ENS 40632: Difference between revisions
Jump to navigation
Jump to search
StriderTol (talk | contribs) (Created page by program invented by Mark Hawes) |
StriderTol (talk | contribs) (Created page by program invented by StriderTol) |
||
| Line 16: | Line 16: | ||
| event date = 03/31/2004 19:19 CST | | event date = 03/31/2004 19:19 CST | ||
| last update date = 04/01/2004 | | last update date = 04/01/2004 | ||
| title = New Worst Case Single Failure May Exceed 10 Cfr 50.46 Acceptance Criterion | | title = New Worst Case Single Failure May Exceed 10 Cfr 50.46 Acceptance Criterion for Sbloca | ||
| event text = A new worst case single failure was identified on 03-31-04 for the small break LOCA analysis of record due to a postulated loss of a DC power bus. This condition may result in the analysis of record exceeding 10 CFR 50.46 acceptance criterion of 2200 F when a small break LOCA with this failure is postulated. | | event text = A new worst case single failure was identified on 03-31-04 for the small break LOCA analysis of record due to a postulated loss of a DC power bus. This condition may result in the analysis of record exceeding 10 CFR 50.46 acceptance criterion of 2200 F when a small break LOCA with this failure is postulated. | ||
The current small break LOCA analysis of record assumes a single failure of one Emergency Diesel Generator (EDG) and credits flow from one charging pump. The peak cladding temperature for the analysis of record is 1929 F compared to the acceptance criteria of less than or equal to 2200 F. Half of the flow from a charging pump is assumed to go to the RCS and half is assumed to flow out the break. It was identified on 03-31-04 that a single failure of a DC power bus would be more limiting than the currently assumed single failure of an EDG. The DC bus failure will result in the EDG failure to start and also cause a charging loop isolation valve to the RCS to fail closed on loss of DC power. The other charging flow path to the RCS is on the assumed broken RCS leg so it is assumed to be spilled to the containment resulting in no charging flow to the RCS. Therefore, no charging flow would be delivered to the RCS as assumed in the current small break LOCA analysis of record. This condition has not been analyzed. | The current small break LOCA analysis of record assumes a single failure of one Emergency Diesel Generator (EDG) and credits flow from one charging pump. The peak cladding temperature for the analysis of record is 1929 F compared to the acceptance criteria of less than or equal to 2200 F. Half of the flow from a charging pump is assumed to go to the RCS and half is assumed to flow out the break. It was identified on 03-31-04 that a single failure of a DC power bus would be more limiting than the currently assumed single failure of an EDG. The DC bus failure will result in the EDG failure to start and also cause a charging loop isolation valve to the RCS to fail closed on loss of DC power. The other charging flow path to the RCS is on the assumed broken RCS leg so it is assumed to be spilled to the containment resulting in no charging flow to the RCS. Therefore, no charging flow would be delivered to the RCS as assumed in the current small break LOCA analysis of record. This condition has not been analyzed. | ||
Latest revision as of 22:23, 1 March 2018
| Where | |
|---|---|
Waterford  Louisiana (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Other Unspec Reqmnt | |
| Time - Person (Reporting Time:+-0.58 h-0.0242 days <br />-0.00345 weeks <br />-7.94484e-4 months <br />) | |
| Opened: | Robert Murillo 00:44 Apr 1, 2004 |
| NRC Officer: | Mike Ripley |
| Last Updated: | Apr 1, 2004 |
| 40632 - NRC Website
| |