Devoluming method of radioactive wastes

Upon finely dividing radioactive wastes comprising carbon steel so as to devolume them, the radioactive wastes are immersed in liquid nitrogen, cooled at or lower than an embrittle temperature, and then stresses are applied so as to break and finely divide them. According to this method, radioactive wastes comprising carbon steel can be broken easily thereby enabling to finely divide them effectively, so that gaps inside thereof can be eliminated to improve the efficiency when they are contained into a low level radioactive waste container. (T.M.)