scholarly journals Simulation of delayed gamma rays from neutron-induced fissions using MCNP 6.1

2020 ◽  
Vol 225 ◽  
pp. 06007
Author(s):  
R. De Stefano ◽  
B. Pérot ◽  
C. Carasco ◽  
E. Simon
Keyword(s):  
Experimental Data ◽  
Homeland Security ◽  
Gamma Rays ◽  
Decay Curve ◽  
Fission Products ◽  
Nuclear Material ◽  
Nuclear Materials ◽  
Time Behavior ◽  
Time Decay ◽  
Waste Drums

As part of its R&xD activities in the fields of radioactivewaste drum storage and homeland security, the NuclearMeasurement Laboratory of CEA Cadarache has started studiesrelated to the detection of induced delayed fission gamma rays asa signature of U/Pu presence either in radioactive wastes or incargo containers and luggage. The study described in the presentpaper explores the feasibility of detecting fission delayed gammarays of nuclear materials interrogated by a pulsed neutrongenerator. For this purpose, Monte Carlo simulations have beenperformed with ACT, the MNCP6 Activation Control Card.Simulated results have been compared with experimental data tovalidate the numerical model. Samples of uranium andplutonium have been irradiated for 2 hours with a pulsed D-Tneutron generator delivering 14 MeV neutrons with an averageemission of 8.107 n/s, which are thermalised in a graphite cellcalled REGAIN. At the end of irradiation, activated nuclearmaterials were placed in a low-background, high-resolutiongamma spectroscopy station in order to detect delayed gammarays emitted by fission products. Anomalies have been observedin the calculated time decay curve of fission delayed gamma rayswith MCNP6 ACT card, but the time behavior is correct for non-fission activated materials like aluminum or copper. On the otherhand, the number of counts recorded in the main simulatedgamma ray lines from activated nuclear material fission productsis consistent with the experimental results, thus validating thesimulation scheme in view of further studies on thecharacterization of radioactive waste drums or special nuclearmaterial detection in cargo containers.

scholarly journals PROCESSING OF EXPERIMENTAL DATA OF THE PROCESS OF REFINING NUCLEAR MATERIAL Zr1%Nb BY ELECTRON-BEAM MELTING BY MEANS OF INTERVAL ANALYSIS METHODS

2019 ◽  
pp. 118-123
Author(s):  
A.V. Yefimov ◽  
M.M. Pylypenko ◽  
T.V. Potanina ◽  
T.A. Yesypenko ◽  
T.A. Harkusha ◽  
...  
Keyword(s):  
Experimental Data ◽  
Electron Beam ◽  
Interval Analysis ◽  
Electron Beam Melting ◽  
Nuclear Material ◽  
Nuclear Materials ◽  
Analysis Methods ◽  
The Relationship ◽  
Content Of Oxygen

The possibilities of applying the methods and models of interval analysis, which take into account the uncertainties in the specification of data for Zr1%Nb alloys, to more accurately determine the relationship between the microhardness of Zr1%Nb alloy samples and the content of oxygen in them, have been investigated. The correctness of the application of methods and models of interval analysis for processing the results of experiments to study the properties of nuclear materials is shown.

scholarly journals Testing and performances of Spectroscopic Radiation Portal Monitor for homeland security

2020 ◽  
Vol 225 ◽  
pp. 07008
Author(s):  
C. Deyglun
Keyword(s):  
Experimental Data ◽  
Homeland Security ◽  
Radioactive Material ◽  
Regulatory Control ◽  
Nuclear Materials ◽  
Operating Characteristics ◽  
Portal Monitor ◽  
Radiation Portal Monitor ◽  
Illicit Trafficking ◽  
Different Sources

Each year States report to IAEA loss, theft or out of regulatory control radioactive materials. Most incidents are minor, but material is potentially available for criminal acts. Measures to reduce the radiological and nuclear threat are many-faceted. An important component is the ability to detect illicit transport of radioactive material. Spectroscopic Radiation Portal Monitors are deployed around the world to detect illegal radioactive material traffic. A combination of experimental data collected during testing campaigns and simulations is a good way to study the performance of Spectroscopic Radiation Portal Monitors in realistic conditions. The paper presents a process to evaluate the performances of a portal, based on a combination of experimental data and MCNP simulations to calculate the detection probability and the false alarm rate. IRSN developed platforms for testing Spectroscopic Radiation Portal Monitors for pedestrian control. Experimental data were collected from an available commercial Spectroscopic Radiation Portal Monitor, tested in the framework of the Illicit Trafficking Radiation Assessment Program phase II Round Robin Test. Many scenarios were tested with different sources using realistic setups and many experimental data were collected. The tested equipment was then simulated with MCNP only based on the data provided in the user manual and the standards found in the industry. To get a realistic idea of the uncertainty, all the variables inherent in the measurement were considered, their relative contributions were identified and quantified, then propagated to predict an overall uncertainty. The combination of experimental data, numerical simulations and uncertainty evaluation showed good agreement with experimental assays. The results were used to test the sensitivity of a Spectroscopic Radiation Portal Monitor to special nuclear materials for different alarm thresholds. This process applied to different scenarios according to defined targets should help in the selection of operating characteristics of the portal.

