Matthew Hodges | University of Nevada, Las Vegas (original) (raw)

Papers by Matthew Hodges

Research paper thumbnail of ICONE15-10669 an Object-Oriented Systems Engineering Model Design for Integrating Spent Fuel Treatment Facility and Chemical Separation Processes

The Proceedings of the International Conference on Nuclear Engineering (ICONE), 2007

In 2003, the United States Department of Energy (US DOE) launched the Advanced Fuel Cycle Initiat... more In 2003, the United States Department of Energy (US DOE) launched the Advanced Fuel Cycle Initiative (AFCI) to address nuclear issues facing the United States. Amongst the major issues as identified by the AFCI were energy and waste management concerns. The interested nuclear wastes, based on their origin and toxicity, are spent nuclear fuel (SNF) and transuranic (TRU) wastes. While SNF wastes are those discharged from a nuclear reactor after being used for at least one cycle or a reactor operation, the TRU wastes are those that contain alpha-bearing radionuclides with atomic numbers greater than uranium. U.S. DOE plans to store its SNF and high-level waste (HLW) in a deep geologic disposal repository located at Yucca Mountain, Nevada. The risks that arise from long-term waste disposal come from approximately 1% of the fuels composition (transuranic group and long-lived isotopes of I and Tc). If transuranic species can be removed from the spent fuel, the toxicity of the waste drops below that of natural U within a period of several hundred years. The mission of the Transmutation Research Program (TRP) at University of Nevada, Las Vegas (UNLV) is to establish a nuclear engineering test bed that carries out effective transmutation and advanced reactor research and development effort. Integrated System for Optimized PROcesses (ISOPRO) package, developed from a multi-year project, integrates a chemical separation module, Argonne Model for Universal Solvent Extraction (AMUSE), from the Argonne National Laboratories (ANL) and commercially available system process package, such as ASPEN-Plus. Current research results focus on demonstrating the integration of the chemical separation program and system process package under the ISOPRO interfaces. Microsoft Visual Basic (MS VB) and MS Access database system has been chosen to develop the ISOPRO package. The developed user interface can directly execute and exchange parameters between the ASPEN-plus and AMUSE packages. The major purpose for such implementation is to create system engineering model providing optimization functionality between ASPEN-plus and AMUSE packages. Such integration provide single entry for researchers interested in SFTF process simulation without spending time on complicate data manipulation and various software packages.

Research paper thumbnail of Fast Neutron Detection in Nuclear Material Photofission Assay Using a 15 MeV Linear Electron Accelerator

The purpose of this research was to use a 15 MeV (K15 model by Varian) linear electron accelerato... more The purpose of this research was to use a 15 MeV (K15 model by Varian) linear electron accelerator (linac) for the photon assay of special nuclear materials (SNM). First, the properties of the photon radiation probe were determined. The stochastic radiation transport code, MCNP5, was used to develop computational models for the linac. The spectral distribution of photons as well as dose rate contour maps of the UNLV accelerator facility were computed for several linac operating configurations. These computational models were validated through comparison with experimental measurements of dose rates. The linac model was used to simulate the photon interrogation of SNM targets of various compositions and shielding materials. The spectra of neutrons produced by the irradiation of shielded SNM was characterized. The effects of shielding material and the SNM enrichment on the neutron yields following photon assay were determined. It was determined that the radiation signatures following t...

Research paper thumbnail of Development of an Integrated Process Simulation System Model for Spent Fuel Treatment Facility (SFTF) Design

by Matthew Hodges Dr. Yitung Chen, Examination Committee Chair Associate Professor of Department ... more by Matthew Hodges Dr. Yitung Chen, Examination Committee Chair Associate Professor of Department of Mechanical Engineering University of Nevada, Las Vegas A major issue concerning nuclear waste storage at Yucca Mountain is that of the safety of long term disposal. Approximately one percent of the content of spent nuclear fuel is that which is responsible for the nearly all the all the associated health risks. The removal of this content will render the toxicity of the remaining waste to that of natural uranium within a hundred years. UNLV has entered into a partnership with the national labs through the Transmutation Research Program (TRP) to study the refinement of nuclear fuels. Specifically, Argonne National Lab wishes to simulate the Light Water Reactor (LWR) Spent Fuel Treatment Facility (SFTF) using the Argonne Model For Universal Solvent Extraction (AMUSE) and ASPEN PLUS commercial process design software. This research contained in this project consists of two main objective...

