Hitachi, Ltd.

Hiroko Mizuno

Makoto Kikuchi

Shin Tamata

Susumu Horiuchi

Tsutomu Baba

Tatsuo Izumida

Satoru Ohashi

Tadashi Sakuraoka

A soluble salt (sodium sulfate or sodium borate (Na.sub.2 SO.sub.4 or Na.sub.2 B.sub.4 O.sub.7) contained as the main component in a concentrated radioactive waste liquid generated in the BWR power plant or the PWR power plant is insolubilized and precipitated, sodium hydroxide (NaOH formed in the insolubilization is separated from the precipitate and the radioactive waste liquid slurry containing the precipitate is solidified with a hydraulic solidifying material. Since the separated caustic soda (NaOH) is free of radioactive substances, it can be easily utilized again, and since the radioactive substances are stably fixed in the solidified body, leakage of radioactivity from the solidified body can be greatly reduced.

Process for treating radioactive waste liquid

A method of and apparatus for pelletizing a radioactive waste powder is disclosed. The apparatus includes a pelletizing section, and a pelletizing die which has one end facing a powder receiving cavity formed in the pelletizing section and the other end exposed to the atmosphere, and a through bore is so formed in the die as to pass from the one end to the other end. A first pelletizing rod can be inserted into and pulled out of the through bore from the one end of the die through the cavity, and a second pelletizing rod can be inserted into a pulled out of the through bore from the other end of the die. The first and second rods are arranged such that, when the second rod takes a predetermined position in the through bore, the first rod is inserted through the receiving cavity into the through bore, thereby enabling the pelletizing operation of the powder within the through bore. The structure is adopted for allowing air compressed in the through bore to be discharged into the cavity without causing the compressed air to leak into the atmosphere during the pelletizing operation.

Method of and apparatus for pelletizing radioactive waste powder

The invention is concerned with radioactive waste pellets in solidified form in which radioactive waste pellets including light waste pellets having specific gravities smaller than that of a filler are solidified with the filler in a container. A cover disposed in an opening portion of the container is provided with filler injection ports which do not permit the passage of the light waste pellets. The invention is further related to a process for forming radioactive waste pellets in solidified form by injecting the filler through the filler injection ports formed in the cover, so that the radioactive waste pellets and the filler are uniformly solidified.

Radioactive waste pellets in solidified form and a process for forming

Growing community of inventors

Hitachi, Japan

Hiroko Mizuno