ML19260D043
| ML19260D043 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 01/30/1980 |
| From: | MISSISSIPPI POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML19260D041 | List: |
| References | |
| AECM-80-31, NUDOCS 8002070286 | |
| Download: ML19260D043 (1) | |
Text
'
.?
FINAL REPORT FOR PRD NO. 79/18 AS DEFINED IN 10 CrR 50.55(e)
I.
Description of Deficiency I
Rosemount Incorporated has identified a problem with their "odel 510DU lbster and Trip Units. The problem is a common mode failure of two switches (S1 and S2). Switch I determines the trip status light logic and is a nonessential component of the trip unit.
Switch S2 determines the trip output logic and is an essential component of the trip unit.
Rosemount defines essential as electronic components required to insure a trip output action. The malfunction of the switches appears as an open circuit. Proper operation of the switch would provide circuit con-tinuity. The result of the open circuit is that the trip output is no longer functional.
II.
Safety Implications Due to the inherent safety function of many of these trip units, failure of the trip output would affect adversely the safe operation of the Grand Gulf Nuclear Station, Units 1 and 2.
III. Corrective Action Taken The switeles are being replaced by Rosemount Inc.
Rosemount will perform a functional test on all reworked units to determine whether these com-ponents are functioning properly per their design intentions. After fins.1 inspection, Rosemount QA will certify that these components have been repair-ed and retested per specification.
Details of the corrective actions are delineated in Management Corrective Action Report, MCAR-GGNS No. 56.
1938 055 80 02 07 0 e[) ff[2
. _..