WorldWideScience

Sample records for adtt

  1. Impact of ADTT concepts on the management of global plutonium inventories

    International Nuclear Information System (INIS)

    The impact of a number of current and future nuclear systems on global plutonium inventories is assessed under realistic forecasts of nuclear power growth. Advanced systems, such as those employing Accelerator Driven Transmutation Technologies (ADTT) and liquid metal reactors, show significant promise for meeting future plutonium management needs. These analyses also indicate requirements for a higher level of detail in the nuclear fuel cycle model and for development of a metric to more quantitatively assess the proliferation risk of plutonium arising from the civilian fuel cycle

  2. ECN contributions to ADTT `96

    Energy Technology Data Exchange (ETDEWEB)

    Koning, A.J.

    1996-07-01

    An outline is presented of the status of nuclear data evaluation for accelerator-driven systems. The international effort consists mainly of measuring, compiling and calculating nuclear data for elements and isotopes relevant for transmutation of radioactive waste (ATW), energy amplification and other accelerator-related nuclear applications. We argue that input for global, macroscopic calculation schemes for hybrid nuclear systems basically should consist of three types of nuclear data: (a) High-energy transport codes for energies above about 150 MeV, (b) neutron and proton transport data files for energies below about 150 MeV and (c) neutron and proton transmutation/activation libraries below about 150 MeV. Our specific contribution to the field concerns (b) and (c). The progress of the evaluation of high-energy nuclear data files for the most important materials and the related compilation of nuclear reaction information is reported. The evaluated data are calculated with the computer codes ECIS95, MINGUS and GNASH and are stored in ENDF6-format. We illustrate the library production with a short outline of the employed physical methods. Finally, we briefly discuss the application of the activation/transmutation library ECNAF96. (orig.).

  3. ECN contributions to ADTT '96

    International Nuclear Information System (INIS)

    An outline is presented of the status of nuclear data evaluation for accelerator-driven systems. The international effort consists mainly of measuring, compiling and calculating nuclear data for elements and isotopes relevant for transmutation of radioactive waste (ATW), energy amplification and other accelerator-related nuclear applications. We argue that input for global, macroscopic calculation schemes for hybrid nuclear systems basically should consist of three types of nuclear data: (a) High-energy transport codes for energies above about 150 MeV, (b) neutron and proton transport data files for energies below about 150 MeV and (c) neutron and proton transmutation/activation libraries below about 150 MeV. Our specific contribution to the field concerns (b) and (c). The progress of the evaluation of high-energy nuclear data files for the most important materials and the related compilation of nuclear reaction information is reported. The evaluated data are calculated with the computer codes ECIS95, MINGUS and GNASH and are stored in ENDF6-format. We illustrate the library production with a short outline of the employed physical methods. Finally, we briefly discuss the application of the activation/transmutation library ECNAF96. (orig.)

  4. The LA-0 project of experimental investigations of ADTT blankets with fluoride salts

    International Nuclear Information System (INIS)

    There was an idea of experimental investigations of accelerator-driven transmuter blanket cores with fluoride salts on the experimental reactor LR-0 in the Nuclear Research Institute Rez plc, the Czech Republic, which has been further developed and elaborated. The results of a preliminary proposal and assessment of possibility of a reconstruction of the LR-0 core for experiments simulating blankets with molten fluoride salt fuel were reported. There is a brief survey of essential conclusions of both those stages presented in this paper. The current status of the complex project called LA-0 which has been proposed to start in 1996 will be given in some details. The project consists of all the basic regions -neutron source and subcritical assembly design and other engineering problems including fluoride chemical technology - of such a system. Nevertheless, the main attention, in this paper, is focused on the methodology of all the regions, i.e. methods of neutronic characteristic predictions, both computational and experimental, as well as some methods selected in the other topical regions are mentioned. Among the methods being taken into account for the first phases of the experimental program the measurements of neutronic characteristics by use of oscillating samples method will be given at the first position. There is also an illustrative description of the existing LR-0 experimental reactor given in the paper. Finally, there are future stages of the project outlined in a rough frame only and their benefits as well as drawbacks critically discussed in the concluding part of the paper. 5 refs., 4 figs

  5. Important requirements for RF generators for Accelerator-Driven Transmutation Technologies (ADTT)

    International Nuclear Information System (INIS)

