GB1060220A - Improvements in heat exchangers adapted for generation of vapour from liquid - Google Patents

Abstract

1,060,220. Vertical boilers. BABCOCK & WILCOX CO. Feb. 28, 1964 [Feb. 28, 1963], No. 8561/64. Heading F4A. A steam generator heated by a liquid metal comprises a vertical elongated pressure vessel having an ellipsoidal lower head (14), Fig. 1 (Figures not shown), and an open, flanged upper end to which a flanged closure head (20) is bolted and welded, within which a cylindrical thin walled liquid metal container (28) is suspended coaxially within the shell by a ring (30) to define a continuous gas space (38), (36), (40) enveloping the container. Liquid metal maintained at a level (86) enters the container through inlet (80), a toroidal leader (82) and feeder pipes (84) and passes out through the lower end of the container and shell. The gas space (36), (38), (40) is filled with inert gas through an inlet (90) and condensed liquid metal removed from this space through drains (92). The level of the liquid metal is controlled by varying the gas pressure as described in Specification 941,315, three blow-out nozzles, provided with diaphragms (96), in the head (20) prevent any excess pressure build up. A cylindrical inlet header (42) having a feedwater inlet (58) and removable access closure (46) is attached to and extends through the head (20). An annular bundle of tubes connected through a tube plate (44) at the bottom of the header and enclosed by coaxial cylindrical conduits (50), (54) extend downwardly to near the bottom of the container where they are connected to a tube bundle (55) passing upwards, e.g. coiling around the conduit (50) and supported from rings (74), (76) as described in Specification 941,315, and terminating in three vapour outlet headers (62) which pass through the head (20) and are then interconnected to a vapour outlet (72). As shown in Fig. 7 the vapour generator is assembled with a superheater (104) and a reheater (204) arranged such that high temperature liquid metal from a nuclear reactor flows first in parallel through the superheater and reheater and their combined outlet flows then pass through the generator before returning to the reactor. Steam passes from the generator through the superheater to a point of use through conduit (139) and steam to be reheated flows to and from the reheater through conduits (242), (244). The superheater, Fig. 3, comprises a U-shaped pressure vessel (106) containing a bundle of U-tubes connected through tube sheets (112), (114) to inlet and outlet plenums from which steam enters and leaves through nozzles (136), (138). Liquid metal passes in counterflow over the tubes around baffles (127) entering and leaving the vessel through inlet and outlets (122), (124). Thermal shields (126) adjacent the tube sheets and pressurized inert gas in the spaces (130) between the tube sheets and the metal level (128) protect the plates from thermal and pressure shocks, high pressure relief blow out nozzles (134) being provided in spaces (130). The reheater has a similar conbut with larger steam inlet and outlet nozzles and a longer U-tube bundle of smaller diameter.