Pure water goes nuclear

Pure water is critical in many research areas, none more so than nuclear research. Here Dr Ruth Edge and Greg Pilbrow discuss the water requirements for Manchester University’s nuclear research facility The University of Manchester’s Dalton Cumbrian Facility (DCF), which was officially opened on 6th September 2013 by The RT Hon the Lord Hutton of Furness, is a state-of-the-art nuclear research complex on the Westlakes Science & Technology Park in West Cumbria. Specifically designed as a national user facility, it provides academia and industry with the opportunity to carry out research in radiation science and nuclear plant decommissioning, and incorporates academic access to the active research facilities within the National Nuclear Laboratory’s Central Laboratory on the Sellafield site. The facility, the result of an initial £20m joint investment by The University of Manchester and the Nuclear Decommissioning Authority, is part of The University of Manchester’s Dalton Nuclear Institute, and provides a forum for world-leading research and the delivery of dedicated skills development programmes. [caption id="attachment_36941" align="alignright" width="200"] Dalton Cumbrian Facility[/caption] The University of Manchester is one of the world’s premier nuclear research universities and the Dalton Nuclear Institute provides the focus for Manchester’s capability across the full range of nuclear science and engineering. Its Dalton Cumbrian Facility is aimed at significantly enhancing the UK nuclear research and education capability, housing about 50 post-doctoral and PhD researchers, academic lecturers and operating personnel, and attracting leading UK and overseas academics to carry out research and deliver lectures in West Cumbria. Alongside the Culham Centre for Fusion Energy (CCFE) and the National Nuclear Laboratory (NNL) Central Laboratory, DCF is part of the new National Nuclear User Facility (NNUF), an initiative announced in March 2013 as part of the UK Government’s published Nuclear Industrial Strategy. NNUF is a multi-site facility that will give academia and industry access to new internationally leading experimental equipment for nuclear research with investment to be used for enhancing the materials research facilities at DCF. These facilities will enable researchers to carry out experiments on materials that are too radioactive for university laboratories. The Dalton Cumbrian Facility has an ion-beam accelerator hall, which contains extensive irradiation equipment, and an adjoining building containing analytical and inspection laboratories, office accommodation, meeting/seminar rooms and a computer modelling capability. [caption id="attachment_36953" align="alignleft" width="200"] Figure 1 – PURELAB OPTION S7[/caption] Research focuses on three main areas: radiation chemistry, physics and radiation damage to materials; nuclear engineering decommissioning; and management of radioactive waste. Experimental work and computational modelling in the science area are aimed at modelling how the performance of materials deteriorates over time in irradiated environments so as to improve the accuracy of lifespan predictions for nuclear engineering components, and identify causes of failure. Decommissioning research involves understanding the contamination processes of pipes, vessels and buildings in order to develop effective decontamination systems. Radioactive waste management develops treatment methodologies for new or novel waste streams including a molecular level understanding of the solution and colloidal behaviour in effluent and decontamination conditions. Key to the research programme is the support provided by the on-site laboratories. The analytical and post-irradiation examination laboratories are equipped with high end equipment to measure gas production, analyse ions in solution, measure polymers and other organics, determine macromolecular weight distributions, perform isotopic analysis and a wide range of other measurements to analyse the molecular structure and surfaces of materials and samples. Among the analytical techniques employed in the laboratories are UV/Vis spectrophotometry; EPR, FT-IR and IR Raman spectroscopy; gas and ion chromatography, HPLC, GC and GC-MS; [caption id="attachment_36945" align="alignright" width="200"] Figure 2 – PURELAB CLASSIC UV[/caption] absorption, reflectance and fluorescence spectrometry and surface area and pore size analysis (BET method). To produce accurate and repeatable results from this kind of equipment, it is critical to have pure water for calibration and sample preparation, and water quality has to be fully traceable. Being an international research centre, the Dalton Cumbrian Facility specified ASTM Type 1 water as the minimum requirement. Samples can, of course, also become contaminated by laboratory glassware, so ASTM Type II water was specified for supplying the laboratory glassware washing machine. Table 1 gives the ASTM Type I and Type II water quality criteria. The water purification system for the new laboratory was designed and supplied by ELGA Process Water using proven laboratory water purification technologies. Type II water is produced directly from the Westlakes mains water supply by a PURELAB Option S7 unit (Figure 1), which uses reverse osmosis and ion exchange. Reverse osmosis removes about 95% of dissolved inorganic species and 99% of organics of molecular weight greater than 100Da. The Type II water is delivered into a 35 litre capacity polyethylene reservoir from which it is continuously recirculated through the ion exchange cartridge in the Option 7S to maintain water quality which would otherwise deteriorate by dissolution of atmospheric carbon dioxide. The reservoir supplies Type II water directly to the glassware washer and also to a “polishing unit” – a PURELAB  Classic UV (Figure 2) – which upgrades it to Type I. Interconnecting pipework is in PEX cross-linked polyethylene with low leaching properties to avoid contamination of the purified water. The system provides purification by UV irradiation at 185nm and 254nm. The former oxidises trace organics left in the Type II water and the latter provides disinfection. Organic oxidation generates carbon dioxide and this is removed by a mixed bed ion exchange cartridge to achieve the required 0.056µS/cm conductivity. The purified water is delivered to a dispense head that can supply up to 2 l/minute. Unused water is continuously recirculated through the UV and ion exchange cartridge to maintain quality. The water qualities produced by the purification system are shown in Table 2. The Dalton Cumbrian Facility is a scientific research base unique in the UK and Europe. Research undertaken at the facility contributes to national and international nuclear programmes, with the DCF offering facilities and support for academic research on key industry-relevant nuclear physics and engineering issues and enabling the transfer of new knowledge and capability to industry. Research follows a holistic approach that spans mathematical modelling, experimental analysis and interpretation, through to development, demonstration and practical application. The analytical facilities that are critical to the research programme are supported by a state-of-the art water purification system supplying the highest quality water currently available. Authors Dr Ruth Edge is Experimental Officer and Laboratory Manager of The University of Manchester’s Dalton Nuclear Institute and Greg Pilbrow of ELGA Process Water