    All Accelerator-Driven Transmutation applications require very large amounts of RF Power. For example, one version of a Plutonium burning system requires an 800-MeV, 80-mA, proton accelerator running at 100% duty factor. This accelerator requires approximately 110-MW of continuous RF power if one assumes only 10% reserve power for control of the accelerator fields. In fact, to minimize beam spill, the RF controls may need as much as 15 to 20% of reserve power. In addition, unlike an electron accelerator in which the beam is relativistic, a failed RF station can disturb the synchronism of the beam, possibly shutting down the entire accelerator. These issues and more lead to a set of requirements for the RF generators which are stringent, and in some cases, conflicting. In this paper, we will describe the issues and requirements, and outline a plan for RF generator development to meet the needs of the Accelerator-Driven Transmutation Technologies. The key issues which will be discussed include: operating efficiency, operating linearity, effect on the input power grid, bandwidth, gain, reliability, operating voltage, and operating current

  6. High-current deuteron cyclotron complex as meson and neutron generator for accelerator driven transmutation technology (ADTT) and energy production

    International Nuclear Information System (INIS)

    The research and development results are given for the Deuteron Cyclotron Complex with the final energy about 900 MeV/nucleon and average beam intensity in the milli ampere range. The complex consists of a radiofrequency quadrupole linear accelerator (RFQ-linac) and two superconducting sector cyclotrons DC-I and DC-II. The possibility of replacing a linac by a cyclotron injector with the deuteron energy 15 MeV and with 'warm' or superconducting sector magnets is discussed. A DC-II version with 10 superconducting sector magnets and 6 main and 2 flat-top radio frequency (RF) resonators is proposed. Information on the constructing of the full-scale prototype for several DC-I systems is given

  7. Comparisons of methods for in vitro dry matter digestibility of ruminant feeds

    OpenAIRE

    Brons, E.; Plaizier, J.C.

    2005-01-01

    Apparent in vitro dry matter digestibilities of selected ruminant feeds were determined with the DAISYII incubator (ADD, ANKOM Technology Corp., Macedon, NY) and the Tilley and Terry technique (ADTT). True in vitro dry matter digestibility was also determined with the DAISYII incubator (TDD). The ADD and ADTT did not differ for grain crop silages and total mixed rations. The ADD was 9.0 percentage points higher than ADTT for grains and 3.4 percentage points lower than ADTT for grass and legum...

  8. AIP conference on accelerator driven transmutation technologies and applications, Las Vegas, Nevada, July 25-29, 1994

    International Nuclear Information System (INIS)

    This conference was the first to bring together US and foreign researchers to define Accelerator Driven Transmutation Technology (ADTT) concepts in several important national and international application areas - nuclear waste transmutation, minimizing of world plutonium inventories, and long-term energy production. The conference covered a number of diverse technological areas - accelerators, target/blankets, separations, materials - that make up ADTT systems. The meeting provided one of the first opportunities for specialists in these technologies to meet together and learn about system requirements, components, and interface issues. It was also an opportunity to formulate plans for future developments in ADTT. During the conference over one hundred technical presentations were made describing ADTT system and technology concepts as well as the impact of ADTT on issues related to global plutonium management and the high-level nuclear waste problem areas. Separate abstracts have been entered into the database for articles from this report

  9. A long view of global plutonium management

    International Nuclear Information System (INIS)

    Dealing with the large and growing world inventories of fissile materials from all sources is a major part of the long term challenge of limiting the danger from nuclear weapons. Providing clean, safe nuclear power may also be needed to prevent conditions from arising which could lead to large scale nuclear weapon (re)armament. ADTT technologies might reconcile the seeming dilemma of providing nuclear power while maintaining a very low world inventory of nuclear materials which can be used in weapons. This vision for ADTT should be tested in a variety of ways, including comparisons with competing approaches and with other objectives. Such testing is one part of constructing a path for a decades-long, worldwide implementation campaign for ADTT

  10. Accelerator-driven transmutation technologies

    International Nuclear Information System (INIS)

    The basic principles of accelerator-driven transmutation technologies (ADTT) are outlined and their assets highlighted. Current designs of ADTT facilities pursue 3 basic objectives: (i) Systems designed to generate power and convert nuclear wastes produced by conventional nuclear reactors into long-lived radioisotopes by transmutation. Such isotopes will be separated from molten salts by centrifugal separation. A single subcritical assembly will 'burn' wastes produced by several conventional NPPs. (ii) Systems for power generation using thorium fuel. Such systems are not designed for transmutation of nuclear wastes. The amount of transuranium elements produced by the thorium cycle is minimal, whereby the problem of storage of very long lived isotopes is virtually eliminated. (iii) Systems for transmutation of plutonium reclaimed from nuclear weapons. As to the future of ADTT in comparison with nuclear fusion, an asset of the former is that there remain no unsolved principal physical problems that would preclude its implementation. What has to be solved is materials and technological problems and, in particular, the financial problem. Implementation of ADTT is impossible in any way other than on the basis of a wide international cooperation. There exists a group of people dealing with ADTT in the Czech Republic, joining academic and industrial experts; this group is fostering contacts with the Los Alamos National Laboratory, U.S.A. The Institute of Nuclear Physics, Academy of Sciences of the Czech Republic, has set up an ADTT Documentation Center, which is accessible to any person interested in this promising field of science and technology. (P.A.). 3 figs

