GB1423069A - Nuclear reactor installations - Google Patents

Abstract

1423069 Cooling nuclear reactors INTERATOM INTERNATIONALE ATOMREAKTORBAU GmbH 16 Aug 1973 [16 Aug 1972] 38870/73 Heading G6C In a nuclear reactor installation (e.g. employing a liquid sodium-cooled, fast reactor) heatexchangers are enclosed in secondary vessels disposed around the reactor bessel, coolant is conveyed between the reactor and secondary vessels by separate ducts forming hot and cold runs, and each secondary vessel is internally divided, by a partition, into two compartments into one of which the hot run opens and into the other of which the cold run opens, the partition affording apertures through which the heatexchangers are suspended. As shown, a cold run 10, provided by a pipe conveying coolant from the pressure side of a pump 4, leads to a core inlet plenum in reactor vessel 1 from a secondary vessel 2 housing heatexchangers 6. A hot run 12, provided by a suction pipe, leads from above the reactor core 3 to the secondary vessel 2 where the hot and cold coolant is maintained separate by a flow apron 9 through apertures of which the heat-exchangers are suspended from a respective shield plug 22. In order to compensate for thermal expansion in the pipes, each run 10, 12 extends, intermediate the vessels 1, 2, to a location above the top neutron shield 13 where the pipes are formed with loops. Gas spaces above the normal coelant levels 7, 8 in the vessels 1, 2 are connected by pressure-equalizing pipes 19. The vessels 1, 2 are surrounded by respective outer containers 17, 18 dimensioned to contain any leakage coolant and, in the instance of rupture of vessel 1, to ensure maintenance of a minimum coolant level 30 in vessel 1. Heated gas can be blown into the interspaces between vessels 1, 17 and 2, 18 for reactor start-up. To prevent all coolant from being withdrawn from vessel 1 in any circumstance, the runs 10, 12 are interconnected, in the region of the loops, by a small diameter pipe 31 which prevents siphon effects. This pipe may include a flow diode to restrict coolant by-pass flow during normal reactor operation. Inlets to the hot run 12 are disposed above the reactor vessel minimum coolant level 30.