GB1370039A - Nuclear reactors - Google Patents

Abstract

1370039 Reactors SIEMENS AG 6 Oct 1972 [8 Oct 1971] 46325/72 Heading G6C A pressurized water reactor comprises a core 2 made up of an array of canless fuel assemblies 10, each of which consists of spacers 17, fuel rods and control rod guide tubes, the core 2 being mounted in a container 7. A number of baffle plates 19 extend laterally from the container 7 to engage spacers 17 of the outer fuel assemblies 10c. Further baffle plates 20 are disposed between the baffle plates 19 but these do not extend as far as the core 2. In the embodiment described the space between the container 7 and the spacers 17 is sealed off in a fluid-tight manner by the baffle plates 19 but this is not an essential feature. The coolant enters the reactor vessel 1 through an inlet port 3 and flows down between the vessel 1 and the container 7 before flowing up through the core 2 to an outlet port 4. Coolant leaving the core 2 through its sides is forced back in again by the baffle plates 19 and this alternating movement of the coolant affords good mixing in the marginal fuel assemblies of the core. The reactor is provided with guide strips 21a, 21b, 21c which serve to guide the outer fuel assemblies on their introduction to or extraction from the core. The guide strips, which extend parallel to the longitudinal axis of the core, may be provided over the entire length of the core.