scholarly journals Investigative radiochemistry – a key element in nuclear forensics

2011 ◽  
Vol 1 (1) ◽  
pp. 145-149 ◽  
Author(s):  
K. Mayer ◽  
M. Wallenius ◽  
Zsolt Varga ◽  
T. Wiss ◽  
T. Fanghänel
Keyword(s):  
Fission Products ◽  
Nuclear Material ◽  
Radioactive Material ◽  
Nuclear Materials ◽  
Additional Information ◽  
Chemical Impurities ◽  
Decay Products ◽  
Activation Products ◽  
Illicit Trafficking ◽  
Nuclear Forensic

AbstractSince the fall of the Iron Curtain illicit trafficking of nuclear and radioactive material has become an issue of concern both on the political and the scientific level. Seized material may be analysed in order to obtain clues on its origin and intended use and to prevent diversion of material from the same source in the future. Nuclear materials (uranium or plutonium) are of particular worry due to the nuclear proliferation risk associated with the material. Nuclear forensic investigations are aimed at the fact that nuclear material carries (inherent) information on its history, including on its origin and the processes applied for its production. Important conclusions can be drawn from decay products, activation products and fission products. Chemical impurities and the isotopic composition of certain major and minor constituents may provide additional information. Comparison of the measured results with nuclear material databases may yield evidence on the production site. The paper will describe the methodologies developed for addressing the above issues, focussing on radiochemical methods. Examples of nuclear forensic casework will illustrate the experience gathered in these areas.

scholarly journals Revisiting the Analysis of the Isochronous Mass Measurements of Uranium Fission Fragments at the ESR

2020 ◽  
Vol 227 ◽  
pp. 02012
Author(s):  
R. S. Sidhu ◽  
R. J. Chen ◽  
Yu. A Litvinov ◽  
Y. H. Zhang ◽  
Keyword(s):  
Experimental Data ◽  
Data Analysis ◽  
State Of The Art ◽  
Fission Products ◽  
Mass Measurements ◽  
Fission Fragments ◽  
Uranium Fission

The re-analysis of experimental data on mass measurements of ura- nium fission products obtained at the ESR in 2002 is discussed. State-of-the-art data analysis procedures developed for such measurements are employed.

scholarly journals New Results on Radioactive Mixture Identification and Relative Count Contribution Estimation

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4155
Author(s):  
Bulent Ayhan ◽  
Chiman Kwan
Keyword(s):  
Deep Learning ◽  
Noise Source ◽  
Simulated Data ◽  
Nuclear Material ◽  
Machine Learning Algorithms ◽  
Detector Response ◽  
Nuclear Materials ◽  
Ratio Estimation ◽  
Analysis Software ◽  
Detector Distance

Detecting nuclear materials in mixtures is challenging due to low concentration, environmental factors, sensor noise, source-detector distance variations, and others. This paper presents new results on nuclear material identification and relative count contribution (also known as mixing ratio) estimation for mixtures of materials in which there are multiple isotopes present. Conventional and deep-learning-based machine learning algorithms were compared. Realistic simulated data using Gamma Detector Response and Analysis Software (GADRAS) were used in our comparative studies. It was observed that a deep learning approach is highly promising.

scholarly journals SiLiF Neutron Counters to Monitor Nuclear Materials in the MICADO Project

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2630
Author(s):  
Luigi Cosentino ◽  
Quentin Ducasse ◽  
Martina Giuffrida ◽  
Sergio Lo Meo ◽  
Fabio Longhitano ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Detector Response ◽  
Nuclear Materials ◽  
Spent Fuel ◽  
Neutron Detectors ◽  
Intermediate Level Radioactive Waste ◽  
Eu Project ◽  
Interim Storage ◽  
Waste Drums

In the framework of the MICADO (Measurement and Instrumentation for Cleaning And Decommissioning Operations) European Union (EU) project, aimed at the full digitization of low- and intermediate-level radioactive waste management, a set of 32 solid state thermal neutron detectors named SiLiF has been built and characterized. MICADO encompasses a complete active and passive characterization of the radwaste drums with neutrons and gamma rays, followed by a longer-term monitoring phase. The SiLiF detectors are suitable for the monitoring of nuclear materials and can be used around radioactive waste drums possibly containing small quantities of actinides, as well as around spent fuel casks in interim storage or during transportation. Suitable polyethylene moderators can be exploited to better shape the detector response to the expected neutron spectrum, according to Monte Carlo simulations that were performed. These detectors were extensively tested with an AmBe neutron source, and the results show a quite uniform and reproducible behavior.

