ML19320A717
| ML19320A717 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 06/24/1980 |
| From: | MISSISSIPPI POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML19320A714 | List: |
| References | |
| NUDOCS 8007020541 | |
| Download: ML19320A717 (1) | |
Text
Attachmint B to AECM-80/141 Page 1 of 1 INTERIM REPORT, PRD-80/11 (Model 510 DU Trip Unit) 1.
Description of Deficiency The Rosemount Model 510 DU Trip / Calibration Unit has a common mode failure of an essential switch that determines the trip output logic. The malfunction reverses the logic, thereby providing an erroneous signal. The trip unit is used in conjunction with the
. pressure transmitter to provide high or low trip signals.
1 Safety Implications Due to the inherent safety functions of these devices, failure would adversely affect the safety of operation of Grand Gulf Nuclear Station, Units 1 and 2.
As an example, when the Model 510 DU is used as a water level trip unit, the deficiency can result in indicating high reactor water level when actually the water level is low.
III. Corrective Action Taken General Electric has issued Field Disposition Instructions (FDI's)
- to return Model 510 DU Trip Units to manufacturer for repair.
Details of the corrective action are delineated in the following FDI's:
Unit 1 Unit 2 Trip Units FDI-WAMD FDI-WBIX f
i e
80o7550 py /