CLEANING METHOD FOR BEDS OF MINOR RIVERS IN PERMAFROST ZONE TO REMOVE BOTTOM SEDIMENTS CONTAMINATED WITH RADIONUCLIDES Russian patent published in 2008 - IPC E02B3/02 E02B15/00 G21F9/24 

FIELD: construction, hydrotechnics.

SUBSTANCE: invention is attributed to cleaning methods for beds of minor rivers in permafrost zone with seasonal flow from sediments contaminated with radionuclides from radioactive solid waste handling. Removal of contaminated sediments is executed in winter by segments in downstream direction after discharge cancellation and their dewatering. Bottom ground is loosened and mechanically shaved by layers as it is freezed by natural cold with stocking it in temporary piles and subsequent transportation outside river floodplain for burying or laying in surface burial hills. To speed-up layer-by-layer freezing the net of trenches with vertical walls is cut in parallel in bottom ground depth as it freezes. Trench width is defined by parameters of equipment being used, their depth is not less than half a meter and distance between trenches corresponds to double trench depth. The invention allows to isolate from biota (for a period of not less than 100 years) the most migration suspectable solid radioactive wastes and hence to lower the risk of people irradiation.

EFFECT: lowering the risk of people irradiation.

1 dwg