Reactor cores for fast liquid metal cooled power reactors

摘要

1431475 Fuel elements INTERATOM INTERNATIONALE ATOMREAKTORBAU GmbH 19 Sept 1973 [6 Oct 1972] 44042/73 Heading G6C A fuel element for use particularly in a fast, molten-metal cooled, power reactor comprises encasing box 3 of hexagonal cross-section extending from a fuel element base 1 and containing a plurality of fuel rods 23. In the lowermost zone 4, the rods have cavities for receiving fission gases, in the next zone 5 (lower axial blanket) they contain breeder material, while in the next zone 6 (reactor core proper) they contain fissile material. Above the zone 6 is a flow-guiding device 7 (shown in detail in Fig. 5), and above the device 7 is a zone 8 (upper axial blanket), the rods of which contain breeder material. Finally, above the zone 8 is a mixing device 9 which mixes the coolant for the purpose of measuring the mean outflow temperature. Arrows 10, 11 indicate the position of support planes in which the fuel element is laterally retained. The flow-guiding device 7 consists of a wall 20 parallel to the encasing box wall and also a plurality of webs 21, 22 extending perpendicular to the wall 20. The webs 21 consist of short curved guide vanes and the webs 22 of continuous duct walls (Fig. 6, not shown). The vanes 21, 22 are limited to the outer zone of the encasing box 3 with the result that only the temperature of the encasing box walls is varied, whereas the inner temperatures are not disturbed. The temperature profile is preferably rotated by the flow-guiding device 7 through 180 degrees, resulting in a negative (or weakly positive) bowing coefficient which has an advantageous effect on plant safety.