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Sample records for accelerator driven subcritical

  1. Subcritical reactivity monitoring in accelerator driven systems

    In this paper, an absolute measurements technique for the subcriticality determination is presented. The development of accelerator driven systems (ADS) requires the development of methods to monitor and control the subcriticality of this kind of system, without interfering with its normal operation mode. This method is based on the stochastic neutron and photon transport theory that can be implemented by presently available neutron transport codes. As a by-product of the methodology a monitoring measurement technique has been developed and verified using two coupled Monte Carlo programs. The first one, LAHET, simulates the spallation collisions and the high energy transport and the other, MCNPDSP, is used to estimate the counting statistics from neutron ray counter in fissile system, and the transport for neutrons with energies less than 20 Mev. Through the analysis of the counter detectors it is possible to determine the kinetics parameters and the keff value. We present two different ways to obtain these parameters using the accelerator or using a Cf-252 source. A good agreement between theory and simulations has been obtained with both sources

  2. Choosing the optimal parameters of subcritical reactors driven by accelerators

    Physical aspects of a subcritical Nuclear Power Plants (NPP) driven by proton accelerators are considered. Estimated theoretical calculations are made for subcritical regimes of various types of reactors. It was shown that the creation of the quite effective explosion-safe NPP is real at an existing level of the accelerator technique by using available reactor units (including the serial ones). (author)

  3. Accelerator-induced transients in Accelerator Driven Subcritical Reactors

    Achieving higher particles energies and beam powers have long been the main focus of research in accelerator technology. Since Accelerator Driven Subcritical Reactors (ADSRs) have become the subject of increasing interest, accelerator reliability and modes of operation have become important matters that require further research and development in order to accommodate the engineering and economic needs of ADSRs. This paper focuses on neutronic and thermo-mechanical analyses of accelerator-induced transients in an ADSR. Such transients fall into three main categories: beam interruptions (trips), pulsed-beam operation, and beam overpower. The concept of a multiple-target ADSR is shown to increase system reliability and to mitigate the negative effects of beam interruptions, such as thermal cyclic fatigue in the fuel cladding and the huge financial cost of total power loss. This work also demonstrates the effectiveness of the temperature-to-reactivity feedback mechanisms in ADSRs. A comparison of shutdown mechanisms using control rods and beam cut-off highlights the intrinsic safety features of ADSRs. It is evident that the presence of control rods is crucial in an industrial-scale ADSR. This paper also proposes a method to monitor core reactivity online using the repetitive pattern of beam current fluctuations in a pulsed-beam operation mode. Results were produced using PTS-ADS, a computer code developed specifically to study the dynamic neutronic and thermal responses to beam transients in subcritical reactor systems.

  4. Candidate molten salt investigation for an accelerator driven subcritical core

    SOOBY Elizabeth; Baty, Austin; BENES ONDREJ; McIntyre, Peter; Pogue, Nathaniel; Salanne, Mathieu; Sattarov, Akhdiyor

    2013-01-01

    We report a design for accelerator-driven subcritical fission in a molten salt core (ADSMS) that utilizes a fuel salt composed of NaCl and transuranic (TRU) chlorides. The ADSMS core is designed for fast neutronics (28% of neutrons >1 MeV) to optimize TRU destruction. The choice of a NaCl-based salt offers benefits for corrosion, operating temperature, and actinide solubility as compared with LiF-based fuel salts. Molecular dynamics (MD) codes have been used to estimate properties of the molt...

  5. The physics of accelerator driven sub-critical reactors

    S B Degweker; Biplab Ghosh; Anil Bajpal; S D Pranjape

    2007-02-01

    In recent years, there has been an increasing worldwide interest in accelerator driven systems (ADS) due to their perceived superior safety characteristics and their potential for burning actinides and long-lived fission products. Indian interest in ADS has an additional dimension, which is related to our planned large-scale thorium utilization for future nuclear energy generation. The physics of ADS is quite different from that of critical reactors. As such, physics studies on ADS reactors are necessary for gaining an understanding of these systems. Development of theoretical tools and experimental facilities for studying the physics of ADS reactors constitute important aspect of the ADS development program at BARC. This includes computer codes for burnup studies based on transport theory and Monte Carlo methods, codes for studying the kinetics of ADS and sub-critical facilities driven by 14 MeV neutron generators for ADS experiments and development of sub-criticality measurement methods. The paper discusses the physics issues specific to ADS reactors and presents the status of the reactor physics program and some of the ADS concepts under study.

  6. BRAHMMA: A compact experimental accelerator driven subcritical facility using D-T/D-D neutron source

    Highlights: • Design of compact zero-power subcritical assembly BRAHMMA is presented. • One of the unique features is the use of beryllium oxide as reflector. • Modular subcritical core which can be modified for different fuel combination. • Preliminary results of reactivity measurement using PNS technique reported. - Abstract: A zero-power, sub-critical assembly BRAHMMA driven by a D-T/D-D neutron generator has been designed and commissioned at Bhabha Atomic Research Centre, India. This facility has been conceived for investigating the static and dynamic neutronics properties of accelerator driven sub-critical systems. This paper describes the design details of the system. Preliminary results of flux measurements and reactivity measurements using pulsed neutron source techniques have also been presented. This system has the advantage of being modular in design which enables its keff values to be changed depending upon type of fuel being used and it is first in the series of subcritical assemblies being designed

  7. Disposition of nuclear waste using subcritical accelerator-driven systems

    Spent fuel from nuclear power plants contains large quantities of Pu, other actinides, and fission products (FP). This creates challenges for permanent disposal because of the long half-lives of some isotopes and the potential for diversion of the fissile material. Two issues of concern for the US repository concept are: (1) long-term radiological risk peaking tens-of-thousands of years in the future; and (2) short-term thermal loading (decay heat) that limits capacity. An accelerator-driven neutron source can destroy actinides through fission, and can convert long-lived fission products to shorter-lived or stable isotopes. Studies over the past decade have established that accelerator transmutation of waste (ATW) can have a major beneficial impact on the nuclear waste problem. Specifically, the ATW concept the authors are evaluating: (1) destroys over 99.9% of the actinides; (2) destroys over 99.9% of the Tc and I; (3) separates Sr-90 and Cs-137; (4) separates uranium from the spent fuel; (5) produces electric power

  8. Disposition of nuclear waste using subcritical accelerator-driven systems

    Venneri, F.; Li, N.; Williamson, M.; Houts, M.; Lawrence, G.

    1998-12-31

    Spent fuel from nuclear power plants contains large quantities of Pu, other actinides, and fission products (FP). This creates challenges for permanent disposal because of the long half-lives of some isotopes and the potential for diversion of the fissile material. Two issues of concern for the US repository concept are: (1) long-term radiological risk peaking tens-of-thousands of years in the future; and (2) short-term thermal loading (decay heat) that limits capacity. An accelerator-driven neutron source can destroy actinides through fission, and can convert long-lived fission products to shorter-lived or stable isotopes. Studies over the past decade have established that accelerator transmutation of waste (ATW) can have a major beneficial impact on the nuclear waste problem. Specifically, the ATW concept the authors are evaluating: (1) destroys over 99.9% of the actinides; (2) destroys over 99.9% of the Tc and I; (3) separates Sr-90 and Cs-137; (4) separates uranium from the spent fuel; (5) produces electric power.

  9. Disposition of Nuclear Waste Using Subcritical Accelerator-Driven Systems

    Doolen, G.D.; Venneri, F.; Li, N.; Williamson, M.A.; Houts, M.; Lawrence, G.

    1998-06-27

    ATW destroys virtually all the plutonium and higher actinides without reprocessing the spent fuel in a way that could lead to weapons material diversion. An ATW facility consists of three major elements: (1) a high-power proton linear accelerator; (2) a pyrochemical spent fuel treatment i waste cleanup system; (3) a liquid lead-bismuth cooled burner that produces and utilizes an intense source-driven neutron flux for transmutation in a heterogeneous (solid fuel) core. The concept is the result of many years of development at LANL as well as other major international research centers. Once demonstrated and developed, ATW could be an essential part of a global non-proliferation strategy for countries that could build up large quantities of plutonium from their commercial reactor waste. ATW technology, initially proposed in the US, has received wide and rapidly increasing attention abroad, especially in Europe and the Far East with major programs now being planned, organized and tided. Substantial convergence presently exists on the technology choices among the programs, opening the possibility of a strong and effective international collaboration on the phased development of the ATW technology.

  10. LAVENDER: A steady-state core analysis code for design studies of accelerator driven subcritical reactors

    Zhou, Shengcheng; Wu, Hongchun; Cao, Liangzhi; Zheng, Youqi, E-mail: yqzheng@mail.xjtu.edu.cn; Huang, Kai; He, Mingtao; Li, Xunzhao

    2014-10-15

    Highlights: • A new code system for design studies of accelerator driven subcritical reactors (ADSRs) is developed. • S{sub N} transport solver in triangular-z meshes, fine deletion analysis and multi-channel thermal-hydraulics analysis are coupled in the code. • Numerical results indicate that the code is reliable and efficient for design studies of ADSRs. - Abstract: Accelerator driven subcritical reactors (ADSRs) have been proposed and widely investigated for the transmutation of transuranics (TRUs). ADSRs have several special characteristics, such as the subcritical core driven by spallation neutrons, anisotropic neutron flux distribution and complex geometry etc. These bring up requirements for development or extension of analysis codes to perform design studies. A code system named LAVENDER has been developed in this paper. It couples the modules for spallation target simulation and subcritical core analysis. The neutron transport-depletion calculation scheme is used based on the homogenized cross section from assembly calculations. A three-dimensional S{sub N} nodal transport code based on triangular-z meshes is employed and a multi-channel thermal-hydraulics analysis model is integrated. In the depletion calculation, the evolution of isotopic composition in the core is evaluated using the transmutation trajectory analysis algorithm (TTA) and fine depletion chains. The new code is verified by several benchmarks and code-to-code comparisons. Numerical results indicate that LAVENDER is reliable and efficient to be applied for the steady-state analysis and reactor core design of ADSRs.

  11. Study on design of superconducting proton linac for accelerator driven subcritical nuclear power system

    Yu Qi; Xu Tao Guang

    2002-01-01

    As a prior option of the next generation of energy source, the accelerator driven subcritical nuclear power system (ADS) can use efficiently the uranium and thorium resource, transmute the high-level long-lived radioactive wastes and raise nuclear safety. The ADS accelerator should provide the proton beam with tens megawatts. The superconducting linac (SCL) is a good selection of ADS accelerator because of its high efficiency and low beam loss rate. It is constitute by a series of the superconducting accelerating cavities. The cavity geometry is determined by means of the electromagnetic field computation. The SCL main parameters are determined by the particle dynamics computation

  12. Study on design of superconducting proton linac for accelerator driven subcritical nuclear power system

    As a prior option of the next generation of energy source, the accelerator driven subcritical nuclear power system (ADS) can use efficiently the uranium and thorium resource, transmute the high-level long-lived radioactive wastes and raise nuclear safety. The ADS accelerator should provide the proton beam with tens megawatts. The superconducting linac (SCL) is a good selection of ADS accelerator because of its high efficiency and low beam loss rate. It is constitute by a series of the superconducting accelerating cavities. The cavity geometry is determined by means of the electromagnetic field computation. The SCL main parameters are determined by the particle dynamics computation

  13. Analysis of burn up effects on kinetic parameters in an Accelerator Driven Subcritical TRIGA reactor

    Highlights: • Among the kinetic parameters, the most important ones are βeff and Λ. • The kinetic parameters at the end of cycle for 20 days operation at 1 MW reactor power have been calculated using MCNPX code. • The system sub-criticality levels, the required accelerator current and power have been calculated for each burnup step. • Burnup effects on neutronic parameters and accelerator requirements are analysed for a life cycle of the reactor core. - Abstract: In this paper, the kinetic parameters at the end of cycle for 20 days operation at 1 MW reactor power have been calculated using MCNPX code for source multiplication factors (Ks) of critical and 0.97 levels. Accelerator Driven Subcritical TRIGA reactor has been considered as the case study of the problem. The system sub-criticality levels, the required accelerator current (Ip) and power (Pacc) have been calculated for each burn up step. According to the results, the required Ip and Pacc increased as system sub-criticality level decreased. Also, the results show that the effective delayed neutron fraction (βeff) does not depend on sub-criticality levels significantly but the neutron reproduction time (Λ) strongly depends on the number of fuel elements in the core and sub-criticality levels. In addition, it was observed that in comparison with the beginning-of-cycle values, at end-of-cycle, the Λ increases by 112.6% and 108.4% respectively but the βeff decreases by 6.1% and 1.8% respectively in critical and 0.97 levels

  14. Temperature Profile of the Solution Vessel of an Accelerator-Driven Subcritical Fissile Solution System

    Dynamic System Simulation (DSS) models of fissile solution systems have been developed and verified against a variety of historical configurations. DSS techniques have been applied specifically to subcritical accelerator-driven systems using fissile solution fuels of uranium. Initial DSS models were developed in DESIRE, a specialized simulation scripting language. In order to tailor the DSS models to specifically meet needs of system designers they were converted to a Visual Studio implementation, and one of these subsequently to National Instrument's LabVIEW for human factors engineering and operator training. Specific operational characteristics of subcritical accelerator-driven systems have been examined using a DSS model tailored to this particular class using fissile fuel.

  15. Temperature Profile of the Solution Vessel of an Accelerator-Driven Subcritical Fissile Solution System

    Klein, Steven Karl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Determan, John C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-14

    Dynamic System Simulation (DSS) models of fissile solution systems have been developed and verified against a variety of historical configurations. DSS techniques have been applied specifically to subcritical accelerator-driven systems using fissile solution fuels of uranium. Initial DSS models were developed in DESIRE, a specialized simulation scripting language. In order to tailor the DSS models to specifically meet needs of system designers they were converted to a Visual Studio implementation, and one of these subsequently to National Instrument’s LabVIEW for human factors engineering and operator training. Specific operational characteristics of subcritical accelerator-driven systems have been examined using a DSS model tailored to this particular class using fissile fuel.

  16. Research program for the 660 MeV proton accelerator driven MOX-plutonium subcritical assembly

    Barashenkov, V. S.; Buttsev, V. S.; Buttseva, G. L.; Dudarev, S. Ju.; Polanski, A.; Puzynin, I. V.; Sissakian, A. N.

    2000-07-01

    This paper presents the research program of the Experimental Accelerator Driven System (ADS), which employs a subcritical assembly and a 660 MeV proton accelerator operating in the Laboratory of Nuclear Problems at the Joint Institute for Nuclear Research in Dubna. Mixed-oxide (MOX) fuel (25% PuO2+75% UO2) designed for the BN-600 reactor use will be adopted for the core of the assembly. The present conceptual design of the experimental subcritical assembly is based on a core nominal unit capacity of 15 kW (thermal). This corresponds to the multiplication coefficient keff=0.945, energetic gain G=30, and accelerator beam power of 0.5 kW.

  17. Accelerator-driven sub-critical reactor system (ADS) for nuclear energy generation

    S S Kapoor

    2002-12-01

    In this talk we present an overview of accelerator-driven sub-critical reactor systems (ADS), and bring out their attractive features for the elimination of troublesome long-lived components of the spent fuel, as well as for nuclear energy generation utilizing thorium as fuel. In India, there is an interest in the programmes of development of high-energy and high-current accelerators due to the potential of ADS in utilizing the vast resources of thorium in the country for nuclear power generation. The accelerator related activities planned in this direction will be outlined.

  18. Nuclear data requirements for accelerator driven sub-critical systems – A roadmap in the Indian context

    S Ganesan

    2007-02-01

    The development of accelerator driven sub-critical systems (ADSS) require significant amount of new nuclear data in extended energy regions as well as for a variety of new materials. This paper reviews these perspectives in the Indian context.

  19. Current status of research and development of reactor noise analysis for accelerator-driven subcritical system

    This report presents a current status of the research and development of reactor noise analyses applicable to accelerator-driven subcritical reactor system. These research activities have been concentrated on the Feynman-α neutron correlation analysis on time domain and the power spectral analysis on frequency domain. At present, the latter power spectral analysis is of greater advantage than the former Feynman-α one, for periodic and pulsed neutron source. While Feynman-α formula for pulsed neutron source is too complicated to be fitted directly to variance-to-mean ratio data, the power spectral analysis has a simpler formula based on the first-order reactor transfer function. The Feynman-α should be improved to consider spatial effect of deeply subcritical system and instability of accelerator operation. Further subject of reactor noise analyses is an improvement for high power operation. (author)

  20. Conceptual study of high power proton linac for accelerator driven subcritical nuclear power system

    Yu Qi; Ouyang Hua Fu; Xu Tao Guang

    2001-01-01

    As a prior option of the next generation of energy source, the accelerator driven subcritical nuclear power system (ADS) can use efficiently the uranium and thorium resource, transmute the high-level long-lived radioactive wastes and raise nuclear safety. The ADS accelerator should provide the proton beam with tens megawatts. The superconducting linac is a good selection of ADS accelerator because of its high efficiency and low beam loss rate. The ADS accelerator presented by the consists of a 5 MeV radio-frequency quadrupole, a 100 MeV independently phased superconducting cavity linac and a 1 GeV elliptical superconducting cavity linac. The accelerating structures and main parameters are determined and the research and development plan is considered

  1. Research Programme for the 660 Mev Proton Accelerator Driven MOX-Plutonium Subcritical Assembly

    Barashenkov, V S; Buttseva, G L; Dudarev, S Yu; Polanski, A; Puzynin, I V; Sissakian, A N

    2000-01-01

    The paper presents a research programme of the Experimental Acclerator Driven System (ADS), which employs a subcritical assembly and a 660 MeV proton acceletator operating at the Laboratory of Nuclear Problems of the JINR, Dubna. MOX fuel (25% PuO_2 + 75% UO_2) designed for the BN-600 reactor use will be adopted for the core of the assembly. The present conceptual design of the experimental subcritical assembly is based on a core of a nominal unit capacity of 15 kW (thermal). This corresponds to the multiplication coefficient k_eff = 0.945, energetic gain G = 30 and the accelerator beam power 0.5 kW.

  2. A steady-state core analysis code for the modeling of accelerator-driven subcritical reactors

    In order to analyze and evaluate Accelerator Driven Subcritical Reactors (ADSR) efficiently, a neutronics/thermal-hydraulics coupling analysis code named LAVENDER has been developed. In the neutronics calculation, the three dimensional deterministic neutron transport method is adopted. The nuclides transmutation analysis is implemented by the micro-depletion method with the Transmutation Trajectory Analysis algorithm (TTA). In the thermal-hydraulics calculation, a heat transfer model is established to consider thermal feedback and examine thermal-hydraulics design. The validations are performed based on several benchmarks. Numerical results indicate that LAVENDER is reliable and efficient to be applied for the design and steady-state analysis of ADSR. (author)

  3. Preliminary neutronics design and analysis for accelerator driven subcritical tritium production reactor ADS-T

    In this paper, by using self-developed multi-functional 4D neutronics simulation system VisualBUS4.2 and hybrid evaluated nuclear data library HENDL3.0, sensitivity analysis on spallation neutron energy, abundance of 6Li in tritium breeding material, structural steel, initial keff, neutron energy spectrum as well as the placement of tritium production assembly was performed for lead-alloy cooled accelerator driven subcritical nuclear waste transmutation and tritium production reactor ADS-T (ADS- Tritium). Finally, preliminary neutronics options of ADS-T were given, an attractive tritium production pathway was provided. (authors)

  4. Operation and reactivity measurements of an accelerator driven subcritical TRIGA reactor

    O'Kelly, David Sean

    Experiments were performed at the Nuclear Engineering Teaching Laboratory (NETL) in 2005 and 2006 in which a 20 MeV linear electron accelerator operating as a photoneutron source was coupled to the TRIGA (Training, Research, Isotope production, General Atomics) Mark II research reactor at the University of Texas at Austin (UT) to simulate the operation and characteristics of a full-scale accelerator driven subcritical system (ADSS). The experimental program provided a relatively low-cost substitute for the higher power and complexity of internationally proposed systems utilizing proton accelerators and spallation neutron sources for an advanced ADSS that may be used for the burning of high-level radioactive waste. Various instrumentation methods that permitted ADSS neutron flux monitoring in high gamma radiation fields were successfully explored and the data was used to evaluate the Stochastic Pulsed Feynman method for reactivity monitoring.

  5. The mechanical integrity of fuel pin cladding in a pulsed-beam accelerator driven subcritical reactor

    Highlights: ► We develop the PTS-ADS code to study transients in ADSR cladding. ► We study thermal response in an ADSR cladding to pulsed beam operation. ► We perform thermal fatigue analysis. ► The cladding mechanical integrity can be assumed unaffected by repetitive temperature variations due to pulsed beam operation. - Abstract: The Accelerator Driven Subcritical Reactor (ADSR) is one of the reactor designs proposed for future nuclear energy production. Interest in the ADSR arises from its enhanced and intrinsic safety characteristics, as well as its potential ability to utilize the large global reserves of thorium and to burn legacy actinide waste from other reactors and decommissioned nuclear weapons. The ADSR concept is based on the coupling of a particle accelerator and a subcritical core by means of a neutron spallation target interface. One of the candidate accelerator technologies receiving increasing attention, the Fixed Field Alternating Gradient (FFAG) accelerator, generates a pulsed proton beam. This paper investigates the impact of pulsed proton beam operation on the mechanical integrity of the fuel pin cladding. A pulsed beam induces repetitive temperature changes in the reactor core which lead to cyclic thermal stresses in the cladding. To perform the thermal analysis aspects of this study a code that couples the neutron kinetics of a subcritical core to a cylindrical geometry heat transfer model was developed. This code, named PTS-ADS, enables temperature variations in the cladding to be calculated. These results are then used to perform thermal fatigue analysis and to predict the stress-life behaviour of the cladding.

