The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
Malcolm J. Joyce - One of the best experts on this subject based on the ideXlab platform.
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High-intensity power-resolved radiation imaging of an operational nuclear Reactor
Nature Communications, 2015Co-Authors: Jonathan Beaumont, Matthew Mellor, Mario Villa, Malcolm J. JoyceAbstract: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.
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High-intensity power-resolved radiation imaging of an operational nuclear Reactor
Nature Communications, 2015Co-Authors: Jonathan S. Beaumont, Mario Villa, Matthew P. Mellor, Malcolm J. JoyceAbstract:Monitoring the activity of nuclear Reactors requires measuring the neutron distribution in the core efficiently and in real time. Here, the authors present an imaging approach for neutrons and gamma-rays that thanks to a slit-pupil-like design, enables radiations to be visualized directly in operative Reactors. 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.
D. Godin - One of the best experts on this subject based on the ideXlab platform.
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Stand-off nuclear Reactor Monitoring with neutron detectors for safeguards and non-proliferation applications
Nature Communications, 2019Co-Authors: B. M. Ende, L. Li, D. GodinAbstract:Safeguards measures are employed at nuclear Reactor facilities worldwide, to ensure that nuclear material is not diverted from peaceful uses. Typical safeguards measures involve periodic inspections, off-line verification and video surveillance of fuel cycle activities. Real-time verification of the fissile contents via stand-off Monitoring can enhance continuity of knowledge for non-traditional Reactor types, including research Reactors and small modular Reactors. Here we demonstrate the feasibility of using large-area neutron detectors for Monitoring nuclear Reactors at stand-off distances up to 100 m outside Reactor shielding, as a potential Reactor safeguards tool. Since the neutron yield per unit Reactor power depends upon the isotopic composition of the Reactor core, declared changes in fissile composition can be verified without accessing the core. The supporting results of experiments conducted at the National Research Universal Reactor in Canada, are presented. Nuclear power Reactors need to be monitored for safety and security while in operation. Here the authors discuss Monitoring and safeguarding research Reactors and small modular Reactors using detection of neutrons up to a hundred meters away from the Reactor shielding.
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Stand-off nuclear Reactor Monitoring with neutron detectors for safeguards and non-proliferation applications
Nature Communications, 2019Co-Authors: B. M. Ende, L. Li, D. GodinAbstract:Safeguards measures are employed at nuclear Reactor facilities worldwide, to ensure that nuclear material is not diverted from peaceful uses. Typical safeguards measures involve periodic inspections, off-line verification and video surveillance of fuel cycle activities. Real-time verification of the fissile contents via stand-off Monitoring can enhance continuity of knowledge for non-traditional Reactor types, including research Reactors and small modular Reactors. Here we demonstrate the feasibility of using large-area neutron detectors for Monitoring nuclear Reactors at stand-off distances up to 100 m outside Reactor shielding, as a potential Reactor safeguards tool. Since the neutron yield per unit Reactor power depends upon the isotopic composition of the Reactor core, declared changes in fissile composition can be verified without accessing the core. The supporting results of experiments conducted at the National Research Universal Reactor in Canada, are presented.
Yu. M. Semchenkov - One of the best experts on this subject based on the ideXlab platform.
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Development of an in-Reactor Monitoring system for VVER
Atomic Energy, 2009Co-Authors: V. I. Mitin, Yu. M. Semchenkov, A. E. KalinushkinAbstract:More than 20 power-generating units with VVER-1000 and more than 30 with VVER-440 Reactors are currently operating in our country and abroad. This article examines the creation and development of in-Reactor Monitoring systems for different types of VVER Reactors as experience in operating them is gained and the level of knowledge increases. The modern concept of an updated SVRK-M system, which was first implemented in operating nuclear power plants with VVER-1000 Reactors, is presented.
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Analysis of neutron flux noise due to coolant parameter fluctuations in a VVÉR core
Atomic Energy, 2007Co-Authors: Yu. M. Semchenkov, V. A. Mil’to, A. A. Pinegin, B. E. ShumskiiAbstract:The results of investigations of noise appearing in the signals from direct-charge sensors of the in-Reactor Monitoring system of VVÉR Reactors as a result of coolant parameter fluctuations are presented. The calculations and experimental data are used to analyze the dependence of the amplitude of the neutron flux oscillations (local intensity) at the locations of sensors as a function of the magnitude and frequency of the fluctuations of a specific coolant parameter. The NOSTRA program was used to perform the calculations. The results of the analysis were used in the in-Reactor noise diagnostics system in the No. 3 unit of the Kalinin and the No. 1 unit of the Tianwan (China) nuclear power plants.
