GB858504A - Improvements relating to nuclear reactors and in the operation thereof - Google Patents

Abstract

858,504. Nuclear reactors. BABCOCK & WILCOX Ltd. May 16, 1957 [May 16, 1956], No. 15202/56. Class 39(4). Coolant flows through a number of zones of a reactor so that the amount flowing through each zone can be controlled to obtain a desired outlet temperature. The coolant from a pump 2, Fig. 1, is controlled separately at 22, 25, 28 according to outlet temperatures at 31, 32, 33 so that gas flowing through fuel channels in a central zone and in two annular zones leaves the reactor core at the same temperature, before passing to a heat exchanger 5. In a further embodiment, Fig. 5, gas in controlled proportions is admitted by different pipes 76 through the wall of a pressure vessel 52 into windboxes 101 to 108 each supplying fuel channels within one of eight zones. These windboxes are formed by cylindrical partitions 91 to 97 beneath a graphite core 51 supported on a plate 56 and grid 57. The outlet from the outermost zone, supplied by windbox 108 may be at a higher temperature and superheat steam generated in a heat exchanger supplied with hot gas from the inner zones. When the fuel elements in the inner zones are partially consumed they may be exchanged for elements in outer zones. Within each zone some channels are permanently throttled to different extents so that those channels in the zone in which the fuel elements are hottest receive the maximum amount of gas in the zone. The reactor is connected to four pairs of heat exchangers, each pair with a pumping system and network of pipes 76, all four pipes for the innermost zone supplying the common windbox 101 and so on outwards. A gas seal 65 divides the upper part of the pressure vessel from the lower part. The reactor described uses natural uranium and carbon dioxide as fuel and coolant.