ML19290E574
| ML19290E574 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 03/10/1980 |
| From: | Stallings C VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0578, RTR-NUREG-578 NUDOCS 8003140226 | |
| Download: ML19290E574 (2) | |
Text
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VIItOINIA EI.ucrItLC Anis l'OWElf CO M PANY Itacrruonz>,vruornr4 unas March 10, 1980 Mr. Harold R. Denton, Director Serial No.
200 Office of Nuclear Reactor Regulation PO/DLB:baw U. S. Nuclear Regulatory Commission Docket No.
50-339 Washington, D. C.
20555
Dear Mr. Denton:
Iassons learned Short Term Requirements North Anna Power Station Unit 2 The following information regarding the implementation of the Short Term Lessons Icarned Requirements on North Anna Unit 2 is submitted as a supple-ment to our previous responses of November 26, 1979 and January 10, 1980.
Items are numbered as in NUREG 0578.
2.1.3.b.
Instrumentation for Detection of Inadequate Core Cooling in PWR's and BWR's Installation of the core subcooling monitor is now complete on North Anna Unit 2.
In our response of January 10, 1980, we stated that we were still reviewing the potential technologies for monitoring reactor vessel level.
While certain operational and design problems are yet to be resolved, we have elected to install a level system based on a differential pressure measurement between the bottom and the head of the reactor vessel.
The differential pressure level instrument will cover the range from the bottom of the core to the top of the vessel head.
Additional details will be provided bs the design is finalized.
2.1. 5.c.
Capability to Install Hydrogen Recombiner at Each Light Water Nuclear Power Plant Since the recombiner system forms a portion of the contain-ment boundary when the recombiner is in operation, the system design has been reviewed to identify any modifications which would be desirable to reduce the potential for leakage.
As a result of this review we will add redundant remotely operated valves to provide isolation of the recombiner system from all connected systems.
These modifications will be completed by January 1, 19 81.
2.1.7.a.
Auto Initiation of Auxiliary Feed Following are clarifications to our responses to Section 2.I.7.a included on pages 2-18 and 2-19 of our October 25, 1979 letter (Serial No. 806/092779) 8003140 2-2 6
~
a.
VinoinA Ex.rcrate Ano Powra CourANY to Mr. Harold R. Denton 2
Item 3 Ihe second sentence of our response to item 3 should be revised to read as follows:
The actuation signals and circuits are testable and these signals are the system actuations on which the FSAR Chapter ?4 accident analyses are based.
Item 4 Our response to item 4 should be revised to read as follows:
All initiating signals and circuits which automatically start the Auxiliary Feedwater System, are powered from vital buses and are backed-up by the emergency power system.
Item 6 All motor driven pumps and valves involved in the actuation of the auxiliary feed system have been properly accounted for in the capability and sequencing calculations for the Emergency Diesel Generators.
Control power to air operated control valves in the auxiliary feed system is from the emergency buses.
Item 7 Dur response to item 7 should be revised to read as follows:
The automatic initiating signals and circuits are designed in such a manner that their failure will not result in the loss of the manual capability to start the Auxiliary Feed-water System from the control room.
Very truly yours, h
\\b aW4 C. M. Stallings Vice President-Power Supply and Production Operations cc:
Mr. James P. O'Reilly
.