PURPOSE: To reduce the volume of a radioactive waste by a method wherein only a part contaminated with radioactivity in a side wall part of a biological shield wall of a nuclear power station is removed by cutting by using a wire saw.
CONSTITUTION: Longitudinal holes are formed at prescribed intervals, by a boring device, along the boundary part between a radio-activated part and a non-radioactivated part of a side wall part 7 of a biological shield wall 1. These longitudinal holes being used, subsequently, a cut face is formed in the vertical direction along a radial direction by a wire saw 31, and then, with the longitudinal holes used as well, the cut face is formed in the vertical direction along a cylindrical face of the boundary part by the wire saw 31. Next, the cut face is formed in the horizontal direction by the wire saw 31 and thus an inside side wall part being radioactivated is removed by cutting sequentially as a block of prescribed dimensions.
WATANABE MORISHIGE
JO YOSHIAKI
SAKAKI SHINJI
HITACHI SHIPBUILDING ENG CO