Fuel subassembly dimensions

Plant Lathee pitch of components on centre plane of eore (mm) Fuel subassembly Dimensions (mm) Fuel enrichment... 

The concept of the fuel subassemblies for the REARA-60 reference design was based on the international experience, with the dimensions taken mostly from ALMR. The number of fuel pins in the subassembly is 61, separated by helicoidal wire wraps and arranged in a triangular matrix, forming a hexagonal set. The fuel is a U-10%Zr metallic alloy with active length equal to 62.0 cm and having two (top and bottom) 30.0 cm nickel reflectors. 

The active ingredient of the MTR, enriched uranium, is introduced as. an aluminum alloy, tolled to sheet form and clad on the edges and faces with 2S aluminum. The finished core dimension is to be 0,020 by 23.75 by 2.55 in. and is to be centered with respect to edges, ends, and faces. Dimensional details are given in Table A6.A. Eighteen of these fuel plates are then furnace brazed to grooved aluminum side plates to form subassemblies. A cross-section of such an assembly is shown in Chap. 2. Fig. 2.2.A. 

The pin-type elements consist of a number of cast, cylindrical, fuel pins stacked end pn end within a thin-waU, circular, metal tube with a thin sodiumbond between the fuel and the tube wall (Fig. 43). The tvibes are spaced in a hexagonal pattern within each subassembly by a slingle, helical rib welded on the outside of each tube. The only difference between the twQ designs of the pin-type is that the Modified Reference Design has smaller diametral dimensions. In the pin-type element the coolant flows on the outside of the tubes. 

For all designs, the core is approximately a right, circular cylinder with a length of 14.3 in. and a volume of 50 liters. The core is composed pf a number of hexagonal subassemblies which fcontain the fuel element. The core is assumed surrounded by a depleted uranium blanket of dimensions such as to provide a reflector savings of 9 cm. 

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