Abstract: Methods for making nuclear fuel compacts containing precise amounts of nuclear fuel material which exhibit low heavy metal contamination and fewer defective coatings following compact fabrication using a hardenable binder including petroleum pitch or the like. Nuclear fuel particles having a multiple layer fission-product-retentive barrier, with a dense outer layer thereof being surrounded by a protective overcoating, e.g., pyrocarbon having a density between about 1 and 1.2 g/cm.sup.3, that is encapsulated within a thin shell of pyrocarbon from about 1.7 to about 2 g/cm.sup.3 in density, can be precisely metered to create charges containing very precise amounts of nuclear fuel material that can be pre-compacted in molds under relatively high pressures and then combined with the fluid binder which is ultimately carbonized to produce carbonaceous compacts containing very precise nuclear fuel loadings.

Abstract: In a high temperature furnace adapted for fuel particle coating applications, an electrode ring forms a portion of the furnace wall, heating elements within the furnace being urged into conductive engagement with an internal surface of the electrode ring by means of adjustable spring mechanisms arranged outside the furnace and interconnected with the heating elements by elongated bolts in order to permit adjustment of the spring load without interrupting operation of the furnace. The spring mechanism provides nearly constant contact pressure between the heating elements and the electrode ring surface under varying thermal and physical conditions and prevents overheating and failure of the electrode ring.

Abstract: Three embodiments of apparatus for gas coating particles suspended in a fluidized bed within a coating chamber are illustrated, each having a base plate with a center opening, an extension nozzle assembly arranged in the opening and mounted on a movable two-piece internally cooled gas probe for supplying reactant gas to the nozzle and an annular unloading passage surrounding the probe and in communication with a side unloading chute. In the three embodiments, different means are provided for raising and lowering the nozzle assembly to permit unloading of coated particles and provide access to the nozzle assembly.