Patent GB-1181002-A (GB)
Title: Method and Apparatus for Generating Steam
Inventor: VUIA ROMUL EUGEN
IPC: F01K3/18
Filed: 1967-02-28
Abstract: 1,181,002. Nuclear power plant. COMBUSTION ENG. SUPERHEATER Ltd. 28 Feb., 1967, No. 9561/67. Heading G6C. [Also in Divisions F1 and F4] In a steam power plant, steam generated by heat exchange with a nuclear reactor coolant, is superheated by the combustion gases of a fossil fuel fired steam generator, the steam from both sources being used in one or more turbines. Steam generated in heat exchanger 4, by heat exchange with coolant fluid from reactor 2, passes through line 5 to superheater 7 located in a flue 47 of independent oil fired steam generator 22. Outlet steam temperature from nuclear steam superheater 7 is controlled by variation of damper 46 and/or gas recirculation fan 50 in recirculation duct 49 to vary the gas flow through flue 47. Alternatively the steam superheat temperature control may be by tilting burners or attemperation. From superheater 7 the steam passes through line 8 to turbine sections 10, 12 and 13 and condenser 14. A full size turbine by-pass 81 is also provided. Condensate from condenser 14 is passed back by pump 17 through heat exchangers 18 and economizer 19 in flue 47, to heat exchanger 4. The wall tubes 40 of steam generator 22 are fed by pump 37 from drum 23 and downcomer 38, the steam/ water mixture passing back to the drum from header 42. Steam from the drum passes through superheaters 24, 25 to the turbines 28, 29 and condenser 32. Condensate is fed by pump 34 through heaters 33 and economizer 35 back to the drum 23. Steam generator 22 may be operated alone in which case damper 46 is closed to prevent gas flow through flue 47. Alternatively reactor heat exchanger 4 may be operated alone, the saturated steam from it by-passing the high pressure turbine section 10 through line 51, the proportion of steam being by-passed being controlled by a valve 52 in response to the high pressure turbine inlet or outlet steam pressure and temperature conditions to maintain suitable inlet steam conditions to the turbine sections. Start up of the plant may be effected by initially firing the generator 22, followed by start up of the reactor, or by starting up the reactor and passing the saturated steam produced through the turbine sections 12, 13 only, section 10 being by-passed until generator 22 is started. In a second embodiment (Fig. 6, not shown) a pulverized fuel fired twin furnace steam generator may be used, both furnaces being lined with steam generating tubes, the exhaust flues of the right-hand furnace containing the surfaces for superheating the nuclear generated steam, and the exhaust flues of the left-hand furnace containing the superheating surfaces of the independent steam generator. In a third embodiment (Fig. 3, not shown) the oil fired generator is of the once through type, whilst both the fuel fired and the nuclear operated turbines are provided with a common by-pass system which may be used during start up of the plant. Helium may be passed through the tubes of the nuclear steam superheater when the reactor alone is inoperative, to prevent their overheating. In further embodiments the steam from the heat exchanger and from the wall tubes of the independent steam generator may be combined together before superheating, and used in the same turbine system (Fig. 4, not shown) or the superheated steam from the steam generator, after expansion in a super-pressure turbine and subsequent reheating may be then combined with the superheated steam from the heat exchanger and used in the lower pressure stages of the turbine system (Fig. 5, not shown).