05000482/FIN-2009007-08
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Finding | |
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| Title | Uncontrolled and Unanalyzed Room Environment Following a Complete Loss of Offsite Power |
| Description | The Wolf Creek Station Blackout Coping Assessment, Section 4.5, evaluated the Effects of Loss of Ventilation, associated with the loss of offsite power. Specifically, the assessment evaluated the loss of auxiliary building ventilation effects on the environment surrounding the turbine-driven auxiliary feedwater pump room. The evaluation states: It is shown that the turbine-driven auxiliary feedwater pump room air temperature will stay below 150 degrees Fahrenheit turbine-pump design specifications provided actions are taken to open doorways to enhance air circulation. The final steady state temperature of the room is determined by a NUMARC methodology. This methodology assumed an open door formula; that is, a need to open the four other doors adjacent to the corridor outside the turbine-driven auxiliary feedwater pump room. This action was not performed during the August 19, 2009, loss of offsite power/loss of auxiliary building ventilation event. Due to this, temperatures in the corridor were recorded above the assumed maximum of 113 degrees Fahrenheit using the open door formula. With the doors remaining closed, the calculation determined that the turbine-driven auxiliary feedwater pump room temperatures would rise to 170 degrees Fahrenheit, which is above that allowable to maintain the rooms equipment operable. The turbine-driven auxiliary feedwater pump steam drain traps in room 1206/1207 below the corridor exhausted to the floor drains. During steady-state conditions, the ventilation system keeps the steam from accumulating in the room. However, during a loss of offsite power event, the ventilation system no longer functions and the steam heats up the room. This additional heat source to the corridor was not accounted for in the station blackout analysis and created conditions not previously analyzed associated with room 1206/1207. The licensee did not provide an adequate evaluation or adequate procedural guidance to address the impact of a loss of offsite power on the auxiliary feedwater system. The concerns associated with the steam environment in room 1206/1207 below the auxiliary feedwater pump rooms were: the safety related transmitters for condensate storage tank swap-over could be challenged; the seismic supports for essential service water piping in the room could be affected by the increased local temperature; Manual operator actions to manipulate an essential service water motor operated valve could be challenged due to visibility and local temperatures. This issue is unresolved pending further NRC inspection of the evaluation by Wolf Creek Generating Station associated with steam exhausting into rooms 1206/1207 and the corridor outside the auxiliary feedwater pump rooms following a loss of offsite power: Unresolved Item 05000482/2009007-08, Uncontrolled and Unanalyzed Room Environment Following a Complete Loss of Offsite Power |
| Site: | Wolf Creek  |
|---|---|
| Report | IR 05000482/2009007 Section 4OA5 |
| Date counted | Dec 31, 2009 (2009Q4) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 93812 |
| Inspectors (proximate) | C Long C Peabody D Dumbacher G Miller G Tutak J Medoff M Runyan R Deeser Deeseg Guerra P Elkmann L Willoughby N O'Keefe C Long C Peabody C Steely D Strickland N Makris |
| INPO aspect | |
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Finding - Wolf Creek - IR 05000482/2009007 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Wolf Creek) @ 2009Q4
Self-Identified List (Wolf Creek)
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