Francesco Venneri - Academia.edu (original) (raw)
Papers by Francesco Venneri
Form No 2336 R5 ST 2629 10B1 wsTRIBuTIoN OF THIS WCXJMEW ts UNLlMnEu ~ DISCLAIMER This report was... more Form No 2336 R5 ST 2629 10B1 wsTRIBuTIoN OF THIS WCXJMEW ts UNLlMnEu ~ DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
Annals of Nuclear Energy, 2004
We have investigated the waste actinide burnup capabilities of a Gas Turbine Modular Helium React... more We have investigated the waste actinide burnup capabilities of a Gas Turbine Modular Helium Reactor (GT-MHR, similar to the reactor being designed by General Atomics and Minatom for surplus weapons plutonium destruction) with the Monte Carlo Continuous Energy Burnup Code MCB, an extension of MCNP developed at the Royal Institute of Technology in Stockholm and University of Mining and Metallurgy in Krakow. The GT-MHR is a gas-cooled, graphite-moderated reactor, which can be powered with a wide variety of fuels, like thorium, uranium or plutonium. In the present work, the GT-MHR is fueled with the transuranic actinides contained in Light Water Reactors (LWRs) spent fuel for the purpose of destroying them as completely as possible with minimum reliance on multiple reprocessing steps. After uranium extraction from the LWR spent fuel (UREX), the remaining waste actinides, including plutonium are partitioned into two distinct types of fuel for use in the GT-MHR: Driver Fuel (DF) and Transmutation Fuel (TF). The DF supplies the neutrons to maintain the fission chain reaction, whereas the TF emphasizes neutron capture to induce a deep burn transmutation and provide reactivity control by a negative feedback. When used in this mode, the GT-MHR is called Deep Burn Modular Helium Reactor (DB-MHR). Both fuels are contained in a structure of triple isotropic coated layers, TRISO coating, which has been proven to retain fission products up to 1600 C and is expected to remain intact for hundreds of thousands of years after irradiation. Other benefits of this reactor consist of: a well-developed technology, both for the graphite-moderated core and the TRISO structure, a high energy conversion efficiency (about 50%), well established passive safety mechanism and a competitive cost. The destruction of more than 94% of 239 Pu and the
Physics World, Aug 1, 1993
If the world is to continue using nuclear-generated electricity, the problem of radioactive waste... more If the world is to continue using nuclear-generated electricity, the problem of radioactive waste disposal must be addressed. Permanent storage of long-lived waste from nuclear power stations is an issue that generates public concern, scientific uncertainty and political pressures. One alternative is to investigate ways of reducing the intensity and lifetime of the radioactivity of the waste so that it can be buried safely almost anywhere.
an affirmative action/equal opportunity employer, is operated by the University of California for... more an affirmative action/equal opportunity employer, is operated by the University of California for the US. Department of Energy under contract W-7405-ENG-36. By acceptance of this article, the publisher recognizes that the US.
Accelerator transmutation of nuclear waste offers exciting possibilities for the disposal of nucl... more Accelerator transmutation of nuclear waste offers exciting possibilities for the disposal of nuclear waste by converting it into more benign Species. The non-aqueous system discussed here contains the materials to be transmuted within a lithium-fluoride salt. The system consists of bundles of graphite tubes containing the salt Solution. The tubes are cooled as lithium flows across their exterior. These circular graphite tubes have an inner circular passage and an outer annulus. Natural convection within the tubes causes the salt to circulate. This paper deals with the thermal-hydraulics of the system; it does not consider the neutronics in detail. Heat transfer and fluid flow were modeled using a custom computer program the system behavior of an graphite tube. Different geometries were tried, while keeping the system volume the same, to determine an optimize graphite tube geometry. I considered both the parallel flow and the counterflow of the lithium coolant, and allowed limited bo...