  6. Investigation of subcritical multiplication parameters in TRIGA Mark II accelerator driven system

    Highlights: • TRIGA ADS neutron external source was numerically investigated. • Source target material, radius, position, and incident beam energy were studied. • Maximum neutron yield for W, Pb, and W–Cu targets are at radii 3.25, 3.5 and 7 cm. • Maximum source efficiency for targets at the given core is achieved at the center. • Maximum source efficiency is achieved at 40 MeV incident electron beam energy. - Abstract: The accelerator driven system (ADS) is a very interesting option to improve the safety of nuclear power reactor and for transmutation of spent fuel. The Texas phase of the reactor–accelerator coupling experiment (RACE), completed in March 2006, demonstrated the feasibility of operating a training research isotopes general atomic (TRIGA) research reactor in a subcritical configuration driven to a significant power by an electron LINAC neutron source (photoneutron). In the present study, the effects of changing the source cylindrical target material, radius, position and the electron beam energy on the final neutron production, fission probability, and the subcritical system multiplication of TRIGA Mark II research reactor, have been numerically investigated. Three target materials are used: Tungsten, Lead and Tungsten–Copper alloy, while varying the target radius from 2 to 8 cm, the source position at three locations, and the beam energy from 10 to 55 MeV. The investigation is based on the numerical calculation of the subcritical multiplication factor and the external source efficiency using Monte Carlo MCNPX code. Through the comparison of the studied cases results, the favorable target material and radius, source position, and beam energy can be obtained

  7. Numerical Simulation of Fluid Flow in the Target of Accelerator-driven Subcritical System

    2001-01-01

    The beam window, which separates the vaccum beam tube and the spallation target, is one of the most crucial components in a liquid metal target of the accelerator-driven subcritical system (ADS). The major difficulties in the window design are the protection against radiation damage and heat removal. It is a challenge to cool down the beam window sufficiently due to its high heat load.Numerical simulations of the fluid flow are performed by using the PHOENICS code for the proposed spallation target of ADS. The main objectives of the study are to investigate the flow behavior in the target systems, especially around the beam window, and to make contribution to the

  8. Preliminary neutronics design analysis on accelerator driven subcritical reactor for nuclear waste transmutation

    By taking minor actinides (MA) transmutation performance as evaluation index, preliminary neutronics design analyses were performed on ADS-NWT which is a lead-alloy cooled accelerator driven subcritical reactor for nuclear waste transmutation. In the specific design, liquid lead-bismuth eutectic (LBE) and transuranic metallic dispersion fuel were used as coolant and a fuel of ADS-NWT, respectively. The neutronics calculations and analyses were performed by using CAD-based multi-functional 4D neutronics and radiation simulation system named VisualBUS and the nuclear data library HENDL (Hybrid Evaluated Nuclear Data Library). The preliminary results showed that based on specific deign of MA/Pu volume ratio of 7 : 3, the transmutation rate of MA was approximately 650 kg/a, the high thermal reactor power output was ∼1000 MW when energy self-sustaining was satisfied and relatively deep subcriticality and negative reactivity coefficients made sure of good inherent safety of ADS-NWT. (authors)

  9. Monte Carlo simulation for calculation of kinetic parameters in an Accelerator Driven Subcritical TRIGA reactor

    Highlights: • Among the kinetic parameters, the most important ones are βeff and Λ. • Several methods including the Rossi-α and Feynman-α techniques, slope fit and MCNPX code have been investigated. • The Monte Carlo MCNPX code was used to simulate a geometrical model of the TRIGA core. • The results of the methods have been validated. - Abstract: In this study, noise analysis techniques including Feynman-α (variance-to-mean) and Rossi-α (correlation) and dynamic method such as slope fit method have been used to calculate effective delayed neutron fraction (βeff) and neutron reproduction time (Λ) in Accelerator Driven Subcritical TRIGA reactor. The obtained results have been compared with MCNPX code results. The relative difference between MCNPX code with Feynman-α and Rossi-α techniques and slope fit method for βeff are approximately −5.4%, 1.2%, and −10.6%, −14.8%, respectively, and also for Λ is approximately 2.1%. According to results, the noise methods can been considered ideal for detection with high efficiency and zero dead time and in the slope fit method, the decay of the delayed neutrons has been neglected and only the prompt neutrons have been taken into account. In addition, quantities simulated in the current study are validated against both the reference data and the results of MCNPX code. Therefore, the purpose of this study is to simulate the commonly used experimental methods by MCNPX code and investigate the convergence as well as accuracy of the computational results for different analysis methods in calculation of the kinetic parameters in an Accelerator Driven Subcritical TRIGA reactor

  10. Study on variance-to-mean method as subcriticality monitor for accelerator driven system operated with pulse-mode

    Two types of the variance-to-mean methods for the subcritical system that was driven by the periodic and pulsed neutron source were developed and their experimental examination was performed with the Kyoto University Critical Assembly and a pulsed neutron generator. As a result, it was demonstrated that the prompt neutron decay constant could be measured by these methods. From this fact, it was concluded that the present variance-to-mean methods had potential for being used in the subcriticality monitor for the future accelerator driven system operated with the pulse-mode. (author)

  11. Neutronic Design of an Accelerator Driven Sub-Critical Research Reactor

    Conceptual design of an accelerator driven sub-critical research reactor (ADSRR), as a new project in the Vinca Institute of Nuclear Sciences, is suggested for support to the Ministry of science, technologies and development of Republic Serbia, Yugoslavia. This paper show initial results of neutronic analyses of the proposed ADSRR carried out by Monte Carlo based MCNP and SHIELD codes. According to the proposal, the ADSRR would be constructed, in a later phase, at high-energy channel H5B of the VINCY cyclotron of the TESLA Accelerator Installation, that is under completion in the Vinca Institute. The fuel elements of 80%-enriched uranium dioxide dispersed in aluminium matrix, available in the Vinca Institute, are proposed for the ADSRR core design. The HEU fuel elements are placed in aluminium tubes filled by the 'primary moderator' - light water. These 'fuel tubes' are placed in a square lattice within lead matrix in a stainless steel tank. The lead is used as a 'secondary moderator' in the core and as the axial and radial reflector. Such design of the ADSRR shows that this small low neutron flux system can be used as an experimental 'demonstration' ADS with some neutron characteristics similar to proposed well-known lead moderated and cooled power sub-critical ADS with intermediate or fast neutron spectrum. The proposed experimental ADSRR, beside usage as a valuable research machine in reactor and neutron physics, will contribute to following and developing new nuclear technologies in the country, useful for eventual nuclear power option and nuclear waste incineration in future. (author)

  12. Conceptual design of thorium-fuelled Mitrailleuse accelerator-driven subcritical reactor using D-Be neutron source

    A distributed accelerator is a charged-particle accelerator that uses a new acceleration method based on repeated electrostatic acceleration. This method offers outstanding benefits not possible with the conventional radio-frequency acceleration method, including: (1) high acceleration efficiency, (2) large acceleration current, and (3) lower failure rate made possible by a fully solid-state acceleration field generation circuit. A 'Mitrailleuse Accelerator' is a product we have conceived to optimize this distributed accelerator technology for use with a high-strength neutron source. We have completed the conceptual design of a Mitrailleuse Accelerator and of a thorium-fuelled subcritical reactor driven by a Mitrailleuse Accelerator. This paper presents the conceptual design details and approach to implementing the subcritical reactor core. We will spend the next year or so on detailed design work, and then will start work on developing a prototype for demonstration. If there are no obstacles in setting up a development organization, we expect to finish verifying the prototype's performance by the third quarter of 2015. (authors)

  13. Monte Carlo Modeling of Fast Sub-critical Assembly with MOX Fuel for Research of Accelerator-Driven Systems

    Polanski, A.; Barashenkov, V.; Puzynin, I.; Rakhno, I.; Sissakian, A.

    It is considered a sub-critical assembly driven with existing 660 MeV JINR proton accelerator. The assembly consists of a central cylindrical lead target surrounded with a mixed-oxide (MOX) fuel (PuO2 + UO2) and with reflector made of beryllium. Dependence of the energetic gain on the proton energy, the neutron multiplication coefficient, and the neutron energetic spectra have been calculated. It is shown that for subcritical assembly with a mixed-oxide (MOX) BN-600 fuel (28%PuO 2 + 72%UO2) with effective density of fuel material equal to 9 g/cm 3 , the multiplication coefficient keff is equal to 0.945, the energetic gain is equal to 27, and the neutron flux density is 1012 cm˜2 s˜x for the protons with energy of 660 MeV and accelerator beam current of 1 uA.

  14. The status of fast reactor technology development and accelerator driven subcritical system researches in China

    Since last May in mainland China there are two nuclear power plants with total capacity of 2.1 GWe in operation and four NPPs in construction. It is envisaged that the total nuclear power capacity will be about 8.5 GWe in the year 2005. Recently the Government is considering four other new NPPs with a total capacity of about 4 GWe and starting their construction during 'tenth five years Plan' (2001-2005). The three new nuclear systems, FBR, ADS and Hybrid, have started to be developed with a rather moderate project and are all still in the early stage. For fast reactor engineering development, the China Experimental Fast Reactor (CEFR) of 65 MWt is the first step. After some additional accidents analysis, especially sodium spray fire accident analysis, the reactor building construction will be continued. The main components including of the reactor block, primary and secondary circuits, fuel handling system have been ordered. It is foreseen to have CEFR reaching first criticality at the end of 2005. The second step 300 MWe Modular Fast Reactor (MPFR) is under consideration, which will be a prototype for large size fast reactor. Based on the size of MPFR, the role of MA transmutation has been evaluated. For the Accelerator Driven Subcritical System (ADS), we are making great efforts to accomplish the research tasks worked out in the first phase program (1998-2002) with emphasis on the system optimization, reactor physics and technology, accelerator physics and technology and nuclear and material data base, and are enthusiastically preparing to step to the second phase program which is marked by ADS concept verification study (2000-2007). As to the Fusion-Fission Hybrid System, in near-term the emphasis will be put on the experiments on two big testing facilities HL-1M and HT-7 on one hand, and on the other hand, we will determine the targets of medium-term and long-term development for Hybrid system and work out relative development program

  15. Conceptual design of minor actinides burner with an accelerator-driven subcritical system.

    Cao, Y.; Gohar, Y. (Nuclear Engineering Division)

    2011-11-04

    In the environmental impact study of the Yucca Mountain nuclear waste repository, the limit of spent nuclear fuel (SNF) for disposal is assessed at 70,000 metric tons of heavy metal (MTHM), among which 63,000 MTHM are the projected SNF discharge from U.S. commercial nuclear power plants though 2011. Within the 70,000 MTHM of SNF in storage, approximately 115 tons would be minor actinides (MAs) and 585 tons would be plutonium. This study describes the conceptual design of an accelerator-driven subcritical (ADS) system intended to utilize (burn) the 115 tons of MAs. The ADS system consists of a subcritical fission blanket where the MAs fuel will be burned, a spallation neutron source to drive the fission blanket, and a radiation shield to reduce the radiation dose to an acceptable level. The spallation neutrons are generated from the interaction of a 1 GeV proton beam with a lead-bismuth eutectic (LBE) or liquid lead target. In this concept, the fission blanket consists of a liquid mobile fuel and the fuel carrier can be LBE, liquid lead, or molten salt. The actinide fuel materials are dissolved, mixed, or suspended in the liquid fuel carrier. Therefore, fresh fuel can be fed into the fission blanket to adjust its reactivity and to control system power during operation. Monte Carlo analyses were performed to determine the overall parameters of an ADS system utilizing LBE as an example. Steady-state Monte Carlo simulations were studied for three fission blanket configurations that are similar except that the loaded amount of actinide fuel in the LBE is either 5, 7, or 10% of the total volume of the blanket, respectively. The neutron multiplication factor values of the three configurations are all approximately 0.98 and the MA initial inventories are each approximately 10 tons. Monte Carlo burnup simulations using the MCB5 code were performed to analyze the performance of the three conceptual ADS systems. Preliminary burnup analysis shows that all three conceptual ADS

  16. The consequences of a sharp temperature change in the fuel pins of an accelerator-driven subcritical system

    The effect of temperature changes and in particular those that are accompanied by strong gradients was extensively investigated for fast reactors. Subcritical systems designed for their transmutation ability are to some extent similar to critical power reactors in their subassembly structure. However, they differ in two main aspects. First, the coolant in a subcritical system is lead or lead-bismuth eutectic (LBE) and not sodium, and second, the main cause for steep temperature gradients in a fast power reactor is sudden control rod insertion, or scram, whereas in subcritical systems shutdown of the accelerator and its proton beam is the main cause for temperature gradients. Furthermore, the increased probability of operational interruptions in an accelerator driven system is largely due to the instability of the accelerator generating the proton beam. This study uses the knowledge gained from fast reactors as a preliminary reference and concentrates further on the unique features of the proposed subcritical systems. In particular, the effect of beam trips on the fuel pin integrity is evaluated as a function of the temperature gradients and the duration of the beam trips. It seems, however, that the largest hazard to the fuel pin integrity is due to the lead (or LBE) coolant. In particular, the stability of the protective oxide layer built on the clad surface with the lead coolant appears quite sensitive to sudden temperature changes. In the second part of this study, several available experimental results show that even very moderate temperature changes are sufficient to cause crack formation in the oxide layer thereby exposing the clad surface to enhanced LBE corrosion. In the worst case, complete exfoliation of the magnetite outer layer is observed. As a consequence, clad failure probability due to corrosion is considerably increased. (authors)

  17. Accelerator-driven sub-critical target concept for transmutation of nuclear wastes

    A means of transmuting key long-lived nuclear wastes, primarily the minor actinides (Np, Am, Cm) and iodine, using a hybrid proton accelerator and sub-critical lattice, is proposed. By partitioning the components of the light water reactor (LWR) spent fuel and by transmuting key elements, such as the plutonium, the minor actinides, and a few of the long-lived fission products, some of the most significant challenges in building a waste repository can be substantially reduced. The proposed machine, based on the described PHOENIX Concept, would transmute the minor actinides and the iodine produced by 75 LWRs, and would generate usable electricity (beyond that required to run the large accelerator) of 850 MWe. 19 refs., 20 figs

  18. Research progress for accelerator driven sub-critical Transmutation system (ADS)

    The minimization of the nuclear waste is the key problem for the long term and sustainable nuclear energy development. Accelerator driven system (ADS) is a kind of high efficient nuclear waste transmutation machine (or incinerator), which is the key technique to solve the nuclear water problem. The basic theory of ADS and driven influence of ADS and driven influence of ADS on the advanced accelerator, advanced cooling technique, etc are introduced. Mean while the present research situations of ADS in some countries are compared. At last, the key problem of the ADS development and the relationship between ADS and the development of nuclear energy in China is discussed. (authors)

  19. Nuclear Waste Transmutation in Subcritical Reactors Driven by Target-Distributed Accelerators

    Blanovsky, A

    2004-01-01

    A radioactive waste transmutation system based extensively on existing nuclear power technology is presented. By replacing the control rods with neutron sources, we could maintain good power distribution and perform long-lived waste burning in high flux subcritical reactors. The design is based on a small pressurized water reactor, fission electric cell (FEC), target-distributed accelerator (TDA) and power monitoring system with in-core gamma-ray detectors, now under development in several countries. The TDA, in which an FEC electric field compensates for lost beam energy in the target, offers a new approach to obtain large neutron fluxes. The analysis takes into consideration a wide range of TDA design aspects including the wave model of observed relativistic phenomena, in-core microwave power source, the FEC with a multistage collector (anode) and layered cathode.

  20. Highly Compact Accelerator-Driven Subcritical Assembly for Medical and Industrial Applications

    A novel, highly compact, fusion neutron source (CNS) based on a coaxial electrostatic accelerator is under development at the Lawrence Berkeley National Laboratory. This source is designed to generate up to ∼1012 D-D n/s. This source intensity is an order of magnitude too small for Boron Neutron Capture Therapy (BNCT) applications. The objective of this project is to assess the feasibility of using a small, safe and inexpensive subcritical fission assembly to multiply the fusion neutrons by a factor of (ge)30. The overall design objective is to get a treatment time for deep seated rain tumors that does not significantly increase beyond one hour when the effective multiplication factor of the SCM is keff = 0.98. There are two major parts to this study: the optimization of the Sub-Critical Multiplier (SCM) and the optimization of the Beam Shaping Assembly (BSA), including the reflector for both subsystems. The SCM optimization objective is to maximize the current of neutrons that leak out from the SCM in the direction of the patient, without exceeding the maximum permissible keff. Minimizing the required uranium inventory is another objective. SCM design variables considered include the uranium enrichment level in the range not exceeding 20% 235U (for proliferation concerns), SCM geometry and dimensions, fuel thickness and moderator thickness. The objective of the BSA optimization is to maximize the tumor dose rate using the optimal SCM while maintaining a tumor-to-normal tissue dose ratio of at least 20 to 12.5 (corresponding to the tumor control dose and to the healthy tissue dose limit). The BSA design variables include its shape, dimensions and composition. The reflector optimization is, in fact, an integral part of the SCM optimization and of the BSA optimization. The reflector design variables are composition and thickness. The study concludes that it is not quite feasible to achieve the project objective. Nevertheless, it appears feasible to develop a

  1. A small scale accelerator driven subcritical assembly development and demonstration experiment at LAMPF

    A small scale experiment designed to demonstrate many of the aspects of accelerator-driven transmutation technology is described. The experiment uses the high-power proton beam from the Los Alamos Meson Physics Facility accelerator to produce neutrons with a molten Lead target. The target is surrounded by a molten salt and graphite moderator blanket. Fissionable material can be added to the molten salt to demonstrate Plutonium burning or transmutation of commercial spent fuel or energy production from Thorium

  2. Saturation condition and evolution of the nuclides for sub-critical system driven by accelerator

    At present work, under initial inventory with 232Th and natU, the evolution of nuclides in subcritical devices under given thermal, fast, hardening fast and fission neutron field are studied without the detail structure of sub-critical device and the burn-up being considered. It is supposed that the subcritical reactor consists of uniform in which the flux of neutron is homogeneous. The fissile nuclides breeding, equilibrium condition, minor activity (MA) accumulation and transmutation, are studied. (author)

  3. Concept of the thorium fuelled accelerator driven subcritical system for both energy production and TRU incineration - 'TASSE'

    The TASSE is the concept of the subcritical accelerator driven system with 'TRU-free' fuel cycle and the continuous Th-feed regime. The tightness of Th neutronics call inevitably the subcritical mode of work. Two types of neutron spectra are recommended: fast and super-thermal (well thermalized) ones. TASSE fuel cycle could have the following options: (i) without any fuel recycling and reprocessing (once-through fuel cycle option) for maximum fuel cycle simplicity. However, subcriticality level (1- Keff) is essential and it requires high power accelerators; (ii) with the partial or, eventually, full U recycling 'on line' including the separation (U + Pa + Th) component from TRU + FP component which can be considered as wastes. Relatively small mass of fuel have to be reprocessed. Moreover, the requirement to separation is very soft. In this case, recycling allows to minimise subcriticality and smaller accelerators can be acceptable. The TASSE is oriented on 'clean' nuclear energy production and TRU burning with the following attractive features: (1) For the long term perspective, TASSEs have a rather limited mass of long-lived radioactive wastes, consisting mostly of Th, U and Pa nuclides. One can see the considerable reduction of waste toxicity by the factor of 1000 (or even more) in the magnitude regarding current PWR's and by the factor of 10-100 regarding (PWR's + dedicated burners) scenario. (2) Relatively low amounts of Th would have to be mined: approximately a factor of 100 lower than the U mined for PWR's. With TASSEs, nuclear power has practically inexhaustible (for a long future) and cheap fuel resources, taking into account that Thorium reserves exceed Uranium PWR fuel reserves by factor of 103. (3) TASSEs are able to burnout all previously accumulated transuraniums as well as weapons grade materials during PWR's replacement over a period of approximately 50 years. No actinide fuel waste is foreseen for this period of time. There is no need to develop

  4. Accelerator Driven Subcritical Reactors and their Function in the Future of Nuclear Power

    The Development of nuclear power reactors has slowed dozen considerably following the Three Mile Island accident in the US, and came to a standstill in most countries after the Chernobyl accident in Russia. This, in spite of the otherwise excellent safety and economic record of nuclear power plants in the west. The major reason is the public concern about safety of these plants and the disposal of the nuclear waste, which is considered by the public to be the most dangerous, produced by any industrial enterprise. The introduction of accelerators, or rather accelerator driven systems, the ADS, is intended to provide a partial response to the above concerns

  5. Status of intense permanent magnet proton source for China-accelerator driven sub-critical system Linac

    Two compact intense 2.45 GHz permanent magnet proton sources and their corresponding low energy beam transport (LEBT) system were developed successfully for China accelerator driven sub-critical system in 2014. Both the proton sources operate at 35 kV potential. The beams extracted from the ion source are transported by the LEBT, which is composed of two identical solenoids, to the 2.1 MeV Radio-Frequency Quadrupole (RFQ). In order to ensure the safety of the superconducting cavities during commissioning, an electrostatic-chopper has been designed and installed in the LEBT line that can chop the continuous wave beam into a pulsed one. The minimum width of the pulse is less than 10 μs and the fall/rise time of the chopper is about 20 ns. The performance of the proton source and the LEBT, such as beam current, beam profile, emittance and the impact to RFQ injection will be presented

  6. Status of intense permanent magnet proton source for China-accelerator driven sub-critical system Linac

    Wu, Q., E-mail: wuq@impcas.ac.cn; Ma, H. Y.; Yang, Y.; Sun, L. T.; Zhang, X. Z.; Zhang, Z. M.; Zhao, H. Y.; He, Y.; Zhao, H. W. [Institute of Modern Physics (IMP), Chinese Academy of Sciences, Lanzhou 730000 (China)

    2016-02-15

    Two compact intense 2.45 GHz permanent magnet proton sources and their corresponding low energy beam transport (LEBT) system were developed successfully for China accelerator driven sub-critical system in 2014. Both the proton sources operate at 35 kV potential. The beams extracted from the ion source are transported by the LEBT, which is composed of two identical solenoids, to the 2.1 MeV Radio-Frequency Quadrupole (RFQ). In order to ensure the safety of the superconducting cavities during commissioning, an electrostatic-chopper has been designed and installed in the LEBT line that can chop the continuous wave beam into a pulsed one. The minimum width of the pulse is less than 10 μs and the fall/rise time of the chopper is about 20 ns. The performance of the proton source and the LEBT, such as beam current, beam profile, emittance and the impact to RFQ injection will be presented.

