Nuclear Engineering Commons^™

Deconvolution Of Mono-Energetic And Multi-Lines Gamma-Ray Spectra Obtained With Nai(Tl) Scintillation Detectors Using Direct Matrix Inversion Method, Mwingereza John Kumwenda Dr

Tanzania Journal of Engineering and Technology (TJET)

Performance of a NaI(Tl) scintillation detector based on the gamma-ray spectroscopy system is not satisfactory in retaining its original peak (which is delta like function) of various gamma ray spectrum. The method of achieving precise peak for the various gamma ray was conducted by converting the observed pulse-height distribution of the NaI(Tl) detector to a true photon spectrum. This method is obtained experimentally with the help of an inverse matrix deconvolution method. The method is based on response matrix generated by the Monte Carlo simulation based on Geant4 package of mono-energy gamma-ray photon ranging from 0.050 to 2.04 MeV in …

Small Modular Reactors And Advanced Reactor Security: Regulatory Perspectives On Integrating Physical And Cyber Security By Design To Protect Against Malicious Acts And Evolving Threats, Raphael Duguay

International Journal of Nuclear Security

How can future nuclear technologies and Small Modular Reactors (SMRs) deter and prevent organized crime groups, terrorists, and malicious actors from attempting to steal or sabotage nuclear materials and facilities? This paper presents the benefits of integrating Security by Design (SeBD) into a regulatory framework to allow more a flexible and effective design of physical protection systems for SMRs. During its effort to modernize the Nuclear Security Regulations, the Canadian Nuclear Safety Commission (CNSC) licensing application process provides for the option of SeBD in moving toward a performance-based approach with less prescriptive requirements. CNSC also recognizes the need for a …

Fast Neutron Assay Of Elemental Content Of Bulk Samples, Calder Emerson Lane

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this research was to analyze the capabilities of fast neutrons in the detection and analysis of various isotopes in bulk samples. The deuterium-tritium (DT) fusion reaction generates highly penetrating, high-energy (14.1-MeV) neutrons which induce nuclear reactions in irradiated targets. Neutrons and gamma rays are generated in these reactions. Emitted gamma rays are characteristic of the emitter; the gamma spectrum enables stoichiometric identification of the assayed samples. Neutron backscattering can also be used for identification of the elemental composition of the sample.

This work had three objectives. The first objective was to develop a computational technique to model …

Experimental Evaluation Of The Deadtime Phenomenon For Gm Detector: Deadtime Dependence On Operating Voltages, Bader Almutairi, Syed B. Alam, Tayfun Akyurek, Cameron S. Goodwin, Shoaib Usman

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

A detailed analysis of Geiger Mueller counter deadtime dependence on operating voltage is presented in the manuscript using four pairs of radiation sources. Based on two-source method, detector deadtime is calculated for a wide range of operating voltages which revealed a peculiar relationship between the operating voltage and the detector deadtime. In the low voltage range, a distinct drop in deadtime was observed where deadtime reached a value as low as a few microseconds (22 µs for ²⁰⁴Tl, 26 µs for ¹³⁷Cs, 9 µs for ²²Na). This sharp drop in the deadtime is possibly due to reduced …

A Two-Dimensional Spherical-Polar Multigroup Discrete Ordinates Code For Atmospheric Particle Transport, Daniel T. Wakeford

Nuclear Engineering ETDs

A natural coordinate system for calculating neutral particle propagation in the atmosphere due to point sources is two-dimensional spherical-polar coordinates. Deterministic methods for solving the transport equation in this coordinate system require some interesting implementation details stemming from the two angular derivatives present in this form of the equation. In this dissertation, we present a bilinear discontinuous spatial discretization of the transport equation in this coordinate system. The weighted diamond difference discretization is applied to the angular derivative term in two angular dimensions, using zero-weighted starting directions to start the differencing. To our knowledge, the only previous deterministic code that …

Computational Modeling Of Radiation Damage In A Multi-Phase Ceramic Waste Form Using Moose, Zeyu Chen