Neutronic analyses of TRU deep-burn (DB) have been performed for a 600 MWth MHR (Modular Helium R... more Neutronic analyses of TRU deep-burn (DB) have been performed for a 600 MWth MHR (Modular Helium Reactor) by using a continuous energy Monte Carlo code, MCCARD. In order to improve the neutronics and reduce the fuel self-shielding effect, a carbon-diluted kernel is introduced in this work. The double-heterogeneity of TRISO fuels are handed with the aid of the RPT (Reactivity-equivalent Physical Transformation) method. It is shown that the RPT method provides a very accurate solution for the diluted-kernel TRISO fuel. Instead of conventional radial fuel shuffling, an axial-only block shuffling strategy is used to reduce the axial neutron leakage. Based on a 4-batch axial-only fuel block shuffling scheme, equilibrium cycle is directly searched with repeated 3-D Monte Carlo depletion calculations. For an equilibrium cycle, TRU transmutation performance is evaluated and core power distributions are analyzed. In addition, core performance of a diluted kernel is compared with that of a con...
AIP Conference Proceedings, 1995
Los Alamos NationalLaboratory, an affirmativeaction/equalopportunityempldyer,is operated by the U... more Los Alamos NationalLaboratory, an affirmativeaction/equalopportunityempldyer,is operated by the Universityof Californiafor the U.S. Department of Energy under contractW-7405-ENG-36. By acceptanceof thisarticle,thepublisherrecognizesthat the U.S. Governmentretains a nonexclusive,royalty-freelicense to publish or reproducethe publishedform ofthiscontribution, or to allowothersto do so, forU.S. Government purposes.The Los Alamos National Laboratory requests that thepublisheridentifythis article as workperformedundertheauspicesofthe U.S. Department of Energy.
Nuclear Technology, 2000
an affirmative action/equal opportunity employer, is operated by the University of California for... more an affirmative action/equal opportunity employer, is operated by the University of California for the US. Department of Energy under contract W-7405-ENG-36. By acceptance of this article, the publisher recognizes that the US.
Progress in Nuclear Energy, 1994
... It is shown that a faster inventory reduction is achieved with the thermal reactor. Waste Cha... more ... It is shown that a faster inventory reduction is achieved with the thermal reactor. Waste Characterization The LWR spent fuel nuclides of interest are discussed in many references, for instance Benedict, et al., (1981), Hebel, et al. (1978), or Binney, et al. (1990). ...
AIP Conference Proceedings, 1995
Portions of this document may be illegible in electronic image products. Images are produced from... more Portions of this document may be illegible in electronic image products. Images are produced from the best available original document.
AIP Conference Proceedings, 1995
This report was .prepared as an account of work sponsored by an agency of the United States Gover... more This report was .prepared as an account of work sponsored by an agency of the United States Government. Neither
Nuclear Engineering and Design, 2003
... To the plant operator, a Deep-Burn Transmuter will be identical to its commercial reactor cou... more ... To the plant operator, a Deep-Burn Transmuter will be identical to its commercial reactor counterpart. Article Outline. ... They operate safely at high temperatures, producing electric power at close to 50% efficiency. ... Fig. 1. Deep-Burn Transmutation of nuclear waste. ...
Applied Physics Letters, 1988
A magnetically stabilized plasma focus with controlled modulations has been demonstrated for the ... more A magnetically stabilized plasma focus with controlled modulations has been demonstrated for the first time. A 3-mm-diam plasma focus with two wiggler periods of 1 cm each was kept stable for about 30 ns. Similar configurations with shorter periods could be used as intense wigglers for short-wavelength free-electron lasers.
The helium-cooled, graphite-moderated Very High Temperature Reactor (VHTR) has become the centerp... more The helium-cooled, graphite-moderated Very High Temperature Reactor (VHTR) has become the centerpiece of the U.S. Department of Energy’s (DOE) Next Generation Nuclear Plant (NGNP) program. The NGNP program aims to construct a VHTR prototype, with the participation of industry, by the year 2021.