  7. Conceptual design for accelerator-driven sodium-cooled sub-critical transmutation reactors using scale laws

    Lee, Kwang Gu; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1998-12-31

    The feasibility study on conceptual design methodology for accelerator-driven sodium-cooled sub-critical transmutation reactors has been conducted to optimize the design parameters from the scale laws and validates the reactor performance with the integrated code system. A 1000 MWth sodium-cooled sub-critical transmutation reactor has been scaled and verified through the methodology in this paper, which is referred to Advanced Liquid Metal Reactor (ALMR). A Pb-Bi target material and a partitioned fuel are the liquid phases, and they are cooled by the circulation of secondary Pb-Bi coolant and by primary sodium coolant, respectively. Overall key design parameters are generated from the scale laws and they are improved and validated by the integrated code system. Integrated Code System (ICS) consists of LAHET, HMCNP, ORIGEN2, and COMMIX codes and some files. Through ICS the target region, the core region, and thermal-hydraulic related regions are analyzed once-through Results of conceptual design are attached in this paper. 5 refs., 4 figs., 1 tab. (Author)

  8. A small scale accelerator driven subcritical assembly development and demonstration experiment at LAMPF

    A small scale experiment is described that will demonstrate many of the aspects of accelerator-driven transmutation technology. This experiment uses the high-power proton beam from the Los Alamos Meson Physics Facility accelerator and will be located in the Area-A experimental hall. Beam currents of up to 1 mA will be used to produce neutrons with a molten lead target. The target is surrounded by a molten salt and graphite moderator blanket. Fissionable material can be added to the molten salt to demonstrate plutonium burning or transmutation of commercial spent fuel or energy production from thorium. The experiment will be operated at power levels up to 5 MWt

  9. The physics of sub-critical lattices in accelerator driven hybrid systems: The MUSE experiments in the MASURCA facility

    Since 1991, the CEA has studied the physics of hybrid systems, involving a sub-critical reactor coupled with an accelerator. These studies have provided information on the potential of hybrid systems to transmute actinides and, long lived fission products. The potential of such a system remains to be proven, specifically in terms of the physical understanding of the different phenomena involved and their modelling, as well as in terms of experimental validation of coupled systems, sub-critical environment/accelerator. This validation must be achieved through mock-up studies of the sub-critical environments coupled to a source of external neutrons. The MUSE-4 mock-up experiment is planed at the MASURCA facility and will use an accelerator coupled to a tritium target. The great step between the generator used in the past and the accelerator will allow to increase the knowledge in hybrid physic and to decrease the experimental biases and the measurement uncertainties

  10. Monitoring method for neutron flux for a spallation target in an accelerator driven sub-critical system

    Zhao, Qiang, He, Zhi-Yong; Yang, Lei; Zhang, Xue-Ying; Cui, Wen-Juan; Chen, Zhi-Qiang; Xu, Hu-Shan

    2016-07-01

    In this paper, we study a monitoring method for neutron flux for the spallation target used in an accelerator driven sub-critical (ADS) system, where a spallation target located vertically at the centre of a sub-critical core is bombarded vertically by high-energy protons from an accelerator. First, by considering the characteristics in the spatial variation of neutron flux from the spallation target, we propose a multi-point measurement technique, i.e. the spallation neutron flux should be measured at multiple vertical locations. To explain why the flux should be measured at multiple locations, we have studied neutron production from a tungsten target bombarded by a 250 MeV-proton beam with Geant4-based Monte Carlo simulations. The simulation results indicate that the neutron flux at the central location is up to three orders of magnitude higher than the flux at lower locations. Secondly, we have developed an effective technique in order to measure the spallation neutron flux with a fission chamber (FC), by establishing the relation between the fission rate measured by FC and the spallation neutron flux. Since this relation is linear for a FC, a constant calibration factor is used to derive the neutron flux from the measured fission rate. This calibration factor can be extracted from the energy spectra of spallation neutrons. Finally, we have evaluated the proposed calibration method for a FC in the environment of an ADS system. The results indicate that the proposed method functions very well. Supported by Strategic Priority Research Program of Chinese Academy of Sciences (XDA03010000 and XDA03030000) and the National Natural Science Foundation of China(91426301).

  11. Noise method for monitoring the sub-criticality in accelerator driven systems

    In this paper, an absolute measurements technique for the sub-criticality determination is presented. The development of ADS, requires of methods to monitor and control the sub-criticality of this kind of systems, without interfering it's normal operation mode. This method is based on the Stochastic Neutron and Photon Transport Theory developed by Munoz-Cobo et al., and which can be implemented in presently available neutron transport codes. As a by-product of the methodology a monitoring measurement technique has been developed and verified using two coupled Monte Carlo programs. The spallation collisions and the high-energy transport are simulated with LAHET. The neutrons transports with energies less than 20 MeV and the estimation of the count statistics for neutron and/or gamma ray counters in fissile systems, is simulated with MCNP-DSP. It is possible to get the kinetics parameters and the keff value of the sub-critical system through the analysis of the counter detectors. (author)

  12. Noise method for monitoring the subcriticality in accelerator-driven systems

    In this paper, an absolute measurement technique for the subcriticality determination is presented. The development of A.D.S., requires of methods to monitor and control the subcriticality of this kind of systems, without interfering its normal operation mode. This method is based on the Stochastic Neutron and Photon Transport Theory developed by Munoz-Cobo et al, and which can be implemented in presently available neutron transport codes. As a by-product of the methodology a monitoring measurement technique has been developed and verified using two coupled Monte Carlo programs. The first one LAHET simulates the spallation collisions and the high energy transport and the other MCNP-DSP is used to estimate the counting statistics from neutron ray counter in fissile system, and the transport for neutrons with energies less than 20 MeV. With the coupling LAHET+MCNP-DSP has been checked that a subcriticality monitoring system, is feasible. Through the analysis of the counter detectors is possible to get the kinetics parameters and the Keff value. (orig.)

  13. Energy production in a thorium subcritical lattice driven by accelerated protons

    It has been proposed to sustain a thorium fuel cycle in a tight lattice driven by spallation reactions neutrons, these reactions being initiated by bombarding the lattice with high- energy, high-current, protons. The proposal lacks a consistent evolution calculation of actinides and fission product densities. In order to assess the true potential of the concept, the capacity of a criticality burnup calculation with the WIMS code was tested as a replacement to a source-driven' burnup calculation. Tests of 'source-driven' burnup were conducted with calculations based on a package program combining the high-energy code HETC, the Monte-Carlo code MCNP, and the depletion code KORIGEN. (author). 2 refs., 1 tab

  14. Sensitivity analysis of core neutronic parameters in accelerator driven subcritical reactors

    Highlights: • Sensitivity analysis of ADSR core neutronic parameters has been investigated. • Uniform and parabolic proton beam spatial distributions have been considered. • TRIGA reactor was considered as the case study of the problem. - Abstract: In this paper, sensitivity of the ADSRs core neutronic parameters to the accelerator related parameters such as beam profile, source multiplication coefficient (ks) and proton beam energy (Ep) has been investigated. TRIGA reactor has been considered as the case study of the problem. Monte Carlo code MCNPX has been used to calculate neutronic parameters such as: effective multiplication coefficient (keff), net neutron multiplication (M), spallation neutron yield (Yn/p), energy constant gain (G0), energy gain (G), importance of neutron source (φ*), axial and radial distributions of neutron flux and power peaking factor (Pmax/Pave) in two axial and radial directions of the reactor core for three eigen values levels (ks) including: 0.91, 0.97 and 0.99. According to the results, using a parabolic spatial distribution instead of a uniform spatial distribution increases the relative differences of spallation neutron yield, net neutron multiplication and energy gain by 4.74%, 4.05% and 10.26% respectively. In consequence the required accelerator current (Ip) will be reduced by 7.14% to preserve the reactivity. Although safety margin is decreased in highest case of ks, but energy gain increases by 93.43% and the required accelerator current and importance of neutrons source decrease by 48.3% and 2.64% respectively. In addition, increasing Ep from 115 MeV up to1 GeV, improves spallation neutron yield and energy gain by 2798.71% and 205.12% and decreases the required accelerator current and power by 96.83% and 72.44%, respectively. Therefore, our results are indicative of the fact that investigating sensitivity of the core neutronic parameters to the accelerator related parameters are necessary in order to optimally design a

  15. Subcritical Multiplication Parameters of the Accelerator-Driven System with 100 MeV Protons at the Kyoto University Critical Assembly

    Jae-Yong Lim

    2012-01-01

    Full Text Available Basic experiments on the accelerator-driven system (ADS at the Kyoto University Critical Assembly are carried out by combining a solid-moderated and -reflected core with the fixed-field alternating gradient accelerator. The reaction rates are measured by the foil activation method to obtain the subcritical multiplication parameters. The numerical calculations are conducted with the use of MCNPX and JENDL/HE-2007 to evaluate the reaction rates of activation foils set in the core region and at the location of the target. Here, a comparison between the measured and calculated eigenvalues reveals a relative difference of around 10% in C/E values. A special mention is made of the fact that the reaction rate analyses in the subcritical systems demonstrate apparently the actual effect of moving the tungsten target into the core on neutron multiplication. A series of further ADS experiments with 100 MeV protons needs to be carried out to evaluate the accuracy of subcritical multiplication parameters.

  16. Minimising the economic cost and risk to accelerator-driven subcritical reactor technology: The case of designing for flexibility: Part 1

    Highlights: ► Accelerator performance is a risk to ADSR reactor technology demonstration. ► Sensitivity of ADSR economic value to accelerator performance is assessed. ► Economic value of ADSRs with and without accelerator redundancy is tested. ► Real options identify design flexibility to accelerator performance uncertainty. ► Multiple ADSR “park” with a single integrated accelerator system is proposed. - Abstract: Demonstrating the generation of electricity for commercial markets with accelerator-driven subcritical reactor (ADSR) technology will incur substantial financial risk. This risk will arise from traditional uncertainties associated with the construction of nuclear power stations and also from new technology uncertainties such as the reliability of the required accelerator system. The sensitivity of the economic value of ADSRs to the reliability of the accelerator system is assessed. Using linear accelerators as an example of choice for the accelerator technology, the economic assessment considers an ADSR with either one or two accelerators driving it. The extent to which a second accelerator improves the accelerator system reliability is determined, as are the costs for that reliability improvement. Two flexible designs for the accelerator system are also considered, derived from the real options analysis technique. One seeks to achieve the benefits of both the single and dual accelerator ADSR configurations through initially planning to build a second accelerator, but only actually constructing it once it is determined to be economically beneficial to do so. The other builds and tests an accelerator before committing to constructing a reactor. Finally, a phased multiple-reactor park with an integrated system of accelerators is suggested and discussed. The park uses the principles of redundancy as for the Dual accelerator ADSR and flexibility as for the real options design, but for a lower cost per unit of electricity produced.

  17. Basic concept for an accelerator-driven subcritical system to be used as a long-pulse neutron source for Condensed Matter research

    A model for an accelerator-driven subcritical system to be operated as a source of cold neutrons for Condensed Matter research is developed at the conceptual level. Its baseline layout relies upon proven accelerator, spalattion target and fuel array technologies, and consists in a proton accelerator able to deliver some 67.5 mA of proton beam with kinetic energy 0.6 GeV, a pulse length of 2.86 ms, and repetition rate of 14 Hz. The particle beam hits a target of conventional design that is surrounded by a multiplicative core made of fissile/fertile material, composed by a subcritical array of fuel bars made of aluminium Cermet cooled by light water poisoned with boric acid. Relatively low enriched uranium is chosen as fissile material. An optimisation of several parameters is carried out, using as components of the objective function several characteristics pertaining the cold neutron pulse. The results show that the optimal device will deliver up to 80% of the cold neutron flux expected for some of the ongoing projects using a significantly lower proton beam power than that managed in such projects. The total power developed within the core rises up to 22.8 MW, and the criticality range shifts to a final keff value of around 0.9 after the 50 days cycle

  18. Basic concept for an accelerator-driven subcritical system to be used as a long-pulse neutron source for Condensed Matter research

    Vivanco, R., E-mail: raul.vivanco.sanchez@gmail.com [ESS-BILBAO, Parque Tecnológico Bizkaia, Laida Bidea, Edificio 207 B Planta Baja, 48160 Derio (Spain); Instituto de Fusión Nuclear - UPM, ETS Ingenieros Industriales, C/ José Gutiérrez Abascal, 2, 28006 Madrid Spain (Spain); Ghiglino, A.; Vicente, J.P. de; Sordo, F.; Terrón, S.; Magán, M. [ESS-BILBAO, Parque Tecnológico Bizkaia, Laida Bidea, Edificio 207 B Planta Baja, 48160 Derio (Spain); Instituto de Fusión Nuclear - UPM, ETS Ingenieros Industriales, C/ José Gutiérrez Abascal, 2, 28006 Madrid Spain (Spain); Perlado, J.M. [Instituto de Fusión Nuclear - UPM, ETS Ingenieros Industriales, C/ José Gutiérrez Abascal, 2, 28006 Madrid Spain (Spain); Bermejo, F.J. [Instituto de Estructura de la Materia, IEM-CSIC, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid (Spain)

    2014-12-11

    A model for an accelerator-driven subcritical system to be operated as a source of cold neutrons for Condensed Matter research is developed at the conceptual level. Its baseline layout relies upon proven accelerator, spalattion target and fuel array technologies, and consists in a proton accelerator able to deliver some 67.5 mA of proton beam with kinetic energy 0.6 GeV, a pulse length of 2.86 ms, and repetition rate of 14 Hz. The particle beam hits a target of conventional design that is surrounded by a multiplicative core made of fissile/fertile material, composed by a subcritical array of fuel bars made of aluminium Cermet cooled by light water poisoned with boric acid. Relatively low enriched uranium is chosen as fissile material. An optimisation of several parameters is carried out, using as components of the objective function several characteristics pertaining the cold neutron pulse. The results show that the optimal device will deliver up to 80% of the cold neutron flux expected for some of the ongoing projects using a significantly lower proton beam power than that managed in such projects. The total power developed within the core rises up to 22.8 MW, and the criticality range shifts to a final k{sub eff} value of around 0.9 after the 50 days cycle.

  19. YALINA facility a sub-critical Accelerator- Driven System (ADS) for nuclear energy research facility description and an overview of the research program (1997-2008).

    Gohar, Y.; Smith, D. L.; Nuclear Engineering Division

    2010-04-28

    The YALINA facility is a zero-power, sub-critical assembly driven by a conventional neutron generator. It was conceived, constructed, and put into operation at the Radiation Physics and Chemistry Problems Institute of the National Academy of Sciences of Belarus located in Minsk-Sosny, Belarus. This facility was conceived for the purpose of investigating the static and dynamic neutronics properties of accelerator driven sub-critical systems, and to serve as a neutron source for investigating the properties of nuclear reactions, in particular transmutation reactions involving minor-actinide nuclei. This report provides a detailed description of this facility and documents the progress of research carried out there during a period of approximately a decade since the facility was conceived and built until the end of 2008. During its history of development and operation to date (1997-2008), the YALINA facility has hosted several foreign groups that worked with the resident staff as collaborators. The participation of Argonne National Laboratory in the YALINA research programs commenced in 2005. For obvious reasons, special emphasis is placed in this report on the work at YALINA facility that has involved Argonne's participation. Attention is given here to the experimental program at YALINA facility as well as to analytical investigations aimed at validating codes and computational procedures and at providing a better understanding of the physics and operational behavior of the YALINA facility in particular, and ADS systems in general, during the period 1997-2008.

  20. YALINA facility a sub-critical Accelerator-Driven System (ADS) for nuclear energy research facility description and an overview of the research program (1997-2008)

    The YALINA facility is a zero-power, sub-critical assembly driven by a conventional neutron generator. It was conceived, constructed, and put into operation at the Radiation Physics and Chemistry Problems Institute of the National Academy of Sciences of Belarus located in Minsk-Sosny, Belarus. This facility was conceived for the purpose of investigating the static and dynamic neutronics properties of accelerator driven sub-critical systems, and to serve as a neutron source for investigating the properties of nuclear reactions, in particular transmutation reactions involving minor-actinide nuclei. This report provides a detailed description of this facility and documents the progress of research carried out there during a period of approximately a decade since the facility was conceived and built until the end of 2008. During its history of development and operation to date (1997-2008), the YALINA facility has hosted several foreign groups that worked with the resident staff as collaborators. The participation of Argonne National Laboratory in the YALINA research programs commenced in 2005. For obvious reasons, special emphasis is placed in this report on the work at YALINA facility that has involved Argonne's participation. Attention is given here to the experimental program at YALINA facility as well as to analytical investigations aimed at validating codes and computational procedures and at providing a better understanding of the physics and operational behavior of the YALINA facility in particular, and ADS systems in general, during the period 1997-2008.

  1. Physics study of D-D/D-T neutron driven experimental subcritical assembly

    An experimental program to design and study external source driven subcritical assembly has been initiated at BARC. This program is aimed at understanding neutronic characteristics of accelerator driven system at low power level. In this series, a zero-power, sub-critical assembly driven by a D-D/D-T neutron generator has been developed. This system is modular in design and it is first in the series of subcritical assemblies being designed

  2. A novel concept for CRIEC-driven subcritical research reactors

    A novel scheme is proposed to drive a low-power subcritical fuel assembly by means of a long Cylindrical Radially-convergent Inertial Electrostatic Confinement (CRIEC) used as a neutron source. The concept is inherently safe in the sense that the fuel assembly remains subcritical at all times. Previous work has been done for the possible implementation of CRIEC as a subcritical assembly driver for power reactors. However, it has been found that the present technology and stage of development of IEC-based neutron sources can not meet the neutron flux requirements to drive a system as big as a power reactor. Nevertheless, smaller systems, such as research and training reactors, could be successfully driven with levels of neutron flux that seem more reasonable to be achieved in the near future by IEC devices. The need for custom-made expensive nuclear fission fuel, as in the case of the TRIGA reactors, is eliminated, and the CRIEC presents substantial advantages with respect to the accelerator-driven subcritical reactors in terms of simplicity and cost. In the present paper, a conceptual design for a research/training CRIEC-driven subcritical assembly is presented, emphasizing the description, principle of operation and performance of the CRIEC neutron source, highlighting its advantages and discussing some key issues that require study for the implementation of this concept. (author)

  3. Macroscopic cross sections of neutron radiation capture by Pb-208, U-238 and Tc-99 nuclides in the accelerator driven subcritical core cooled with molten Pb-208 - 286

    In the paper macroscopic cross sections for several isotopes: 208Pb, 238U, 99Tc and natural mix of lead isotopes, natPb, averaged over neutron spectra of the accelerator driven subcritical core cooled with natPb or 208Pb are given. It is shown that macro cross sections for a coolant from 208Pb are by 6.2 times smaller than those for the coolant consisted from natPb. The economy of neutrons in the core cooled with molten 208Pb can be used for reducing initial fuel load, increasing plutonium breeding and enhancing transmutation of such long lived fission products as 99Tc. The values of macro cross sections calculated for 238U and 99Tc, equal to 0.6 and 0.8 barns, respectively, are comparable with the values of the same nuclide macro cross sections for neutron spectrum of the fast reactor core cooled with sodium. Good neutron and physical features of molten 208Pb permit to assume it as perspective coolant for fast reactors and accelerator driven systems. (authors)

  4. Calculation of the neutron importance and weighted neutron generation time using MCNIC method in accelerator driven subcritical reactors

    Highlights: • All reactor kinetic parameters are importance weighted quantities. • MCNIC method has been developed for calculating neutron importance in ADSRs. • Mean generation time has been calculated in spallation driven systems. -- Abstract: The difference between non-weighted neutron generation time (Λ) and the weighted one (Λ†) can be quite significant depending on the type of the system. In the present work, we will focus on developing MCNIC method for calculation of the neutron importance (Φ†) and importance weighted neutron generation time (Λ†) in accelerator driven systems (ADS). Two hypothetic bare and graphite reflected spallation source driven system have been considered as illustrative examples for this means. The results of this method have been compared with those obtained by MCNPX code. According to the results, the relative difference between Λ and Λ† is within 36% and 24,840% in bare and reflected illustrative examples respectively. The difference is quite significant in reflected systems and increases with reflector thickness. In Conclusion, this method may be used for better estimation of kinetic parameters rather than the MCNPX code because of using neutron importance function

  5. Experimental study on neutronics in bombardment of thick targets by high energy proton beams for accelerator-driven sub-critical system

    The experimental study on neutronics in the target region of accelerator-driven sub-critical system is carried out by using the high energy accelerator in Joint Institute for Nuclear Research, Dubna, Russia. The experiments with targets U(Pb), Pb and Hg bombarded by 0.533, 1.0, 3.7 and 7.4 GeV proton beams show that the neutron yield ratio of U(Pb) to Hg and Pb to Hg targets is (2.10 +- 0.10) and (1.76 +- 0.33), respectively. Hg target is disadvantageous to U(Pb) and Pb targets to get more neutrons. Neutron yield drops along 20 cm thick targets as the thickness penetrated by protons increases. The lower the energy of protons, the steeper the neutron yield drops. In order to get more uniform field of neutrons in the targets, the energy of protons from accelerators should not be lower than 1 GeV. The spectra of secondary neutrons produced by different energies of protons are similar, but the proportion of neutrons with higher energy gradually increases as the proton energy increases

  6. Accelerator driven radiation clean nuclear power system conceptual research symposium

    The R and D of ADS (Accelerators Driven Subcritical System) in China introduced. 31 theses are presented. It includes the basic principle of ADS, accelerators, sub-critical reactors, neutron physics, nuclear data, partitioning and transmutation

  7. Review of Subcritical Source-Driven Noise Analysis Measurements

    Valentine, T.E.

    1999-11-01

    Subcritical source-driven noise measurements are simultaneous Rossia and randomly pulsed neutron measurements that provide measured quantities that can be related to the subcritical neutron multiplication factor. In fact, subcritical source-driven noise measurements should be performed in lieu of Rossia measurements because of the additional information that is obtained from noise measurements such as the spectral ratio and the coherence functions. The basic understanding of source-driven noise analysis measurements can be developed from a point reactor kinetics model to demonstrate how the measured quantities relate to the subcritical neutron multiplication factor.