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Measurement of the Absolute Power of a Fuel Assembly and Current by Direct-Charge Detectors on a SK-fiz Critical Test Stand
Atomic Energy, 2002Co-Authors: I. N. Aborina, V. Yu. Aborin, N. I. Alekseev, S. S. Gorodkov, Yu. A. Epanechnikov, A. D. Klochkov, Yu. A. Krainov, A. A. Ognev, V. R. Ostrovskii, Yu. M. SemchenkovAbstract:A series of investigations studying the currents of rhodium sensors in in-Reactor Monitoring systems and the relation between the currents and the energy release in the fuel elements in the nearest neighbor environment in a VVER-1000 fuel assembly model was completed in 2001–2002 at the Russsian Science Center Kurchatov Institute. The experiments were performed on the SK-fiz critical test stand; the calculations were performed using the high precision MCU-REA/2 computer program, implementing the Monte Carlo method. The reference experimental-computational method for determining the relation between the DCD current and the number of fissions in the six neighboring fuel elements and fuel assembly is described, the effects due to the arrangement of the DCDs at the center and in the fourth row of the fuel assembly are studied, and the experimental data are compared with the computational results.
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Measurement of the Absolute Power of a Fuel Assembly and Current by Direct-Charge Detectors on a SK-fiz Critical Test Stand
Atomic Energy, 2002Co-Authors: I. N. Aborina, V. Yu. Aborin, N. I. Alekseev, S. S. Gorodkov, Yu. A. Epanechnikov, A. D. Klochkov, Yu. A. Krainov, A. A. Ognev, V. R. Ostrovskii, Yu. M. SemchenkovAbstract:A series of investigations studying the currents of rhodium sensors in in-Reactor Monitoring systems and the relation between the currents and the energy release in the fuel elements in the nearest neighbor environment in a VVÉR-1000 fuel assembly model was completed in 2001–2002 at the Russsian Science Center Kurchatov Institute. The experiments were performed on the SK-fiz critical test stand; the calculations were performed using the high precision MCU-REA/2 computer program, implementing the Monte Carlo method. The reference experimental-computational method for determining the relation between the DCD current and the number of fissions in the six neighboring fuel elements and fuel assembly is described, the effects due to the arrangement of the DCDs at the center and in the fourth row of the fuel assembly are studied, and the experimental data are compared with the computational results. The possibilities of the only high-flux critical test stand in the industry are demonstrated (the thermal-neutron flux density 10^11 sec^–1·cm^–2, high accuracy of the experimental and computational methods). The SK-fiz stand and the high precision MCU-REA/2 computer program make it possible to perform comprehensive and detailed investigations of the relationship between the DCD current and the local and integral energy release in fuel assemblies.
Jonathan S. Beaumont - One of the best experts on this subject based on the ideXlab platform.
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High-intensity power-resolved radiation imaging of an operational nuclear Reactor
Nature Communications, 2015Co-Authors: Jonathan S. Beaumont, Mario Villa, Matthew P. Mellor, Malcolm J. JoyceAbstract:Monitoring the activity of nuclear Reactors requires measuring the neutron distribution in the core efficiently and in real time. Here, the authors present an imaging approach for neutrons and gamma-rays that thanks to a slit-pupil-like design, enables radiations to be visualized directly in operative Reactors. 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.
S Dazeley - One of the best experts on this subject based on the ideXlab platform.
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The Physics and Nuclear Nonproliferation Goals of WATCHMAN: A WAter CHerenkov Monitor for ANtineutrinos
arXiv: Instrumentation and Detectors, 2015Co-Authors: M. Askins, S Dazeley, Adam Bernstein, M. Bergevin, T. Handler, A. Hatzikoutelis, D. Hellfeld, P. Jaffke, Yuri KamyshkovAbstract:This article describes the physics and nonproliferation goals of WATCHMAN, the WAter Cherenkov Monitor for ANtineutrinos. The baseline WATCHMAN design is a kiloton scale gadolinium-doped (Gd) light water Cherenkov detector, placed 13 kilometers from a civil nuclear Reactor in the United States. In its first deployment phase, WATCHMAN will be used to remotely detect a change in the operational status of the Reactor, providing a firstever demonstration of the potential of large Gd-doped water detectors for remote Reactor Monitoring for future international nuclear nonproliferation applications. A demonstration of remote Monitoring of a Reactor has been called for in the U.S. National Nuclear Security Adminstration’s (NNSA) Strategic Plan [1].