  11. The Los Alamos accelerator driven transmutation of nuclear waste (ATW) concept development of the ATW target/blanket system

    International Nuclear Information System (INIS)

    The studies carried out in the frame of the Accelerator Driven Transmutation Technology (ADTT) program developed at Los Alamos in order to solve the nuclear waste problem and to build a new generation of safer and non-proliferant nuclear power plants, are presented

  12. Nuclear Methods for Transmutation of Nuclear Waste: Problems, Perspextives, Cooperative Research - Proceedings of the International Workshop

    Science.gov (United States)

    Khankhasayev, Zhanat B.; Kurmanov, Hans; Plendl, Mikhail Kh.

    1996-12-01

    The Table of Contents for the full book PDF is as follows: * Preface * I. Review of Current Status of Nuclear Transmutation Projects * Accelerator-Driven Systems — Survey of the Research Programs in the World * The Los Alamos Accelerator-Driven Transmutation of Nuclear Waste Concept * Nuclear Waste Transmutation Program in the Czech Republic * Tentative Results of the ISTC Supported Study of the ADTT Plutonium Disposition * Recent Neutron Physics Investigations for the Back End of the Nuclear Fuel Cycle * Optimisation of Accelerator Systems for Transmutation of Nuclear Waste * Proton Linac of the Moscow Meson Factory for the ADTT Experiments * II. Computer Modeling of Nuclear Waste Transmutation Methods and Systems * Transmutation of Minor Actinides in Different Nuclear Facilities * Monte Carlo Modeling of Electro-nuclear Processes with Nonlinear Effects * Simulation of Hybrid Systems with a GEANT Based Program * Computer Study of 90Sr and 137Cs Transmutation by Proton Beam * Methods and Computer Codes for Burn-Up and Fast Transients Calculations in Subcritical Systems with External Sources * New Model of Calculation of Fission Product Yields for the ADTT Problem * Monte Carlo Simulation of Accelerator-Reactor Systems * III. Data Basis for Transmutation of Actinides and Fission Products * Nuclear Data in the Accelerator Driven Transmutation Problem * Nuclear Data to Study Radiation Damage, Activation, and Transmutation of Materials Irradiated by Particles of Intermediate and High Energies * Radium Institute Investigations on the Intermediate Energy Nuclear Data on Hybrid Nuclear Technologies * Nuclear Data Requirements in Intermediate Energy Range for Improvement of Calculations of ADTT Target Processes * IV. Experimental Studies and Projects * ADTT Experiments at the Los Alamos Neutron Science Center * Neutron Multiplicity Distributions for GeV Proton Induced Spallation Reactions on Thin and Thick Targets of Pb and U * Solid State Nuclear Track Detector and

  13. The physics design of accelerator-driven transmutation systems

    International Nuclear Information System (INIS)

    Nuclear systems under study in the Los Alamos Accelerator-Driven Transmutation Technology program (ADTT) will allow the destruction of nuclear spent fuel and weapons-return plutonium, as well as the production of nuclear energy from the thorium cycle, without a long-lived radioactive waste stream. The subcritical systems proposed represent a radical departure from traditional nuclear concepts (reactors), yet the actual implementation of ADTT systems is based on modest extrapolations of existing technology. These systems strive to keep the best that the nuclear technology has developed over the years, within a sensible conservative design envelope and eventually manage to offer a safer, less expensive and more environmentally sound approach to nuclear power

  14. Review of ORNL's MSR technology and status

    International Nuclear Information System (INIS)

    The current status of molten salt reactor development is discussed with reference to the experience from the Oak Ridge Molten Salt Reactor Experiment. Assessment of the future for this reactor system is reviewed with consideration of both advantages and disadvantages. Application of this concept to ADTT (accelerator driven transmutation technology) needs appears to be feasible by drawing on the MSRE experience. Key chemical considerations remain as: solubility, redox behavior, and chemical activity and their importance to ADTT planning is briefly explained. Priorities in the future development of molten salts for these applications are listed, with the foremost being the acceptance of the 2LiF-BeF2 solvent system. 8 refs, 2 figs

  15. Basis and objectives of the Los Alamos Accelerator-Driven Transmutation Technology Project

    International Nuclear Information System (INIS)