  8. Design of a molten heavy-metal coolant and target for fast-thermal accelerator driven sub-critical system (ADS)

    Accelerator Driven sub-critical Systems (ADS) have evoked considerable interest in recent years. The Energy Amplifier concept developed by C. Rubbia and others at CERN incorporates a buoyancy driven, lead-coolant primary system for extracting the heat generated in the fast reactor as well as that in neutron spallation target. In earlier publications, our BARC group has proposed a one-way coupled booster reactor system which could be operated at proton beam currents as low as 1-2 mA for a power output of 750 MWth. Here, the basic idea is to have a fast booster reactor zone of low power (- 100 MWth) which is separated by a large gap from the main thermal reactor zone. In this arrangement, the spallation neutron source feeds neutrons to the fast reactor zone where neutrons are further multiplied. Further in this system, the neutrons from the booster region enter the main reactor but very few neutrons from main reactor return to booster, thus ensuring one-way coupling. In earlier work, several possible configurations of the booster and thermal regions were presented. In the present work, we describe an engineering design particularly with respect to thermal hydraulics of lead/lead-bismuth eutectic coolant also acting as spallation neutron source. This hybrid ADS reactor consists of fast and thermal reactor zones producing about 100 MWth and 650 MWth respectively. The scheme of the system is shown. The fast core consists of 48 hexagonal fuel bundles each containing 169 fuel pins of 8.2 mm diameter arranged in 11.4 mm triangular array pitch. The average thermal power per fuel pin is about 13.46 kw. However, due to neutron flux peaking effect, the maximum fuel pin power can be up to 2.5 times this average power. The thermal reactor consists of heavy water as moderator and coolant similar to a typical CANDU type Indian PHWR except for fuel composition. Though the gap between fast and thermal zones essentially provides one way coupling of neutron flux, a thermal neutron

  9. Comparative study of fast critical burner reactors and subcritical accelerator driven systems and the impact on transuranics inventory in a regional fuel cycle

    Research highlights: → Double-strata fuel cycle has a potential to minimize transuranics mass in Europe. → European Minor Actinides legacy can be reduced down to 0 before the end of century. → 40% higher capacity needed to burn MA for fast critical reactor then for EFIT fleet. → Na cooled fast reactor cores with high content of MA and low CR have been assessed. → Fast critical and ADS-EFIT reactors show comparable MA transmutation performance. - Abstract: In the frame of Partitioning and Transmutation (P and T) strategies, many solutions have been proposed in order to burn transuranics (TRU) discharged from conventional thermal reactors in fast reactor systems. This is due to the favourable feature of neutron fission to capture cross section ratio in a fast neutron spectrum for most TRU. However the majority of studies performed use the Accelerator Driven Systems (ADS), due to their potential flexibility to utilize various fuel types, loaded with significant amounts of TRU having very different Minor Actinides (MA) over Pu ratios. Recently the potential of low conversion ratio critical fast reactors has been rediscovered, with very attractive burning capabilities. In the present paper the burning performances of two systems are directly compared: a sodium cooled critical fast reactor with a low conversion ratio, and the European lead cooled subcritical ADS-EFIT reactor loaded with fertile-free fuel. Comparison is done for characteristics of both the intrinsic core and the regional fuel cycle within a European double-strata scenario. Results of the simulations, obtained by use of French COSI6 code, show comparable performance and confirm that in a double strata fuel cycle the same goals could be achieved by deploying dedicated fast critical or ADS-EFIT type reactors. However the critical fast burner reactor fleet requires ∼30-40% higher installed power then the ADS-EFIT one. Therefore full comparative assessment and ranking can be done only by a

  10. The use of linear superconducting electron accelerator for subcritical reactor driving

    At NSC KIPT the opportunity of creating the installation with subcritical reactor, driven by the electron accelerator, is examined. For obtaining the maximal stream of neutrons from neutron-producing target at minimal density of energy emission, the electron energy should lay in the range 100-200 MeV, and the size of target should be maximal. The other important requirements are the beam continuity in time and the long-term stability of the accelerator parameters. The variants of using the superconducting linear accelerator on the basis of accelerating structure TESLA as a driver of subcritical reactor are considered. The basic design parameters and characteristics of this installation are submitted

  11. Pulsed neutron source based on accelerator-subcritical-assembly

    Inoue, Makoto; Noda, Akira; Iwashita, Yoshihisa; Okamoto, Hiromi; Shirai, Toshiyuki [Kyoto Univ., Uji (Japan). Inst. for Chemical Research

    1997-03-01

    A new pulsed neutron source which consists of a 300MeV proton linac and a nuclear fuel subcritical assembly is proposed. The proton linac produces pulsed spallation neutrons, which are multipied by the subcritical assembly. A prototype proton linac that accelerates protons up to 7MeV has been developed and a high energy section of a DAW structure is studied with a power model. Halo formations in high intensity beam are also being studied. (author)

  12. A method for reactivity monitoring in subcritical source-driven systems

    For the operation of subcritical source-driven systems it is very important to develop reliable techniques to monitor the subcriticality level, in order to be able to establish the effective distance from criticality and promptly detect changes in the reactivity that may be relevant for the safety of the plant. In this paper, a new method to interpret flux measurements in a subcritical system is presented, generalizing a technique that has been recently proposed for source-free nuclear systems. The method is based on the mathematical relationship between the power, its derivative, the convolution integral appearing in the delayed neutron precursor balance equations and the stable period of the multiplying system within the point kinetic model. The assessment of the method is carried out interpreting flux evolutions obtained from numerical transient simulations. The results presented prove that the method can yield accurate reactivity predictions for various physical situations and can be of interest for accelerator-driven system technology. (author)

  13. Experimental subcritical facility driven by D-D/D-T neutron generator at BARC, India

    Highlights: •Experimental subcritical facility BRAHMMA coupled to D-D/D-T neutron generator. •Preliminary results of PNS experiments reported. •Feynman-alpha noise measurements explored with continuous source. -- Abstract: The paper presents design of an experimental subcritical assembly driven by D-D/D-T neutron and preliminary experimental measurements. The system has been developed for investigating the static and dynamic neutronic properties of accelerator driven sub-critical systems. This system is modular in design and it is first in the series of subcritical assemblies being designed. The subcritical core consists of natural uranium fuel with high density polyethylene as moderator and beryllium oxide as reflector. The fuel is embedded in high density polyethylene moderator matrix. Estimated keff of the system is ∼0.89. One of the unique features of subcritical core is the use of Beryllium oxide (BeO) as reflector and HDPE as moderator making the assembly a compact modular system. The subcritical core is coupled to Purnima Neutron Generator which works in D-D and D-T mode with both DC and pulsed operation. It has facility for online source strength monitoring using neutron tagging and programmable source modulation. Preliminary experiments have been carried out for spatial flux measurement and reactivity estimation using pulsed neutron source (PNS) techniques with D-D neutrons. Further experiments are being planned to measure the reactivity and other kinetic parameters using noise methods. This facility would also be used for carrying out studies on effect of source importance and measurement of source multiplication factor ks and external neutron source efficiency φ∗ in great details. Experiments with D-T neutrons are also underway

  14. Proliferation Potential of Accelerator-Driven Systems: Feasibility Calculations

    Accelerator-driven systems for fissile materials production have been proposed and studied since the early 1950s. Recent advances in beam power levels for small accelerators have raised the possibility that such use could be feasible for a potential proliferator. The objective of this study is to review the state of technology development for accelerator-driven spallation neutron sources and subcritical reactors. Energy and power requirements were calculated for a proton accelerator-driven neutron spallation source and subcritical reactors to produce a significant amount of fissile material--plutonium

  15. 次锕系元素在加速器驱动的次临界快堆中嬗变的研究%Study of Transmutation of Minor Actinides in Accelerator-Driven Sub-critical Fast Reactor

    杨永伟; 古玉祥

    2001-01-01

    选取加速器驱动次临界快堆(ADSFR),进行嬗变来自于PWR(U)乏燃料 中次锕系元素 的研究。在堆芯内,燃料为NpAmCm的氧化物,选取液态钠为冷却剂。利用下列程序对所选方 案进行物理计算和分析:LAHET -模拟质子与靶核的相互作用;MCNP4A-模拟次临界包层内 20MeV以下的中子与材料核的相互作用;ORIGEN2-利用MCNP4A的输出提供的一群等效截面对 堆芯进行燃耗计算。计算分析的结果表明:考虑临界安全、功率密度和燃耗等因素,利用所 选方案进行次锕系元素嬗变是可行的。%Accelerator-Driven Sub-critical Fast Reactor (ADSFR)is chosenfor transmu ta tion of minor actinides from the spent fuel of PWR(U). In the core, the fuel type is (PuNpAmCm)Ox. Liquid sodium is chosen as coolant The neutronics calcul ation and analysis of the selected scheme have been done by using the following codes: LAHET, for the simulation of the interaction between the protons and the nuclei of the target; MCNP4A, for the simulation of interaction between neutron s with energy below 20MeV and the nuclei of materials in the sub-critical blank e t; ORIGEN2, for the multi-region burnup calculation of the blanket by using the one-group effective cross-section provided in the output of MCNP4A. The neutro ni cs calculation and analysis show that the proposed scheme is feasible for trans mutation of minor actinides, considering the factors such as the criticality s afety, power density, burnup, etc.

  16. Design status and future research programme for a sub-critical assembly driven by a proton accelerator with proton energy 660 MeV for experiments on long-lived fission products and minor actinides transmutation (Sad)

    Report presents project for the construction of a low power integral system on the basis of the proton accelerator of energy 660 MeV and sub-critical MOX blanket with uranium-plutonium fuel. Installation includes sub-critical core with a nominal thermal power of 15-20 kW. Multiplication coefficient keff = 0,95 and the accelerator beam power of 0.75-1 kW. The experimental programme for SAD will be focused on solving different aspects of reactor physics, reaction rates measurements and benchmarking. The first conceptual design of the SAD experiment is completed in the form of the ISTC Project Proposal 2267. Realisation of the SAD facility may be expected in about 3-4 years. (author)

  17. Small type accelerator. Try for accelerator driven system

    Mori, Y

    2003-01-01

    FFAG (Fixed-field alternating gradient) accelerator for accelerator driven subcritical reactor, which aims to change from long-lived radioactive waste to short-lived radioactivity, is introduced. It is ring accelerator. The performance needed is proton as accelerator particle, 10MW (total) beam power, about 1GeV beam energy, >30% power efficiency and continuous beam. The feature of FFAG accelerator is constant magnetic field. PoP (Proof-of-principle)-FFAG accelerator, radial type, was run at first in Japan in 2000. The excursion is about some ten cm. In principle, beam can be injected and extracted at any place of ring. The 'multi-fish' acceleration can accelerate beams to 100% duty by repeating acceleration. 150MeV-FFAG accelerator has been started since 2001. It tried to practical use, for example, treatment of cancer. (S.Y.)

  18. Power spectral analysis for a subcritical reactor system driven by a pulsed spallation neutron source

    A series of power spectral analyses for a thermal subcritical reactor system driven by a pulsed spallation neutron source was carried out at Kyoto University Critical Assembly (KUCA), to determine the prompt-neutron decay constant of the Accelerator-Driven System (ADS). High-energy protons (100 MeV) obtained from the fixed field alternating gradient accelerator were injected onto a lead-bismuth target, whereby the spallation neutrons were generated. In the cross-power spectral density between time-sequence signal data of two neutron detectors, many delta-function-like peaks at the integral multiple of pulse repetition frequency could be observed. However, no continuous reactor-noise component could be measured. This is because these detectors have too high count-rate to be placed closely to the core. From the point data of these delta-function-like peaks, the prompt-neutron decay constant could be determined. At a slightly subcritical state, the decay constant was consistent with that obtained by a previous power spectral analysis for a pulsed 14 MeV neutron source and by a pulsed neutron experiment. At another deeply subcritical state, however, the present analysis leads to an underestimate of the decay constant. (author)

  19. Design of a molten heavy-metal coolant and target for fast-thermal accelerator driven sub-critical system (ADS)

    Reactor physics design of a 750 MWth one way coupled fast-thermal ADS was evolved in BARC earlier. This indicated that a fairly large thermal power output was possible with a proton beam of 1 GeV and current 2-3 mA. We also carried out preliminary studies on the molten Pb/Pb-Bi coolant and spallation-target system in the fast zone of this ADS. The thermal power in this zone was estimated to be about 109 MW. In these studies, analyses related to thermal hydraulics have been carried out for a buoyancy driven system to determine the coolant parameters for both lead as well as lead-bismuth eutectic. This design is similar to the passive lead coolant system design of CERN-EA. Appropriate equations for buoyancy pressure head, pressure drop in the reactor core; coolant velocity, heat transport etc. have been solved for different coolant inlet and outlet temperatures, fuel-pin pitch distances, fuel-power densities etc. The analyses show that coolant height required for generating buoyancy pressure head is a very strong function of power density of the fuel-pin and ΔT (difference between outlet and inlet temperature) of the coolant. Main advantage of lead-bismuth eutectic comes from the inlet temperature that can be significantly lower than that of lead; thus larger ΔT can be obtained which in turn will reduce required coolant height. This will result in saving of coolant inventory and cost. In this paper, preliminary engineering design of coolant and target for the 109 MW fast reactor zone is presented. In addition, the proposed Indian programmes to study thermal-hydraulics and materials for the technology development are discussed. (author)

  20. Electron beam-driven subcritical cascade molten salt unit for three component conception of nuclear industry

    The preliminary sketch of one of the possible conceptions to develop the beam-driven subcritical molten salt reactor have been described earlier. The essence of the concept is the use of the molten salt reactor cascade system to reduce the driving power of the linac units. Following the new concept, prerequisities and motivations will be discussed in the frame of the existing world nuclear power system. In order to avoid a deep technological nuclear industrial reorganization for a short-range plan we would like to examine a concept which consists of three types of nuclear reactors. They are thermal, fast, and burner reactor types. A role and advantage of the use of the molten salt subcritical reactors as a burner reactor type have been shown for the existing nuclear technology structure. The discussed nuclear power system with a closed fuel cycle could be supplemented with dry fluoride volatility reprocessing of spent fuel and molten salt centrifugation, thermal diffusion, and electrochemical methods for separation. The general approach of the discussed conception relates to the third component of the nuclear industry that includes accelerator-driven molten salt subcritical cascade burners, cyclotrons or system of electron linacs and non-purex fission product/actinide separation systems. 10 refs., 3 tabs

  1. Uncertainty assessment for accelerator-driven systems

    The concept of a subcritical system driven by an external source of neutrons provided by an accelerator ADS (Accelerator Driver System) has been recently revived and is becoming more popular in the world technical community with active programs in Europe, Russia, Japan, and the U.S. A general consensus has been reached in adopting for the subcritical component a fast spectrum liquid metal cooled configuration. Both a lead-bismuth eutectic, sodium and gas are being considered as a coolant; each has advantages and disadvantages. The major expected advantage is that subcriticality avoids reactivity induced transients. The potentially large subcriticality margin also should allow for the introduction of very significant quantities of waste products (minor Actinides and Fission Products) which negatively impact the safety characteristics of standard cores. In the U.S. these arguments are the basis for the development of the Accelerator Transmutation of Waste (ATW), which has significant potential in reducing nuclear waste levels. Up to now, neutronic calculations have not attached uncertainties on the values of the main nuclear integral parameters that characterize the system. Many of these parameters (e.g., degree of subcriticality) are crucial to demonstrate the validity and feasibility of this concept. In this paper we will consider uncertainties related to nuclear data only. The present knowledge of the cross sections of many isotopes that are not usually utilized in existing reactors (like Bi, Pb-207, Pb-208, and also Minor Actinides and Fission Products) suggests that uncertainties in the integral parameters will be significantly larger than for conventional reactor systems, and this raises concerns on the neutronic performance of those systems

  2. Accelerator-driven transmutation reactor analysis code system (ATRAS)

    Sasa, Toshinobu; Tsujimoto, Kazufumi; Takizuka, Takakazu; Takano, Hideki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1999-03-01

    JAERI is proceeding a design study of the hybrid type minor actinide transmutation system which mainly consist of an intense proton accelerator and a fast subcritical core. Neutronics and burnup characteristics of the accelerator-driven system is important from a view point of the maintenance of subcriticality and energy balance during the system operation. To determine those characteristics accurately, it is necessary to involve reactions at high-energy region, which are not treated on ordinary reactor analysis codes. The authors developed a code system named ATRAS to analyze the neutronics and burnup characteristics of accelerator-driven subcritical reactor systems. ATRAS has a function of burnup analysis taking account of the effect of spallation neutron source. ATRAS consists of a spallation analysis code, a neutron transport codes and a burnup analysis code. Utility programs for fuel exchange, pre-processing and post-processing are also incorporated. (author)

  3. Accelerator-driven transmutation reactor analysis code system (ATRAS)

    JAERI is proceeding a design study of the hybrid type minor actinide transmutation system which mainly consist of an intense proton accelerator and a fast subcritical core. Neutronics and burnup characteristics of the accelerator-driven system is important from a view point of the maintenance of subcriticality and energy balance during the system operation. To determine those characteristics accurately, it is necessary to involve reactions at high-energy region, which are not treated on ordinary reactor analysis codes. The authors developed a code system named ATRAS to analyze the neutronics and burnup characteristics of accelerator-driven subcritical reactor systems. ATRAS has a function of burnup analysis taking account of the effect of spallation neutron source. ATRAS consists of a spallation analysis code, a neutron transport codes and a burnup analysis code. Utility programs for fuel exchange, pre-processing and post-processing are also incorporated. (author)

  4. The safe, economical operation of a slightly subcritical reactor and transmutor with a small proton accelerator

    I suggest that an accelerator can be used to increase the safety and neutron economy of a power reactor and a transmutor of long-lived radioactive wastes, such as minor actinides and fission products, by providing neutrons for its subcritical operation. Instead of the large subcriticality k=0.9-0.95 which we originally proposed for such transmutor, we propose to use a slightly subcritical reactor, such as k=0.99, which will avoid many of the technical difficulties that are associated with large subcriticality, such as localized power peaking, radiation damage due to injection of medium-energy protons, the high current accelerator, and the requirement for a long beam-expansion section. We analyze the power drop that occurred in Phenix reactor, and show that the operating this reactor in subcritical conditions improves safety. (author). 13 refs., 5 figs

  5. Nonlinear excitation of subcritical fast ion-driven modes

    Lesur, M.; Itoh, K.; Ido, T.; Itoh, S.-I.; Kosuga, Y.; Sasaki, M.; Inagaki, S.; Osakabe, M.; Ogawa, K.; Shimizu, A.; Ida, K.; the LHD experiment group

    2016-05-01

    In collisionless plasma, it is known that linearly stable modes can be destabilized (subcritically) by the presence of structures in phase-space. The growth of such structures is a nonlinear, kinetic mechanism, which provides a channel for free-energy extraction, different from conventional inverse Landau damping. However, such nonlinear growth requires the presence of a seed structure with a relatively large threshold in amplitude. We demonstrate that, in the presence of another, linearly unstable (supercritical) mode, wave–wave coupling can provide a seed, which can lead to subcritical instability by either one of two mechanisms. Both mechanisms hinge on a collaboration between fluid nonlinearity and kinetic nonlinearity. If collisional velocity diffusion is low enough, the seed provided by the supercritical mode overcomes the threshold for nonlinear growth of phase-space structure. Then, the supercritical mode triggers the conventional subcritical instability. If collisional velocity diffusion is too large, the seed is significantly below the threshold, but can still grow by a sustained collaboration between fluid and kinetic nonlinearities. Both of these subcritical instabilities can be triggered, even when the frequency of the supercritical mode is rapidly sweeping. These results were obtained by modeling the subcritical mode kinetically, and the impact of the supercritical mode by simple wave–wave coupling equations. This model is applied to bursty onset of geodesic acoustic modes in an LHD experiment. The model recovers several key features such as relative amplitude, timescales, and phase relations. It suggests that the strongest bursts are subcritical instabilities, with sustained collaboration between fluid and kinetic nonlinearities.

  6. Accelerator-driven transmutation technologies

    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

  7. Preliminary research on safety and control characteristics of accelerator driven reactor

    The safety and control characteristics of accelerator driven reactor are studied with calculation and simulation running. The results show that the prompt criticality for accelerator driven reactor does not easily happen, its safety characteristics are better than critical reactor's, the higher the subcritical degree, the better the safety. The control loop of accelerator driven reactor has a little time constant, a little overshoot, and short regulating time, its control characteristics are also better than critical reactor's

  8. TRIGA Accelerator Driven Experiment (TRADE)

    This short report is derivated from the TRADE FINAL FEASIBILITY REPORT (March 2002) that is the result of the collective effort of a Working Group composed by ENEA, CEA, CERN, ANSALDO under Carlo Rubbia (ENEA) and Massimo Salvatores (CEA) supervision. The TRADE experiment, to be performed in the TRIGA reactor of the ENEA Casaccia Centre consists in the coupling of an external proton accelerator to a target to be installed in the Central thimble of the reactor scrammed to sub-criticality. This pilot experiment, aimed at a global demonstration of the ADS concept, is based on an original idea of Carlo Rubbia, presented at CEA in October 2000. (author)

  9. Discriminators for the Accelerator-Based Conversion (ABC) concept using a subcritical molten salt system

    Discriminators are described that quantify enhancements added to plutonium destruction and/or nuclear waste transmutation systems through use of an accelerator/fluid fuel combination. This combination produces a robust and flexible nuclear system capable of the destruction of all major long-lived actinides (including plutonium) and fission products. The discriminators discussed in this report are (1) impact of subcritical operation on safety, (2) impact of subcritical and fluid fuel operation on plutonium burnout scenarios, and (3) neutron economy enhancements brought about by subcritical operation. Neutron economy enhancements are quantified through assessment of long-term dose reduction resulting from transmutation of key fission products along with relaxation of processing frequencies afforded by subcritical operation

  10. Radioactive isotope production for medical applications using Kharkov electron driven subcritical assembly facility.

    Talamo, A.; Gohar, Y.; Nuclear Engineering Division

    2007-05-15

    Kharkov Institute of Physics and Technology (KIPT) of Ukraine has a plan to construct an accelerator driven subcritical assembly. The main functions of the subcritical assembly are the medical isotope production, neutron thereby, and the support of the Ukraine nuclear industry. Reactor physics experiments and material research will be carried out using the capabilities of this facility. The United States of America and Ukraine have started collaboration activity for developing a conceptual design for this facility with low enrichment uranium (LEU) fuel. Different conceptual designs are being developed based on the facility mission and the engineering requirements including nuclear physics, neutronics, heat transfer, thermal hydraulics, structure, and material issues. Different fuel designs with LEU and reflector materials are considered in the design process. Safety, reliability, and environmental considerations are included in the facility conceptual design. The facility is configured to accommodate future design improvements and upgrades. This report is a part of the Argonne National Laboratory Activity within this collaboration for developing and characterizing the subcritical assembly conceptual design. In this study, the medical isotope production function of the Kharkov facility is defined. First, a review was carried out to identify the medical isotopes and its medical use. Then a preliminary assessment was performed without including the self-shielding effect of the irradiated samples. Finally, more detailed investigation was carried out including the self-shielding effect, which defined the sample size and irradiation location for producing each medical isotope. In the first part, the reaction rates were calculated as the multiplication of the cross section with the unperturbed neutron flux of the facility. Over fifty isotopes were considered and all transmutation channels are used including (n,{gamma}), (n,2n), (n,p), and ({gamma},n). In the second part

  11. Super- and sub-critical regions in shocks driven by radio-loud and radio-quiet CMEs

    Alessandro Bemporad

    2013-05-01

    Full Text Available White-light coronagraphic images of Coronal Mass Ejections (CMEs observed by SOHO/LASCO C2 have been used to estimate the density jump along the whole front of two CME-driven shocks. The two events are different in that the first one was a “radio-loud” fast CME, while the second one was a “radio quiet” slow CME. From the compression ratios inferred along the shock fronts, we estimated the Alfvén Mach numbers for the general case of an oblique shock. It turns out that the “radio-loud” CME shock is initially super-critical around the shock center, while later on the whole shock becomes sub-critical. On the contrary, the shock associated with the “radio-quiet” CME is sub-critical at all times. This suggests that CME-driven shocks could be efficient particle accelerators at the shock nose only at the initiation phases of the event, if and when the shock is super-critical, while at later times they lose their energy and the capability to accelerate high energetic particles.