Research paper thumbnail of Radiation Safety Aspects of Linac Operation with Bremsstrahlung Converters

Accelerator Physics - Radiation Safety and Applications, Feb 21, 2018

This chapter provides a discussion of radiation safety aspects of operation of electron linear ac... more This chapter provides a discussion of radiation safety aspects of operation of electron linear accelerators equipped with bremsstrahlung converters. Electron accelerators with 3, 6, 9 and 15 MeV electron beams are discussed. High-energy photon and photoneutron production during linac operation was analyzed using Monte Carlo methods. Radiation dose rates for different configurations of linacs were evaluated and compared with experimental results.

Research paper thumbnail of Computational study of radiation doses at UNLV accelerator facility

EPJ Web of Conferences, 2017

A Varian K15 electron linear accelerator (linac) has been considered for installation at Universi... more A Varian K15 electron linear accelerator (linac) has been considered for installation at University of Nevada, Las Vegas (UNLV). Before experiments can be performed, it is necessary to evaluate the photon and neutron spectra as generated by the linac, as well as the resulting dose rates within the accelerator facility. A computational study using MCNPX was performed to characterize the source terms for the bremsstrahlung converter. The 15 MeV electron beam available in the linac is above the photoneutron threshold energy for several materials in the linac assembly, and as a result, neutrons must be accounted for. The angular and energy distributions for bremsstrahlung flux generated by the interaction of the 15 MeV electron beam with the linac target were determined. This source term was used in conjunction with the K15 collimators to determine the dose rates within the facility.

Research paper thumbnail of Characterization of a 6 MeV Accelerator Driven Mixed Neutron/Photon Source

Physics Procedia, 2017

There are many applications which require high yield radiation sources with mixed fluxes of photo... more There are many applications which require high yield radiation sources with mixed fluxes of photons and neutrons. In particular, such sources are necessary to test radiation detectors and materials. This study was concerned with the determination of photon and neutron fluxes generated by the interaction of a 6 MeV linear electron accelerator driven photon beam with a beryllium photoneutron converter. The double step procedure of an (e,γ) reaction followed by an (γ,n) emission results in a mixed radiation environment. The optimal converter geometry was determined by comparison of the computed neutron fluxes for each converter position. Computational results have shown that photon fluxes up to 10 11 photons/cm 2 /s and neutron fluxes up to 10 7 neutrons/cm 2 /s are achievable with the optimal setup. This paper is focused on the results of the MCNPX modeling and experiments and discussion of the converter orientation which leads to the largest radiation fluxes.

Research paper thumbnail of Characterization of a 6 MeV Accelerator Driven Mixed Neutron/Photon Source

Physics Procedia, 2017

There are many applications which require high yield radiation sources with mixed fluxes of photo... more There are many applications which require high yield radiation sources with mixed fluxes of photons and neutrons. In particular, such sources are necessary to test radiation detectors and materials. This study was concerned with the determination of photon and neutron fluxes generated by the interaction of a 6 MeV linear electron accelerator driven photon beam with a beryllium photoneutron converter. The double step procedure of an (e,γ) reaction followed by an (γ,n) emission results in a mixed radiation environment. The optimal converter geometry was determined by comparison of the computed neutron fluxes for each converter position. Computational results have shown that photon fluxes up to 10 11 photons/cm 2 /s and neutron fluxes up to 10 7 neutrons/cm 2 /s are achievable with the optimal setup. This paper is focused on the results of the MCNPX modeling and experiments and discussion of the converter orientation which leads to the largest radiation fluxes.