The Modular Helium Reactor (MHR) is one of the advanced reactor concepts within the international... more The Modular Helium Reactor (MHR) is one of the advanced reactor concepts within the internationally-supported Generation IV program. Because of its design features and design maturity, the MHR was selected by the U.S. Department of Energy (DOE) as the U.S. Generation IV design concept for the Next Generation Nuclear Plant (NGNP). Other countries, including Russia, Japan, South Korea, China, South Africa, and France are also developing this technology, and large-scale deployment of MHR technology is a realistic element of future energy-growth scenarios. In this paper, we discuss MHR conceptual designs for electricity and hydrogen production and their role in a sustainable energy future with significant growth in nuclear energy. For hydrogen production, two conceptual designs are described; one coupling the MHR to thermochemical water splitting using the sulfur-iodine (SI) process and the other coupling the MHR to high-temperature electrolysis (HTE). (authors)
It is now practical with present-day linac technology to produce accelerators with average curren... more It is now practical with present-day linac technology to produce accelerators with average currents above 100 mA for energies in the giga-electron-volt region. Average beam powers as large as 400 MW have been proposed for tritium production, although the needs for accelerator-driven systems for nuclear energy production or transmutation of commercial spent fuel may be substantially smaller. The authors believe that for these high beam powers, practical systems will require flowing liquid targets. Some of the important features that must be considered in target design are as follows: (1) high beam-to-neutron conversion efficiency; (2) minimal long-lived spallation product; (3) minimal production of long-lived isotopes that are different from those found in commercial spent fuel; (4) maximum target lifetime; (5) compact size with physical dimensions matching the dimensions of the surrounding blanket; (6) integration of target cooling with heat removal from the blanket; (7) minimizatio...
A nuclear energy scenario for the 21st century that included a denatured thorium-uranium-oxide (D... more A nuclear energy scenario for the 21st century that included a denatured thorium-uranium-oxide (DTU) fuel cycle and new light water reactors (LWRs) supported by accelerator-driven transmutation of waste (ATW) systems was previously described. This coupled system with the closed DTU fuel cycle provides several improvements beyond conventional LWR (CLWR) (once-through, UO{sub 2} fuel) nuclear technology: increased proliferation resistance, reduced waste, and efficient use of natural resources. However, like CLWR fuel cycles, the spent fuel in the first one-third core discharged after startup contains higher-quality Pu than the equilibrium fuel cycle. To eliminate this high-grade Pu, Np is separated and recycled with Th and U--rather than with higher actinides [(HA) including Pu]. The presence of Np in the LWR feed greatly increases the production of {sup 238}Pu so that a few kilograms of Pu generated enough alpha-decay heat that the separated Pu is highly resistant to proliferation. T...
