PURPOSE: To develop a crucible for evaporating uranium where evaporation efficiency can be improved without deteriorating heat insulating effect by arranging mixedly tungsten powders and tungsten blocks in an evaporating crucible where the uramium is melted by irradiating electron beams.
CONSTITUTION: Plural tungsten blocks 7a are disposed so as to be in contact with the whole face of inner wall in the crucible body 1 and further, on the tungsten blocks 7a, the tungsten fine powders 5 and particles 6 are charged. On the tungsten fine powders 5 and particles 6, uramium pellets 4a are placed and this is melted with the heat of the electron beam A and penetrated into the tungsten fine powders 5 and particles 6. In such a manner, when the tungsten fine powders 5 and particles 6 coexist with the molten uranium 4, since the solid tungsten fine powders 5 and particles 6 become a resistor to the heat convection of the molten uranium 4, consequently, this becomes the same condition as increasing the viscosity thereof, and heat conductivity and heat convection of the molten uranium 4 are restrained, and the evaporation efficiency is promoted.
NAKAGAWA JUN
NAKAISHI NOBUYOSHI
YONAGO AKINOBU
KANEKAWA AKIHIRO
MITSUBISHI HEAVY IND LTD