The only non-conventional reactor concept considered in this report, the Compact High Temperature Reactor (CHTR) of BARC (India), is based on a synthesis of the technology of 233U-Th HTGR type pin-in­block fuel and that of a lead-bismuth coolant; see Annex X. The CHTR is a very high temperature reactor concept. Smaller reactor capacity facilitates:

— Passive heat removal from the core in normal operation, with no main circulation pumps being employed; as well as passive and passively actuated heat removal from the core during and after accidents, including those based on the use of heat pipe systems;

— Relatively high heat capacity of the ceramic core, resulting in slow temperature transients, at a reasonable reactor size;

— Prevention of the consequences of transient overpower events;

— Passive power regulation and increased reactor self-control in transients without scram.