| 摘要 |
1,108,349. Controlling reactors. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. 29 June, 1966 [8 Oct., 1965; 29 Oct., 1965; 5 Nov., 1965; 17 Nov., 1965; 4 Jan., 1966; 28 Jan., 1966], Nos. 42875/65, 45907/65, 47077/65, 48932/65, 358/66 and 4014/66. Heading G6C. A reactor is controlled by causing a change between the liquid and vapour phases in a vaporizable moderator liquid present in discrete zones which are in or around the reactor core and are bounded by absorber material having neutron capturing characteristics predominantly in the thermal energy region. Thus, the ability of the absorber material to capture neutrons is affected by the variable moderating effect of the discrete zones so that, for example, a change of the moderator liquid into the vapour phase reduces neutron capture in the absorber material and causes an increase in the reactivity of the reactor core. Means for controlling selectively whether the vaporizable moderator liquid in the discrete zones is in the vapour or liquid phase may comprise either: (a) high and low pressure supplies of the moderator liquid which are selectively connected with the zones, the pressure being respectively high enough to ensure the liquid phase and low enough to ensure the vapour phase, or (b) the circulation of the moderator liquid through the zones at a selectively variable rate; the heating of the zones in the core vaporizing slow flow rates, fast flow rates remaining unvaporized. An undermoderated pressurized water reactor of the " integral " type using plutonium fuel and employing method (a) above is described with reference to drawings, the vaporizable moderator liquid in the discrete zones also being water. As shown in Fig. 4, which is a plan view of one compartment of the core, the core is formed into a plurality of compartments by means of parallel walls 40, 41 and hollow cross-walls 42, 43. Each compartment receives two fuel assemblies as disclosed in Specification 1,108,350, each assembly comprising vertical fuel plates 11, burnable poison plates 19, 20 and end plates 23, 24 of neutron absorber material, e.g. cadmium, the plates being clamped together to form a removable unit retained in the core by a spring-load fastening 59 (Figs. 7-9, not shown). The spaces in the hollow cross-walls 42, 43 form the discrete zones filled with the vaporizable moderator liquid. |
