The control part IND-100, which interfaces the field signals to the control networks in the control systems of PIEF (Post-Irradiated Examination Facility) and RWTF (Radioactive Waste Treatment Facility), was designed and fabricated. Preamplifier boards for radiation detectors, proportional counter and Geiger-Mueller tube which are in use in the radiation monitoring systems, were also designed and fabricated. Control parts which may be replaced with the domestic parts were surveyed, and a domestic relay model and a recorder model were selected as the replaceable ones. To improve the control systems, adoption of programmable controller to the conventional relay logic system were considered and analyzed. (Author).