Carbon in Sodium Measurements with Various Carbon Meters

Abstract

Carbon transport in sodium systems of fast breeder reactors is of significance as it affects the mechanical properties of the structural materials severely. This may determine the useful life of certain components of the system. A thorough understanding of this process in an operating sodium system requires the thermodynamic driving force (the carbon activity gradient) to be known. Conventional methods of analysis of carbon in sodium and then relating to the carbon activity gradient is complicated because of the lack of clear understandig of Na-C system. Moreover the analytical methods suffer from sensitivity requirements at the expected levels of carbon, apart from contamination during sampling. On-line carbon meters are of help at this juncture. They determine the carbon activity directly and do not face the problems of sampling. In this paper experimental results with two diffusion based carbon meters, namely Harwell Carbon Meter (HCM) (1) and an improved version of the carbon meter originally designed by United Nuclear Corporation (UNC) (2) and also with an electrochemical carbon meter (3) are presented.