ENS Event | |
|---|---|
13:00 Jun 18, 2007 | |
| Title | Digital Control System Failed for Unknown Reason |
| Event Description | At approximately 0800, lost all FMB control room monitors associated with Digital Control System (DCS). Several valves in UF6 process failed in unexpected position. No release and no exposures. System immediately put in a safe configuration. Root cause has begun and system will be kept in safe configuration for now (not restarted) until cause determined and corrected. This is a Courtesy Notification.
The NRC Resident Inspector and the NRC Regional Project Manager (Pelchat) were informed of this information call by the licensee.
The cause has been determined to be attributable to a UPS failure. This UPS failure resulted in a re-initialization of system configuration which, upon power restoration, caused process valves to move to the system's default configuration for the subsequent re-start mode. This default configuration was not correct for the state the system was in at the time of the re-initialization. The programming logic for valve alignment in the event of a re-initialization has since been corrected. There was no release and no exposure, and the system was immediately put in a safe configuration. The root cause is continuing. This is an update to the Courtesy Notification made on 6/18/07. Notified R2DO (Hopper), FSME (Burgess). |
| Where | |
|---|---|
| Honeywell International, Inc. Metropolis, Illinois (NRC Region 2) | |
| License number: | SUB-526 |
| Reporting | |
| Information Only | |
| Time - Person (Reporting Time:+1.52 h0.0633 days <br />0.00905 weeks <br />0.00208 months <br />) | |
| Opened: | Larry Parscale 14:31 Jun 18, 2007 |
| NRC Officer: | John Mackinnon |
| Last Updated: | Jul 11, 2007 |
| 43429 - NRC Website | |
Honeywell International, Inc. with Information Only | |
WEEKMONTHYEARENS 434292007-06-18T13:00:00018 June 2007 13:00:00
[Table view]Information Only Digital Control System Failed for Unknown Reason 2007-06-18T13:00:00 | |