The objective of this project is to perform feasibility assessment and technology gap analysis an... more The objective of this project is to perform feasibility assessment and technology gap analysis and establish a development roadmap for an innovative and highly compact Micro Modular Reactor (MMR) concept that integrates power production, power conversion and electricity generation in a single unit. The MMR is envisioned to use fully ceramic microencapsulated (FCM) fuel, a particularly robust form of TRISO fuel, and to be gas-cooled (e.g., He or CO 2) and capable of generating power in the range of 10 to 40 MW-thermal. It is designed to be absolutely melt-down proof (MDP) under all circumstances including complete loss of coolant scenarios with no possible release of radioactive material, to be factory produced, to have a cycle length of greater than 20 years, and to be highly proliferation resistant. In addition, it will be transportable, retrievable and suitable for use in remote areas. As such, the MDP-MMR will represent a versatile reactor concept that is suitable for use in various applications including electricity generation, process heat utilization and propulsion. Background: An important difference at the point of operation between non-nuclear and nuclear power generators is the release of substantial amounts of decay heat after power production has ceased and the reactor has shut down. With the production of decay heat comes the possibility that a reactor core Final
Form No 2336 R5 ST 2629 10B1 wsTRIBuTIoN OF THIS WCXJMEW ts UNLlMnEu ~ DISCLAIMER This report was... more Form No 2336 R5 ST 2629 10B1 wsTRIBuTIoN OF THIS WCXJMEW ts UNLlMnEu ~ DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
Annals of Nuclear Energy, 2004
We have investigated the waste actinide burnup capabilities of a Gas Turbine Modular Helium React... more We have investigated the waste actinide burnup capabilities of a Gas Turbine Modular Helium Reactor (GT-MHR, similar to the reactor being designed by General Atomics and Minatom for surplus weapons plutonium destruction) with the Monte Carlo Continuous Energy Burnup Code MCB, an extension of MCNP developed at the Royal Institute of Technology in Stockholm and University of Mining and Metallurgy in Krakow. The GT-MHR is a gas-cooled, graphite-moderated reactor, which can be powered with a wide variety of fuels, like thorium, uranium or plutonium. In the present work, the GT-MHR is fueled with the transuranic actinides contained in Light Water Reactors (LWRs) spent fuel for the purpose of destroying them as completely as possible with minimum reliance on multiple reprocessing steps. After uranium extraction from the LWR spent fuel (UREX), the remaining waste actinides, including plutonium are partitioned into two distinct types of fuel for use in the GT-MHR: Driver Fuel (DF) and Transmutation Fuel (TF). The DF supplies the neutrons to maintain the fission chain reaction, whereas the TF emphasizes neutron capture to induce a deep burn transmutation and provide reactivity control by a negative feedback. When used in this mode, the GT-MHR is called Deep Burn Modular Helium Reactor (DB-MHR). Both fuels are contained in a structure of triple isotropic coated layers, TRISO coating, which has been proven to retain fission products up to 1600 C and is expected to remain intact for hundreds of thousands of years after irradiation. Other benefits of this reactor consist of: a well-developed technology, both for the graphite-moderated core and the TRISO structure, a high energy conversion efficiency (about 50%), well established passive safety mechanism and a competitive cost. The destruction of more than 94% of 239 Pu and the
Physics World, Aug 1, 1993
If the world is to continue using nuclear-generated electricity, the problem of radioactive waste... more If the world is to continue using nuclear-generated electricity, the problem of radioactive waste disposal must be addressed. Permanent storage of long-lived waste from nuclear power stations is an issue that generates public concern, scientific uncertainty and political pressures. One alternative is to investigate ways of reducing the intensity and lifetime of the radioactivity of the waste so that it can be buried safely almost anywhere.
an affirmative action/equal opportunity employer, is operated by the University of California for... more an affirmative action/equal opportunity employer, is operated by the University of California for the US. Department of Energy under contract W-7405-ENG-36. By acceptance of this article, the publisher recognizes that the US.
Accelerator transmutation of nuclear waste offers exciting possibilities for the disposal of nucl... more Accelerator transmutation of nuclear waste offers exciting possibilities for the disposal of nuclear waste by converting it into more benign Species. The non-aqueous system discussed here contains the materials to be transmuted within a lithium-fluoride salt. The system consists of bundles of graphite tubes containing the salt Solution. The tubes are cooled as lithium flows across their exterior. These circular graphite tubes have an inner circular passage and an outer annulus. Natural convection within the tubes causes the salt to circulate. This paper deals with the thermal-hydraulics of the system; it does not consider the neutronics in detail. Heat transfer and fluid flow were modeled using a custom computer program the system behavior of an graphite tube. Different geometries were tried, while keeping the system volume the same, to determine an optimize graphite tube geometry. I considered both the parallel flow and the counterflow of the lithium coolant, and allowed limited bo...