  12. Super- and Sub-critical Regions in Shocks driven by Radio-Loud and Radio-Quiet CMEs

    Bemporad, Alessandro

    2012-01-01

    White-light coronagraphic images of Coronal Mass Ejections (CMEs) observed by SOHO/LASCO C2 have been used to estimate the density jump along the whole front of two CME-driven shocks. The two events are different in that the first one was a "radio-loud" fast CME, while the second one was a "radio quiet" slow CME. From the compression ratios inferred along the shock fronts, we estimated the Alfv\\'en Mach numbers for the general case of an oblique shock. It turns out that the "radio-loud" CME shock is initially super-critical around the shock center, while later on the whole shock becomes sub-critical. On the contrary, the shock associated with the "radio-quiet" CME is sub-critical at all times. This suggests that CME-driven shocks could be efficient particle accelerators at the shock nose only at the initiation phases of the event, if and when the shock is super-critical, while at later times they lose their energy and the capability to accelerate high energetic particles.

  13. Feasibility study of a hybrid subcritical fission system driven by Plasma-Focus fusion neutrons

    Highlights: • A model of a subcritical cascade driven by a Plasma Focus device is presented. • Optimum parameters to achieve given levels of neutron amplification are produced. • Monte Carlo calculations for spherical shells of enriched Uranium were performed. • Break-even conditions can be achieved with Plasma Focus of tens of kJ. - Abstract: A feasibility analysis of a hybrid fusion–fission system consisting of a two-stage spherical subcritical cascade driven by a Plasma Focus device is presented. The analysis is based on the one-group neutron diffusion equation, which was appropriately cast to assess the neutronic amplification of a spherical configuration. A design chart was produced to estimate the optimum dimensions of the fissile shells required to achieve different levels of neutron amplification. It is found that cascades driven by Plasma Focus of tens of kJ are feasible. The results were corroborated by means of Monte Carlo calculations

  14. Ashing vs. electric generation in accelerator driven system

    Accelerator Driven Systems have been conceived as an alternative for the processing of the radioactive wastes contained in spent fuel elements from nuclear power plants. These systems are formed by the coupling of a nuclear reactor - preferably a subcritical reactor - with a particle accelerator providing particles with energy in the order of the GeV. The long-lived fission products and actinides of the spent fuels are transformed by nuclear reactions in stable isotopes or in short-lived radioisotopes. The basic parameters for the electric energy production of the different systems are analysed. (author)

  15. Laser driven particle acceleration

    This dissertation summarizes the last ten years of research at the Laboratory of Applied Optics on laser-plasma based electron acceleration. The main result consists of the development and study of a relativistic electron source with unique properties: high energy (100-300 MeV) in short distances (few millimeters), mono-energetic, ultra-short (few fs), stable and tunable. The manuscript describes the steps that led to understanding the physics, and then mastering it in order to produce this new electron source. Non linear propagation of the laser pulse in the plasma is first presented, with phenomena such as non linear wakefield excitation, relativistic and ponderomotive self-focusing in the short pulse regime, self-compression. Acceleration and injection of electrons are then reviewed from a theoretical perspective. Experimental demonstrations of self-injection in the bubble regime and then colliding pulse injection are then presented. These experiments were among the first to produce monoenergetic, high quality, stable and tunable electron beams from a laser-plasma accelerator. The last two chapters are dedicated to the characterization of the electron beam using transition radiation and to its applications to gamma radiography and radiotherapy. Finally, the perspectives of this research are presented in the conclusion. Scaling laws are used to determine the parameters that the electron beams will reach using peta-watt laser systems currently under construction. (author)

  16. Accelerator-driven Transmutation of Waste

    Venneri, Francesco

    1998-04-01

    Nuclear waste from commercial power plants contains large quantities of plutonium, other fissionable actinides, and long-lived fission products that are potential proliferation concerns and create challenges for the long-term storage. Different strategies for dealing with nuclear waste are being followed by various countries because of their geologic situations and their views on nuclear energy, reprocessing and non-proliferation. The current United States policy is to store unprocessed spent reactor fuel in a geologic repository. Other countries are opting for treatment of nuclear waste, including partial utilization of the fissile material contained in the spent fuel, prior to geologic storage. Long-term uncertainties are hampering the acceptability and eventual licensing of a geologic repository for nuclear spent fuel in the US, and driving up its cost. The greatest concerns are with the potential for radiation release and exposure from the spent fuel for tens of thousands of years and the possible diversion and use of the actinides contained in the waste for weapons construction. Taking advantage of the recent breakthroughs in accelerator technology and of the natural flexibility of subcritical systems, the Accelerator-driven Transmutation of Waste (ATW) concept offers the United States and other countries the possibility to greatly reduce plutonium, higher actinides and environmentally hazardous fission products from the waste stream destined for permanent storage. ATW does not eliminate the need for, but instead enhances the viability of permanent waste repositories. Far from being limited to waste destruction, the ATW concept also brings to the table new technologies that could be relevant for next-generation power producing reactors. In the ATW concept, spent fuel would be shipped to the ATW site where the plutonium, transuranics and selected long-lived fission products would be destroyed by fission or transmutation in their first and only pass through the

  17. JAERI accelerator driven system project

    In Japan a national program called OMEGA was started in 1988 for research and development of new technologies for partitioning and transmutation of nuclear waste. Under this program JAERI is carrying out research and development for proton accelerator-driven transmutation, together with transmutation with fast burner reactor and advanced partitioning technology. Two types of accelerator driven transmutation systems are proposed: a solid system and a molten-salt system. An outline of the OMEGA program and the partitioning and transmutation studies at JAERI are presented in this report

  18. Measurement of subcriticality using delayed neutron source combined with pulsed neutron accelerator

    A new experimental method for subcriticality measurement was developed by using delayed neutron source which is produced by external pulsed neutron source to increase accuracy of measured results by overcoming the space dependency problem which means difference of measured results in different detector position and often appeared in almost all other subcriticality measurement techniques. Experiments were performed at Kyoto University Critical Assembly (KUCA) combined with a DT accelerator to produce pulsed neutron in outside of the core repeatedly. In this method, neutron detection counts in the prompt neutron time region which are appeared just after injection of pulsed neutron are omitted, whereas neutron counts in the delayed neutron time region which are appeared after disappearance of exponential decay of the prompt neutron are adopted in analysis based on neutron source multiplication method or neutron noise analysis method; the variance to mean ratio method. In the delayed neutron time region, neutron sources to initiate fission chain reactions in subcritical state are delayed neutrons from delayed neutron precursors which are mainly produced by fission chain reactions in the prompt neutron time region, and delayed neutron precursors exist only in the fuel region, which makes possible to decrease the space dependency problem. The obtained results were compared with conventional pulsed neutron method, and it was found that the space dependency problem in subcriticality measurement can be fairly decreased by using the present new method compared with conventional one. (author)

  19. Dynamic response of an accelerator driven system to accelerator beam interruptions for criticality

    Subcritical nuclear reactors driven by intense neutron sources can be very suitable tools for nuclear waste transmutation, particularly in the case of minor actinides with very low fractions of delayed neutrons. A proper control of these systems needs to know at every time the absolute value of the reactor subcriticality (negative reactivity), which must be measured by fully reliable methods, usually conveying a short interruption of the accelerator beam in order to assess the neutron flux reduction. Those interruptions should be very short in time, for not disturbing too much the thermal magnitudes of the reactor. Otherwise, the cladding and the fuel would suffer from thermal fatigue produced by those perturbations, and the mechanical integrity of the reactor would be jeopardized. It is shown in this paper that beam interruptions of the order of 400 μs repeated every second would not disturb significantly the reactor thermal features, while enabling for an adequate measurement of the negative reactivity

  20. Activation Characteristics of Fuel Breeding Blanket Module in Fusion Driven Subcritical System

    HUANG Qun-Ying; LI Jian-Gang; CHEN Yi-Xue

    2004-01-01

    @@ Shortage of energy resources and production of long-lived radioactivity wastes from fission reactors are among the main problems which will be faced in the world in the near future. The conceptual design of a fusion driven subcritical system (FDS) is underway in Institute of Plasma Physics, Chinese Academy of Sciences. There are alternative designs for multi-functional blanket modules of the FDS, such as fuel breeding blanket module (FBB)to produce fuels for fission reactors, tritium breeding blanket module to produce the fuel, i.e. tritium, for fusion reactor and waste transmutation blanket module to try to permanently dispose of long-lived radioactivity wastes from fission reactors, etc. Activation of the fuel breeding blanket of the fusion driven subcritical system (FDS-FBB) by D-T fusion neutrons from the plasma and fission neutrons from the hybrid blanket are calculated and analysed under the neutron wall loading 0.5 MW/m2 and neutron fluence 15 MW. yr/m2. The neutron spectrum is calculated with the worldwide-used transport code MCNP/4C and activation calculations are carried out with the well known European inventory code FISPACT/99 with the latest released IAEA Fusion Evaluated Nuclear Data Library FENDL-2.0 and the ENDF/B-V uranium evaluated data. Induced radioactivities, dose rates and afterheats, etc, for different components of the FDS-FBB are compared and analysed.

  1. Introduction to Physical and Technical Analysis of Accelerator Driven System

    In the present paper the main elements of the accelerator driven system (ADS) are discussed. Describing the spallation source it is underlined that beside the well accepted theory of spallation, the spallation phenomena is not yet sufficiently investigated. Dealing with the sub-critical reactor as an energy amplifier of the primary spallation source a suggestion for the specific neutron spectrum is proposed to obtain optimal conditions for energy production, burn-up and transmutation. In the chapter devoted for the accelerators which accelerates the charged particles, the two accelerator principles are presented on the examples of working accelerators: the linear accelerator - LINAC and cyclotron. Finally, there is presented the project of accelerator driven system - MYRHA for research and development worked out by the Belgian Nuclear Research Centre - SCK-CEN and the conception of nuclear power station of RBMK-1000 type with spallation source together with analysis of the balance of energy worked out by the Joint Institute of Nuclear Research, Dubna, Russia. (author)

  2. Subcritical assemblies with fast and thermal neutron spectrum driven with high intensity neutron generator NG-12-1

    Full text: The investigations in the field of nuclear physics, development of numerical calculation methods for nuclear reactors, neutron physics and etc. are carried out at the Joint Institute for Power and Nuclear Research - Sosny (JIPNR-Sosny) since the 60s after putting into operation the research reactor and the critical assemblies. A large range of different configuration (geometry,composition) of critical assemblies have been constructed at the NAS Belarus during 25 years of studding neutronic of the special (fast and thermal) reactors. The Chernobyl accident brought a massive public reaction to nuclear efforts and the reactor ceased operation in 1987 and was shut down in 1991 and all investigations using of the reactor neutrons were interrupted. Closure of the reactor led to new endeavors being undertaken at NAS Belarus including the coupling of a high-yield neutron generator to a sub-critical assemblies fuelled with high enriched uranium. The neutron generator NG-12-1 consists of a high-current deuteron accelerator, highly effective water-cooling rotating Ti3H (TiD) 230 mm diameter target and has been operated since 1997 as intense continuous neutron source of (1.5-2.0) 1012 n/s at maximum with neutron energy 13.0 - 15.0 MeV and a continuous neutron source of (2.0-3.0) 1010 n/s at maximum with neutron energy 2.0- 3.0 MeV. When operating in the pulse mode the neutron beam pulse can be adjusted from 0.5μs up to 100μs and pulse repetition rate can be vary from 1 Hz to 10 000 Hz. According research program of the NAS of Belarus the experimental facility 'Yalina' consisting of the sub-critical assembly with neutron thermal spectrum (source neutron multiplication factor Ms of the assembly is in the range of 10 ≤ Ms ≥ 50), high intensity neutron generator and measurement systems was developed and put into operation in 2001. The core of the subcritical assembly is a rectangular parallelepiped 40.0cm width, 40.0cm length and 57.0 cm height. It is assembled

  3. Terahertz-driven linear electron acceleration

    Nanni, Emilio Alessandro; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Miller, R J Dwayne; Kärtner, Franz X

    2014-01-01

    The cost, size and availability of electron accelerators is dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency (RF) accelerating structures operate with 30-50 MeV/m gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional RF structures. However, laser-driven electron accelerators require intense sources and suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here, we demonstrate the first linear acceleration of electrons with keV energy gain using optically-generated terahertz (THz) pulses. THz-driven accelerating structures enable high-gradient electron accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. Increasing the operational frequency of accelerators into the THz band allows for greatly increased accelerating ...

  4. Disposition of nuclear waste using subcritical accelerator-driven systems

    Studies have shown that the repository long-term radiological risk is from the long-lived transuranics and the fission products Tc-99 and I-129, thermal loading concerns arise mainly form the short-lived fission products Sr-90 and Cs-137. In relation to the disposition of nuclear waste, ATW is expected to accomplish the following: (1) destroy over 99.9% of the actinides; (2) destroy over 99.9% of the Tc and I; (3) separate Sr and Cs (short half-life isotopes); (4) separate uranium; (5) produce electricity. In the ATW concept, spent fuel would be shipped to a ATW site where the plutonium, other transuranics and selected long-lived fission products would be destroyed by fission or transmutation in their only pass through the facility. This approach contrasts with the present-day reprocessing practices in Europe and Japan, during which high purity plutonium is produced and used in the fabrication of fresh mixed-oxide fuel (MOX) that is shipped off-site for use in light water reactors

  5. Simulator for an Accelerator-Driven Subcritical Fissile Solution System

    Klein, Steven Karl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Day, Christy M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Determan, John C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-14

    LANL has developed a process to generate a progressive family of system models for a fissile solution system. This family includes a dynamic system simulation comprised of coupled nonlinear differential equations describing the time evolution of the system. Neutron kinetics, radiolytic gas generation and transport, and core thermal hydraulics are included in the DSS. Extensions to explicit operation of cooling loops and radiolytic gas handling are embedded in these systems as is a stability model. The DSS may then be converted to an implementation in Visual Studio to provide a design team the ability to rapidly estimate system performance impacts from a variety of design decisions. This provides a method to assist in optimization of the system design. Once design has been generated in some detail the C++ version of the system model may then be implemented in a LabVIEW user interface to evaluate operator controls and instrumentation and operator recognition and response to off-normal events. Taken as a set of system models the DSS, Visual Studio, and LabVIEW progression provides a comprehensive set of design support tools.

  6. Disposition of nuclear waste using subcritical accelerator-driven systems

    Venneri, F.; Li, N.; Williamson, M.; Houts, M.; Lawrence, G.

    1998-12-01

    Studies have shown that the repository long-term radiological risk is from the long-lived transuranics and the fission products Tc-99 and I-129, thermal loading concerns arise mainly form the short-lived fission products Sr-90 and Cs-137. In relation to the disposition of nuclear waste, ATW is expected to accomplish the following: (1) destroy over 99.9% of the actinides; (2) destroy over 99.9% of the Tc and I; (3) separate Sr and Cs (short half-life isotopes); (4) separate uranium; (5) produce electricity. In the ATW concept, spent fuel would be shipped to a ATW site where the plutonium, other transuranics and selected long-lived fission products would be destroyed by fission or transmutation in their only pass through the facility. This approach contrasts with the present-day reprocessing practices in Europe and Japan, during which high purity plutonium is produced and used in the fabrication of fresh mixed-oxide fuel (MOX) that is shipped off-site for use in light water reactors.

  7. Design study of a fast spectrum zero-power reactor dedicated to source driven sub-critical experiments

    Mercatali, L.; Serikov, A. [Forschungszentrum Karlsruhe, Institute for Neutron Physics and Reactor Technology, P.O. Box 3640, 76021 Karlsruhe (Germany); Baeten, P.; Uyttenhove, W. [SCK-CEN, Boeretang 200, B-2400 Mol (Belgium); Lafuente, A. [Univerisdad Politecnica de Madrid, 28006 Madrid (Spain); Teles, P. [Instituto Tecnologico e Nuclear, EN 10, 2680-953 Sacavem (Portugal)

    2010-09-15

    In the framework of the European P and T program (IFP6-EUROTRANS), the Generation of Uninterrupted Intense NEutrons pulses at the lead VEnus REactor (GUINEVERE) project consists of an Accelerator Driven System (ADS) that is composed by a fast lead simulated-cooled reactor operated in sub-critical conditions, coupled with an updated version of the GENEPI neutron generator previously used for the MUSE experiments. The GUINEVERE facility aims at developing and improving different techniques for the reactivity monitoring of sub-critical ADS's. As such, the GUINEVERE project will comprise a series of major experiments that will be performed in the near future. The GUINEVERE facility will be located at the VENUS light water moderated research reactor at the SCK-CEN site of Mol (Belgium), which needs to be modified in order to accommodate a completely different and new type of core. A series of constraints were taken into account in the technical design of the GUINEVERE core, in order to properly conjugate the technical feasibility of this facility and the necessity to comply with the envisioned experimental program and its associated scientific outcome. The complete design study of the GUINEVERE core is the subject of this paper. The final design of the fuel assemblies, safety and control rods is provided. Also, the critical core configuration, to be used as reference for absolute reactivity measurements, is presented along with its associated reactor physics parameters, calculated by means of Monte Carlo methodologies. Finally, for licensing purposes, the GUINEVERE facility must satisfy the required nuclear safety criteria of the Belgian safety authorities, and in this paper, an overview of the safety analysis that has been performed with regard to the core physics, thermal assessment and shielding issues is also provided. (author)

  8. Investigation of local spectral differences between critical and driven sub-critical configurations in muse-4

    Studies of spectral characteristics of different critical and driven sub-critical MUSE-4 configurations are presented in this paper. The current investigations have permitted to quantify important aspects, such as the influence of the intrinsic source, the asymmetry of the core along the north/south axis, the impact of the two different types of external sources to be employed, and the moderation/multiplication effects of the central diffusing lead region. One of the principal goals has been to define a suitable measurement programme using different threshold reaction rates and fission rate traverses (235U and 238U). These measurements will constitute an important experimental database for validating the calculational methods and data employed for analysing the neutron coupling in these ADS-representative configurations. (author)

  9. Developments in laser-driven plasma accelerators

    Hooker, Simon Martin

    2014-01-01

    Laser-driven plasma accelerators provide acceleration gradients three orders of magnitude greater than conventional machines, offering the potential to shrink the length of accelerators by the same factor. To date, laser-acceleration of electron beams to particle energies comparable to those offered by synchrotron light sources has been demonstrated with plasma acceleration stages only a few centimetres long. This article describes the principles of operation of laser-driven plasma accelerators, and reviews their development from their proposal in 1979 to recent demonstrations. The potential applications of plasma accelerators are described and the challenges which must be overcome before they can become a practical tool are discussed.

  10. Proton-driven plasma acceleration at CERN

    Plasma-based acceleration methods have seen important progress over the last years. Recently, it has been proposed to experimentally study plasma acceleration driven by proton beams, in addition to the established research directions of electron and laser-driven plasmas. This talk presents the planned experiment and the research efforts carried out at CERN.

  11. Neutronic parameters characterizing accelerator driven system (ADS)

    An hybrid system is a reactor where an external source of spallation neutrons is supplied to a subcritical multiplying medium. The neutronic parameters characterising such a system include, in addition to the multiplication factor which measures the sub-criticality level, another physics parameter measuring the 'importance' of the external source. The aim of this thesis is, on the one hand, to investigate basic neutronic phenomena taking place in fast sub- critical media in either steady-state or transient operation, and, on the other hand, to assess the performance of the ERANOS neutronic code package applied to the analysis of such systems. To this aim, the first part of the work is focused on the MUSE program and in particular the MUSE3 experiment, which consists of different sub-critical configurations driven by a 14-MeV neutron source. This study has been pursued in two directions : the first one was the interpretation of the calculation-experiment (C-E) discrepancies which lead to the development of original calculation methods for sensitivity studies ; the second one was the experimental analysis which allowed an extensive neutronic characterization of the sub-critical system. A correlation between the external source importance and some directly measurable parameters (i.e. fission rate) was derived. The second part of the thesis addresses representativity issues between an experimental facility and an actual power reactor. Important conclusions have been drawn with regard to the operation of an ADS. Finally, representativity studies lead to the recommendation that a demonstration reactor should be built before an industrial plant is constructed. (author)

  12. Alternative definitions of kinetic parameters for accelerator driven systems

    Highlights: ► New definition of kinetic parameters for accelerator driven systems. ► Difference between effective and average delayed neutron fraction. ► Difference between effective and average prompt neutron lifetime. ► Effect of the neutron source (Cf, D–D, D–T) on ksrc. ► Effect of the (n, xn) reactions and source energy-angle distribution on ksrc. - Abstract: This study introduces a new formulation of kinetic parameters for accelerator driven systems and it is structured into two parts. The first part is dedicated to the classic definition of the kinetic parameters and compares different calculation methodologies. The second part considers a new definition of the kinetic parameters for subcritical assemblies, with particular emphasis on the delayed neutron fraction and the prompt neutron lifetime. This new definition takes into account neutrons from the external neutron source and (n, xn) reactions, which increase the fraction of prompt neutrons. The developed theoretical framework has been applied by Monte Carlo and deterministic calculations to the YALINA Thermal subcritical assembly located in Belarus. This facility can be driven by californium, deuterium–deuterium (D–D), or deuterium–tritium (D–T) external neutron sources. For the D–T neutron source, (n, xn) reactions must be taken into account in order to produce accurate results because the average energy of D–T source neutrons is 14.1 MeV, a value which is much higher than the threshold energy of the (n, 2n) cross section of uranium isotopes.

