05000237/FIN-2011002-03
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Finding | |
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| Title | Adequacy of Control Room Ventilation Smoke Purge Function |
| Description | The inspectors identified an Unresolved Item regarding the adequacy of the Control Room Ventilation Smoke Purge Function. The inspectors identified that the inlet and outlet to the Control Room Ventilation A Train are within 5 feet of one another on the exterior of the turbine building. The UFSAR Section 6.4.4.3 describes the smoke purge function. The control room HVAC system is designed to isolate and maintain the design conditions within the control room during fires in either the control room or outside the emergency zone. Smoke detectors, located in the control room return air ducts, will annunciate in the control room and the Train A HVAC system will be switched manually to the smoke purge mode. During this mode, the system supplies 100% outdoor air. This will prevent the recirculation of smoke into any of the occupied areas in the event of fire while exhausting 100% of the return air to the outdoors. The smoke purge capability is only available on Train A. The UFSAR Section 6.4.4.3 states, A smoke detector in the Train A control room HVAC System outside air intake will annunciate and the Train A HVAC system will be manually switched to the recirculation mode. This will prevent the intake of smoke into the control room envelope in the event of an outside fire adjacent to the Train A HVAC system outside air intake. This statement is only partially correct. The smoke detector will also prevent the ventilation system from entering the smoke purge mode and will automatically take the system out of the smoke purge mode if it detects smoke. To completely isolate the control room from outside smoke takes manual action. The licensing basis and adequacy of design of the control room ventilation smoke purge function due to the location of the system inlet and outlet is an Unresolved Item pending additional inspector review. (URI 05000237/2011002-03; 05000249/2011002-03) |
| Site: | Dresden  |
|---|---|
| Report | IR 05000237/2011002 Section 1R04 |
| Date counted | Mar 31, 2011 (2011Q1) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.04 |
| Inspectors (proximate) | G Roach D Melendez-Colon C Phillips T Go J Cameron M Learn R Edwardsc Zoiad Melendez-Colon C Phillips D Reeser R Baker M Ring T Go J Draper |
| INPO aspect | |
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Finding - Dresden - IR 05000237/2011002 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Dresden) @ 2011Q1
Self-Identified List (Dresden)
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