Neutronic analyses of TRU deep-burn (DB) have been performed for a 600 MWth MHR (Modular Helium R... more Neutronic analyses of TRU deep-burn (DB) have been performed for a 600 MWth MHR (Modular Helium Reactor) by using a continuous energy Monte Carlo code, MCCARD. In order to improve the neutronics and reduce the fuel self-shielding effect, a carbon-diluted kernel is introduced in this work. The double-heterogeneity of TRISO fuels are handed with the aid of the RPT (Reactivity-equivalent Physical Transformation) method. It is shown that the RPT method provides a very accurate solution for the diluted-kernel TRISO fuel. Instead of conventional radial fuel shuffling, an axial-only block shuffling strategy is used to reduce the axial neutron leakage. Based on a 4-batch axial-only fuel block shuffling scheme, equilibrium cycle is directly searched with repeated 3-D Monte Carlo depletion calculations. For an equilibrium cycle, TRU transmutation performance is evaluated and core power distributions are analyzed. In addition, core performance of a diluted kernel is compared with that of a con...
AIP Conference Proceedings, 1995
Los Alamos NationalLaboratory, an affirmativeaction/equalopportunityempldyer,is operated by the U... more Los Alamos NationalLaboratory, an affirmativeaction/equalopportunityempldyer,is operated by the Universityof Californiafor the U.S. Department of Energy under contractW-7405-ENG-36. By acceptanceof thisarticle,thepublisherrecognizesthat the U.S. Governmentretains a nonexclusive,royalty-freelicense to publish or reproducethe publishedform ofthiscontribution, or to allowothersto do so, forU.S. Government purposes.The Los Alamos National Laboratory requests that thepublisheridentifythis article as workperformedundertheauspicesofthe U.S. Department of Energy.
Nuclear Technology, 2000
an affirmative action/equal opportunity employer, is operated by the University of California for... more an affirmative action/equal opportunity employer, is operated by the University of California for the US. Department of Energy under contract W-7405-ENG-36. By acceptance of this article, the publisher recognizes that the US.
Progress in Nuclear Energy, 1994
... It is shown that a faster inventory reduction is achieved with the thermal reactor. Waste Cha... more ... It is shown that a faster inventory reduction is achieved with the thermal reactor. Waste Characterization The LWR spent fuel nuclides of interest are discussed in many references, for instance Benedict, et al., (1981), Hebel, et al. (1978), or Binney, et al. (1990). ...
AIP Conference Proceedings, 1995
Portions of this document may be illegible in electronic image products. Images are produced from... more Portions of this document may be illegible in electronic image products. Images are produced from the best available original document.
AIP Conference Proceedings, 1995
This report was .prepared as an account of work sponsored by an agency of the United States Gover... more This report was .prepared as an account of work sponsored by an agency of the United States Government. Neither
Nuclear Engineering and Design, 2003
... To the plant operator, a Deep-Burn Transmuter will be identical to its commercial reactor cou... more ... To the plant operator, a Deep-Burn Transmuter will be identical to its commercial reactor counterpart. Article Outline. ... They operate safely at high temperatures, producing electric power at close to 50% efficiency. ... Fig. 1. Deep-Burn Transmutation of nuclear waste. ...
Applied Physics Letters, 1988
A magnetically stabilized plasma focus with controlled modulations has been demonstrated for the ... more A magnetically stabilized plasma focus with controlled modulations has been demonstrated for the first time. A 3-mm-diam plasma focus with two wiggler periods of 1 cm each was kept stable for about 30 ns. Similar configurations with shorter periods could be used as intense wigglers for short-wavelength free-electron lasers.
The helium-cooled, graphite-moderated Very High Temperature Reactor (VHTR) has become the centerp... more The helium-cooled, graphite-moderated Very High Temperature Reactor (VHTR) has become the centerpiece of the U.S. Department of Energy’s (DOE) Next Generation Nuclear Plant (NGNP) program. The NGNP program aims to construct a VHTR prototype, with the participation of industry, by the year 2021.
