| 摘要 |
1,092,107. Reactors. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. Nov. 2, 1964 [Nov. 12, 1963; Jan. 14, 1964], Nos. 44591/63 and 1714/64. Heading G6C. A reactor having a core through which pressurized liquid coolant-moderator is circulated includes a pressurizer and a flow guide to isolate a stream of coolant in the core for delivery to the pressurizer, so that in operation the pressurizing stream is hotter than the remaining coolant in the core. The reactor has a core 11 comprising a plurality of fuel assemblies mounted between grid plates 12, 13. The pressurizer 35 is situated above the core and is fed with the isolated stream of hotter pressurized water, derived from the centre fuel assembly, through an orifice 38e and pipe 38. The pipe end 38c is closed and the pressurizer water is delivered to the pressurizer through spray nozzles in the pipe upper side walls. The coolant is circulated by pumps 21 through inner coaxial duct 23 to an inlet plenum chamber, through the core fuel assemblies to a space 26 (and pipe 38), upwards within a cylindrical containment 25 to the upper end of the heat exchangers 27, through the heat exchangers, to an annular chamber 18, and finally to the pump inlet. Pressurizer water is fed to the main coolant stream through inverted U tubes 39 which extend downwards through the heat exchangers to discharge at a point just above the mainstream core outlets. In a modification, the inverted U tubes are dispensed with, and instead the bottom of the pressurizer tank is left open. Containment and insulation,-The pressurizer tank 35, pipe 38 and pressure vessel 17 are all provided with heat insulation skins. A gas layer is maintained between the pressure vessel 17 and a shroud 41. Vessel 42 is filled with water, to a level 45, which is cooled by heat exchanger pipes 46. If the pressure vessel burst, water passes from it to the shroud 42, which contains a rupture disc 48 which allows contaminated pressurized reactor water to be absorbed below the surface of the water in the shell 42. Modifications.-The pressurizer fuel assembly may be in a core position of depressed neutron flux, thus enabling the pressurizer stream to attain a higher temperature without fuel burnout. Variable flow restrictors may be incorporated in the pressurizer circuit to adjust the over-pressure. The pressurizer stream may be derived from a fraction of normal coolant flow being returned from the core outlet to a second pass through an isolated part of the core. |
