The current scenario of radioactive waste management requires innovative and automated solutions to ensure its effectiveness and safety. In response to this need, the Proximity Imaging System for Sort and Segregate Operations (PI3SO) project was proposed. It is a gamma radiation proximity scanner system for radioactive waste with the primary goal of speeding up some aspects of the waste management cycle while reducing direct human operations. The system will provide proximity imaging for hot-spot finding and spectral analysis for radiological characterization, enabling semiautomatic recognition, sorting and separation of radioactive waste. The core of the proposed scanning system consists of an array of 128 CsI(Tl) scintillators, 1 cm3 size, coupled with silicon photomultipliers (SiPMs), installed on a motorized bridge sliding along a suitable table in order to scan the materials under investigation.

The current scenario of radioactive waste management requires innovative and automated solutions to ensure effectiveness and safety. In response to this need, the PI3SO (Proximity Imaging System for Sort and Segregate Operations) project was proposed. It is a gamma radiation proximity scanner system for radioactive waste with the primary goal of speeding up some aspects of the waste management cycle while reducing direct human operations. The system will provide proximity imaging for hot spot finding and spectral analysis for radiological characterization, enabling semiautomatic recognition, sorting and separation of radioactive waste. The core of the proposed scanning system consists of an array of 128 CsI(Tl) scintillators, 1 cm3 size, coupled with silicon photomultipliers (SiPM), installed on a motorized bridge sliding along a suitable table in order to scan the materials under investigation.

Monitoring radioactive waste (radwaste) is a critical aspect of nuclear waste management, ensuring environmental safety and compliance with regulatory standards. A few initiatives, funded by EURATOM within Horizon 2020, focused on long-term repository surveillance, thus enhancing measurement precision, and ensuring traceability of stored radioactive materials. Among the advanced technologies explored for this purpose, scintillating fibers have emerged as promising tools to monitor gamma radiation due to their sensitivity, flexibility, and real-time data acquisition capabilities. Promising as well was the development of solid state ³He-free neutron sensors. These gamma and neutron sensors we developed can monitor both types of highly penetrating radiation from radwaste drums.

Peak detection is a fundamental task in spectral and time-series data analysis across diverse scientific and engineering disciplines, yet traditional approaches are highly sensitive to the choice of algorithm parameters, complicating reliable and consistent interpretation. Triggered by the requirement for the energy calibration for the 128 detectors of the PI3SO gamma ray scanner, we introduce a versatile methodology inspired by concepts from persistent homology, extending the traditional notion of persistence to a multi-parameter setting. Our approach systematically explores the space defined by multiple detection parameters and quantifies peak robustness through the hyper-volume in the parameter space where each peak is consistently identified. This volumetric multi-parameter persistence (VM-PP) measure enables robust peak ranking and significantly reduces the sensitivity of detection outcomes to individual parameter selection, demonstrating utility across simulated and experimental spectral datasets. Extensive validation reveals that this method reliably differentiates genuine peaks from noise-induced fluctuations under diverse noise conditions, proving effective in practical spectroscopic calibration scenarios. This framework, general by design, can be readily adapted to diverse signal-processing applications, enhancing interpretability and reliability in complex feature-detection tasks.

In the framework of the three Euratom H2020 projects MICADO, PREDIS and CLEANDEM several devices and systems were developed suitable for radioactive waste drums monitoring in store and possibly during transportation. The radiological gamma and neutron data, collected in real time, represent a useful tool both for safety and security and are also suitably stored in databases. Two miniature low cost sensors for gamma and neutrons, constituting the so called MiniRadMeter device, were integrated inside a small box and installed on top of a robotic vehicle for a quick dose rate mapping in radiologically hostile environments in case of nuclear decommissioning or accident remediation. These systems were installed and tested in several real or realistic nuclear environments and the outcome was absolutely promising. The test missions and the corresponding results are described.

The reconditioning of radioactive waste (radwaste) from energy and non-energy activities is a key challenge in nuclear decommissioning. Proper waste management is crucial, especially for Low-Level Waste (LLW) and Intermediate-Level Waste (ILW), which make up most of the radwaste. According to the IAEA, effective storage is essential for isolation, environmental protection, and potential future recovery. Sorting and segregation are vital steps in this process. The PI3SO project (Proximity Imaging System for Sort and Segregate Operations) was developed as a gamma radiation spectroscopic scanner for radioactive waste. Its main goal is to speed up waste management while minimizing human intervention. The system uses proximity imaging and spectral analysis to identify “hot-spots” in materials, with precision down to 1 cm². It consists of two linear arrays of 64 CsI(Tl) scintillators coupled to SiPMs, mounted on a motorized bridge to scan radwaste. Preliminary tests show a minimum detectable activity of a few hundred Bq, with an energy resolution of 5–6% FWHM at 662 keV ¹³⁷Cs peak. The system has successfully detected isotopes like ⁴⁴Ti, ⁴⁴Sc, and ²²Na during real-world tests. PI3SO promises to enhance safety, reduce human exposure, and improve the efficiency of waste management, particularly for ILW and LLW during decommissioning.