Speaker
Description
In the context of the “Grand Challenges”, special attention is paid to the reconditioning of radioactive waste (radwaste) generated by energy and non-energy activities. Institutions such as the Nuclear Decommissioning Authority (NDA) promote projects that aim to develop new, safe, affordable, and accessible technologies for better protection of both people and the environment. Effective waste management is critical to the success of nuclear decommissioning missions. Nuclear decommissioning generates several types of waste, including Low-Level Waste (LLW) and Intermediate-Level Waste (ILW), which represent most of the radwaste. These spoiled materials are typically stored in specialized drums at near-surface disposal sites. Delaying operations can reduce ILW and increase LLW, which may be exempt from regulatory control. Decommissioning strategies include keeping the facility in safe confinement mode or dismantling, conditioning the waste, and storing it temporarily until it decays to levels that allow for standard disposal. According to the International Atomic Energy Agency (IAEA), storage is critical for isolation, environmental protection, and the possibility of future recovery if necessary. Waste sorting and segregation are key steps in this process.
In this context, the PI3SO project (Proximity Imaging System for Sort and Segregate Operations) was developed as a gamma radiation spectroscopic scanner/imager tool for radioactive waste. The primary goal of PI3SO is to accelerate the waste management cycle while minimizing human intervention. The system provides detailed information via proximity imaging and spectral analysis, enabling the identification of "hot-spots" in activated materials. The system consists of a table equipped with two linear arrays of scintillators, installed on a motorized bridge that slides along the table to scan the radwaste from above and below. It employs two linear arrays of 64 CsI(Tl) scintillators and each of them is coupled to a SiPMs to perform a scan with precision down to 1 cm2. Preliminary promising results form the basis for further optimization of the prototype and sensor technology.
The PI3SO system has undergone successful testing with radioactive sources, achieving a minimum detectable activity of a few hundred Bq and showing an interesting 5-6% energy resolution at the 662 keV peak of 137Cs. Real-world tests on decommissioned accelerator parts at INFN-LNS further demonstrated the system's ability to detect radioactive isotopes, including 44Ti, 44Sc, 22Na, 60Co, and 133Ba. The PI3SO system promises to improve safety by reducing direct human exposure to radioactive materials, minimizing operational errors, and offering a faster, more efficient waste management process. This innovative approach holds promising potential for enhancing the sorting, segregation, and storage of ILW and LLW during nuclear facilities decommissioning, thus reducing costs and facilitating the release of storage space.
