Speaker
Description
Nuclear waste management requires testing and analyses of the radioactive content and assessing the quality of the final waste forms and packages to characterize the waste and check for potential radiological hazards. The radioactive substances can be contained into a variety of materials, like concrete, steel, wood, etc. Quality of the measurements as well as time and adaptability to specific different geometries will be an asset especially during nuclear decommissioning activities where maximization of material recycling together with minimization of waste volume is a key cost driver.
Scintillators allow to execute in many cases most of the required characterization measurements thanks to the very high efficiency they are offering and that are scalable in size, to allow also even very large forms/packages up to BigBags and ISO container or large metal plate of conveyor belt for soil sorting.
The work presents a detailed characterization with a 220 l mock-up nuclear waste drum composed of four different layers of materials with different thickness and density. The MDAs (Minimum Detectable Activities) have been calculated in all the configurations using a Cs-137 radioactive source and different types of organic scintillating crystals, like NaI(Tl), BGO, CeBr3 of different sizes and comparison with HPGe. In addition, other measurement conditions were tested, including the depth of the source in the matrices, the distance between the detectors and the drum, and the rotation angle, to be able to obtain a comprehensive study of the MDA in different configurations of the setup.
The study intends to offer an analysis for the selection of the detectors most suited for efficient gamma spectroscopy in nuclear waste applications and the characterization of the waste packages. This work can make a significant contribution in the determination of the specific setup (detector and geometry configuration) for the best waste characterization where MDAs below the national regulation limits for free release are required.
