ML19309E831
| ML19309E831 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 02/27/1980 |
| From: | Swart F PUBLIC SERVICE CO. OF COLORADO |
| To: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| IEB-79-27, NUDOCS 8004240469 | |
| Download: ML19309E831 (1) | |
Text
bec to DAC:ADM:
3,64WTRAL FILES PDR:HQ public service company ce cda s" February 27, 1980 Fort St. Vrain STATE Unit No. 1 P-80032 Mr. Karl V. Seyfrit Nuclear Regulatory Commission Region IV Office of Inspection & Enforcement 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76012 Docket 50-267
Subject:
HRC I&E Bulletin 79-27 dated November 30, 1979
Dear Mr. Seyfrit:
This letter is to infonn you of the action being taken in response to I&E Bulletin 79-27 concerning Class 1E and Nonclass 1E 120 vac instrument buses.
The configuration of Fort St Vrain Class 1E instrument buses was originally designed to assure that loop related equipment would be supplied instrument power from an associated bus, and would not be affected when a disturbance was experienced in the opposite loop and associated bus.
In addition, many of the valves have two solenoids, one feed from bus 1 and the second solenoid feed from bus 2.
This redundancy within loop redundancy.ias incorporated into the original design to provide additional safety in depth.
The Plant Protective System (PPS) is basically a 2 out of 3 design concept.
Each of the 3 channels of instrumentation is powered from separate noninterruptable Class 1E buses.
The review and analysis of the four instrument buses (Three Class 1E and one Nonclass IE) in the Fort St. Vrain facility is progressing, and to date, no violations of the basic design criteria have been identified.
Maximum effort is being expended to respond to the Bulletin, however, we will not be in a position to complete our review and analysis until April 25,1980 at which time we will respond to I&E Bulletin 79-27 in detail.
Very truly yours, GrAA Frederic E. Swart Nuclear Project Manager FES/JRR:pa 8004240