  13. Accelerator-driven system design concept for disposing of spent nuclear fuels

    At present, the US SNF (Spent Nuclear Fuel) inventory is growing by about 2,000 metric tonnes (MT) per year from the current operating nuclear power plants to reach about 70,000 MT by 2015. This SNF inventory contains about 1% transuranics (700 MT), which has about 115 MT of minor actinides. Accelerator-driven systems utilising proton accelerators with neutron spallation targets and subcritical blankets can be utilised for transmuting these transuranics, simultaneously generating carbon free energy, and significantly reducing the capacity of the required geological repository storage facility for the spent nuclear fuels. A fraction of the SNF plutonium can be used as a MOX fuel in the current/future thermal power reactors and as a starting fuel for future fast power reactors. The uranium of the spent nuclear fuel can be recycled for use in future nuclear power plants. This paper shows that only four to five accelerator-driven systems operating for less than 33 full power years can dispose of the US SNF inventory expected by 2015. In addition, a significant fraction of the long-lived fission products will be transmuted at the same time. Each system consists of a proton accelerator with a neutron spallation target and a subcritical assembly. The accelerator beam parameters are 1 GeV protons and 25 MW beam power, which produce 3 GWt in the subcritical assembly. A liquid metal (lead or lead-bismuth eutectic) spallation target is selected because of design advantages. This target is located at the centre of the subcritical assembly to maximise the utilisation of spallation neutrons. Because of the high power density in the target material, the target has its own coolant loop, which is independent of the subcritical assembly coolant loop. Mobile fuel forms with transuranic materials without uranium are considered in this work with liquid lead or lead-bismuth eutectic as fuel carrier

  14. Burnup studies of the subcritical fusion-driven in-zinerator

    A fusion-driven subcritical core, 'In-Zinerator', has been proposed for nuclear waste transmutation [1]. In this concept, a powerful Z-pinch neutron source will produce pulses of 14 MeV neutrons that multiply in a surrounding subcritical core consisting of spent fuel from the LWR fuel cycle or from deep burn high temperature reactors. The proposed design has pulse frequency 0.1 Hz and a thermal power of 3 GWth. The Z-pinch fusion experiment is located at Sandia Laboratories, USA, and can today fire once a day. However, investigations have been made how to increase the frequency to several fires per minute. Each fire yields 300 MJ corresponding to 1020 neutrons per pulse. The source chamber will in the In-Zinerator concept be surrounded by spent fuel to reach an effective multiplication factor, keff, of 0.97. The core will be cooled by liquid lead. In this paper, the burnup of different fuel compositions in the In-Zinerator will be studied as function of initial keff. The Monte Carlo based continuous energy burnup code MCB [2][3]will be used. References: [1] B.B. Cipiti, Fusion Transmutation of Waste and the Role of the In-Zinerator in the Nuclear Fuel Cycle, Sandia Report SAND2006-3522, Sandia National Laboratories, USA, 2006. [2] J. Cetnar, J Wallenius and W Gudowski, MCB: A continuous energy Monte-Carlo burnup simulation code, Actinide and fission product partitioning and transmutation, Proc. of the Fifth Int. Information Exchange Meeting, Mol, Belgium, 25-27 November 1998, 523, OECD/NEA, 1998. [3] http://www.nea.fr/abs/html/nea-1643.html

  15. Terahertz-driven linear electron acceleration

    Nanni, Emilio A.; Huang, Wenqian R.; Hong, Kyung-Han; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Dwayne Miller, R. J.; Kärtner, Franz X.

    2015-10-01

    The cost, size and availability of electron accelerators are dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency accelerating structures operate with 30-50 MeV m-1 gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional radio-frequency structures. However, laser-driven wakefield accelerators require intense femtosecond sources and direct laser-driven accelerators suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here we demonstrate linear acceleration of electrons with keV energy gain using optically generated terahertz pulses. Terahertz-driven accelerating structures enable high-gradient electron/proton accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. These ultra-compact terahertz accelerators with extremely short electron bunches hold great potential to have a transformative impact for free electron lasers, linear colliders, ultrafast electron diffraction, X-ray science and medical therapy with X-rays and electron beams.

  16. MYRRHA: a multipurpose accelerator driven system for research and development

    SCK-CEN, the Belgian Nuclear Research Centre, and IBA s.a., Ion Beam Application, a world leader in accelerator technology, want to fulfil a prominent role in the Accelerator Driven Systems field and are designing an ADS prototype, the MYRRHA Project, and conducting an associated R and D programme. The partners are foreseeing MYRRHA as a first step towards the European ADS-Demo facility. The project focuses primarily on ADS related research, i.e. structural materials and nuclear fuel research, liquid metals and associated aspects, sub-critical reactor physics and subsequently on applications such as waste transmutation, radioisotope production and safety research on sub-critical systems. In this respect, the MYRRHA system should become a new major research infrastructure for the European partners presently involved in the ADS Demo development, supporting and enabling the international R and D programs. Ion Beam Applications, the Belgium world leader in particle accelerators, had joined the MYRRHA Project to perform the accelerator development. Currently the study and preliminary conceptual design of the MYRRHA system is going on and an intensive R and D programme is conducted to assess the most risky points of the present design. This study will define the final choice of the characteristics of the facility depending on the selected fields of application to be achieved. The MYRRHA concept, as it is today, is based on the coupling of an upgraded commercial proton accelerator with a spallation target surrounded by a subcritical neutron-multiplying medium. Its design is determined by the versatility m applications that should be made possible. Further technical and/or strategic developments of the project might change the concept. A cyclotron, based on positive ion acceleration technology brings the protons up to an energy level of 350 MeV. The nominal current is 5 mA of protons. The spallation target system consists in a circuit with, at the upper part, a free

  17. Inherent Safety Features and Passive Prevention Approaches for Pb/Bi-cooled Accelerator-Driven Systems

    CARLSSON Johan

    2003-01-01

    This thesis is devoted to the investigation of passivesafety and inherent features of subcritical nucleartransmutation systems - accelerator-driven systems. The generalobjective of this research has been to improve the safetyperformance and avoid elevated coolant temperatures inworst-case scenarios like unprotected loss-of-ow accidents,loss-of-heat-sink accidents, and a combination of both theseaccident initiators. The specific topics covered are emergencydecay heat removal by reactor vessel ...

  18. Neutronic and burnup studies of accelerator-driven systems dedicated to nuclear waste transmutation

    Tucek, Kamil

    2004-01-01

    Partitioning and transmutation of plutonium, americium, and curium is inevitable if the radiotoxic inventory of spent nuclear fuel is to be reduced by more than a factor of 100. But, admixing minor actinides into the fuel severely degrades system safety parameters, particularly coolant void reactivity, Doppler effect, and (effective) delayed neutron fractions. The incineration process is therefore envisioned to be carried out in dedicated, accelerator-driven sub-critical reactors (ADS). Howev...

  19. System and safety studies of accelerator driven transmutation systems

    The research on safety of Accelerator-Driven Transmutation Systems (ADS) at the department has been focused on: a) ADS core design and development of advanced nuclear fuel optimised for high transmutation rates and good safety features; b) analysis of ADS-dynamics c) computer code and nuclear data development relevant for simulation and optimization of ADS; d) participation in ADS experiments including 1 MW spallation target manufacturing, subcritical experiments MUSE (CEA-Cadarache). Moreover, during the reporting period the EU-project 'IABAT', co-ordinated by the department has been finished and 4 other projects have been initiated in the frame of the 5th European Framework Programme. Most of the research topics reported in this paper are referred to appendices, which have been published in the open literature. The topics, which are not yet published, are described here in more details

  20. The physics design of accelerator-driven transmutation systems

    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

  1. Application of gas-cooled Accelerator Driven System (ADS) transmutation devices to sustainable nuclear energy development

    Abánades, A.; Garcia Hernandez, Carlos Rafael; GARCÍA FAJARDO, LAURA; Escrivá, A.; Pérez-Navarro Gómez, Ángel; Rosales, J.

    2011-01-01

    The conceptual design of a pebble bed gas-cooled transmutation device is shown with the aim to evaluate its potential for its deployment in the context of the sustainable nuclear energy development, which considers high temperature reactors for their operation in cogeneration mode, producing electricity, heat and Hydrogen. As differential characteristics our device operates in subcritical mode, driven by a neutron source activated by an accelerator that adds clear safety advantages and fuel f...

  2. Application of gas-cooled Accelerator Driven System (ADS) transmutation devices to sustainable nuclear energy development

    Abánades Velasco, Alberto; C. García; García, L.; Escrivá, A.; Pérez-Navarro, A.; Rosales, J.

    2011-01-01

    The conceptual design of a pebble bed gas-cooled transmutation device is shown with the aim to evaluate its potential for its deployment in the context of the sustainable nuclear energy development, which considers high temperature reactors for their operation in cogeneration mode, producing electricity, heat and Hydrogen. As differential characteristics our device operates in subcritical mode, driven by a neutron source activated by an accelerator that adds clear safety advantages and fu...

  3. System and safety studies of accelerator driven transmutation systems

    Gudowski, W.; Wallenius, J.; Tucek, K.; Eriksson, Marcus; Carlsson, Johan; Seltborg, P.; Cetnar, J. [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Nuclear and Reactor Physics

    2001-05-01

    The research on safety of Accelerator-Driven Transmutation Systems (ADS) at the department has been focused on: a) ADS core design and development of advanced nuclear fuel optimised for high transmutation rates and good safety features; b) analysis of ADS-dynamics c) computer code and nuclear data development relevant for simulation and optimization of ADS; d) participation in ADS experiments including 1 MW spallation target manufacturing, subcritical experiments MUSE (CEA-Cadarache). Moreover, during the reporting period the EU-project 'IABAT', co-ordinated by the department has been finished and 4 other projects have been initiated in the frame of the 5th European Framework Programme. Most of the research topics reported in this paper are referred to appendices, which have been published in the open literature. The topics, which are not yet published, are described here in more details.

  4. FZK proposal on transient benchmark in accelerator driven transmuter

    The benchmark should help to understand the behavior of a subcritical system with external source under transient conditions. It should allow to test and compare available methods and codes; include the knowledge base gained by experiments. The benchmark should be largely flexible, starting from simple configurations and transients up to comprehensive dynamics problems. It should help improving the description of transient and accident related phenomena in an ADS. General proposals on transient benchmark in accelerator driven transmuter are described. Select one or more systems to be analysed in details: solid and movable (molten salt) fuel systems; oxide, nitride, and other fuels for the solid option; Pb/I, Pb, Na coolants for the solid option; Pu+MA, LWR Pu, introduction of Th, other fuels; ADS and critical reactors; small (k-eff>0.97), very small (>0.99) or large deviations from k=1; intermediate, small, large reactor. Select types type of analyses: transient, static (reactivity coefficients, power peak factors), MA incineration rate calculations. In the transient case select: unprotected (no Control Rod, constant beam power) reactivity transients: benchmark exercise, investigation of the influence of the subcriticality level, other types of analyses. The investigation of dynamics of the ADS could be structured as short time-scale and long time-scale. Study of the ADT with dedicated fuels and cores is proposed including the safety aspects. Benchmark cores and fuels are defined. Spec-time kinetics of subcritical ADS should be recalculated. ADS/critical reactor behaviour and point kinetics should be included

  5. Laser-driven electron accelerators

    The following possibilities are discussed: inverse free electron laser (wiggler accelerator); inverse Cerenkov effect; plasma accelerator; dielectric tube; and grating linac. Of these, the grating acceleraton is considered the most attractive alternative

  6. Advanced Computational Models for Accelerator-Driven Systems

    In the nuclear engineering scientific community, Accelerator Driven Systems (ADSs) have been proposed and investigated for the transmutation of nuclear waste, especially plutonium and minor actinides. These fuels have a quite low effective delayed neutron fraction relative to uranium fuel, therefore the subcriticality of the core offers a unique safety feature with respect to critical reactors. The intrinsic safety of ADS allows the elimination of the operational control rods, hence the reactivity excess during burnup can be managed by the intensity of the proton beam, fuel shuffling, and eventually by burnable poisons. However, the intrinsic safety of a subcritical system does not guarantee that ADSs are immune from severe accidents (core melting), since the decay heat of an ADS is very similar to the one of a critical system. Normally, ADSs operate with an effective multiplication factor between 0.98 and 0.92, which means that the spallation neutron source contributes little to the neutron population. In addition, for 1 GeV incident protons and lead-bismuth target, about 50% of the spallation neutrons has energy below 1 MeV and only 15% of spallation neutrons has energies above 3 MeV. In the light of these remarks, the transmutation performances of ADS are very close to those of critical reactors.

  7. Macroscopic multigroup constants for accelerator driven system core calculation

    The high-level wastes stored in facilities above ground or shallow repositories, in close connection with its nuclear power plant, can take almost 106 years before the radiotoxicity became of the order of the background. While the disposal issue is not urgent from a technical viewpoint, it is recognized that extended storage in the facilities is not acceptable since these ones cannot provide sufficient isolation in the long term and neither is it ethical to leave the waste problem to future generations. A technique to diminish this time is to transmute these long-lived elements into short-lived elements. The approach is to use an Accelerator Driven System (ADS), a sub-critical arrangement which uses a Spallation Neutron Source (SNS), after separation the minor actinides and the long-lived fission products (LLFP), to convert them to short-lived isotopes. As an advanced reactor fuel, still today, there is a few data around these type of core systems. In this paper we generate macroscopic multigroup constants for use in calculations of a typical ADS fuel, take into consideration, the ENDF/BVI data file. Four energy groups are chosen to collapse the data from ENDF/B-VI data file by PREPRO code. A typical MOX fuel cell is used to validate the methodology. The results are used to calculate one typical subcritical ADS core. (author)

  8. Design windows for accelerator driven pebble-bed transmutators

    Nuclear waste transmutation can be achieved by different strategies. In this paper, the studies are focused in the 'Once Through' scenario, consisting in the nuclear waste transmutation until a maximum burnup (BU) is achieved. After transmutation, the fuel elements can be disposed in a Deep Storage Facility (DSF.) The main advantage of this strategy is that only one reprocess step is necessary. The drawback of this strategy consists mainly in the need of a fuel element design capable of withstanding very high burn-ups. It has been demonstrated that pebbles fuel elements in a pebble bed reactor design can withstand 700 MWd/Kg BU. This reactor presents the possibility of attainment different neutron spectrum with different fuel element designs, presents good safety characteristics, and the possibility of replacing the fuel elements easily inside the reactor (necessary for recycling strategies.) The transmutation process can be achieved in two steps. The first one, as a critical reactor, and the second one, as a subcritical assembly driven by an accelerator. In this paper, the optimum spectrum for the 'Once Through' strategy is presented, and some safety characteristics of the subcritical assembly are introduced. (authors)

  9. Design of an accelerator-driven system for the destruction of nuclear waste

    Progress in particle accelerator technology makes it possible to use a proton accelerator to produce energy and to destroy nuclear waste efficiently. The Energy Amplifier (EA) proposed by Carlo Rubbia and his group is a sub-critical fast neutron system driven by a proton accelerator. It is particularly attractive for destroying, through fission, transuranic elements produced by present nuclear reactors. The EA could also transform efficiently and at minimal cost long-lived fission fragments using the concept of Adiabatic Resonance Crossing (ARC) recently tested at CERN with the TARC experiment. (author)

  10. A study of the transmutation performance of externally driven sub-critical assemblies

    For transmutation systems based on externally driven sub-critical assemblies with a fast neutron spectrum, there is an incentive to expose the actinides directly to the source neutrons, since these neutrons have higher energies than the fission neutrons. To evaluate the transmutation effectiveness of such systems, a parameter study based on the PHOENIX system, i.e. a sodium-cooled system with a minor actinide (MA) oxide fuelled target was performed. An interesting result is that the high-energy source neutrons give rise to a 20-25% increase in the fission-to-capture ratio of the important (fissionable) nuclides. Moreover, the performance of such a system can be further improved by substituting the oxide fuel by metal fuel and by reducing the volume fraction of steel in the target. Replacing the liquid sodium coolant by liquid lead has only a small effect on the fission-to-capture ratio, however, for a given proton current, the neutron production in the target increases. 17 refs., 5 tabs., 2 figs

  11. The Physics Design for a Fusion Driven Sub-critical System

    Bin, Wu

    2002-11-01

    The Fusion Driven Sub-critical System (FDS) is a sub-critical nuclear energy system drive by fusion neutron source, which provides a feasible, safe, economic and highly efficient potential of disposing High Level Waste (HLW) and produce fission nuclear fuel as a early application of fusion technology. This paper reviews the past physics reactor design of fusion-fission hybrid reactor in China, and a low aspect ratio tokamak energy system that has been proposed, which aims at high β, good confinement, and steady-state operation in a compact configuration at modest field. The system includes a low aspect ratio tokamak as fusion neutron driver, a radioactivity clean nuclear power system as blanket and novel concept of liquid metal conductor as centre conductor post. Parameters of such kind reactor are the following. Major radius 1.4m, Minor radius 1m, plasma current 9.2MA, Toroidal field 2.5T, Plasma edge q=5, Average density 1.6 10^20m^3, Average temperature 10keV, Plasma volume 50m^3, Bootstrap current fraction 0.72, Fusion power 100MW, Drive power 28MW, Neutron wall loading 1.0MW/m-2. The plasma configuration is an important part in the low-A tokamak. The Eq code has been used to get a equilibrium. From this calculation, we have found a simple set of PF coils that satisfies the requirements of the large elongation plasma configuration and a vertical field with less curve field lines in the low-A tokamak. The natural elongation can be attributed mostly to differences in the current density profile. In order to determine the feasibility of the low-A tokamak operation, a transient simulation has been made which includes the equilibrium, transport and plasma position shape control in the low-A tokamak. A 1-1/2 equilibrium evolution code has been used to make this simulation. The code is two-dimensional time dependent free boundary simulation code that advances the MHD equations describing the transport time-scale evolution of a axisymmetric tokamak plasma.

  12. Progress of Laser-Driven Plasma Accelerators

    There is a great interest worldwide in plasma accelerators driven by ultra-intense lasers which make it possible to generate ultra-high gradient acceleration and high quality particle beams in a much more compact size compared with conventional accelerators. A frontier research on laser and plasma accelerators is focused on high energy electron acceleration and ultra-short X-ray and Tera Hertz radiations as their applications. These achievements will provide not only a wide range of sciences with benefits of a table-top accelerator but also a basic science with a tool of ultrahigh energy accelerators probing an unknown extremely microscopic world.Harnessing the recent advance of ultra-intense ultra-short pulse lasers, the worldwide research has made a tremendous breakthrough in demonstrating high-energy high-quality particle beams in a compact scale, so called ''dream beams on a table top'', which represents monoenergetic electron beams from laser wakefield accelerators and GeV acceleration by capillary plasma-channel laser wakefield accelerators. This lecture reviews recent progress of results on laser-driven plasma based accelerator experiments to quest for particle acceleration physics in intense laser-plasma interactions and to present new outlook for the GeV-range high-energy laser plasma accelerators

  13. IAEA coordinated research project (CRP) on 'Analytical and experimental benchmark analyses of accelerator driven systems'

    In December 2005, the International Atomic Energy Agency (IAEA) has started a Coordinated Research Project (CRP) on 'Analytical and Experimental Benchmark Analyses of Accelerator Driven Systems'. The overall objective of the CRP, performed within the framework of the Technical Working Group on Fast Reactors (TWGFR) of IAEA's Nuclear Energy Department, is to increase the capability of interested Member States in developing and applying advanced reactor technologies in the area of long-lived radioactive waste utilization and transmutation. The specific objective of the CRP is to improve the present understanding of the coupling of an external neutron source (e.g. spallation source) with a multiplicative sub-critical core. The participants are performing computational and experimental benchmark analyses using integrated calculation schemes and simulation methods. The CRP aims at integrating some of the planned experimental demonstration projects of the coupling between a sub-critical core and an external neutron source (e.g. YALINA Booster in Belarus, and Kyoto University's Critical Assembly (KUCA)). The objective of these experimental programs is to validate computational methods, obtain high energy nuclear data, characterize the performance of sub-critical assemblies driven by external sources, and to develop and improve techniques for sub-criticality monitoring. The paper summarizes preliminary results obtained to-date for some of the CRP benchmarks. (authors)

  14. Development and analysis of a metal-fueled accelerator-driven burner

    Lypsch, F. [Institute for Safety Research and Reactor Technology, Juelich GmbH (Germany); Hill, R.N. [Argonne National Lab., IL (United States)

    1994-08-01

    The purpose of this paper is to compare the safety characteristics of an accelerator driven metal fueled fast system to a critical core on a consistent basis to determine how these characteristics are affected solely by subcritically of the system. To accomplish this an accelerator proton beam/tungsten neutron source model is surrounded by a subcritical blanket using metallic fuel and sodium as coolant. The consequences of typical accident transients, namely unprotected transient overpower (TOP), loss of heat sink (LOHS), and loss of flow (LOP) were calculated for the hybrid system and compared to corresponding results for a metal-fueled fast reactor. Results indicate that the subcritical system exhibits superior performance for TOP (reactivity-induced) transits; however, only in the critical system are reactivity feedbacks able to cause passive shutdown in the LOHS ad LOP events. Therefore, for a full spectrum of accident initiators considered, the overall safety behavior of accelerator-driven metal-fueled systems can neither be concluded to be worse nor to be better than advanced reactor designs which rely on passive safety features.

  15. Subcritical set coupled to accelerator (ADS) for transmutation of radioactive wastes: an approach of computational modelling

    Nuclear fission devices coupled to particle accelerators ADS are being widely studied. These devices have several applications, including nuclear waste transmutation and producing hydrogen, both applications with strong social and environmental impact. The essence of this work was to model an ADS geometry composed of small TRISO fuel loaded with a mixture of MOX uranium and thorium target material spallation of uranium, using methods of computational modeling probabilistic, in particular the MCNPX 2.6e program to evaluate the physical characteristics of the device and their ability to transmutation. As a result of the characterization of the spallation target, it can be concluded that production of neutrons per incident proton increases with increasing dimensions of the spallation target (thickness and radius), until it reached the maximum production of neutrons per incident proton or call the region saturation. The results obtained in modeling the ADS device bed kind of balls with respect to isotopic variation in the isotopes of plutonium and minor actinides considered in the analysis revealed that accumulation of mass of the isotopes of plutonium and minor actinides increase for subcritical configuration considered. In the particular case of the isotope 239Pu, it is observed a reduction of the mass from the time of burning of 99 days. The increase of power in the core, whereas tungsten spallation targets and Lead is among the key future developments of this work

  16. Study of characteristics Of An experimental subcritical nuclear fuel assembly driven by the 660 MeV phasotron

    An experimental subcritical spallation nuclear fuel assembly (SAD) driven by a 660 MeV proton phasotron is describe in brief. Such a facility is planed to be built at, the Joint Institute for Nuclear Research (Dubna). It consists of a spallation interchangeable target (W and Pb), a subcritical core based on MOX fuel elements (0.297 PuO2+0.703 UO2), lead reflector and concrete shielding, Spallation neutrons are to be produced by the proton beam in a multilayer target (W, Pb). The research program intends to elaborate optimal parameters of a facility dedicated to the safe and efficient energy production together with transmutation and incineration of long-lived radioactive nuclides (LLRN), For this reason studied are, in particular, the following main characteristics of SAD: neutron and proton spectra for different spallation materials and target geometry, heat distribution, transmutation rates of LLRN and energy gain

  17. Weapon plutonium in accelerator driven power system

    The purpose and problems of the research - creation of a safe and reliable ADS for processing of about 25 tons of weapons plutonium in 30 years on the basis of a proton-accelerator with energies 0.8-1.2 GeV and a current of 10-30 mA; liquid Pb/Bi eutectic targets; one-directionally coupled fast/thermal blanket with plutonium fuel. The approach to weapons-Pu utilization is based on the understanding of the unconditional priority of safety features of ADS over economic considerations and, accordingly, on the priority of subcritical systems over critical. The description of a variant of ADS from the point of view of possibilities of its realization in an acceptable period of time on the base of approbated technologies is presented here. 7 refs., 4 figs., 1 tab

  18. Technology of magnetically driven accelerators

    The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approaching 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability. 8 figs., 1 tab

  19. Diagnostics for laser-driven plasma accelerators

    When generating relativistic plasmas with high power laser systems small-scale particle accelerators can be realized producing particle pulses which exhibit parameters complementary to conventional accelerators. To be able to resolve the physical processes underlying the acceleration mechanisms diagnostics well-suited for this plasma environment need to be designed and realized. In this presentation, several techniques are introduced, and recent results are discussed. They have lead to the first time-resolved visualization of the plasma wave necessary for laser-driven electron acceleration, its non-linear evolution and the actual breaking of the plasma wave. Furthermore, diagnostic techniques relevant for laser-driven ion acceleration based on optical and particle probing are presented.