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Advances toward a transportable antineutrino detector system for Reactor Monitoring and safeguards
2011 2nd International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications, 2011Co-Authors: Dalila Reyna, Jim Lund, S. Kiff, B. Cabrera-Palmer, Nicholas S Bowden, Abraham Bernstein, S Dazeley, G. KeeferAbstract:Nuclear Reactors have served as the neutrino source for many fundamental physics experiments. The techniques developed by these experiments make it possible to use these very weakly interacting particles for a practical purpose. The large flux of antineutrinos that leaves a Reactor carries information about two quantities of interest for safeguards: the Reactor power and fissile inventory. Our SNL/LLNL collaboration has demonstrated that such antineutrino based Monitoring is feasible using a relatively small cubic meter scale liquid scintillator detector at tens of meters standoff from a commercial Pressurized Water Reactor (PWR). With little or no burden on the plant operator we have been able to remotely and automatically monitor the Reactor operational status (on/off), power level, and fuel burnup. The initial detector was deployed in an underground gallery that lies directly under the containment dome of an operating PWR. The gallery is 25 meters from the Reactor core center, is rarely accessed by plant personnel, and provides a muon-screening effect of some 20-30 meters of water equivalent earth and concrete overburden. Unfortunately, many Reactor facilities do not contain an equivalent underground location. We have therefore attempted to construct a complete detector system which would be capable of operating in an aboveground location and could be transported to a Reactor facility with relative ease. A standard 6-meter shipping container was used as our transportable laboratory - containing active and passive shielding components, the antineutrino detector and all electronics, as well as climate control systems. This aboveground system was deployed and tested at the San Onofre Nuclear Generating Station (SONGS) in southern California in 2010 and early 2011. We will first present an overview of the initial demonstrations of our belowground detector. Then we will describe the aboveground system and the technological developments of the two antineutrino detecto- s that were deployed. Finally, some preliminary results of our aboveground test will be shown.
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Advances towards readily deployable antineutrino detectors for Reactor Monitoring and safeguards
2009 1st International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications, 2009Co-Authors: B. Cabrera-Palmer, Jim Lund, S. Kiff, Nicholas S Bowden, Dalila Reyna, Abraham Bernstein, L. Sadler, S DazeleyAbstract:The large flux of neutrinos that leaves a nuclear Reactor carries information about two quantities of interest for safeguards: the Reactor power and fissile inventory. Our SNL/LLNL collaboration has demonstrated that antineutrino-based nuclear Reactor Monitoring is feasible using a relatively small cubic scale detector made of Gadolinium loaded liquid scintillator at tens of meters standoff from a commercial Pressurized Water Reactor, deployed in an underground gallery that lies directly under the containment. Recently we have investigated several technologies paths that could allow such devices to be more readily deployed in the field - of particular concern to Reactor operators and safeguards practitioners is the flammability of the Gd doped liquid scintillator. In addition, many PWR facilities do not have an available underground gallery to provide the screening of muon induced backgrounds. As a result, we have developed and fielded three new detectors: a low cost, non-flammable water based design; a robust solid-state design based upon plastic scintillator; and a smaller cryogenic detector based on ultra-high purity Germanium. All three of these technologies have been deployed at our below-ground facility at the San Onofre Nuclear Generating Station in southern California. We first present an overview of the use of antineutrinos in Reactor Monitoring. We then explain the detection mechanism based on inverse beta decay and the dominant sources of above-ground background that would contaminate this signal. Next, we discuss conceptual ideas under consideration for a future aboveground detector. Separate sections are devoted to describe the design, construction and deployment of each of our three new technologies that have already been deployment. We discuss the various levels of sensitivity to the Reactor antineutrino signature that each of these detectors was able to demonstrate and the tradeoffs that accompany them.
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Advances towards readily deployable antineutrino detectors for Reactor Monitoring and safeguards
2009 1st International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications, 2009Co-Authors: B. Cabrera-Palmer, S. Kiff, Dalila Reyna, Adam Bernstein, Nathaniel Bowden, Lorraine E. Sadler, J.c. Lund, S DazeleyAbstract:The large flux of neutrinos that leaves a nuclear Reactor carries information about two quantities of interest for safeguards: the Reactor power and fissile inventory. Our SNL/LLNL collaboration has demonstrated that antineutrino-based nuclear Reactor Monitoring is feasible using a relatively small cubic scale detector made of Gadolinium loaded liquid scintillator at tens of meters standoff from a commercial Pressurized Water Reactor, deployed in an underground gallery that lies directly under the containment.
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The deployment of three prototype detectors for Reactor Monitoring and safeguards
Journal of Physics: Conference Series, 2008Co-Authors: Nathaniel Bowden, Dalila Reyna, S Dazeley, Adam Bernstein, Lorraine E. Sadler, J.c. Lund, R SvobodaAbstract:Fission Reactors emit large numbers of antineutrinos and this flux may be useful for the measurement of two quantities of interest for Reactor safeguards: the Reactor's power and plutonium inventory throughout its cycle. The high antineutrino flux and relatively low background rates means that simple cubic meter scale detectors at tens of meters standoff can record hundreds or thousands of antineutrino events per day. Such antineutrino detectors would add online, quasi-real-time bulk material accountancy to the set of Reactor Monitoring tools available to the IAEA and other safeguards agencies with minimal impact on Reactor operations. Our LLNL/SNL collaboration has deployed a total of three prototype safeguards detectors at a Reactor in Southern California in order to test both the method and the practicality of its implementation in the field. Results from these detectors will be presented, and their respective advantages and disadvantages described. LLNL-POST-404014 This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory in part under Contract W-7405-Eng-48 and in part under Contract DE-AC52-07NA27344. Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.
