CONSTRUCTION METHOD OF CAPILLARY BARRIER

PROBLEM TO BE SOLVED: To provide a construction method of a capillary barrier capable of reliably absorbing and effectively collecting a radioactive material such as cesium and draining with respect to the seepage water having a possibility of contamination with cesium or the like by contacting with the radioactive waste.SOLUTION: A construction method of a capillary barrier having formed a sand layer of a top part of a gravel layer: replaces the sand layer of the top part by a sand layer formed of zeolite; uses the capillary barrier layer constructed by the above two layers as a gradient layer; makes a seepage water containing an extremely low level radioactive material infiltrated from a capillary barrier layer top part of the gradient layer stay in a boundary part between the gradient layer and the sand layer formed of the zeolite; and makes the zeolite absorb the extremely low level radioactive material contained in the seepage water.