  20. Preliminary physics design of accelerator-driven thorium cycle fast breeder reactor

    A preliminary reactor physics design of a lead cooled fast accelerator-driven system has been explored as a thorium-uranium cycle breeder reactor. The sub-critical reactor core operates at an effective neutron multiplication factor of 0.95 and when driven by 1 GeV proton beams of intensity 30 mA, produces about ∼ 900 MWth power. Variation of total thermal power, 233U inventory, Keff, radial and axial power distribution through the operating cycle as well as breeding ratio and doubling time are presented. (author)

  1. Weapon plutonium in accelerator driven power system

    Accelerator Driven Systems are planned to be developed for the use (or destruction) of dozens of tons of weapon-grade Plutonium (W-Pu) resulted from the reducing of nuclear weapons. In the paper are compared the parameters of various types of accelerators, the physical properties of various types of targets and blankets, and the results of fuel cycle simulation. Some economical aspects are also discussed

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

    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

  3. Proton-driven plasma-wakefield acceleration

    Caldwell, Allen; Pukhov, Alexander; Simon, Frank

    2013-01-01

    Plasmas excited by laser beams or bunches of relativistic electrons have been used to produce electric fields of 10–100 GV m$^{-1}$. This has opened up the possibility of building compact particle accelerators at the gigaelectronvolt scale. However, it is not obvious how to scale these approaches to the energy frontier of particle physics—the teraelectronvolt regime. Here, we introduce the possibility of proton-bunch-driven plasma-wakefield acceleration, and demonstrate through numerical simulations that this energy regime could be reached in a single accelerating stage.

  4. IAEA activities on accelerator-driven systems

    A brief account is given of the following IAEA programmes and events: Special Scientific Programme on 'Use of High Energy Accelerators for Transmutation of Actinides and Power Production'; Status report on actinide and fission product transmutation studies; Accelerator-driven systems: energy generation and transmutation of nuclear waste (status report); Coordinated Research Programme on the Use of Thorium-based Fuel Cycle in Accelerator Driven Systems to Incinerate Plutonium and to Reduce Long-term Waste Toxicities; Technical Committee Meeting on 'Feasibility and Motivation for Hybrid Concepts for Nuclear Energy Generation and Transmutation'; Data-base on experimental facilities and computer codes for ADS related research and development; Co-ordinated Research Project (CRP) on Safety, Environmental and Non-Proliferation Aspects of Partitioning and Transmutation of Actinides and Long-lived Fission Products. (P.A.)

  5. MYRRHA, a multipurpose accelerator driven system for research and development. February 2003 Progress status

    SCK-CEN in partnership with IBA s.a. is designing a 40 MWth multipurpose ADS (Accelerator Driven System) for R and D applications - MYRRHA - driven by a proton accelerator delivering a 1.75 MW beam (350 MeV x 5 mA). The spallation target is made of liquid Pb-Bi with a windowless concept in an isolated circuit from the sub-critical core coolant circuit. The sub-critical core is made out of typical fast reactor MOX fuel with a total Pu content limited to 30% in weight. The primary coolant chosen for the core is also liquid Pb-Bi. SCK CEN is conducting an associated R and D support programme for alleviating the most demanding topics as regards to the proposed design. In the first stage, the project focuses mainly on demonstration of the ADS concept and safety research on sub-critical hybrid systems. In a later stage, the device will also be used as an irradiation facility for research on structural materials, nuclear fuel, liquid metals and associated aspects and on sub-critical reactor physics. Subsequently, it will be used for research on applications such as nuclear waste transmutation and radioisotope production. The MYRRHA system is expected to become a major research infrastructure for the European partners involved in the ADS Demo development. The preliminary conceptual design of MYRRHA will be completed at the fall of 2003 and an intensive R and D programme is established. In this paper we will be presenting the MYRRHA concept and will report on the status of the MYRRHA project at the end of 2002 and on the methods and results of the R and D support programme presently conducted at SCK-CEN with a series of partners. (author)

  6. Development of Three-dimensional Reactor Analysis Code System for Accelerator-Driven System, ADS3D

    To investigate an Accelerator-Driven System (ADS) with sub-criticality control mechanism such as control rods or burnable poison, the ADS3D code has been developed on MARBLE which is a next generation reactor analysis code system developed by JAEA. In the past neutronics calculation for the ADS, JAEA employed RZ calculation models to realize efficient investigations. However, it was very difficult to model sub-criticality control mechanisms in RZ calculation models. The ADS3D code system is able to calculate the transportation of protons and neutrons, the burn-up calculation and the fuel exchange in three-dimensional calculation models. It means this code system can treat ADS concepts with sub-criticality control mechanism and makes it possible to investigate a new concept of ADS. (author)

  7. Cosmic acceleration driven by mirage inhomogeneities

    A cosmological model based on an inhomogeneous D3-brane moving in an AdS5 x S5 bulk is introduced. Although there are no special points in the bulk, the brane universe has a centre and is isotropic around it. The model has an accelerating expansion and its effective cosmological constant is inversely proportional to the distance from the centre, giving a possible geometrical origin for the smallness of a present-day cosmological constant. Besides, if our model is considered as an alternative of early-time acceleration, it is shown that the early stage accelerating phase ends in a dust-dominated FRW homogeneous universe. Mirage-driven acceleration thus provides a dark matter component for the brane universe final state. We finally show that the model fulfils the current constraints on inhomogeneities

  8. Photonic Crystal Laser-Driven Accelerator Structures

    Cowan, Benjamin M.

    2007-08-22

    Laser-driven acceleration holds great promise for significantly improving accelerating gradient. However, scaling the conventional process of structure-based acceleration in vacuum down to optical wavelengths requires a substantially different kind of structure. We require an optical waveguide that (1) is constructed out of dielectric materials, (2) has transverse size on the order of a wavelength, and (3) supports a mode with speed-of-light phase velocity in vacuum. Photonic crystals---structures whose electromagnetic properties are spatially periodic---can meet these requirements. We discuss simulated photonic crystal accelerator structures and describe their properties. We begin with a class of two-dimensional structures which serves to illustrate the design considerations and trade-offs involved. We then present a three-dimensional structure, and describe its performance in terms of accelerating gradient and efficiency. We discuss particle beam dynamics in this structure, demonstrating a method for keeping a beam confined to the waveguide. We also discuss material and fabrication considerations. Since accelerating gradient is limited by optical damage to the structure, the damage threshold of the dielectric is a critical parameter. We experimentally measure the damage threshold of silicon for picosecond pulses in the infrared, and determine that our structure is capable of sustaining an accelerating gradient of 300 MV/m at 1550 nm. Finally, we discuss possibilities for manufacturing these structures using common microfabrication techniques.

  9. Linear accelerator driven (LADR) and regenerative reactors (LARR) for nuclear non-proliferation

    Linear accelerator breeders (LAB) could be used to produce fissile fuel in two modes, either with fuel reprocessing or without fuel reprocessing. With fuel reprocessing, the fissile material would be separated from the target and refabricated into a fuel element for use in a burner power reactor. Without reprocessing, the fissile material would be produced in-situ, either in a fresh fuel element or in a depleted or burned element after use in a power reactor. In the latter mode the fissile material would be increased in concentration for reuse in a power reactor. This system is called a Linear Accelerator Regenerative Reactor (LARR). The LAB can also be conceived of operating in a power production mode in which the spallation neutrons would be used to drive a subcritical assembly to produce power. This is called a Linear Accelerator Driven Reactor (LADR). A discussion is given of the principles and some of the technical problems of both types of accelerator breeders

  10. Thorium fuel cycle concept for KAERI's accelerator driven system project

    Korea Atomic Energy Research Institute (KAERI) has been carrying out accelerator driven system related research and development called HYPER for transmutation and energy production. HYPER program is aiming to develop the elemental technologies for the subcritical system by 2001 and build a small bench scale test facility (∼5MW(th)) by the year 2006. Some major features of HYPER have been developed and employed, which are on-power fueling concepts, a hollow cylinder-type metal fuel, and Pb-Bi as a coolant and spallation target material. Another fuel cycle concept for HYPER has been also studied to utilize thorium as a molten salt form to produce electricity as well as to transmute TRU elements. At the early stage of the fuel cycle, fissile plutonium isotopes in TRU will be incinerated to produce energy and to breed 233U from thorium. Preliminary calculation showed that periodic removal of fission products and small amount of TRU addition could maintain the criticality without separation of 233Pa. At the end of the fuel cycle, the composition of fissile plutonium isotopes in TRU was significantly reduced from about 60% to 18%, which is not attractive any more for the diversion of plutonium. Thorium molten salt fuel cycle may be one of the alternative fuel cycles for the transmutation of TRU. The TRU remained at the end of fuel cycle can be incinerated in HYPER having fast neutron spectrums. (author)

  11. Update on Proton Driven Plasma Wakefield Acceleration

    Xia, G; Lotov, K; Pukhov, A; Kumar, N; An, W; Lu, W; Mori, W B; Joshi, C; Huang, C; Muggli, P; Assmann, R; Zimmermann, F

    2010-01-01

    In this paper, the update of proton driven plasma wakefield acceleration (PDPWA) is given. After a brief introduction to the scheme of PDPWA, a future demonstration experiment is discussed. The particle-in-cell simulation results based on the realistic proton beams from the CERN Super Proton Synchrotron (SPS) are presented, followed by a simulation study of proton bunch compression. Presented at AAC’10, 13-19 June 2010, Annapolis, MD, USA

  12. Spike avalanches in vivo suggest a driven, slightly subcritical brain state

    Viola Priesemann

    2014-06-01

    Our results suggest that neural activity in vivo shows a mélange of avalanches, and not temporally separated ones, and that their global activity propagation can be approximated by the principle that one spike on average triggers a little less than one spike in the next step. This implies that neural activity does not reflect a SOC state but a slightly sub-critical regime without a separation of time scales. Potential advantages of this regime may be faster information processing, and a safety margin from super-criticality, which has been linked to epilepsy.

  13. Thorium utilization in heavy water moderated Accelerator Driven Systems

    much more realistic option, since it gives us a good gain with heavy water as coolant and even with light water cooled heavy water moderated reactor, the gain is somewhat lower, but still acceptable. We show that the self sustaining cycle for a critical system gives rather low discharge burnup. To obtain higher burnup, the critical reactor needs an external feed of fissile material. We show that the accelerator driven sub-critical mode of operation gives acceptable burnup in a self sustaining cycle. (author)

  14. A Fusion Neutron Source Driven Sub-Critical Nuclear Energy System: A Way for Early Application of Fusion Technology

    吴宜灿

    2001-01-01

    This paper proposes a sub-critical nuclear energy system driven by fusion neutron source, FDS, which can be used to transmute long-lived radioactive wastes and to produce fissile nuclear fuel as a way for early application of fusion technology. The necessity and feasibility to develop that system in China are illustrated on the basis of prediction of the demand of energy source in the first half of the 21th century, the status of current fission energy supply and the progress in fusion technology in the vorld. The characteristics of fusion neutron driver and the potential for transmutation of long-lived nuclear wastes and breeding of fissile nuclear fuel in a blanket are analyzed. A scenario of development steps is proposed.``

  15. Designing of the laser driven dielectric accelerator

    A phase-modulation-masked-type laser-driven dielectric accelerator was studied. Although the preliminary analysis made a conclusion that a grating period and an electron speed must satisfy the matching condition of LG=λ=v=c, a deformation of a wavefront in a transmission grating relaxed the matching condition and enabled the slow electron to be accelerated. The simulation results by using the FDTD code, Meep, showed that the low energy electron of 20 keV felt the acceleration field strength of 20 MV/m and gradually felt higher field as the speed was increased. The ultra relativistic electron felt the field strength of 600 MV/m. The Meep code also showed that a length of the accelerator to get energy of 1 MeV was 3.8 mm, the required laser power and energy were 11 GW and 350 mJ, respectively. Restrictions on the laser was eased by adopting sequential laser pulses. If the accelerator is illuminated by sequential N pulses, the pulse power, pulse width and the pulse energy are reduced to 1=N, 1=N and 1=N2, respectively. The required laser power per pulse is estimated to be 2.2 GW when ten pairs of sequential laser pulse is irradiated. (author)

  16. Accelerator-Driven System with Current Technology

    World needs a safer and cleaner nuclear power plant. A nuclear power plant that will not cause a disaster and that will produce radiotoxic nuclear waste as small as possible. At the moment, the closest system is the accelerator driven system (ADS) making use of the Thorium fuel. First of all, it is safer in a disaster such as an earthquake, because the deriving accelerator stops immediately by the earthquake. And, there won't be a Fukushima-like accident, because this Thorium ADS reactor uses air cooling. It also minimizes the nuclear waste problem by reducing the amount of the toxic waste and shortening their half lifetime to only a few hundred years. Finally, it solves the Uranium reserve problem. The Thorium reserve is much larger than that of Uranium. Although the idea of ADS was proposed long time ago, it has not been utilized yet first by technical difficulty of accelerator. The accelerator-based system needs 0.6-1 GeV and at least a few MW power proton beam, which is an unprecedentedly high power. The most powerful 1 GeV proton linear accelerator is the Spallation Neutron Source, USA, which operates now at the power of 1.5 MW with the length of 350 m. A conventional linear accelerator would need several hundred m length, which is highly costly particularly in Korea because of the high land cost. Another difficulty is reliability of accelerator operation. To be used as a power plant facility, accelerator should obviously operate such that the power plant may continuously generate electricity at least for months with no interruption. However, the reality is that a high power proton accelerator is hardly operated even a few hours without interruption, although very short interruptions are tolerable. Anyway, it will take a time to develop an accelerator sufficiently reliable to be used for power generation. Now the question is if it is possible to realize ADS with the current level of accelerator technology. This paper seeks the possibility

  17. Accelerator-Driven System with Current Technology

    Lee, Hee Seok; Lee, Tae Yeon [Pohang Accelerator Laboratory, Pohang (Korea, Republic of)

    2013-10-15

    World needs a safer and cleaner nuclear power plant. A nuclear power plant that will not cause a disaster and that will produce radiotoxic nuclear waste as small as possible. At the moment, the closest system is the accelerator driven system (ADS) making use of the Thorium fuel. First of all, it is safer in a disaster such as an earthquake, because the deriving accelerator stops immediately by the earthquake. And, there won't be a Fukushima-like accident, because this Thorium ADS reactor uses air cooling. It also minimizes the nuclear waste problem by reducing the amount of the toxic waste and shortening their half lifetime to only a few hundred years. Finally, it solves the Uranium reserve problem. The Thorium reserve is much larger than that of Uranium. Although the idea of ADS was proposed long time ago, it has not been utilized yet first by technical difficulty of accelerator. The accelerator-based system needs 0.6-1 GeV and at least a few MW power proton beam, which is an unprecedentedly high power. The most powerful 1 GeV proton linear accelerator is the Spallation Neutron Source, USA, which operates now at the power of 1.5 MW with the length of 350 m. A conventional linear accelerator would need several hundred m length, which is highly costly particularly in Korea because of the high land cost. Another difficulty is reliability of accelerator operation. To be used as a power plant facility, accelerator should obviously operate such that the power plant may continuously generate electricity at least for months with no interruption. However, the reality is that a high power proton accelerator is hardly operated even a few hours without interruption, although very short interruptions are tolerable. Anyway, it will take a time to develop an accelerator sufficiently reliable to be used for power generation. Now the question is if it is possible to realize ADS with the current level of accelerator technology. This paper seeks the possibility.

  18. Accelerator-driven X-ray Sources

    Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-09

    After an introduction which mentions x-ray tubes and storage rings and gives a brief review of special relativity, the subject is treated under the following topics and subtopics: synchrotron radiation (bending magnet radiation, wiggler radiation, undulator radiation, brightness and brilliance definition, synchrotron radiation facilities), x-ray free-electron lasers (linac-driven X-ray FEL, FEL interactions, self-amplified spontaneous emission (SASE), SASE self-seeding, fourth-generation light source facilities), and other X-ray sources (energy recovery linacs, Inverse Compton scattering, laser wakefield accelerator driven X-ray sources. In summary, accelerator-based light sources cover the entire electromagnetic spectrum. Synchrotron radiation (bending magnet, wiggler and undulator radiation) has unique properties that can be tailored to the users’ needs: bending magnet and wiggler radiation is broadband, undulator radiation has narrow spectral lines. X-ray FELs are the brightest coherent X-ray sources with high photon flux, femtosecond pulses, full transverse coherence, partial temporal coherence (SASE), and narrow spectral lines with seeding techniques. New developments in electron accelerators and radiation production can potentially lead to more compact sources of coherent X-rays.

  19. Accelerator driven systems for transmutation and energy production: challenges and dangers

    Accelerator driven systems (ADS) are an old technological idea: relativistic proton accelerators deliver their beams onto massive heavy element targets, thus producing abundant neutron fluences. Placing this target into sub-critical nuclear fission assemblies is yielding substantial fission reactions, thus additional fission energy (Rubbia called such a system ''energy amplifier''). This technology has recently attracted considerable attention due to advances in the construction of powerful accelerators. It allows the safe and cheap production of nuclear energy simultaneously with the destruction (transmutation) of long lived radioactive waste, in particular plutonium and other minor actinides (neptunium and americium). The principles and the present-state-of-the-art are described, including first experiments to transmute plutonium this way. This technology needs, however, many more years of further ''research and development'' before large scale ADS's can be constructed. It may be even necessary to investigate the question, if all basic physics phenomena of this technology are already sufficiently well understood. (orig.)

  20. Analytical benchmarks for the kinetics of accelerator-driven systems

    The work presented in this paper illustrates the analytical benchmark philosophy with applications to subcritical source-driven system dynamics. Results for different complexity problems are presented in the frame of multigroup diffusion theory. The analysis performed on systems having physical characteristics typical of the Yalina Booster experiment are presented. The comparisons with the results of numerical calculations enlighten the convergence trend of discretized schemes and the limits of applicability to the analysis of experiments. (authors)

  1. Experimental study of subcritical laboratory magnetized collisionless shocks using a laser-driven magnetic piston

    Schaeffer, D. B., E-mail: dschaeffer@physics.ucla.edu; Everson, E. T.; Bondarenko, A. S.; Clark, S. E.; Constantin, C. G.; Gekelman, W.; Niemann, C. [Department of Physics and Astronomy, University of California—Los Angeles, Los Angeles, California 90095 (United States); Winske, D. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2015-11-15

    Recent experiments at the University of California, Los Angeles have successfully generated subcritical magnetized collisionless shocks, allowing new laboratory studies of shock formation relevant to space shocks. The characteristics of these shocks are compared with new data in which no shock or a pre-shock formed. The results are consistent with theory and 2D hybrid simulations and indicate that the observed shock or shock-like structures can be organized into distinct regimes by coupling strength. With additional experiments on the early time parameters of the laser plasma utilizing Thomson scattering, spectroscopy, and fast-gate filtered imaging, these regimes are found to be in good agreement with theoretical shock formation criteria.

  2. Experimental study of subcritical laboratory magnetized collisionless shocks using a laser-driven magnetic piston

    Recent experiments at the University of California, Los Angeles have successfully generated subcritical magnetized collisionless shocks, allowing new laboratory studies of shock formation relevant to space shocks. The characteristics of these shocks are compared with new data in which no shock or a pre-shock formed. The results are consistent with theory and 2D hybrid simulations and indicate that the observed shock or shock-like structures can be organized into distinct regimes by coupling strength. With additional experiments on the early time parameters of the laser plasma utilizing Thomson scattering, spectroscopy, and fast-gate filtered imaging, these regimes are found to be in good agreement with theoretical shock formation criteria

  3. Spike avalanches in vivo suggest a driven, slightly subcritical brain state.

    Priesemann, Viola; Wibral, Michael; Valderrama, Mario; Pröpper, Robert; Le Van Quyen, Michel; Geisel, Theo; Triesch, Jochen; Nikolić, Danko; Munk, Matthias H J

    2014-01-01

    In self-organized critical (SOC) systems avalanche size distributions follow power-laws. Power-laws have also been observed for neural activity, and so it has been proposed that SOC underlies brain organization as well. Surprisingly, for spiking activity in vivo, evidence for SOC is still lacking. Therefore, we analyzed highly parallel spike recordings from awake rats and monkeys, anesthetized cats, and also local field potentials from humans. We compared these to spiking activity from two established critical models: the Bak-Tang-Wiesenfeld model, and a stochastic branching model. We found fundamental differences between the neural and the model activity. These differences could be overcome for both models through a combination of three modifications: (1) subsampling, (2) increasing the input to the model (this way eliminating the separation of time scales, which is fundamental to SOC and its avalanche definition), and (3) making the model slightly sub-critical. The match between the neural activity and the modified models held not only for the classical avalanche size distributions and estimated branching parameters, but also for two novel measures (mean avalanche size, and frequency of single spikes), and for the dependence of all these measures on the temporal bin size. Our results suggest that neural activity in vivo shows a mélange of avalanches, and not temporally separated ones, and that their global activity propagation can be approximated by the principle that one spike on average triggers a little less than one spike in the next step. This implies that neural activity does not reflect a SOC state but a slightly sub-critical regime without a separation of time scales. Potential advantages of this regime may be faster information processing, and a safety margin from super-criticality, which has been linked to epilepsy. PMID:25009473

  4. On the use of WIMS-7 for calculations on accelerator-driven systems

    De Kruijff, W.J.M.; Freudenreich, W.J.M

    1998-02-01

    The WIMS-7 code package has successfully been applied for a simple benchmark of a lead-cooled accelerator-driven system (ADS). With WIMS-7 it is possible to model a fixed source and to calculate the multiplication in a subcritical system. The calculations have shown that WIMS-7 is capable of treating this benchmark of a homogenized lead-cooled system with a fast neutron spectrum. The results described in this report are very promising and stimulate further investigation of WIMS-7 to study ADS-applications and lead-cooled reactor cores. It is useful to have a more extensive validation of WIMS-7 for lead-cooled ADS. In this report we have only considered a simple homogenized system. In the near future the application of WIMS-7 will be twofold. First, WIMS-7 can be applied to calculate the neutron spectrum in an accelerator-driven system in order to perform transmutation studies with a burnup code. Second, WIMS-7 can be used to study in more detail the neutronics of accelerator-driven systems. This is useful in order to learn more about the physics of accelerator-driven systems. 6 refs.