LARGE TIME DECAY OF SOLUTIONS TO ISENTROPIC GAS DYNAMICS WITH SPHERICAL SYMMETRY

2009 ◽  
Vol 06 (02) ◽  
pp. 371-387
Author(s):  
NAOKI TSUGE
Keyword(s):  
Spherical Symmetry ◽  
Gas Dynamics ◽  
Large Time ◽  
Approximate Solutions ◽  
Large Time Behavior ◽  
Time Behavior ◽  
Time Decay ◽  
Decay Of Solutions ◽  
Isentropic Gas Dynamics ◽  
Isentropic Gas

We consider the large time behavior of solutions to isentropic gas dynamics with spherical symmetry. In the present paper, we show the decay of the pressure in particular. To do this, we investigate approximate solutions constructed by a difference scheme.

scholarly journals Compact lightweight imager of both gamma rays and neutrons based on a pixelated stilbene scintillator coupled to a silicon photomultiplier array

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jihwan Boo ◽  
Mark D. Hammig ◽  
Manhee Jeong
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Sampling Rate ◽  
High Sensitivity ◽  
Pulse Shape Discrimination ◽  
Nuclear Materials ◽  
Silicon Photomultiplier ◽  
Analog To Digital ◽  
Particle Imaging ◽  
Imaging Plane

AbstractDual particle imaging, in which both neutrons and gamma-rays in the environment can be individually characterized, is particularly attractive for monitoring mixed radiation emitters such as special nuclear materials (SNM). Effective SNM localization and detection benefits from high instrument sensitivity so that real-time imaging or imaging with a limited number of acquired events is enabled. For portable applications, one also desires a dual particle imager (DPI) that is readily deployable. We have developed a hand-held type DPI equipped with a pixelated stilbene-silicon photomultiplier (SiPM) array module and low sampling-rate analog-to-digital converters (ADCs) processed via a multiplexed readout. The stilbene-SiPM array (12 × 12 pixels) is capable of effectively performing pulse shape discrimination (PSD) between gamma-ray and neutron events and neutron/gamma-ray source localization on the imaging plane, as demonstrated with 252Cf neutron/gamma and 137Cs gamma-ray sources. The low sampling rate ADCs connected to the stilbene-SiPM array module result in a compact instrument with high sensitivity that provides a gamma-ray image of a 137Cs source, producing 6.4 μR/h at 1 m, in less than 69 s. A neutron image for a 3.5 × 105 n/s 252Cf source can also be obtained in less than 6 min at 1 m from the center of the system. The instrument images successfully with field of view of 50° and provides angular resolution of 6.8°.

scholarly journals Nuclear Fuel Assay through analysis of Uranium L-shell by Hybrid L-edge/XRF Densitometer using a Surrogate Material

2018 ◽  
Vol 170 ◽  
pp. 07009
Author(s):  
Seunghoon Park ◽  
Sungyeop Joung ◽  
Jerry Park
Keyword(s):  
Radiation Effects ◽  
Nuclear Material ◽  
Minor Actinide ◽  
Nuclear Materials ◽  
Promising Candidate ◽  
X Ray ◽  
Liquid Nitrogen Cooling ◽  
Material Solution ◽  
X Ray Absorption

Assay of L-series of nuclear material solution is useful for determination of amount of nuclear materials and ratio of minor actinide in the materials. The hybrid system of energy dispersive X-ray absorption edge spectrometry, i.e. L-edge densitometry, and X-ray fluorescence spectrometry is one of the analysis methods. The hybrid L-edge/XRF densitometer can be a promising candidate for a portable and compact equipment due to advantage of using low energy X-ray beams without heavy shielding systems and liquid nitrogen cooling compared to hybrid K-edge/XRF densitometer. A prototype of the equipment was evaluated for feasibility of the nuclear material assay using a surrogate material (lead) to avoid radiation effects from nuclear materials. The uncertainty of L-edge and XRF characteristics of the sample material and volume effects was discussed in the article.

Robotics in Nuclear Materials Processing at LANL: Capabilities and Needs

2009 ◽  
Author(s):  
Cameron J. Turner ◽  
Troy A. Harden ◽  
Jane A. Lloyd
Keyword(s):  
Material Handling ◽  
National Laboratory ◽  
Nuclear Material ◽  
Nuclear Industry ◽  
Nuclear Materials ◽  
Automated Systems ◽  
Los Alamos National Laboratory ◽  
Materials Handling ◽  
Automation Systems ◽  
Manual Tasks

Nuclear material processing operations present numerous challenges for effective automation. Confined spaces, hazardous materials and processes, particulate contamination, radiation sources, and corrosive chemical operations are but a few of the significant hazards. However, automated systems represent a significant safety advance when deployed in place of manual tasks performed by human workers. The replacement of manual operations with automated systems has been desirable for nearly 40 years, yet only recently are automated systems becoming increasingly common for nuclear materials handling applications. This paper reviews several automation systems which are deployed or about to be deployed at Los Alamos National Laboratory for nuclear material handling operations. The needs that resulted in the development of these systems can be found throughout the nuclear industry. Highlighted are the current social and technological challenges faced in deploying automated systems into hazardous material handling environments and the opportunities for future innovations.

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