| 摘要 |
1,042,543. Reactors. UNITED STATES ENERGY COMMISSION. May 17, 1965 [June 3, 1964], No. 20701/65. Heading G6C. A fuel element, for use in a liquid metal cooled fast breeder reactor, comprises a fuel section 12 abutted at each end by a breeder section 13, 14, the three sections being enclosed in cladding 11; a fission products venting system includes a collector conduit 51 extending from the upper portion of the fuel section to an external manifold, in the lower part of the cladding, which includes a uni-directional flow control valve; a number of coolant tubes 17 extend through the fuel section which also contains transverse heat sink barriers to prevent central melting of the fuel made, e.g. of lower heat producing fuel, and transverse mechanical support barriers, e.g. of tungsten sheet to prevent mass slumping of the fuel; a control rod 25 passes centrally through the fuel section. The fuel, through which the coolant tubes and control rod containing tube pass, may be in the form of a vibratory compacted mass of fissile and moderator material, with or without fertile material, or it may be in the form of an ordered array briquettes of these materials. Fission product gases accumulate in a reservoir in the fuel section containing granulated beryllia and in space 53 until their pressure is sufficient to open ball valve 52 and to force liquid sodium 16 down U-tube 54, the accumulated gases and small amount of coolant being then expelled into line 77 and conduit 76. The tap end of bore 77 is closed by a flap valve 78 (Fig. 4, not shown), when the fuel element is fully seated. The coolant tubes have varying internal cross-sections along each individual length (Fig. 7, not shown). The breeder sections have coolant flow passages through them, and the fertile material is housed in containers.
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