Development of microfluidic devices to support actinide analysis

In each nuclear fuel cycle steps, from ore discovery to fuel fabrication, requires careful monitoring and control of the composition of the nuclear materials. This is essential for material accountancy, accident prevention and ensuring the safety and efficiency of any nuclear operation including reactors.

Traditional separation and pre-concentration processes for actinide analysis are difficult to perform, as dissolution of actinides such as uranium and plutonium generally requires concentrated mineral acid. The radioactivity and presence of strong mineral acid means most of the very labour intensive and time-consuming processes need to be contained to ensure safety. Such containment methods presents significant challenges for applying automated handling processes, and instead reliance typically falls upon manual handling methods using containments (e.g gloveboxes) to deliver user safely which also requires the handling of relatively large sample volumes with the loss of dexterity a typical consequence of containment.

Following the as low as reasonably achievable approach to the reduction of the overall waste and potential exposure, microfluidics technology presents a viable alternative route in the handing of radioactive and toxic materials at microscales. Microfluidics exploits fluid behaviour at scales (micro to picolitres) far smaller than those conventionally used in the laboratory. Fluid flow at this scale provides improved chemical mixing and offers better process control (such as temperature). Several analytical processes can then be integrated on to a single miniaturised device of a few centimetres in size. The reduction in consumption of hazardous radioactive material and reagent reduces costs and the potential risk of radiation exposure to workers.

There is limited research on the application of microfluidics for environments that are commonly present in the nuclear industry. The bulk of the microfluidic device-based studies for processes involving radionuclides focuses on separation and recovery of actinides from waste recovery solutions, particularly in spent nuclear fuel recycle, but there are limited studies on their use in the general analysis of actinides. .

This project will attempt to develop microfluidic devices and methods that can analyse for actinide materials with minimal sample and reagent consumption, and waste generation. Initial work will assessing the viability of various common microfluidic fabrication materials for these actinide analysis devices. In addition, a review will be conducted to examine the possible assay, detection, and separation methods that can be integrated either as an online-on chip system or off-chip on-line system. Separation methods such as solvent extraction and ion chromatography, and detection methods such as mass spectroscopy and X-ray fluorescence will be considered. The development of these devices will consider typical operating environments in common nuclear laboratories. The associated ancillary system used in this case has also needs to be compatible with likely extreme conditions that may encountered. While the radiochemistry involved in separation and pre-concentration of the samples and integration of optical, electrochemical, or spectroscopic detection with microfluidic technologies are all challenging areas that must be addressed to produce a functional microfluidic device for actinide analysis.

The target of an integrated device that supports actinide analysis would present an improvement path for the modern nuclear analytical facilities, potentially improving radiological safety for workers, safeguard features because of the potential for automation, reduced sample volume requirement and waste generation, and reducing analysis costs. This is an interdisciplinary project that brings together the research areas of microsystems, nuclear fission, and analytical sciences that fall under the remit of EPSRC.