Determination of trace uranium in waste using a gamma-ray measurement system

Ohashi, Yusuke 

Much metal waste is generated during decommissioning of uranium processing facilities. In this paper, measurement tests were performed on a typical simulated metal waste generated by the decommissioning using the clearance measurement device equipped with NaI detectors, and the results were compared with the simulation results by the MCNP code. Results showed the proper placement of dismantled materials in a drum can be estimated by evaluating the detection efficiency of each waste placement by simulation in advance. Moreover, it was confirmed that the relative errors between simulation and measurement results were within 35% at 0.1 Bq/g. It was found that the uranium concentration below the clearance level (1 Bq/g) can be confirmed even if the error is included, and the clearance level can be safely verified by considering the relative error between the simulation result and the experimental result.