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When built, the technology will, for the first time, be able to assess radiation – particularly neutron and gamma-ray fields - under water to check the safety and stability of material within submerged areas of nuclear sites. The technology could also be used to speed up the removal of nuclear waste from decaying storage ponds at the Sellafield Reprocessing facility in Cumbria – shortening decommissioning programmes and potentially delivering significant savings for taxpayers. Led by engineers at Lancaster University, and involving colleagues at the University of Manchester, Hybrid Instruments Ltd. as well as Japanese partners, the international research project, which is funded by the Engineering and Physical Sciences Research Council, will develop a remote-controlled vehicle that can go into these harsh submerged environments to assess radiation levels. When Fukushima was hit by huge Tsunami waves in the wake of the most powerful earthquake ever to hit Japan, the cores of three of the six reactors were damaged and had to be flooded by sea water to keep them cool to prevent more extensive damage. Nuclear fuel debris needs to be removed to enable safe decommissioning of the reactors, however it is not known how much there is, its condition and the likelihood of accidental reactions being triggered. New detection instruments developed through the project will help identify nuclear fuel and help operators to deal with it safely. Malcolm Joyce, Professor of Nuclear Engineering at Lancaster University and lead author of the research, said: "A key task is the removal of the nuclear fuel from the reactors. Once this is removed and stored safely elsewhere, radiation levels fall significantly making the plant much more safer, and cheaper, to decommission. "Our research will focus on developing a remote-operated submersible vehicle with detection instruments that will be able to identify the radioactive sources. This capability does not currently exist and it would enable clean-up of the stricken Fukushima reactors to continue." Engineers at Lancaster University have expertise in radiation detection technology and experts at the University of Manchester will concentrate of developing the remote-operated vehicle. Barry Lennox, Professor of Applied Control at the University of Manchester said: "A key challenge with the remote-operated vehicle will be to design it so that it can fit through the small access ports typically available in nuclear facilities. These ports can be less than 100 mm in diameter, which will create significant challenges." This two and a half-year international research project also involves Japanese partners, including the Japan Atomic Energy Agency, the National Maritime Research Institute of Japan and the Nagaoka University of Technology. There is potential for the resulting technology to also be used by the oil and gas sector for assessment of naturally-occurring radioactive material in offshore fields. Professor Philip Nelson, Chief Executive of the Engineering and Physical Sciences Research Council, said: "The disaster at Fukushima has created massive challenges for Japan, the safe removal of the fuel rods from the site is just one, but it is a critical step in decommissioning the plant and its material. This EPSRC-funded research will provide the authorities with the tools to assess the site and prepare for removal. EPSRC is proud to be assisting this international project." Explore further: First of four Fukushima reactors cleared of nuclear fuel

Beaumont J.S.,Lancaster University | Mellor M.P.,Createc Ltd. | Villa M.,Vienna University of Technology | Joyce M.J.,Lancaster University | Joyce M.J.,Hybrid Instruments Ltd.
Nature Communications | Year: 2015

Knowledge of the neutron distribution in a nuclear reactor is necessary to ensure the safe and efficient burnup of reactor fuel. Currently these measurements are performed by in-core systems in what are extremely hostile environments and in most reactor accident scenarios it is likely that these systems would be damaged. Here we present a compact and portable radiation imaging system with the ability to image high-intensity fast-neutron and gamma-ray fields simultaneously. This system has been deployed to image radiation fields emitted during the operation of a TRIGA test reactor allowing a spatial visualization of the internal reactor conditions to be obtained. The imaged flux in each case is found to scale linearly with reactor power indicating that this method may be used for power-resolved reactor monitoring and for the assay of ongoing nuclear criticalities in damaged nuclear reactors. © 2015 Macmillan Publishers Limited.

