METHOD OF RECYCLING AND REUSING RADIOACTIVE CONCRETE RESULTING FROM RADIOLOGICAL AND NUCLEAR INSTALLATION DECOMMISSIONING

摘要

The invention relates to a process for treating low-activity reactive concrete resulting from radiological and nuclear installation decommissioning. According to the invention, the process consists, in a first stage, in crushing the radioactive concrete wastes with sizes of less than 350 mm, using a jaw crusher preset to a nominal slot size of 65 mm. The resulting gravel is then sorted into three dimensional fractions: of more than 50 mm; between 16 and 50 mm and of less than 16 mm. The dimensional fraction between 16 and 50 mm is placed in steel containers with a capacity of 200 l. The gravel fraction higher than 50 mm is crushed in a second stage, using a hammer crusher with screens having a mesh size of 9 mm. The resulting material is sorted using a screen with a mesh size of 2.5 mm, to result in two dimensional fractions: smaller than 2.5 mm and bigger than 2.5 mm, respectively. The fractions bigger than 2.5 mm and smaller than 16 mm are crushed in a third stage, using a hammer crusher with screens having a mesh size of 6 mm. The fine aggregates obtained thereby are further mixed with cement, water and usual additives, to result in a mortar which is poured into containers over gravel and, possibly, over a radioactive concrete block, up to a radioactive waste filling degree of 70...75%. It results in a composite product consisting of radioactive gravel in a mortar matrix based on fine radioactive aggregates. The so-obtained radioactive waste package provides, when stored, a radiation dose rate of max 2 mSv/h at the container wall.