To improve reliability by completely sealing the powder treating part from throwing processing matter to taking out after the processing, prevent contamination of the pot and improve maintainability by arranging the pot body outside a glove box.

By narrowing one half of a rotary shell 1 containing nuclear fuel scrap, its extended end 9 is connected to the side of a connection part 6 freely rotatably. A scrap throw-in part 4 is placed in the upper part of the connection part 6 and a taking-out part 5, in the lower part, which are connected freely opening. A supply and an exhaust pipes X and Y for atmosphere gas are connected to the connection part 6. These connection part 6, throw-in part 4 and taking-out part 5 are contained in a glove box 18 for sealing from the air, and the rotary shell 1, a rotation driver 2, a heater part 3 and an inclination device 8 are arranged outside the glove box.