Design Change and Operational Consideration of the HVAC System during Nuclear Power Plant Decommissioning

Table 3

HVAC operation strategies for decommissioning.

System	Transition period	Decommissioning phase
RCB HVAC and purge	Natural ventilation, intermittent purge (with recirculation operation using 2 RCFCs and recirculation fans)	Recirculation operation, entire ventilation operation (continuous or intermittent purge), partial ventilation operation (portable temporary HVAC units)
FHB HVAC	Normal operation (same as normal operating NPP)	—
MCR HVAC	Continuously forced ventilation (using supply and exhaust fan without recirculating flow), natural ventilation, temporary HVAC unit operation	—