    The Accelerator-Driven Transmutation Technology (ADTT) Project carries three approaches for dealing with waste from the defense and commercial nuclear energy enterprise. First, the problem of excess weapons plutonium in the US and Russia originating both from stockpile reductions and from defense production site clean-up is one of significant current and long-term concern. The ADTT technology offers the possibility of almost complete destruction of this plutonium by fission. The technology might be particularly effective for destruction of the low quality plutonium from defense site clean-up since the system does not require the fabrication of the waste into fuel assemblies, does not require reprocessing and refabrication, and can tolerate a high level of impurities in the feed stream. Second, the ADTT system also can destroy the plutonium, other higher actinide, and long-lived fission product from commercial nuclear waste which now can only be dealt with by geologic storage. And finally, and probably most importantly the system can be used for the production of virtually unlimited electric power from thorium with concurrent destruction of its long-lived waste components so that geologic containment for them is not required. In addition plutonium is not a significant byproduct of the power generation so that non-proliferation concerns about nuclear power are almost completely eliminated. All of the ADTT systems operate with an accelerator supplementing the neutrons which in reactors are provided only by the fission process, and therefore the system can be designed to eliminate the possibility for a runaway chain reaction. The means for integration of the accelerator into nuclear power technology in order to make these benefits possible is described including estimates of accelerator operating parameters required for the three objectives

  16. Project of Molten Salt Reactor for spent fuel transmutations. Neutron-physical characteristics. Models and calculations. Technical proposals on the software

    International Nuclear Information System (INIS)

    A brief review of the codes available for the neutron-physical calculations of the heterogeneous nuclear reactors and critical assemblies is presented. These programs can be used for simulation of the reactor part in the accelerator Driven Transmutations Technology (ADTT) for Molten Salt Reactor Project. The programs are described that do not use empirical coefficients typical for the existing engineering program complexes intended for the calculation of thermal reactors. This is particularly important for the calculation of the non-standard situations in reactor as well as for designing the new reactor concepts. (author)

  17. A new approach to modeling linear accelerator systems

    International Nuclear Information System (INIS)

    A novel computer code is being developed to generate system level designs of radiofrequency ion accelerators with specific applications to machines of interest to Accelerator Driven Transmutation Technologies (ADTT). The goal of the Accelerator System Model (ASM) code is to create a modeling and analysis tool that is easy to use, automates many of the initial design calculations, supports trade studies used in accessing alternate designs and yet is flexible enough to incorporate new technology concepts as they emerge. Hardware engineering parameters and beam dynamics are to be modeled at comparable levels of fidelity. Existing scaling models of accelerator subsystems were used to produce a prototype of ASM (version 1.0) working within the Shell for Particle Accelerator Related Code (SPARC) graphical user interface. A small user group has been testing and evaluating the prototype for about a year. Several enhancements and improvements are now being developed. The current version of ASM is described and examples of the modeling and analysis capabilities are illustrated. The results of an example study, for an accelerator concept typical of ADTT applications, is presented and sample displays from the computer interface are shown

  18. Particle accelerator requirements for burning radioactive wastes

    International Nuclear Information System (INIS)

    One of the four subprograms of the Accelerator Driven Transmutation Technology (ADTT) program is the Accelerator Transmutation of Waste (ATW) subprogram which in term is a program. The capacity to burn waste is given by the enhanced neutron economy made possible by the presence of the extra accelerator-produced neutrons. The better neutron economy increases the capacity of burning (transmute) anything that absorbs neutrons including long-lived fission products and actinides. By these transmuted or 'burning' systems, the bulk of long-lived radionuclides in disposed radioactive wastes can be reduced by factors of 1000 and the storage time of residual products can be greatly reduced from hundreds of thousands of years to several centuries. This paper presents particle beam requirements for ADTT applications. These are most often specified with a nominal 1 GeV energy and an average beam current for ATW ranging from 100 to 250 m A depending on different applications and different system concepts. It is sketched the reference RF-Linac Accelerator Design for ATW systems. (author)

  19. New Development of Accelerator Methods for Energy Production in the 21st Century - Alternative to Nuclear reactors

    International Nuclear Information System (INIS)