Joyce M.J.,Lancaster University | Aspinall M.D.,Hybrid Instruments Ltd. | Cave F.D.,Hybrid Instruments Ltd. | Lavietes A.,International Atomic Energy Agency | Lavietes A.,Lawrence Livermore National Laboratory
IEEE Transactions on Nuclear Science | Year: 2014

In recent years, real-time neutron/γ-ray pulse-shape discrimination has become feasible for use with scintillator-based detectors that respond extremely quickly, on the order of 25 ns in terms of pulse width, and their application to a variety of nuclear material assays has been reported. For the in-situ analysis of nuclear materials, measurements are often based on the multiplicity assessment of spontaneous fission events. An example of this is the 240Pueff assessment stemming from long-established techniques developed for 3He-based neutron coincidence counters when 3He was abundant and cheap. However, such measurements when using scintillator detectors can be plagued by low detection efficiencies and low orders of coincidence (often limited to triples) if the number of detectors in use is similarly limited to 3 or 4. Conversely, an array of > 10 detector modules arranged to optimize efficiency and multiplicity sensitivity, shifts the emphasis in terms of performance requirement to the real-time digital analyzer and, critically, to the scope remaining in the temporal processing window of the firmware in these systems. In this paper we report on the design, development and commissioning of a custom-built, 16-channel real-time pulse-shape discrimination analyzer specified for the materials assay challenge summarized above. The analyzer incorporates 16 dedicated and independent high-voltage supplies along with 16 independent digital processing channels offering pulse-shape discrimination at a rate of 3 × 106 events per second. These functions are configured from a dedicated graphical user interface, and all settings can be adjusted on-the-fly with the analyzer effectively configured one-time-only (where desired) for subsequent plug-and-play connection, for example to a fuel bundle organic scintillation detector array. © 2014 IEEE.

Joyce M.J.,Lancaster University | Gamage K.A.A.,Lancaster University | Aspinall M.D.,Hybrid Instruments Ltd | Cave F.D.,Hybrid Instruments Ltd | Lavietes A.,International Atomic Energy Agency
IEEE Transactions on Nuclear Science | Year: 2014

The design, principle of operation and the results of measurements made with a four-channel organic scintillator system are described. The system comprises four detectors and a multiplexed analyzer for the real-time parallel processing of fast neutron events. The function of the real-time, digital multiple-channel pulse-shape discrimination analyzer is described together with the results of laboratory-based measurements with 252Cf 241Am-Li and plutonium. The analyzer is based on a single-board solution with integrated high-voltage supplies and graphical user interface. It has been developed to meet the requirements of nuclear materials assay of relevance to safeguards and security. Data are presented for the real-time coincidence assay of plutonium in terms of doubles count rate versus mass. This includes an assessment of the limiting mass uncertainty for coincidence assay based on a 100 s measurement period and samples in the range 0-50 g. Measurements of count rate versus order of multiplicity for 252Cf and 241Am-Li and combinations of both are also presented. © 1963-2012 IEEE.

Joyce M.J.,Lancaster University | Aspinall M.D.,Hybrid Instruments Ltd. | Cave F.D.,Hybrid Instruments Ltd. | Lavietes A.D.,International Atomic Energy Agency
IEEE Transactions on Nuclear Science | Year: 2012

Pulse-shape discrimination (PSD) in fast, organic scintillation detectors is a long-established technique used to separate neutrons and γ rays in mixed radiation fields. In the analogue domain the method can achieve separation in real time, but all knowledge of the pulses themselves is lost thereby preventing the possibility of any post- or repeated analysis. Also, it is typically reliant on electronic systems that are largely obsolete and which require significant experience to set up. In the digital domain, PSD is often more flexible but significant post-processing has usually been necessary to obtain neutron/γ-ray separation. Moreover, the scintillation media on which the technique relies usually have a low flashpoint and are thus deemed hazardous. This complicates the ease with which they are used in industrial applications. In this paper, results obtained with a new portable digital pulse-shape discrimination instrument are described. This instrument provides real-time, digital neutron/γ-ray separation whilst preserving the synchronization with the time-of-arrival for each event, and realizing throughputs of 3 × 10 6 events per second. Furthermore, this system has been tested with a scintillation medium that is non-flammable and not hazardous. © 2012 IEEE.

Joyce M.J.,Lancaster University | Aspinall M.D.,Hybrid Instruments Ltd. | Cave F.D.,Hybrid Instruments Ltd. | Georgopoulos K.,Lancaster University | Jarrah Z.,Hybrid Instruments Ltd.
IEEE Transactions on Nuclear Science | Year: 2010

The design, build and test of a digital analyzer for mixed radiation fields is described. This instrument has been developed to provide portable, real-time discrimination of hard mixed fields comprising both neutrons and γ rays with energies typically above 0.5 MeV. The instrument in its standard form comprises a sensor head and a system unit, and affords the flexibility to provide processed data in the form of the traditional scatter-plot representation separating neutron and γ-ray components, or the full, sampled pulse data itself. The instrument has been tested with an americium-beryllium source in three different shielding arrangements to replicate the case in which there are only neutrons, only γ rays and where both neutrons and γ-rays are present. The instrument is observed to return consistent results. © 2010 IEEE.