Theses and Dissertations

Ceramic waste forms have been proposed to replace the traditional glassy waste forms for long term stabilization of radionuclides. These waste forms are constantly exposed to self-irradiation emitted from the constituent radionuclides causing their material properties to change accordingly. It has been known that the radiation damage in waste forms is dominated by alpha particles emitted from transuranic (TRU) radionuclides. Since alpha particles usually have a range of 10~20 μm in such waste forms, some fraction of any non-transuranic containing phases (for a multiphase waste form) will be undamaged (or less damaged) if containing large enough grain sizes. Modeling and …

Corrigendum: “A Correlation For Interfacial Area Concentration In High Void Fraction Flows In Large Diameter Channels” ([Chem. Eng. Sci.131 (2015) 172–186] (2015) 131 (172–186), (S0009250915002547), (10.1016/J.Ces.2015.04.004)), Joshua P. Schlegel, T. Hibiki

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

There is a Typographical Mistake in Eq. (21), Used in the Derivation of the Final Model, Which Should Read [Fourmula Presented] This Typographical Mistake is Also Present in Eq. (22b), Which is Necessary for Implementation of the Final Model, Which Should Read

A 3d Image-Guided System To Improve Myocardial Revascularization Decision-Making For Patients With Coronary Artery Disease, Haipeng Tang

Dissertations

OBJECTIVES. Coronary artery disease (CAD) is the most common type of heart disease and kills over 360,000 people a year in the United States. Myocardial revascularization (MR) is a standard interventional treatment for patients with stable CAD. Fluoroscopy angiography is real-time anatomical imaging and routinely used to guide MR by visually estimating the percent stenosis of coronary arteries. However, a lot of patients do not benefit from the anatomical information-guided MR without functional testing. Single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is a widely used functional testing for CAD evaluation but limits to the absence of anatomical information. …

Characterization Of Partial Charge Collection Induced By Neutron Damage In High-Purity Germanium Detectors, James W. Evans

Nuclear Engineering ETDs

This paper investigates the correlation of damage induced by neutron interactions and degradation in the spectra of HPGe detectors. As neutrons kinetically interact with germanium crystals, they create interstitial and vacancy defects within the lattice. These defects then interfere with the charge migration of electron-hole pairs and reduce resolution in the observed energy spectrum. The partial charge collection produces observable spectral changes by increasing the peak width and reducing resolution (full width half maximum). A detailed characterization using various check sources was performed before and after iterations of neutron exposure in order to observe the effects of the neutron damage. …

Promoting Nuclear Security Education And Training Activities At Amity University, India, Arpita Datta, Dr. Alpana Goel

International Journal of Nuclear Security

In the present era of global nuclear governance, it is the responsibility of every individual not only the security personals to be accountable for the security of nuclear materials, facilities and radioactive materials. Amity university and other universities of India are the largest educational networks for young professionals who will enter the nuclear programme in India and will be involved in the management of nuclear and other radioactive materials in a wide variety of applications such as hospitals, industrial applications and nuclear facilities. Amity University Uttar Pradesh is taking leading part to sensitize the importance of nuclear security amongst the …

Eusectra: European Nuclear Security Training Centre Providing Hands-On Training And Education In Nuclear Security And Safeguards, Willem Janssens, Veronique Berthou, Abbas Kamel, Jean Galy, Klaus Luetzenkirchen, Klaus Mayer, Stefan Nonneman

International Journal of Nuclear Security

The European Nuclear Security Training Centre (EUSECTRA) inaugurated under this global name about 10 years ago and operated by the European Commission Joint Research Centre (JRC), located both on the Karlsruhe (Germany) and Ispra (Italy) sites, includes a large variety of capacity building and professional development activities which span from the hands-on training for nuclear security and safeguards actors (e.g. respectively border guards or customs and nuclear inspectors) to educational efforts in both nuclear security and safeguards. Whereas the first ones, which gave rise to the new name, focus mainly on detection, on-site assistance, crime-scene management, technical reach-back and nuclear …

