Helium heated steam generator

1,048,518. Vertical boilers. BABCOCK & WILCOX CO. Sept. 23, 1965 [Sept. 24, 1964], No. 40554/65. Heading F4A. A vapour generator heated by helium from a nuclear reactor comprises a vertical pressure vessel 12 enclosing an insulated stainless steel container 18 to define an annular space 20 therebetween. Helium enters the vessel 12 and the container 18 through inlet duct 24 and is distributed by frusto-conical baffles 28 over helically coiled reheating tube bank 86, supported by radial arms 94, and which extends from inlet header 78, up and around conduit 62 and then down through it to outlet header 80. The helium then passes over a similar combined boiler-superheater tube bank 68 extending between inlet header 52 and outlet header 54; alternatively the reheater and the combined boiler-superheater tube banks may be arranged in parallel. The helium next passes through passageways 38 to chamber 22, below the container 18, wherein a blower 104 circulates it through passageways 48, chamber 50 and annular space 20 to outlet passageway 27 about the inlet duct 24, so preventing excessive thermal stresses in the vessel shell 12. Nozzles 111, 113 for emergency circulation of the helium in case of failure of the blower 104 are provided. Further tube banks may also be incorporated in the shell.