    In recent years, and particularly in light of a growing influence of ecological and political factors in the field of energy development, new concepts of nuclear technology based on the use of nuclear particle accelerators are being considered. Subcritical source-driven nuclear systems (SSDNS) are given close attention, whereby the application of a high-intensity external neutronic source can cause major fission power by affecting the subcritical nucleus. Recent research within the project of the accelerator driven transmutation technology (ADTT) in Los Alamos shows that now it is possible to use this concept, specially owing to a considerable improvement of the high-power accelerators predominantly realised in the military project for the development of space weapons. Accelerator driven neutronic spallation is considered a particularly promising source in achieving the subcritical fission. The project also reviews the development of new technologies related to the problem of nuclear waste by means of accelerator driven transmutation of waste (ATW). This method could result in the demolition of plutonium, trans-uranium elements and long-lasting fission products and thereby in their removal from the environment- Possible consequences of ADTT and ATW on the energy sector development in the 21st century are being considered. (author)

  20. Materials considerations for molten salt accelerator-based plutonium conversion systems

    International Nuclear Information System (INIS)

    Accelerator-driven transmutation technology (ADTT) refers to a concept for a system that uses a blanket assembly driven by a source of neutrons produced when high-energy protons from an accelerator strike a heavy metal target. One application for such a system is called Accelerator-Based Plutonium Conversion, or ABC. Currently, the version of this concept being proposed by the Los Alamos National Laboratory features a liquid lead target material and a blanket fuel of molten fluorides that contain plutonium. Thus, the materials to be used in such a system must have, in addition to adequate mechanical strength, corrosion resistance to molten lead, corrosion resistance to molten fluoride salts, and resistance to radiation damage. In this report the corrosion properties of liquid lead and the LiF-BeF2 molten salt system are reviewed in the context of candidate materials for the above application. Background information has been drawn from extensive past studies. The system operating temperature, type of protective environment, and oxidation potential of the salt are shown to be critical design considerations. Factors such as the generation of fission products and transmutation of salt components also significantly affect corrosion behavior, and procedures for inhibiting their effects are discussed. In view of the potential for extreme conditions relative to neutron fluxes and energies that can occur in an ADTT, a knowledge of radiation effects is a most important factor. Present information for potential materials selections is summarized

  1. Separations technology development to support accelerator-driven transmutation concepts

    International Nuclear Information System (INIS)

    This is the final report of a one-year Laboratory-Directed Research and Development (LDRD) Project at the Los Alamos National Laboratory (LANL). This project investigated separations technology development needed for accelerator-driven transmutation technology (ADTT) concepts, particularly those associated with plutonium disposition (accelerator-based conversion, ABC) and high-level radioactive waste transmutation (accelerator transmutation of waste, ATW). Specific focus areas included separations needed for preparation of feeds to ABC and ATW systems, for example from spent reactor fuel sources, those required within an ABC/ATW system for material recycle and recovery of key long-lived radionuclides for further transmutation, and those required for reuse and cleanup of molten fluoride salts. The project also featured beginning experimental development in areas associated with a small molten-salt test loop and exploratory centrifugal separations systems

  2. The Czech national R and D program of nuclear incineration of PWR spent fuel in a transmuter with liquid fuel

    International Nuclear Information System (INIS)

    The principle drawbacks of any kind of solid nuclear fuel are listed and briefly analysed in the first part of the paper. On the basis of this analysis, the liquid fuel concept and its benefits are introduced and briefly described in the following parts of the paper allowing to developed new reactor systems for nuclear incineration of spent fuel from conventional reactors and a new clean source of energy. As one of the first realistic attempts to utilize the advantages of liquid fuel, the reactor/blanket system with molten fluoride salts in the role of fuel and coolant simultaneously, as incorporated in the accelerator-driven transmutation technology (ADTT) being proposed in [1], has been proposed for a deeper, both theoretical and experimental studies in [2]. There will be a preliminary design concept of an experimental assembly LA-0 briefly introduced in the paper which is under preparation in the Czech Republic for such a project [3]. (author)

  3. National R and D program of nuclear incineration of PWR spent fuel in a transmuter with liquid fuel as being developed in the Czech Republic

    International Nuclear Information System (INIS)

    The principal drawbacks of any kind of solid nuclear fuel are listed and briefly analysed in the first part of the paper. On the basis of this analysis, the liquid fuel concept and its benefits are introduced and briefly described in the following parts of the paper allowing to develop new reactor systems for nuclear incineration of spent fuel from conventional reactors and a new clean source of energy. As one of the first realistic attempts to utilise the advantages of liquid fuel, the reactor/blanket system with molten fluoride salts in the role of fuel and coolant simultaneously, as incorporated in the accelerator-driven transmutation technology (ADTT), has been proposed for a deeper, both theoretical and experimental studies. There will be a preliminary design concept of an experimental assembly LA-0 briefly introduced in the paper which is under preparation in the Czech Republic for such a project

  4. Automation of the CFD Process on Distributed Computing Systems

    Science.gov (United States)

    Tejnil, Ed; Gee, Ken; Rizk, Yehia M.

