Real-time detection and discrimination of radioactive gas mixtures using nanoporous inorganic scintillators

The nuclear industry’s expansion to encompass carbon-free electricity generation from small modular reactors and nuclear fuel reprocessing necessitates enhanced detection and monitoring of pure beta-emitting radioactive elements such as ³H and ⁸⁵Kr; this endeavour is crucial for nuclear safety authorities tasked with environmental monitoring. However, the short range of electrons emitted by these gases makes detection challenging. Current methods, such as ionization chambers and liquid scintillation, do not offer at the same time good sensitivity, real-time analysis and ease of implementation. We demonstrate an approach using a gas–solid mixture to overcome these limitations. We synthetized a transparent and scintillating nanoporous material, an aerogel of Y₃Al₅O₁₂:Ce⁴⁺, and achieved real-time detection with an efficiency of 96% for ⁸⁵Kr and 18% for ³H. The method reaches a sensitivity below 100 mBq per cm³ over 100 s measurement time. We are able to measure simultaneously as mixtures containing both ³H and ⁸⁵Kr a capability not possible previously. Our results demonstrate a compact and robust detection system for inline measurement of strategic radioactive gases. This combination of concept and method enhances nuclear power plant management and contributes to environmental safeguarding. Beyond the detection issues, this concept opens a wide field of new methods for radionuclide metrology.