Parking Garage Measurements Indicating A Gamma Spectrometer-Neutron Counter Background Correlation, Jackson N. Wagner, Craig Marianno, Thomas Mccullough

International Journal of Nuclear Security

Gamma spectroscopy and gross neutron counting systems are commonly employed together during nuclear security operations, particularly mobile searches. The data from these systems are typically analyzed independently; however, operational data suggest a relationship between the background signals from both systems. This relationship appears to occur between the neutron count rate and the high energy (greater than 3 MeV) gamma spectrometer count rate for background conditions. To verify the presence of this correlation, high energy gamma ray and neutron count rates were measured in five parking garages on the Texas A&M University campus. These measurements employed one 4” x 4” x …

Consideration Of Administrative Monetary Penalties In Nuclear Safety And Security, Jelena Vucicevic, Edward Waller

International Journal of Nuclear Security

An Administrative Monetary Penalty (AMP) is a penalty imposed by the Canadian Nuclear Safety Commission (CNSC), without court involvement for a violation of a regulatory requirement. An AMP can be applied against any individual or corporation subject to the Nuclear Safety Control Act, which regulates the development, production and use of nuclear energy and the production, possession and use of nuclear and radioactive material. However, AMPs are not the same as criminal offences. They are civil sanctions which try to secure compliance through the application of monetary penalties for non-compliance with regulatory requirements. The AMP program was introduced in 2013 …

Applications Of Portable Libs For Actinide Analysis, Ashwin P. Rao, John D. Auxier Ii, Dung Vu, Michael B. Shattan

Faculty Publications

A portable LIBS device was used for rapid elemental impurity analysis of plutonium alloys. This device demonstrates the potential for fast, accurate in-situ chemical analysis and could significantly reduce the fabrication time of plutonium alloys.

A Physics-Based Machine Learning Study Of The Behavior Of Interstitial Helium In Single Crystal W–Mo Binary Alloys, Adib J. Samin

Faculty Publications

In this work, the behavior of dilute interstitial helium in W–Mo binary alloys was explored through the application of a first principles-informed neural network (NN) in order to study the early stages of helium-induced damage and inform the design of next generation materials for fusion reactors. The neural network (NN) was trained using a database of 120 density functional theory (DFT) calculations on the alloy. The DFT database of computed solution energies showed a linear dependence on the composition of the first nearest neighbor metallic shell. This NN was then employed in a kinetic Monte Carlo simulation, which took into …

Leveraging Commercial Nuclear Reactors To Power Space Exploration, Ben Johnson

Utah Space Grant Consortium

This study is aimed at exploring the adaptation of commercial nuclear reactors as an alternative to NASA’s current high-power fission reactor systems, particularly with respect to applications on the surface of Mars. The study concludes that while the Kilopower architecture is brilliantly poised to provide affordable, near-term power in the 1-10 kilowatts electric (kWe) range, the financial barrier to higher power scaling of such systems is significant. This financial barrier adds risk to the development of greater than 10kWe systems and is likely to result in the failure to successfully scale the technology to higher powers for space exploration applications. …

Gen-Foam Multiphysics Model Development For Molten Salt Reactors, Jeffrey Stewart

UNLV Theses, Dissertations, Professional Papers, and Capstones

In thermal neutron spectrum Molten Salt Reactors (MSR), a graphite moderator contributes a positive reactivity value to the overall temperature reactivity coefficient of the core. When irradiated in the core, graphite undergoes dimensional changes which depend on the neutron spectrum. The graphite lifespan is a limiting parameter in MSR designs; it correlates strongly with the graphite’s dimensional changes. Multi-physics modeling is necessary to evaluate the graphite thermal and mechanical responses to the MSR core conditions. To assess graphite dimensional changes associated with irradiation, a computational model was developed upon the foundation of the multi-physics solver, GeN-Foam. Irradiated graphite dimensional change …

