Experimental investigation on suppression of thermal stratification in large water pool using seven shroud arrangement

Abstract

Accident in Fukushima has drawn the attention of the world to use passive safety systems to cope with station blackout (SBO) condition during which all active system fails to function. A passive system is used to remove decay heat from reactor core during the total station Blackout (SBO) condition with the help of Isolation Condenser system (ICS). ICS is immersed in a large pool of water which acts as a heat sink. Heat transfer by natural convection in large pools creates a problem of thermal stratification. As a result of thermal stratification in large pool hot layer of water assemble over the cold layer of water, because of this IC surrounds with a hot plume, which deteriorates the performance of IC. The water pool with immersed ICS converted to thermally stratified water pool, which preventing the mixing of the hot and cold water layer. A new concept was developed by installing seven shrouds surrounding the heat source. The installation of seven shrouds around the heat source split the large water pool in eight compartments which ensures whole water in the pool should involve in the heat removal process, thereby facilitating the mixing of cold and hot water, which suppress the stratification. In this paper experimental study is presented with and without seven shroud arrangement for 1 kW power. The result indicates that the seven shrouds arrangement able to eliminate thermal stratification in a large pool of water.Accident in Fukushima has drawn the attention of the world to use passive safety systems to cope with station blackout (SBO) condition during which all active system fails to function. A passive system is used to remove decay heat from reactor core during the total station Blackout (SBO) condition with the help of Isolation Condenser system (ICS). ICS is immersed in a large pool of water which acts as a heat sink. Heat transfer by natural convection in large pools creates a problem of thermal stratification. As a result of thermal stratification in large pool hot layer of water assemble over the cold layer of water, because of this IC surrounds with a hot plume, which deteriorates the performance of IC. The water pool with immersed ICS converted to thermally stratified water pool, which preventing the mixing of the hot and cold water layer. A new concept was developed by installing seven shrouds surrounding the heat source. The installation of seven shrouds around the heat source split the large water poo...