Patent GB-1198001-A (GB)
Title: Nuclear Reactors
Inventor: ORSZAK PETER
IPC: G21C1/12
Filed: 1967-01-24
Abstract: 1,198,001. Reactors. ENGLISH ELECTRIC CO. Ltd. 22 Jan., 1968 [24 Jan., 1967], No. 3363/68. Divided out of 1,196,915. Heading G6C. A reactor has one or more elongated connecting assemblies within the reactor vessel connecting two structures between which, in operation of the reactor, substantial relative movement is liable to occur, at least in a direction other than longitudinally with respect to the connecting assembly or assemblies, the latter including a first connecting member arranged for rolling contact in one plane with and between two further connecting members which are arranged for rolling contact, in a plane at right angles to the first plane, with surfaces fixed relative to the respective structures. One of the structures may for example be the vessel itself, which may be a pressure vessel of concrete or other material, or a reactor tank; or it may be the pile cap or cover for a reactor tank; or it may be the core, or a structure comprising the core and another member or members fixed relative to the core. In the reactor shown in Fig. 2, a concrete pressure vessel 10 is divided near its top by a membrane 11 into a " hot box " or coolant outlet chamber 12 and a larger core chamber 13 housing the reactor core. The reactor, which is of the split-flow type, is similar to that described in Specification 1,196,915. Suitable thermal insulation 27 is provided over the whole internal surface of the hot box 12, and further insulation 28 over that of the steel liner 26 of the pressure vessel 10 in the core chamber 13 and on the underside of the skirt 33 of the membrane 11. Each fuel stringer is connected with a standpipe plug (not shown) in a standpipe 17 penetrating the roof 18 of the pressure vessel 10, by connecting means (not shown) passing up through or connecting tube assembly 29 which extends from the corresponding standpipe 17 down through the hot box 12 to an extension tube 16 fixed to and passing through the membrane 11. The connecting tube assembly 29 comprises a tube member 35 formed from two tubes 36, 37 joined by straps 38 with their adjacent ends spaced so as to form outlets 19 for the coolant. The upper and lower end faces 35A, 35B of the tube member 35 are formed as diametrically-opposite parts of a first cylinder of revolution, the axis of which is transverse to that of the tube member. The faces 35A, 35B engage flat inner faces of two intermediate tube members 39, 40 arranged coaxially above and below the tube member 35. The upper end of the upper intermediate tube member 39 comprises an outer face engaging the flat lower end face of the corresponding standpipe 17, while the lower end of the lower intermediate tube member 40 comprises an outer face engaging the flat upper end face of the corresponding extension tube 16. These outer faces are formed as diametricallyopposite parts of a further cylinder of revolution, the axis of which is transverse to that of the tube member 35 when this is aligned with the intermediate tube members 39, 40. The axes of the two cylinders of revolution are at right angles to each other. Two sleeves 41, 42 are fixed to and extend axially beyond the standpipe 17 and extension tube 16 respectively. Radial dowels in these sleeves engage holes in the tube member 35, or vice versa. When the reactor is not in operation, the pressures above and below the membrane 11 are equal and the dowels therefore carry a load and the tube member 35 is in tension. When the reactor is in operation, the coolant pressure below the membrane 11 is much greater than that above and consequently supports the membrane with the tube member 35 now in compression. The invention is also applicable where the connecting assemblies do not convey fluid but are provided solely for structural purposes, e.g. for supporting the reactor core. In such cases, the assemblies may be of hollow or solid members or both.