Feasibility Study on the Nuclide Analysis of the Radwaste Drum Using the Spectrum to Dose Conversion Factor

Estimating the radioisotope inventory of a drum based on the measured dose rate information, which is called as the dose to curie (DTC) conversion [1–3], has been known that there could be extremely high uncertainty associated with establishing the radioactivity of gamma emitters in a drum. However, the DTC method is still an effective assay method to calculate the radioisotope inventory because of their simple and easy procedures to be applied. To make the DTC method practical, numerous assumptions have to be made and limitations placed on its use. These assumptions and limitations were related to the dose rate measurement and the relative abundance of gamma emitters in a drum. These two variables were generally obtained from the different detection mechanism. Unfortunately, that expanded the limitation of using the DTC method. The spectrum to dose (STD) conversion factor [4,5] that was calculated from the measure pulse height spectrum of the gamma ray detector could be made obtaining two variables from the drum to be assayed at once. This method could be made estimating the radioisotope inventory of a drum more practical.