Decommissioning of nuclear facilities generates large quantities of different types of radioactive material. According to the requirement of the waste packaging, most incompressible waste must be put into steel boxes directly, which makes it difficult to measure and obtain the activity of the radioactive material in the steel boxes.
This study aims to establish an approach for measuring radioactive waste in steel box based on the in situ objects counting system (ISOCS).
In this work, ISOCS was used to characterize the radioactive material in steel boxes. The corrections for the absorption coefficients and the geometry factors of the big bulky sources were calculated using the ISOXSW (ISOCS Calibration SoftWare) in situ efficiency calibration without a radioactive source software. The verification experiments were carried out using standard sources with similar size and geometry.
The results show that the measurement error of six symmetrical positions of steel box with standard 137Cs and 60Co radioactive source by ISOCS is less than 30%.
The study verifies that ISOCS software is able to accurately estimate the composition and activity of radioactive material in a steel box.