Research paper thumbnail of An Object-Oriented Systems Engineering Model Design for Integrating Spent Fuel Extraction and System Processes

Energy Conversion and Resources, 2005

The mission of the Transmutation Research Program (TRP) at University of Nevada, Las Vegas (UNLV)... more The mission of the Transmutation Research Program (TRP) at University of Nevada, Las Vegas (UNLV) is to establish a nuclear engineering test bed that can carry out effective transmutation and advanced reactor research and development effort. TRPSEMPro package, developed from previous project period, integrated a chemical separation code from the Argonne National Laboratories (ANL). Current research focus has two folds: development of simulation system processes applied to Spent Fuel Treatment Facility (SFTF) using ASPEN-plus and further interaction of ASPEN+ program from TRPSEMPro interface. More details will be discussed below. ANL has identified three processes simulations using their separation technologies. The first process is to separate aqueous acid streams of acetic acid, nitric acid, water and a variety of fission product nitric salts. Distillation separation method is used to remove the desired components from the streams. The second simulation is to convert plutonium nitrate to plutonium metal. Steps used for the process simulation are precipitation, calcinations, fluorination and reduction. The third process currently under development is vitrification of fission product of raffinate streams. During the process, various waste streams from the plant are mixed and fed to a process that converts them to a solid state glass phase. The vitrification process used by the Hanford and Savannah River facilities was selected as a guideline to develop the prototype simulation process using ASPEN-Plus. Current research is focusing on identifying unit operations required to perform the vitrification of the waste streams. The first two processes are near completion stage. Microsoft Visual Basic (MS VB) has been used to develop the entire system engineering model package, TRPSEMPro. Currently a user friendly interface is under development to facilitate direct execution of ASPEN-plus within TRPSEMPro. The major purpose for the implementation is to create iterative interaction among system engineering modeling, ANL separation model and ASPEN-Plus process that outputs optimized separation/process simulation results. The ASPEN-plus access interface from TRPSEMPro allows users to modify and execute process parameters derived from the ASPEN Plus simulations without navigating through ASPEN-Plus. All ASPEN-plus simulation results can be also accessible by the interface. Such integration provide a single interaction gateway for researchers interested in SFTF process simulation without struggling with complicate data manipulation and joggling among various software packages.

Research paper thumbnail of ICONE15-10669 an Object-Oriented Systems Engineering Model Design for Integrating Spent Fuel Treatment Facility and Chemical Separation Processes

The Proceedings of the International Conference on Nuclear Engineering (ICONE), 2007

In 2003, the United States Department of Energy (US DOE) launched the Advanced Fuel Cycle Initiat... more In 2003, the United States Department of Energy (US DOE) launched the Advanced Fuel Cycle Initiative (AFCI) to address nuclear issues facing the United States. Amongst the major issues as identified by the AFCI were energy and waste management concerns. The interested nuclear wastes, based on their origin and toxicity, are spent nuclear fuel (SNF) and transuranic (TRU) wastes. While SNF wastes are those discharged from a nuclear reactor after being used for at least one cycle or a reactor operation, the TRU wastes are those that contain alpha-bearing radionuclides with atomic numbers greater than uranium. U.S. DOE plans to store its SNF and high-level waste (HLW) in a deep geologic disposal repository located at Yucca Mountain, Nevada. The risks that arise from long-term waste disposal come from approximately 1% of the fuels composition (transuranic group and long-lived isotopes of I and Tc). If transuranic species can be removed from the spent fuel, the toxicity of the waste drops below that of natural U within a period of several hundred years. The mission of the Transmutation Research Program (TRP) at University of Nevada, Las Vegas (UNLV) is to establish a nuclear engineering test bed that carries out effective transmutation and advanced reactor research and development effort. Integrated System for Optimized PROcesses (ISOPRO) package, developed from a multi-year project, integrates a chemical separation module, Argonne Model for Universal Solvent Extraction (AMUSE), from the Argonne National Laboratories (ANL) and commercially available system process package, such as ASPEN-Plus. Current research results focus on demonstrating the integration of the chemical separation program and system process package under the ISOPRO interfaces. Microsoft Visual Basic (MS VB) and MS Access database system has been chosen to develop the ISOPRO package. The developed user interface can directly execute and exchange parameters between the ASPEN-plus and AMUSE packages. The major purpose for such implementation is to create system engineering model providing optimization functionality between ASPEN-plus and AMUSE packages. Such integration provide single entry for researchers interested in SFTF process simulation without spending time on complicate data manipulation and various software packages.

