A Proposal of an evaluation method in ray measurements for clearance of various decommissioning materials in forms

Ishimori, Yuu  ; Yokoyama, Kaoru*; Naganuma, Masaki

Although the clearance of uranium was institutionalized for metals, its implementation has been actually limited only to metals with simple shapes because of problems of the measurement. The present study proposes an evaluation method in ray measurements for the clearance of various decommissioning materials in forms. The proposed method was based on the analysis technique, called "equivalent model" focusing on rays scattered by the Compton effect, developed in Ningyo-toge Environmental Engineering Center. This model was applied to the analysis of test results of simulated drums measured using a commercially-available -ray measurement system. The analysis result indicated the validity of this application for the clearance level of 1Bq/g (total uranium). The presentation will describe the concept of a new evaluation method including an improvement of the measurement system.