Thermionic energy converters

Claim 1

A thermionic device for the conversion into electrical energy of nuclear energy released by a fissionable material comprising: a tubular anode formed of niobium; a cylindrical cathode having a sealed interior chamber positioned concentrically within said tubular anode with an interelectrode gap therebetween, said cathode being formed of a refractory metal composition consisting essentially of a mixture of molybdenum and approximately 1/2% titanium and having on its outer surface an emitter coating of ruthenium; a nuclear fuel solid of annular configuration with an axial void on the centerline thereof bonded metallurgically to the interior of said cathode and partially filling said sealed interior chamber, said axial void being evacuated for the collection and containment of fission product gases within said interior chamber, said fuel solid consisting essentially of particles of a fissionable material-containing ceramic composition dispersed in a matrix of molybdenum to promote the transfer of thermal energy through said fuel solid to said cathode; and a cesium vapor located at least partially within said interelectrode gap in operation.