PURPOSE: To improve reducing the volume efficiency in safety by breaking the used fuel channel which is made brittle by being dipped in brittle treating liquid, and washing and drying the broken fuel channel.

CONSTITUTION: The used fuel channel 3 which is taken out a used fuel nuclear fuel assembly is dipped in a container 5 where the brittle treating liquid is charged. The channel 3 which is made brittle is sent to a channel breaking machine 6. The broken channel 3 is put in the cleaning and drying machine 7 consisting of a vacuum dryer and brittle treating liquid components are removed from the channel 3. A brittle treating liquid collecting machine 8 condenses air discharged from the dryer 7 to recover the brittle treating liquid components. The recovered brittle treating liquid is put back to the container 5 and reused. Thus, zirconium alloy 9 in the form of powder is treated as solid refuse.