves.
These thermocouples require no power supply but are indicated in the control room on a strip chart recorder which is driven by power from the instrument bus. A second back-up for position indication for the safety valves is provided by the indication of containment pressure, also indicated in the control room.
8004010254
United States Nuclear Regulatory Commission March 24, 1980 Office of Nuclear Reactor Regulation Page 2 M
The routing of the signal cables from these three systems, i.e., pressure switches, acoustic accelerometers, and thermocouples, has been reviewed for adequate separation in the primary containment, the reactor building, and the control room.
In no case do cables from any of these systems run in the same cable tray or conduit from the source of the signal to the control room.
We trust that this information is satisfactory. Should you have any additional questions please contact us.
Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION NH&//
W. F. Conway Manager of Operations RLS/ncj