Joyce M.J.,Lancaster University | Gamage K.A.A.,Hybrid Instruments Ltd.
IEEE Nuclear Science Symposium Conference Record | Year: 2012

Scanning-based methods for the spatial characterization of radioactivity represent an important application of radiation instrumentation. In this paper, the use of a single, fast liquid scintillation detector for this purpose is described which enables radionuclides that emit both γ rays and neutrons to be characterized at the same time, in real-time. This approach combines the use of an autonomous astronomical mount, fast digital mixed-field analyzer and scintillation/high-Z collimator to enable an image of the origin of both neutrons and γ rays to be constructed on-the-fly as the data are detected. The events are detected, digitized, discriminated, logged and assigned to a corresponding component in one of two separate images (either neutron of γ ray) before the eyes of the user. In particular, this technique has potential uses for the environmental characterization of radioactive contamination in nuclear facilities, security applications and in accident response scenarios. The technique complements current, established γ-ray imaging capabilities that rely on inorganic scintillators, to the combined assay of neutron- and γ-ray emitters. This opens up the assessment to neutron-emitting fissile materials and heavy actinides that are susceptible to spontaneous fission. The research is topical since the system is not reliant on now-scarce quantities of 3He and could readily exploit non-hazardous high-flashpoint scintillation liquids. Of particular novelty in this paper is the real-time acquisition of a mixed-field image, improved spatial resolution due to a refined collimator geometry and the characterization of an accelerator-borne field. © 2011 IEEE.

Agency: GTR | Branch: Innovate UK | Program: | Phase: Feasibility Study | Award Amount: 78.99K | Year: 2017

Tritium (T) is a radioactive isotope of hydrogen made during routine operation of nuclear reactors. This can give rise to waterborne tritium (as tritiated water HTO) in, inter alia, spent fuel (SF) cooling ponds and SF processing & waste treatment facilities – all potential sources of leaks to ground. HTO behaves identically to H2O and so is highly mobile in the environment and human tissue, with resultant human health risks. Thus, there are pressing safety, environmental & economic needs for fast, accurate & precise measurement of T around nuclear sites and in the waste streams arising from their operation/decommissioning. T emits a soft beta radiation making radiometric detection hard. However, data from successful Hybrid Instruments/Lancaster University projects funded by NERC & InnovateUK provide proof-of-principle that T can be selectively & reversibly gathered by palladium from HTO, this pre-concentrated T then being easily detected by solid scintillation counting. Building on this innovation, we aim to incorporate this technology in automated, fast & interference free monitors at TRL7 for faster testing of groundwater, effluent and materials without human exposure.

Hybrid Instruments Ltd | Date: 2011-10-05

Embodiments of the present invention provide an apparatus for radiation analysis, comprising a pulse discrimination module arranged to receive a signal corresponding to a pulse output by a scintillator and to determine a discrimination value indicative of one or more characteristics of the pulse, and a radiation type determination module for determining a type of radiation responsible for the pulse according to the discrimination value.

Agency: GTR | Branch: Innovate UK | Program: | Phase: Feasibility Study | Award Amount: 123.31K | Year: 2015

Tritium (T) is a radioactive isotope of hydrogen made during routine operation of nuclear reactors. This can give rise to waterborne tritium (as tritiated water HTO) in nuclear facilities process and waste streams and tanks – all potential sources of leakage to ground. HTO behaves identically to H2O and so is highly mobile in both the environment and human tissue, with associated health risks on ingestion. There are therefore good safety, environmental & economic reasons for fast, accurate & precise measurement of tritium around nuclear sites. Tritium’s radiation is very weak, making its measurement by radiation detectors very difficult. We have devised a method by which tritium can be selectively absorbed by palladium metal from HTO, this pre-concentrated tritium then being easily detected by radiometric counting. Building on this innovation, we aim to explore the feasibility of building a palladium based tritium sensor that offers cheaper, faster, more sensitive and more relaiable tritium detection than current technology.

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