A novel technique for trace actinides spectrometry directly in water samples

Vulnerability of drinking water distribution systems which would have major public health, economic and psychosocial consequences, has become a big concern to governmental agencies and water supply authorities. In case of an extremely alerting situation, such as Fukushima, the alpha emitters in water are probed on samples after very long chemical operations and time for the delivery of results extends over several days. The main objective of the ActiFind project is the realization of a high sensitivity alpha particles sensor working into water for the rapid detection and identification of traces of actinides at the 1 Bq/L level, after a short electro precipitation step. A 200 μm thick BDD layer is deposited on a CANBERRA PIPS detector. Under low cathodic current density, nitrate reduction occurs and produces a layer of (OH
^-
) at the BDD surface and solid actinides hydroxides are accumulated at the entrance window of the PIPS sensor. After deposition, the ActiFind sensor is directly connected to a spectrometry chain. The coupling of the system to an integrated microfluidic F.F.E. platform has been developed in order to render the system compatible with more complex aqueous solutions in real environments containing interfering ions or substances. Further extension of the system will explore the possibility to use it as a decontaminating system on a scale up basis. The ability to perform alpha spectrometry directly in liquid media at trace levels constitutes a real breakthrough. Bq/L range is reachable within 10 minutes, opening the field to the development of a portable system with low energy requirement, and enabling real time monitoring of media at risk. This new technology can be used in the analysis of water used for cleaning surfaces in fuel reprocessing plants, sampling of environmental water around waste storage facilities, analysis of water samples after a nuclear accident or in the Mining sector where water quality should be assessed in the surrounding area.