Experimental evaluation of safety grade decay heat removal in prototype fast breeder reactor

Abstract

After the reactor shutdown, decay heat in prototype fast breeder reactor (PFBR) will be removed through normal heat transport path (OGDHR) and separate dedicated passive safety grade decay heat removal (SGDHR) system. If normal heat transport path is not available for decay heat removal due to various reasons, the highly reliable passive SGDHR system is the only means of decay heat removal. To study the performance of SGDHR system of PFBR, an experimental set up in sodium, SADHANA was designed, constructed and commissioned. The scaled down model of 1:22 in power was modelled with Richardson number and Euler number similitude. Sodium to sodium decay heat exchanger and sodium to air heat exchanger in SADHANA is similar to the corresponding heat exchangers of the prototype reactor system. Steady state experiments were carried out in SADHANA facility to evaluate the heat transport characteristics of the system under various conditions. From the steady state experiments it is concluded that the SGDHR system in PFBR is capable of removing the intended amount of decay heat from the hot sodium pool of the reactor. This paper gives the details of the steady state experiments conducted to characterise the heat transport behaviour of the SGDHR system and the results of the experiments.