Research paper thumbnail of Fast Neutron Detection in Nuclear Material Photofission Assay Using a 15 MeV Linear Electron Accelerator

The purpose of this research was to use a 15 MeV (K15 model by Varian) linear electron accelerato... more The purpose of this research was to use a 15 MeV (K15 model by Varian) linear electron accelerator (linac) for the photon assay of special nuclear materials (SNM). First, the properties of the photon radiation probe were determined. The stochastic radiation transport code, MCNP5, was used to develop computational models for the linac. The spectral distribution of photons as well as dose rate contour maps of the UNLV accelerator facility were computed for several linac operating configurations. These computational models were validated through comparison with experimental measurements of dose rates. The linac model was used to simulate the photon interrogation of SNM targets of various compositions and shielding materials. The spectra of neutrons produced by the irradiation of shielded SNM was characterized. The effects of shielding material and the SNM enrichment on the neutron yields following photon assay were determined. It was determined that the radiation signatures following t...

Research paper thumbnail of Development of an Integrated Process Simulation System Model for Spent Fuel Treatment Facility (SFTF) Design

by Matthew Hodges Dr. Yitung Chen, Examination Committee Chair Associate Professor of Department ... more by Matthew Hodges Dr. Yitung Chen, Examination Committee Chair Associate Professor of Department of Mechanical Engineering University of Nevada, Las Vegas A major issue concerning nuclear waste storage at Yucca Mountain is that of the safety of long term disposal. Approximately one percent of the content of spent nuclear fuel is that which is responsible for the nearly all the all the associated health risks. The removal of this content will render the toxicity of the remaining waste to that of natural uranium within a hundred years. UNLV has entered into a partnership with the national labs through the Transmutation Research Program (TRP) to study the refinement of nuclear fuels. Specifically, Argonne National Lab wishes to simulate the Light Water Reactor (LWR) Spent Fuel Treatment Facility (SFTF) using the Argonne Model For Universal Solvent Extraction (AMUSE) and ASPEN PLUS commercial process design software. This research contained in this project consists of two main objective...

Research paper thumbnail of Radiation Safety Aspects of Linac Operation with Bremsstrahlung Converters

Accelerator Physics - Radiation Safety and Applications, Feb 21, 2018

This chapter provides a discussion of radiation safety aspects of operation of electron linear ac... more This chapter provides a discussion of radiation safety aspects of operation of electron linear accelerators equipped with bremsstrahlung converters. Electron accelerators with 3, 6, 9 and 15 MeV electron beams are discussed. High-energy photon and photoneutron production during linac operation was analyzed using Monte Carlo methods. Radiation dose rates for different configurations of linacs were evaluated and compared with experimental results.

Research paper thumbnail of Computational study of radiation doses at UNLV accelerator facility

EPJ Web of Conferences, 2017

A Varian K15 electron linear accelerator (linac) has been considered for installation at Universi... more A Varian K15 electron linear accelerator (linac) has been considered for installation at University of Nevada, Las Vegas (UNLV). Before experiments can be performed, it is necessary to evaluate the photon and neutron spectra as generated by the linac, as well as the resulting dose rates within the accelerator facility. A computational study using MCNPX was performed to characterize the source terms for the bremsstrahlung converter. The 15 MeV electron beam available in the linac is above the photoneutron threshold energy for several materials in the linac assembly, and as a result, neutrons must be accounted for. The angular and energy distributions for bremsstrahlung flux generated by the interaction of the 15 MeV electron beam with the linac target were determined. This source term was used in conjunction with the K15 collimators to determine the dose rates within the facility.

