NANOstructured Beta Detectors for Detection Of Tritium (NANODOT)

Tritium is a radioactive isotope of hydrogen that is produced from nuclear fission reactions and from the action of corrosion, radiolytic and microbial processes on radioactive wastes. It decays to He-3 by soft beta decay of average kinetic energy 5.7 keV. This low energy makes it difficult to detect even by scintillation counting. Fast, accurate and precise measurement of gaseous tritium is required for, inter alia: environmental monitoring & leak detection around interim storage sites for higher level radioactive wastes; development of the environmental safety case for the geologic repository for those same wastes; environmental and safety monitoring in and around nuclear reactor and nuclear fuel processing plant; and nuclear forensics, including applications in counter-terrorism, homeland security and non-proliferation. Palladium is a metal that shows an almost unique capacity for absorbing H2 into its crystal matrix. There are a number of commercial H2 sensors on the market based on the interaction of H with palladium metal, most of which quantify this uptake by measurement of the metal capacitance or resistance. No one to date has explored the possibility of exploiting the unique Pd-H interaction as a means to selectively preconcentrate tritium from gas phase sample matrices in order to improve its detection using a Pd-modified scintillation detector. We therefore propose to exploit new concepts in nanomaterials synthesis to allow us to couple nanoporous palladium layer-modified transducers / scintillation counters and digitized data capture from ionizing radiation events to develop a novel radiometric sensor-based measurement system for gaseous tritium detection. The use of nanoporous palladium will increase the surface area of metal available for tritium absorption whilst the use of digitised data capture will allow for whole data sets to be captured for posterity and post-processing. Both measures are expected to lead to improved signal to noise ratios assistive to the achieving of lower limits of detection and so greater accuracy and precision in measurement. In developing this sensor for the applications mentioned above , the proposed work addresses the following NERC Theme Action Plans (TAPs):Technologies; Environment, Pollution & Human Health; and natural Hazards. We aim to develop the sensor system through to Technology Readiness Level 5 (Demonstration). This project is a partnership between the Engineering Dept and the Lancaster Environment Centre (LEC) at Lancaster University and Hybrid Instruments, a Lancaster spin-out. The National Nuclear Laboratory (who have served as partners on predecessor projects to this), and the Nuclear Decommissioning Authority Radioactive Waste Management Directorate will be a key end user.