INTEGRAL NUCLEAR-POWER REACTOR WITH NATURAL COOLANT CIRCULATION - INVESTIGATION OF PASSIVE RHR SYSTEM

The development of a small power (up to 240 MWe) integral PWR for nucl ear co-generation power plants has been carried out. The distinctive f eatures of this advanced reactor are: primary circuit arrangement in a single pressure vessel; natural coolant circulation; passive safety s ystems with self-activated control devices; use of a second (guard) ve ssel housing the reactor; favourable conditions for the most severe ac cident management. A passive steam condensing channel has been develop ed which is activated by the direct action of the primary circuit pres sure without an automatic controlling action or manual intervention fo r emergency cooling of an integral reactor with an in-built pressurize r. In an emergency situation as pressure rises in the reactor a self-a ctivated device blows out non-condensable gases from the condenser tub e bundle and returns them in the steam-condensing mode of the operatio n with the returing primary coolant condensate into the reactor. The t hermo-physical test facility is constructed and the experimental devel opment of the steam-condensing channels is performed aiming at the ver ification of mathematical models for these channels operation in integ ral reactors both at loss-of-heat removal and LOCA accidents.