Influence of gamma radiation on sodium metal aerosol characteristics in inert gas

In the normal operating condition of sodium cooled fast reactor (SFR), evaporation of sodium from the pool surface and subsequent condensation results in the formation of sodium aerosol within the cover gas space. Presence of these aerosols modify the total heat transfer to the cooled roof structure by absorption and scattering of thermal radiation and further the aerosols get deposited on the cooler surfaces like annular gaps, roof top, control plug, rotating plug and fuel handling machine. The characteristics of sodium aerosols changes with (i) temperature difference between the sodium pool surface and the bottom of the roof top plug and (ii) effect of geometric dimension (diameter of the sodium pool surface, height of the argon cover gas and shape of roof top) of the cover gas region. It is to be noted that cover gas region is always being subjected to intense radiation field that results in significant ionization of the gas resulting large amount of bi-polar ions. When the sodium aerosols are immersed in the sea of bi-polar ions, aerosols acquire charges (steady state charging)