    2000-01-01

    A script system was developed to automate and streamline portions of the CFD process. The system was designed to facilitate the use of CFD flow solvers on supercomputer and workstation platforms within a parametric design event. Integrating solver pre- and postprocessing phases, the fully automated ADTT script system marshalled the required input data, submitted the jobs to available computational resources, and processed the resulting output data. A number of codes were incorporated into the script system, which itself was part of a larger integrated design environment software package. The IDE and scripts were used in a design event involving a wind tunnel test. This experience highlighted the need for efficient data and resource management in all parts of the CFD process. To facilitate the use of CFD methods to perform parametric design studies, the script system was developed using UNIX shell and Perl languages. The goal of the work was to minimize the user interaction required to generate the data necessary to fill a parametric design space. The scripts wrote out the required input files for the user-specified flow solver, transferred all necessary input files to the computational resource, submitted and tracked the jobs using the resource queuing structure, and retrieved and post-processed the resulting dataset. For computational resources that did not run queueing software, the script system established its own simple first-in-first-out queueing structure to manage the workload. A variety of flow solvers were incorporated in the script system, including INS2D, PMARC, TIGER and GASP. Adapting the script system to a new flow solver was made easier through the use of object-oriented programming methods. The script system was incorporated into an ADTT integrated design environment and evaluated as part of a wind tunnel experiment. The system successfully generated the data required to fill the desired parametric design space. This stressed the computational

  5. Measurement of solubility of plutonium trifluoride and rare-earth fluorides in molten LiF-BeF{sub 2}-ZrF{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Naumov, V.S.; Bychkov, A.V.; Kormilitsyn, M.V. [and others

    1996-12-01

    Data on behavior of plutonium fluoride and fission products (FP) dissolved in fuel composition are needed to calculate the duration of an operating cycle of the ADTT facility (Accelerator-Driver Transmutation Technologies) and to determine the effect of their equilibrium concentrations on nuclear-physical characteristics of reactor operation. The data on the FP fluoride solubility in the molten salts are of great important for some industrial processes (electrolytical metal deposition, development of physical-chemical mean for processes of chemical technology, etc.) As noted above, some information on this question is given in monography and articles. Data concerning fluoride salts are given in reports. However, it was impossible to make the substantial analysis of mutual solubility of fluoride melts. The primary investigation of CeF{sub 3} and neodymium, samarium and lanthanum fluorides showed that the solubility of the melt LiF-BeF{sub 2} and LiF-BeF{sub 2}-ThF{sub 4} was a linear function of reverse temperature and increases from lanthanum to samarium in the row of rare-earth elements. Disagreement in estimation of plutonium trifluoride solubility and incomplete data on the solubility of rare-earth elements prompted this study.

  6. Neutron Production in Spallation Reactions of 0.9- and 1.5-GeV Protons on a Thick Lead Target - Comparison of Experimental Data and MCNPX Simulations

    International Nuclear Information System (INIS)

    This study is part of a complex research of Accelerator Driven Transmutation Technologies (ADTT) carried out by a collaboration of the NPI ASCR in Rez with the JINR in Dubna. The aim of the experiment was to check the validity of the model descriptions and the cross-section libraries used in the corresponding Monte-Carlo simulations of spallation reactions, and the propagation of the produced high-energy neutrons passed through a thick target. The experiments were carried out at the synchrophasotron and the Nuclotron accelerators of the Laboratory for High Energies at the JINR. Relativistic protons interacting with a massive cylindrical lead target produced the spallation neutrons. The spatial and energetic distributions of the produced neutron field were measured by the activation of Al, Au, Bi, Co and Cu foils placed on the surface of and next to the target. The HPGe detectors then measured the activity of the foils. The resulting γ-spectra of the activated foils were analysed, the yields of the corresponding radioactive nuclei were determined, and compared with Monte-Carlo based simulations performed both with the LAHET+MCNP code and the MCNPX code

  7. Accelerator-driven transmutation: a high-tech solution to some nuclear waste problems

    International Nuclear Information System (INIS)

    This paper discusses current technical and political issues regarding the innovative concept of using accelerator-driven transmutation processes for nuclear waste management. Two complex and related issues are addressed. First, the evolution and improvements of the design technologies are identified to indicate that there has been sufficient technological advancement with regard to a 1991 scientific peer review to warrant the advent of a large-scale national research and development program. Second, the economics and politics of the transmutation system are examined to identify non-technical barriers to the implementation of the program. Transmutation of waste has been historically viewed by nuclear engineers as one of those technologies that is too good to be true and probably too expensive to be feasible. The concept discussed in the present paper uses neutrons ( which result from protons accelerated into spallation targets)to transmute the major very long-lived hazardous materials such as the radioactive isotopes of technetium, iodine, neptunium, plutonium, americium, and curium. Although not a new concept, accelerator-driven transmutation technology (ADTT) lead by a team at Los Alamos National Laboratory (LANL) has made some significant advances which are discussed in the present paper. (authors)

