ENS 43379: Difference between revisions
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| event date = 05/21/2007 12:31 CDT | | event date = 05/21/2007 12:31 CDT | ||
| last update date = 05/21/2007 | | last update date = 05/21/2007 | ||
| title = Potential Division 1 Edg Damage Due | | title = Potential Division 1 Edg Damage Due to Loss of Service Water Cooling During Control Room Fire | ||
| event text = During a review of an Operating Experience issue (LO-GLO-2006-0090 CA5), a condition was found which is not consistent with the assumptions of the River Bend post-fire safe shutdown analysis. 10CFR50 Appendix R states that for alternate shutdown capability (i.e shutdown from outside the main control room) support systems (service water cooling) for critical post-fire safe shutdown components must remain free from fire damage. Generic Letter 86-10, 'Implementation of Fire Protection Requirements' state that the following assumptions are required for evaluation of a control room fire: 1) fire induced spurious operation of safe shutdown components has occurred; 2) offsite power is lost and; 3) loss of automatic starting of the onsite AC generators as well as the automatic function of valves and pumps whose circuits could be affected by a control room fire. | | event text = During a review of an Operating Experience issue (LO-GLO-2006-0090 CA5), a condition was found which is not consistent with the assumptions of the River Bend post-fire safe shutdown analysis. 10CFR50 Appendix R states that for alternate shutdown capability (i.e shutdown from outside the main control room) support systems (service water cooling) for critical post-fire safe shutdown components must remain free from fire damage. Generic Letter 86-10, 'Implementation of Fire Protection Requirements' state that the following assumptions are required for evaluation of a control room fire: 1) fire induced spurious operation of safe shutdown components has occurred; 2) offsite power is lost and; 3) loss of automatic starting of the onsite AC generators as well as the automatic function of valves and pumps whose circuits could be affected by a control room fire. | ||
In addition to loss of automatic start of the emergency diesel generators, the post-fire safe shutdown analysis must also evaluate the consequences if the diesel generators do start concurrent with fire induced multiple spurious actuations. Since control circuits for motor operated valves for the standby service water system are routed in the control room, fire induced shorts could place these valves in a position that would prevent service water from cooling the Division 1 emergency diesel generator. In the time required for Operations personnel to evacuate the control room and re-establish control of the standby service water system at the Division 1 Remote Shutdown panel, thermal damage to the diesel generators could render the Division 1 generator incapable from performing its post-fire function. | In addition to loss of automatic start of the emergency diesel generators, the post-fire safe shutdown analysis must also evaluate the consequences if the diesel generators do start concurrent with fire induced multiple spurious actuations. Since control circuits for motor operated valves for the standby service water system are routed in the control room, fire induced shorts could place these valves in a position that would prevent service water from cooling the Division 1 emergency diesel generator. In the time required for Operations personnel to evacuate the control room and re-establish control of the standby service water system at the Division 1 Remote Shutdown panel, thermal damage to the diesel generators could render the Division 1 generator incapable from performing its post-fire function. | ||
Latest revision as of 22:16, 1 March 2018
| Where | |
|---|---|
River Bend  Louisiana (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
| Time - Person (Reporting Time:+1.77 h0.0738 days <br />0.0105 weeks <br />0.00242 months <br />) | |
| Opened: | Vern Carlson 19:17 May 21, 2007 |
| NRC Officer: | Jeff Rotton |
| Last Updated: | May 21, 2007 |
| 43379 - NRC Website
| |