GB1394752A - Nuclear reactor cooling systems - Google Patents

Abstract

1394752 Cooling nuclear reactors BRITISH NUCLEAR DESIGN & CONSTRUCTION Ltd 22 June 1973 [22 March 1972] 13422/72 Heading G6C A nuclear reactor cooling water supply assembly (Figs. 1 and 2), comprises a header pipe 27 formed in a closed loop with opposed runs 27A, 27B; a plurality of water inlet pipes 23, 24 for connection to supply pumps 15, 16 the inlet pipes opening into the header pipe 27 at spaced apart locations around the loop and being of equal internal cross-sectional area which is not substantially less than that of the header pipe; and a plurality of sub-header pipes 28 having first and second ends connected, respectively, to the header pipe runs 27A, 27B and spaced apart therealong with at least approximately equal numbers of sub-header pipe ends disposed between each two water inlet pipes which are mutually adjacent around said loop, each sub-header pipe 28 having, between its ends, a plurality of water outlets, spaced apart along its length, for connection to a respective pressure tube 18. In one embodiment (Figs. 1 and 2), the header pipe 27 and sub-header pipes 28 are disposed in a vertical plane. The two inlet pipes 23, 24 are connected to the header pipe runs 27A, 27B together with two further inlet pipes (not shown), from two further pumps (not shown), such that eight sub-header pipe ends lie between any pair of adjacent pipe inlets around the loop. The pumps draw water from a steam drum 14 to which the upper ends of the pressure tubes are connected. The reactor is the steamgenerating heavy water reactor (SGHWR). The arrangement acts to limit the escape of cooling water in the event of a circuit breach, while maintaining a supply of water to the pressure tubes, the arrangement supplying coolant to half the reactor core; a similar arrangement supplies the other half. In a modification (Fig. 4, not shown), the header pipe 27 and sub-header pipes 28 are disposed in a horizontal plane. In another embodiment (Fig. 5), in which each header pipe (of four such), provides supply to pressure tubes in a quadrant of the core, the header pipes are arranged in a square formation about the periphery (but below), the core. Each header pipe is supplied from four pumps 115 each of which has its supply outlet 116 connected to a respective manifold 126 from whence upper, 130, and lower, 131, pairs of water inlet pipes conduct the supply to the upper, 127A, and lower, 127B, runs, respectively, of the header pipe. The header pipes may be connected in pairs by means of pipes 133-135.