  8. Measurement of solubility of plutonium trifluoride and rare-earth fluorides in molten LiF-BeF2-ZrF4

    International Nuclear Information System (INIS)

    Data on behavior of plutonium fluoride and fission products (FP) dissolved in fuel composition are needed to calculate the duration of an operating cycle of the ADTT facility (Accelerator-Driver Transmutation Technologies) and to determine the effect of their equilibrium concentrations on nuclear-physical characteristics of reactor operation. The data on the FP fluoride solubility in the molten salts are of great important for some industrial processes (electrolytical metal deposition, development of physical-chemical mean for processes of chemical technology, etc.) As noted above, some information on this question is given in monography and articles. Data concerning fluoride salts are given in reports. However, it was impossible to make the substantial analysis of mutual solubility of fluoride melts. The primary investigation of CeF3 and neodymium, samarium and lanthanum fluorides showed that the solubility of the melt LiF-BeF2 and LiF-BeF2-ThF4 was a linear function of reverse temperature and increases from lanthanum to samarium in the row of rare-earth elements. Disagreement in estimation of plutonium trifluoride solubility and incomplete data on the solubility of rare-earth elements prompted this study

  9. Installation of a cw radiofrequency quadrupole accelerator at Los Alamos National Laboratory

    International Nuclear Information System (INIS)

    Chalk River Laboratories (CRL) has had a long history of cw proton beam development for production of intense neutron sources and fissile fuel breeders. In 1986 CRL and Los Alamos National Laboratory (LANL) entered into a collaborative effort to establish a base technologies program for the development of a cw radiofrequency quadrupole (RFQ). The initial cw RFQ design had 50-keV proton injection energy with 600-keV output energy. The 75-mA design current at 600-keV beam energy was obtained in 1990. Subsequently, the RFQ output energy was increased to 1250 keV by replacing the RFQ vanes, still maintaining the 75-m A design current. A new 250-kW cw klystrode rf power source at 267-MHz was installed at CRL. By April of 1993, 55-mA proton beams had been accelerated to 1250 keV. Concurrent developments were taking place on proton source development and on 50-keV low-energy beam transport (LEBT) systems. Development of a dc, high-proton fraction (≥ 70%) microwave ion source led to utilization of a single-solenoid RFQ direct injection scheme. It was decided to continue this cw RFQ demonstration project at Los Alamos when the CRL project was terminated in April 1993. The LANL goals are to find the current limit of the 1250-keV RFQ, better understand the beam transport properties through the single-solenoid focusing LEBT, continue the application of the cw klystrode tube technology to accelerators, and develop a two-solenoid LEBT which could be the front end of an Accelerator-Driven Transmutation Technologies (ADTT) linear accelerator

  10. A prototype Accelerator Driven System in Belgium: the Myrrha project

    International Nuclear Information System (INIS)

    The renewed interest in Accelerator Driven Systems (ADS) world-wide, has given a new increased effort in several related research domains. The communications within the ICANS, ICENES and ADTT meetings have shown that all major research institutes are somehow conducting research in this new field. Within this research forum, most of the e proposed systems deal with spallation sources in the MW-range, addressing needs for accelerators and sub-critical facilities that are out of current reliability and sometimes even out of current technology range. The necessary research in several sub-domains has to be addressed once and will need prototype systems enabling the validation and test of calculational tools and technological items. At SCK.CEN, the Belgian nuclear research center, the Myrrha project has been started end of 1995. This project intends to design, develop and possibly realize a prototype accelerator driven system as advanced neutron source and with four main objectives. . research of ADS-development as an option for transmutation . in-core irradiation experiments as extension and continuing support in the field of reactor physics and technology and safety-related experiments; . medical and industrial applications (including radioisotope production, known as the ADONIS-project) . extension of current SCK.CEn-research and extensions into new fields based on the availability of performing in-core and neutron-beam experiments This paper will describe the current status of this project and planning og ongoing research as well the description of two specific applications, i. e. radioisotope production and transmutation studies. (Author) 10 refs

