Performance evaluation of decay heat removal system of PFBR with partial availability of air side dampers

Decay heat in PFBR is rejected to the atmosphere by the air flowing over the finned tube bundle of sodium to air heat exchangers which is part of the decay heat removal system of the reactor. Air flow over the tube bundle is driven by buoyancy forces generated by a chimney. Dampers with two louvers are provided in the air flow path at upstream and downstream of air heat exchanger to facilitate the heat removal through decay heat removal system on demand and minimise the loss of useful heat when the reactor is in normal operating condition. Experimental studies have been conducted to characterise the heat transport capability of the system when the air dampers are partially available. Hydraulic resistance of the finned tube bundle and air dampers were also evaluated for the operating conditions. From the studies it has been verified that the non-availability of one of the louvers in the two louver damper system is not affecting the heat transport capability of the decay heat removal system. It is also quantified that the hydraulic resistance offered by the finned tube bundle of air heat exchanger is 29% of the total hydraulic resistance of the air flow path.