Remote Radiation Sensing Using Robotic Platforms, Monia Kazemeini

UNLV Theses, Dissertations, Professional Papers, and Capstones

Remote sensing of ionizing radiation has a significant role in waste management, nuclear material management and nonproliferation, radiation safety, and accident response in situations such as the Fukushima nuclear power plant accident. Robotic platforms are able to surpass the number of tasks that could be achieved by humans. With the use of robots, the operator’s radiation exposure can be considerably decreased. Remote sensing allows for the evaluation and monitoring of radiological contamination in hazardous and hard to reach areas and locating radiation sources. In this work, gamma-ray and neutron sensors were integrated onto the unmanned aerial systems (UAS) making it …

A Forward Analytic Model Of Neutron Time-Of-Flight Signals With Single Elastic Scattering And Beamline Attenuation For Inferring Ion Temperatures From Maglif Experiments, Colin A. Weaver

Nuclear Engineering ETDs

A forward analytic model is required to rapidly simulate the neutron time-of-flight (nToF) signals that result from magnetized liner inertial fusion (MagLIF) experiments at Sandia’s Z Pulsed Power Facility. Various experimental parameters, such as the burn-weighted fuel-ion temperature and liner areal density, determine the shape of the nToF signal and are important for characterizing any given MagLIF experiment. Extracting these parameters from measured nToF signals requires an appropriate analytic model that includes the primary DD neutron peak, once-scattered neutrons in the beryllium liner of the MagLIF target, and direct beamline attenuation. Mathematical expressions for this model were derived from the …

Modeling And Simulation Of Stochastic Neutron And Cumulative Deposited Fission Energy Distributions, Patrick O'Rourke

Nuclear Engineering ETDs

Methods of stochastic neutron transport are investigated and applied to novel formulations for the neutron number distribution and the cumulative fission energy deposition distribution. We utilize two Monte Carlo algorithms: the event-based Monte Carlo (EBMC) method and the Stochastic Simulation Algorithm (SSA) to benchmark and analyze systems. We show that the SSA outperforms the EBMC for the parameter space we are interested in. We then utilize the SSA to analyze systems composed of multiple spherical regions with fast and thermal neutrons with time-dependent reactivity insertions and determine whether group-dependent number distributions approach a gamma distribution. We develop two methods for …

Characterization Of Uranium Foil Irradiations At The Wsu Triga Reactor Using A New Reactor Model In Scale, Kimberly A. Hinrichs

Nuclear Engineering ETDs

A new reactor model of the Washington State University TRIGA was developed in the SCALE neutron transport code, and its fidelity was verified by comparison to MCNP and available data for several reactor parameters. The model was used to characterize irradiations designed to produce the short-lived actinides ²³⁷U and ²³⁹U, two key isotopes for nuclear forensics. These short-lived actinides, their decay daughters ²³⁷Np and ²³⁹Pu, and total fissions (via ⁹⁹Mo) were measured in irradiated foils at Los Alamos National Laboratory and other labs with good agreement among parent/daughter pairs and among labs. The laboratory-measured isotope …

Space And Defense – Volume Eleven – Number One – Spring 2019, Space And Defense Journal

Space and Defense

No abstract provided.

Space And Defense – Volume Nine – Number One – Spring 2016, Space And Defense Journal

Space and Defense

No abstract provided.

Space And Defense – Volume Eight – Number One – Spring 2015, Space And Defense Journal

Space and Defense

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Space And Defense – Volume Seven – Number One – Winter 2014, Space And Defense Journal

Space and Defense

No abstract provided.

Space And Defense – Volume Six – Number One – Fall 2012, Space And Defense Journal

Space and Defense

No abstract provided.

Space And Defense – Volume Five – Number One – Summer 2011, Space And Defense Journal

Space and Defense

No abstract provided.

Space And Defense – Volume Four – Number Two – Summer 2010, Space And Defense Journal

Space and Defense

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Space And Defense – Volume Four – Number One – Winter 2010, Space And Defense Journal

Space and Defense

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Space And Defense – Volume Three – Number Two – Fall 2009, Space And Defense Journal

Space and Defense

No abstract provided.