The Modular Helium Reactor (MHR) is one of the advanced reactor concepts within the international... more The Modular Helium Reactor (MHR) is one of the advanced reactor concepts within the internationally-supported Generation IV program. Because of its design features and design maturity, the MHR was selected by the U.S. Department of Energy (DOE) as the U.S. Generation IV design concept for the Next Generation Nuclear Plant (NGNP). Other countries, including Russia, Japan, South Korea, China, South Africa, and France are also developing this technology, and large-scale deployment of MHR technology is a realistic element of future energy-growth scenarios. In this paper, we discuss MHR conceptual designs for electricity and hydrogen production and their role in a sustainable energy future with significant growth in nuclear energy. For hydrogen production, two conceptual designs are described; one coupling the MHR to thermochemical water splitting using the sulfur-iodine (SI) process and the other coupling the MHR to high-temperature electrolysis (HTE). (authors)
It is now practical with present-day linac technology to produce accelerators with average curren... more It is now practical with present-day linac technology to produce accelerators with average currents above 100 mA for energies in the giga-electron-volt region. Average beam powers as large as 400 MW have been proposed for tritium production, although the needs for accelerator-driven systems for nuclear energy production or transmutation of commercial spent fuel may be substantially smaller. The authors believe that for these high beam powers, practical systems will require flowing liquid targets. Some of the important features that must be considered in target design are as follows: (1) high beam-to-neutron conversion efficiency; (2) minimal long-lived spallation product; (3) minimal production of long-lived isotopes that are different from those found in commercial spent fuel; (4) maximum target lifetime; (5) compact size with physical dimensions matching the dimensions of the surrounding blanket; (6) integration of target cooling with heat removal from the blanket; (7) minimizatio...
A nuclear energy scenario for the 21st century that included a denatured thorium-uranium-oxide (D... more A nuclear energy scenario for the 21st century that included a denatured thorium-uranium-oxide (DTU) fuel cycle and new light water reactors (LWRs) supported by accelerator-driven transmutation of waste (ATW) systems was previously described. This coupled system with the closed DTU fuel cycle provides several improvements beyond conventional LWR (CLWR) (once-through, UO{sub 2} fuel) nuclear technology: increased proliferation resistance, reduced waste, and efficient use of natural resources. However, like CLWR fuel cycles, the spent fuel in the first one-third core discharged after startup contains higher-quality Pu than the equilibrium fuel cycle. To eliminate this high-grade Pu, Np is separated and recycled with Th and U--rather than with higher actinides [(HA) including Pu]. The presence of Np in the LWR feed greatly increases the production of {sup 238}Pu so that a few kilograms of Pu generated enough alpha-decay heat that the separated Pu is highly resistant to proliferation. T...
The objective of this project is to perform feasibility assessment and technology gap analysis an... more The objective of this project is to perform feasibility assessment and technology gap analysis and establish a development roadmap for an innovative and highly compact Micro Modular Reactor (MMR) concept that integrates power production, power conversion and electricity generation in a single unit. The MMR is envisioned to use fully ceramic microencapsulated (FCM) fuel, a particularly robust form of TRISO fuel, and to be gas-cooled (e.g., He or CO 2) and capable of generating power in the range of 10 to 40 MW-thermal. It is designed to be absolutely melt-down proof (MDP) under all circumstances including complete loss of coolant scenarios with no possible release of radioactive material, to be factory produced, to have a cycle length of greater than 20 years, and to be highly proliferation resistant. In addition, it will be transportable, retrievable and suitable for use in remote areas. As such, the MDP-MMR will represent a versatile reactor concept that is suitable for use in various applications including electricity generation, process heat utilization and propulsion. Background: An important difference at the point of operation between non-nuclear and nuclear power generators is the release of substantial amounts of decay heat after power production has ceased and the reactor has shut down. With the production of decay heat comes the possibility that a reactor core Final