Development of a Technique to detect the presence of Depleted Uranium in the radiation shielding of highly radioactive sources

Abstract

Depleted Uranium (DU) metal is commonly used as shielding in medical radiation therapy and industrial radiography equipment because of its high atomic number and density. DU though is classified as a nuclear material by the International Atomic Energy Agency (IAEA) and must be accounted for and subject to IAEA verification measures. Nowadays shielding containers may be replaced by lead and tungsten, thus Nuclear Regulating Authorities should be able to check the presence of DU. They may however lack the proper equipment to detect low energy gamma from DU particularly while having the high activity source present. In this research, low energy gamma-ray spectrometry using Cadmium Telluride (CdTe) and High Purity Germanium (HPGe) detectors was experimentally tested in laboratory and field measurements with various DU samples as well as with industrial radiography source projectors and Co-60 cancer treatment equipment. The proposed method was applied successfully with all gamma radiography source projectors containing Ir-192 up to 85 Ci. However, it was deemed unnecessary to inspect the Co-60 cancer treatment equipment since DU was no longer used as the shielding material.