  11. Extensive utilization of training reactor VR-1

    International Nuclear Information System (INIS)

    provide special training for selected specialists from Czech and Slovak Nuclear Power Plants. Scientific research respects reactor parameters and requirements of the so-called clean reactor core (free from a major effect of the fission products). Research on VR-1 is mainly aimed at the preparation and testing of new educational methodologies, investigation of reactor lattice parameters, reactor dynamics study, research in the control equipment field, neutron detector calibration, etc. Information services and promotional activities in the nuclear power field are important parts of the reactor operation. Many visitors, mainly high school students, come to the reactor. The reactor staff prepares an attractive program including reactor operation. Every year, more than 1500 high school students come to visit the reactor, as do many foreigner visitors. The plan for the training reactor VR-1 for the next 10 years covers essential activities (less important activities describes the annual plan for each year) in five fields: education activities, research activities, public relation activities, international cooperation, and human resources, innovation and new equipment.Education activities: Keeping the current state in the field number of user schools, number of students and number of offered experimental exercises; Improving existing experimental exercises and establishing new according requests users from Universities and Nuclear Engineering companies, for example: study of neutron noise and it's application, study of thermal effects, study of digital control systems, study of transmutation technologies ADTT, study of neutron detectors. Research activities: Seeking research activities which can use advantages of 'clean' core without temperature, pressure, burn-up feedback etc.; Continuing in study of the digitally controlled nuclear research reactors; Continuing development of control equipment the VR-1 reactor; Continuing wide co-operation with Czech and Slovak institutions

  12. 美国焊接桥梁的疲劳设计准则%Fatigue Design Criteria for Welded Bridges in the U.S.

    Institute of Scientific and Technical Information of China (English)

    JohnW.Fisher

    2011-01-01

    Fifty years ago,fatigue design was not considered a serious bridge performance issue in the US.Fatigue design utilized the concept of Iimiting the maximum stress at details by using the R-ratio of minimum/maximum stress and an assumption that the fatigue limit occurred at 2 million cycle.The HS-20 design truck was usd for specific cycles based on the type of road and the average daily truck traffic (ADTT).Fatigue cracks were observed to develop in steel bridges in the late 1960s and early 70's.This development and the results of large scale beam tests on welded details that were carried out between 1967 and 1987 provided a statistically sound data base and established that stress range alone was the only statistical significant design stress.The fatigue provisions adopting stress range were changed by AASHTO in 1974.This meant that only the live load cyclic stress was important.The basic fatigue resistance curves provide a log normal lower bound design basis for fatigue life that is used world wide today.Experience with steel bridges also showed that a rule adopted after WWⅡ whiCH avoided welding to tension flanges,has resulted in extensive web gap cracking from out of plane distortions.During the last decade these small web gaps have resulted in unanticipated brittle fractures as a result of tri-axial stresses even in the absence of fatigue crack growth.%50年前,疲劳设计在美国人看来并非是一个很严重的桥梁性能问题.疲劳设计运用了限制最大应力的概念,即假定疲劳极限发生在2×106次循环荷载时,利用最小应力与最大应力的比R,限制各点的最大应力.根据道路类型与每日平均车流量,采用型号为HS-20的设计车来测定特定周期.在20世纪60年代末至70年代初,发现钢结构桥梁中存在疲劳裂纹.1967-1987年,针对焊接部位进行了大量的梁试验.根据试验结果,统计得到了数据库,并认为应力幅度才是唯一主要的设计应力.1974年,美国AASHTO规

  13. Review of national accelerator driven system programmes for partitioning and transmutation. Proceedings of an advisory group meeting

    International Nuclear Information System (INIS)

    : Comprehensive presentations from groups conducting the most active research and development projects (Prof. Rubbia (on behalf of the '3 countries initiative': French-Italian-Spanish collaboration), CERN, CEA, JAERI, USA (LANL, BNL, LLNL, ANL, ONL), EC ADS-project (TARC, IABAT), Russian Federation. The presentations centered on the following issues: General issues and motivations: national/international views, specifically: Why is ADS needed for the country; Role of ADS in future nuclear cycles and waste management; General safety issues and requirements of ADS; Public acceptance; ADS Technology; Accelerators for ADTT (cyclotrons and linacs); Specific requirements and features of ADS accelerators; Reliability of operation; Design efficiency; Development of ADS-oriented codes and methods; Benchmark reports; Experiments and validation of codes; Deterministic and Monte-Carlo codes; Coupling of high and low energy transport; Static and dynamic methods for subcritical systems; Spallation and fission product modeling; Targets and nuclear assemblies for ADS; ADS Targets (solid and liquid); Damage to materials (Materials irradiation in Proton field, High energy neutron field, Temperature/shock effects, etc., experiments related to Technology of heavy liquid metals, Thermohydraulics, Corrosion); Experiments (Hg target experiments at BNL; Subcritical cores, Fuels and fuel processes, Molten salt reactors)