Research paper thumbnail of Characterization of a 6 MeV Accelerator Driven Mixed Neutron/Photon Source

Physics Procedia, 2017

There are many applications which require high yield radiation sources with mixed fluxes of photo... more There are many applications which require high yield radiation sources with mixed fluxes of photons and neutrons. In particular, such sources are necessary to test radiation detectors and materials. This study was concerned with the determination of photon and neutron fluxes generated by the interaction of a 6 MeV linear electron accelerator driven photon beam with a beryllium photoneutron converter. The double step procedure of an (e,γ) reaction followed by an (γ,n) emission results in a mixed radiation environment. The optimal converter geometry was determined by comparison of the computed neutron fluxes for each converter position. Computational results have shown that photon fluxes up to 10 11 photons/cm 2 /s and neutron fluxes up to 10 7 neutrons/cm 2 /s are achievable with the optimal setup. This paper is focused on the results of the MCNPX modeling and experiments and discussion of the converter orientation which leads to the largest radiation fluxes.

Research paper thumbnail of Characterization of a 6 MeV Accelerator Driven Mixed Neutron/Photon Source

Physics Procedia, 2017

There are many applications which require high yield radiation sources with mixed fluxes of photo... more There are many applications which require high yield radiation sources with mixed fluxes of photons and neutrons. In particular, such sources are necessary to test radiation detectors and materials. This study was concerned with the determination of photon and neutron fluxes generated by the interaction of a 6 MeV linear electron accelerator driven photon beam with a beryllium photoneutron converter. The double step procedure of an (e,γ) reaction followed by an (γ,n) emission results in a mixed radiation environment. The optimal converter geometry was determined by comparison of the computed neutron fluxes for each converter position. Computational results have shown that photon fluxes up to 10 11 photons/cm 2 /s and neutron fluxes up to 10 7 neutrons/cm 2 /s are achievable with the optimal setup. This paper is focused on the results of the MCNPX modeling and experiments and discussion of the converter orientation which leads to the largest radiation fluxes.

Research paper thumbnail of An Object-Oriented Systems Engineering Model Design for Integrating Spent Fuel Extraction and System Processes

Energy Conversion and Resources, 2005

The mission of the Transmutation Research Program (TRP) at University of Nevada, Las Vegas (UNLV)... more The mission of the Transmutation Research Program (TRP) at University of Nevada, Las Vegas (UNLV) is to establish a nuclear engineering test bed that can carry out effective transmutation and advanced reactor research and development effort. TRPSEMPro package, developed from previous project period, integrated a chemical separation code from the Argonne National Laboratories (ANL). Current research focus has two folds: development of simulation system processes applied to Spent Fuel Treatment Facility (SFTF) using ASPEN-plus and further interaction of ASPEN+ program from TRPSEMPro interface. More details will be discussed below. ANL has identified three processes simulations using their separation technologies. The first process is to separate aqueous acid streams of acetic acid, nitric acid, water and a variety of fission product nitric salts. Distillation separation method is used to remove the desired components from the streams. The second simulation is to convert plutonium nitrate to plutonium metal. Steps used for the process simulation are precipitation, calcinations, fluorination and reduction. The third process currently under development is vitrification of fission product of raffinate streams. During the process, various waste streams from the plant are mixed and fed to a process that converts them to a solid state glass phase. The vitrification process used by the Hanford and Savannah River facilities was selected as a guideline to develop the prototype simulation process using ASPEN-Plus. Current research is focusing on identifying unit operations required to perform the vitrification of the waste streams. The first two processes are near completion stage. Microsoft Visual Basic (MS VB) has been used to develop the entire system engineering model package, TRPSEMPro. Currently a user friendly interface is under development to facilitate direct execution of ASPEN-plus within TRPSEMPro. The major purpose for the implementation is to create iterative interaction among system engineering modeling, ANL separation model and ASPEN-Plus process that outputs optimized separation/process simulation results. The ASPEN-plus access interface from TRPSEMPro allows users to modify and execute process parameters derived from the ASPEN Plus simulations without navigating through ASPEN-Plus. All ASPEN-plus simulation results can be also accessible by the interface. Such integration provide a single interaction gateway for researchers interested in SFTF process simulation without struggling with complicate data manipulation and joggling among various software packages.