  5. On the use of WIMS-7 for calculations on accelerator-driven systems

    The WIMS-7 code package has successfully been applied for a simple benchmark of a lead-cooled accelerator-driven system (ADS). With WIMS-7 it is possible to model a fixed source and to calculate the multiplication in a subcritical system. The calculations have shown that WIMS-7 is capable of treating this benchmark of a homogenized lead-cooled system with a fast neutron spectrum. The results described in this report are very promising and stimulate further investigation of WIMS-7 to study ADS-applications and lead-cooled reactor cores. It is useful to have a more extensive validation of WIMS-7 for lead-cooled ADS. In this report we have only considered a simple homogenized system. In the near future the application of WIMS-7 will be twofold. First, WIMS-7 can be applied to calculate the neutron spectrum in an accelerator-driven system in order to perform transmutation studies with a burnup code. Second, WIMS-7 can be used to study in more detail the neutronics of accelerator-driven systems. This is useful in order to learn more about the physics of accelerator-driven systems. 6 refs

  6. Laser driven proton acceleration and beam shaping

    Sinigardi, Stefano

    2014-01-01

    In the race to obtain protons with higher energies, using more compact systems at the same time, laser-driven plasma accelerators are becoming an interesting possibility. But for now, only beams with extremely broad energy spectra and high divergence have been produced. The driving line of this PhD thesis was the study and design of a compact system to extract a high quality beam out of the initial bunch of protons produced by the interaction of a laser pulse with a thin solid target, usi...

  7. Absolute reactivity calibration of accelerator-driven systems after RACE-T experiments

    The RACE-T experiments that were held in november 2005 in the ENEA-Casaccia research center near Rome allowed us to improve our knowledge of the experimental techniques for absolute reactivity calibration at either startup or shutdown phases of accelerator-driven systems. Various experimental techniques for assessing a subcritical level were inter-compared through three different subcritical configurations SC0, SC2 and SC3, about -0.5, -3 and -6 dollars, respectively. The area-ratio method based of the use of a pulsed neutron source appears as the most performing. When the reactivity estimate is expressed in dollar unit, the uncertainties obtained with the area-ratio method were less than 1% for any subcritical configuration. The sensitivity to measurement location was about slightly more than 1% and always less than 4%. Finally, it is noteworthy that the source jerk technique using a transient caused by the pulsed neutron source shutdown provides results in good agreement with those obtained from the area-ratio technique. (authors)

  8. The IAEA Co-ordinated Research Project (CRP) on 'Analytical and Experimental Benchmark Analyses of Accelerator-driven Systems'

    Document in abstract form only. Full text of publication follows: Since December 2005, the International Atomic Energy Agency (IAEA) has been conducting the Co-ordinated Research Project (CRP) on 'Analytical and Experimental Benchmark Analyses of Accelerator-driven Systems' within the framework of the Technical Working Group on Fast Reactors (TWG-FR). The overall objective of the CRP is to increase the capability of interested member states in developing and applying advanced reactor technologies in the area of long-lived radioactive waste utilisation and transmutation. The specific objective of the CRP is to improve the present understanding of the coupling of an external neutron source (e.g. spallation source) with a multiplicative subcritical core. The participants are performing computational and experimental benchmark analyses using integrated calculation schemes and simulation methods. The CRP aims at integrating some of the planned experimental demonstration projects of the coupling between a subcritical core and an external neutron source [e.g. YALINA Booster in Belarus, and Kyoto University's Critical Assembly (KUCA)]. The objective of these experimental programmes is to validate computational methods, to obtain high-energy nuclear data, to characterise the performance of subcritical assemblies driven by external sources, and to develop and improve techniques for subcriticality monitoring. With the CRP in its final year, the paper summarises, on behalf of all the participants, the status of work and preliminary CRP benchmarks results. (authors)

  9. Simulation study of an accelerator driven as a transmutation and energy generation system

    In twenty first century world is facing two issues of future concern, generation of clean energy and the protection of the environment. Oil price is soaring to a level of jeopardizing world economy and on the other hand burning fossil fuel is reaching to a point of endangering life of all creatures. The sole solution to compete the energy shortage is exploiting nuclear energy and other clean energy sources. The main concern of nuclear energy is long term radioactive waste. In principle, any nuclear reactor is able to burn and transmute minor actinides, but reactors with fast neutron spectrum must be preferred, as they allow a positive neutron gain throughout the burning process. A core dedicated to the transmutation of the minor actinides should be designed in order to minimize its self-production of actinides. A possible solution to these problems is represented by a subcritical system driven by an accelerator, which is able to safely bum and/or transmute actinides and long lived fission products, as it does not rely on delayed neutrons for control or power change and the reactivity feedbacks have only limited importance during transient response. In this study, an accelerator driven system based on Japanese design was simulated using MCNPX code to calculate neutron spectrum flux level, core sub-criticality and peaking factor

  10. Accelerator driven systems (ADS): A principal neutronics and transmutation potential

    An accelerator-based system using a beam of high energy protons to produce supplementary neutrons as a result of spallation processes in a target is investigated. The spallation neutrons are successively used to feed a subcritical blanket where they create a neutron surplus available for incineration of those long-lived toxic nuclei which require neutrons (long-lived fission products and minor actinides), and enhance the deterministic safety features for reactivity-type of accidents

  11. Accelerating Science Driven System Design With RAMP

    Wawrzynek, John [Univ. of California, Berkeley, CA (United States)

    2015-05-01

    Researchers from UC Berkeley, in collaboration with the Lawrence Berkeley National Lab, are engaged in developing an Infrastructure for Synthesis with Integrated Simulation (ISIS). The ISIS Project was a cooperative effort for “application-driven hardware design” that engages application scientists in the early parts of the hardware design process for future generation supercomputing systems. This project served to foster development of computing systems that are better tuned to the application requirements of demanding scientific applications and result in more cost-effective and efficient HPC system designs. In order to overcome long conventional design-cycle times, we leveraged reconfigurable devices to aid in the design of high-efficiency systems, including conventional multi- and many-core systems. The resulting system emulation/prototyping environment, in conjunction with the appropriate intermediate abstractions, provided both a convenient user programming experience and retained flexibility, and thus efficiency, of a reconfigurable platform. We initially targeted the Berkeley RAMP system (Research Accelerator for Multiple Processors) as that hardware emulation environment to facilitate and ultimately accelerate the iterative process of science-driven system design. Our goal was to develop and demonstrate a design methodology for domain-optimized computer system architectures. The tangible outcome is a methodology and tools for rapid prototyping and design-space exploration, leading to highly optimized and efficient HPC systems.

  12. Transmutation of neptunium, americium, technetium, and iodine in fast spectrum cores driven by accelerated protons

    A neutronic analysis is presented of three incinerator subcritical lattices, driven by accelerated protons and designed to transmute the minor actinides, the 99Tc and the 129I, of light water reactor (LWR) waste. A calculational methodology must first be established to enable a neutronic burnup analysis of fission cores driven by high-energy protons. The methodology is based on the following codes: HERMES, the Forschungszentrum Juelich adaptation of HETC, for high-energy interactions; MCNP3, for neutron interactions below 20 MeV of neutron energy; and KORIGEN, the Forschungszentrum Karlsruhe adaptation of ORIGEN, for burnup analysis. A result of applying the methodology is that the minor actinides, the 99Tc, and the 129I, of LWR waste may be transmuted in subcritical cores, driven by the spallation neutrons emanating from the bombardment of the cores with 1600-MeV protons. Three cores types are required. Core type 1 is fueled by the minor actinides and is a modification of the Brookhaven National Laboratory PHOENIX. With a proton current of 20 mA, the core incinerates the minor actinide waste of 14 LWRs. Core type 2 contains the 99Tc, 129I, and plutonium waste of 19 LWRs. With a proton beam of 130 mA, the core incinerates the technetium and 60% of the iodine. With a faction of the plutonium coming out of this core, the remaining 40% of 129I is incinerated in core type 3. All three cores run to 100,000 MWd/tonne or slightly higher; on the average, no core is a net consumer of grid electricity; all are cooled by sodium but remain subcritical with the loss of coolant

  13. Impact of criticality level on safety of accelerator driven systems with conventional Mox and advanced fertile free fuels

    Two types of Accelerator Driven Systems are currently investigated in Europe: with conventional MOX fuel (of e.g. Superphenix type) for demonstration and experimental purposes; and with Advanced Fertile Free Fuels for nuclear waste burning. Usually a similar subcriticality level is assumed acceptable in the both cases: with keff being around 0,95 - 0,97. In the paper, analyses of protected and unprotected (i.e. with and without accelerator shutdown) transients are performed for a wider range of initial (at the beginning of the transient) keff values to assess corresponding advantages and disadvantages (from the safety point of view) for the both types of ADS. (authors)

  14. A European roadmap for developing accelerator driven systems (ADS) for nuclear waste incineration. Executive summary

    In 1998 the Research Ministers of France, Italy and Spain, set up a Ministers' Advisors Group on the use of accelerator driven systems (ADS) for nuclear waste transmutation. This led to the establishing of a technical working group under the chairmanship of Prof. Carlo Rubbia to identify the critical technical issues and to prepare a 'Roadmap' for a demonstration programme to be performed within 12 years. In the following Roadmap, the technical working group (consisting of representatives from Austria, Belgium, Finland, France, Germany, Italy, Portugal, Spain, Sweden and the JRC) has identified the steps necessary to start the construction of an experimental accelerator driven system towards the end of the decade. This is considered as an essential prerequisite to assess the safe and efficient behaviour of such systems for a large-scale deployment for transmutation purposes in the first half of this century. The development and deployment of accelerator driven systems requires three steps: a comprehensive mid- and long-term R and D program, to develop the single elements and components of the system. This includes development of new fuels and fuel cycle systems; planning, design, construction and operation of an Experimental Accelerator Driven System for the demonstration of the concept; planning, design, construction and operation of a large size prototype accelerator driven systems with subsequent large-scale deployment. Following a first phase of R and D focused on the understanding of the basic principles of ADS (already partly underway), the programmes should be streamlined and focused on a practical demonstration of the key issues. These demonstrations should cover high intensity proton accelerators (beam currents in the range 1-20 mA), spallation targets of high power (of power in excess of 1 megawatt), and their effective coupling with a sub-critical core. Cost estimates are taken into account as well as the ADS activities in Japan and USA

  15. The Italian R and D and industrial programme for an accelerator driven system experimental plant

    Accelerator Driven Systems (ADS), coupling an accelerator with a target and a sub-critical reactor, could simultaneously burn minor actinides and transmute long-lived fission products, while producing a consistent amount of electrical energy. A team of Italian R and D organizations and industries has set up a network of coordinated programs addressed to study the design issues of an 80 MWth Experimental Facility. The present memo focalizes the attention on some results obtained by the R and D activities and by the on-going industrial short term activities aiming at the preparation of the proposed preliminary design, leaving the deal to define the details of the subsequent medium term activities to the expected common program in the European context. (author)

  16. Status of Accelerator Driven Systems Research and Technology Development

    One of the greatest challenges for nuclear energy is how to properly manage the highly radioactive waste generated during irradiation in nuclear reactors. In order for nuclear power to exploit its full potential as a major sustainable energy source, there needs to be a safe and effective way to deal with this waste. Since 1995, several scenario studies have been conducted on different advanced nuclear fuel cycle and waste management options in various countries. Examples include the collaborative projects under “Global sustainable nuclear energy scenarios for long term development and deployment of nuclear energy” of the IAEA International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO) initiative, and the scenario studies conducted under the auspices of the OECD Nuclear Energy Agency and the Euratom research project PATEROS — Partitioning and Transmutation European Roadmap for Sustainable Nuclear Energy. Some of the proposed long term nuclear fuel cycles include an innovative concept of a hybrid system for the transmutation of long lived radioisotopes. This is usually the called accelerator driven system (ADS) — or accelerator driven transmutation of waste (ATW) — and consists of a high power proton accelerator, a heavy metal spallation target that produces neutrons when bombarded by the high power beam, and a subcritical core that is neutronically coupled to the spallation target. The ADS, which has been developed in different countries for more than 40 years, is claimed to offer new prospects and advantages for the transmutation of high level radioactive waste. The ADS would convert highly radioactive material to non-radioactive material or material with a much shorter half-life. In addition, these hybrid systems can generate electricity during the conversion of transuranic waste. In 1997, under the guidance of its Technical Working Group on Fast Reactors (TWG-FR), the IAEA published IAEA-TECDOC-985, Accelerator Driven Systems: Energy

  17. Identification of Super- and Sub-critical Regions in Shocks driven by Coronal Mass Ejections

    Bemporad, Alessandro; Mancuso, Salvatore

    2011-01-01

    In this work, we focus on the analysis of a CME-driven shock observed by SOHO/LASCO. We show that white-light coronagraphic images can be employed to estimate the compression ratio X = rho_d / rho_u all along the front of CME-driven shocks. X increases from the shock flanks (where X ~ 1.2) to the shock center (where X ~ 3.0 is maximum). From the estimated X values, we infer the Alfv\\'en Mach number for the general case of an oblique shock. It turns out that only a small region around the shoc...

  18. Preliminary design of a gas-cooled accelerator driven system demonstrator

    At the present time, nuclear power appears to be the best solution for producing a large amount of electricity from both economical and ecological viewpoints, provided that acceptable answers to the nuclear waste concern are found. In France, this is the subject of the law 91-1381 (December 30th , 1991). The transmutation of most of the long-lived radioactive wastes is a promising solution which could play a substantial role for the safety of the fuel cycle. Sub-critical Accelerator Driven System (ADS), coupling an ion accelerator and a sub-critical reactor, seems to have a high capacity for the fission of minor actinides and transmutation of long life fission products. The practicality on an industrial scale of partitioning and transmutation through ADS for reducing the amount of long life radio-nuclides has to be evaluated. It was recognised that the most efficient way, in terms of cost and planning, to conclusively assess the potential and the feasibility of a full scale industrial programme on ADS was to design and operate an ADS Demonstrator. The main ADS DF characteristics, defined within a joint working group, and reactor design features are described and justified. Then, main issues which call for research and development support are identified. (authors)

  19. Application of variance reduction technique to nuclear transmutation system driven by accelerator

    Sasa, Toshinobu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    In Japan, it is the basic policy to dispose the high level radioactive waste arising from spent nuclear fuel in stable deep strata after glass solidification. If the useful elements in the waste can be separated and utilized, resources are effectively used, and it can be expected to guarantee high economical efficiency and safety in the disposal in strata. Japan Atomic Energy Research Institute proposed the hybrid type transmutation system, in which high intensity proton accelerator and subcritical fast core are combined, or the nuclear reactor which is optimized for the exclusive use for transmutation. The tungsten target, minor actinide nitride fuel transmutation system and the melted minor actinide chloride salt target fuel transmutation system are outlined. The conceptual figures of both systems are shown. As the method of analysis, Version 2.70 of Lahet Code System which was developed by Los Alamos National Laboratory in USA was adopted. In case of carrying out the analysis of accelerator-driven subcritical core in the energy range below 20 MeV, variance reduction technique must be applied. (K.I.)

  20. Reactivity and derivations of point kinetics equations for subcritical systems

    In recent years, there has been an increasing interest in the analysis time dependent behavior of subcritical systems with external source (accelerator-driven systems). The so called 'point kinetics equations' are widely used in the reactor analysis. Correct derivation of point kinetics equation on the deep subcritical level and close to criticality will help to understand 'point kinetics approximation' in general. At present is in MOBY-DICK macro code used 'quasi-critical' adjoint flux solution. It was found that the role of adjoint weighting function in subcritical system is not negligible. To understand physical background of the role of weighting functions in point kinetics methodology is provided derivation point kinetics equations from the variational principle. Extension of the present algorithm SKODA to the subcritical systems with external source is also derived. For comparisons is given brief information about other approaches : Gandini perturbation methodology and Ott - (SIMMER code) methodology (Author)

  1. Adjoint equation of ADS sub-critical reactor

    Compared with the critical reactor, the distributions of source neutron and fission neutron are asymmetric inside ADS (accelerator driven sub-critical system) sub-critical reactor, as well as the importance function is different. The multigroup-diffusion approximation was used to simplify the steady-state transport equation into multigroup equation. Then an adjoint equation normalized by the power of reactor core and an importance function associated with the relative power were derived. The physical significance of neutron importance in the sub-critical reactor was also derived. Finally, two different expressions of multiplication factor for sub-critical reactor with external neutron source were derived based on steady-state adjoint equations. (authors)

  2. A New Type of Plasma Wakefield Accelerator Driven by Magnetowaves

    Chen, Pisin(Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, 10617, Taipei, Taiwan); Chang, Feng-Yin; Lin, Guey-Lin; Noble, Robert J.; Sydora, Richard

    2008-01-01

    We present a new concept for a plasma wakefield accelerator driven by magnetowaves (MPWA). This concept was originally proposed as a viable mechanism for the "cosmic accelerator" that would accelerate cosmic particles to ultra high energies in the astrophysical setting. Unlike the more familiar Plasma Wakefield Accelerator (PWFA) and the Laser Wakefield Accelerator (LWFA) where the drivers, the charged-particle beam and the laser, are independently existing entities, MPWA invokes the high-fre...

  3. Activity report of working party on reactor physics of accelerator-driven system. July 1999 to March 2001

    Under the Research Committee on Reactor Physics, the Working Party on Reactor Physics of Accelerator-Driven System (ADS-WP) was set in July 1999 to review and investigate special subjects related to reactor physics research for the Accelerator-Driven Subcritical System (ADS). The ADS-WP, at the first meeting, discussed a guideline of its activity for two years and decided to concentrate upon three subjects: (1) neutron transport calculations in high energy range, (2) static and kinetic (safety-related) characteristics of subcritical system, and (3) system design including ADS concepts and elemental technology developments required. The activity of ADS-WP continued from July 1999 to March 2001. In this duration, the members of ADS-WP met together four times and discussed the above subjects. In addition, the ADS-WP conducted a questionnaire on requests and proposals for the plan of Transmutation Physics Experimental Facility in the High-Intensity Proton Accelerator Project, which is a joint project between JAERI and KEK (High Energy Accelerator Research Organization). This report summarizes the results obtained by the above ADS-WP activity. (author)

  4. Development of accelerator driven transmutation system concept and related R and D activities at JAERI

    JAERI has carried out R and D on transmutation of long-lived nuclides with a special emphasis placed on accelerator-driven systems (ADS) under the Japanese OMEGA Program. The ADS is designed to be introduced as a dedicated transmutation system into the second stratum of a double-strata nuclear fuel cycle concept. Early ADS concepts employed sodium coolant and solid tungsten target. A chloride molten-salt system and a molten-alloy system were investigated as advanced options to pursue the possibility of taking full advantages of liquid fuel systems. The current reference ADS design employs eutectic lead-bismuth as spallation target material and coolant. The fuel for the subcritical core is minor-actinide mononitride. The system consists of a 1.5-GeV, 14-mA proton accelerator and an 800-MWt subcritical core with an effective neutron multiplication factor of 0.95. The design incorporates salient features that the coolant inventory is large due to the tank-type configuration, the temperature rise through the core is relatively low, and the power conversion is operated on a saturated steam turbine cycle. These features help mitigate the problems of plant transient during beam interruptions. ADS related R and D is underway in various fields such as scenario study, lead-bismuth technology development, nitride fuel and fuel cycle technology development, nuclear data development, and high-intensity accelerator development. Construction of ADS experimental facilities is planned under the JAERI-KEK Joint Project of a high-power proton accelerator. (author)

  5. System and safety studies of accelerator driven transmutation. Annual Report 2001

    Gudowski, W.; Wallenius, J.; Tucek, K.; Eriksson, Marcus; Carlsson, Johan; Seltborg, P.; Cetnar, J.; Chakarova, R.; Westlen, D. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Nuclear and Reactor Physics

    2002-03-01

    The research on safety of Accelerator-Driven Transmutation Systems (ADS) at the Dept. of Nuclear and Reactor Physics has been focused in year 2001 on: a) ADS core design and development of advanced nuclear fuel optimised for high transmutation rates and good safety features; b) analysis of ADS-dynamics; c) computer code and nuclear data development relevant for simulation and optimization of ADS; d) participation in ADS experiments including 1 MW spallation target manufacturing, subcritical experiments MUSE (CEA-Cadarache) and YALINA experiment in Minsk. The Dept. is very actively participating in many European projects in the 5th Framework Programme of the European Community. Most of the research topics reported in this paper are referred to by appendices, which have been published in the open literature. The topics, which are not yet published, are described here in more details.

  6. System and safety studies of accelerator driven transmutation. Annual Report 2001

    The research on safety of Accelerator-Driven Transmutation Systems (ADS) at the Dept. of Nuclear and Reactor Physics has been focused in year 2001 on: a) ADS core design and development of advanced nuclear fuel optimised for high transmutation rates and good safety features; b) analysis of ADS-dynamics; c) computer code and nuclear data development relevant for simulation and optimization of ADS; d) participation in ADS experiments including 1 MW spallation target manufacturing, subcritical experiments MUSE (CEA-Cadarache) and YALINA experiment in Minsk. The Dept. is very actively participating in many European projects in the 5th Framework Programme of the European Community. Most of the research topics reported in this paper are referred to by appendices, which have been published in the open literature. The topics, which are not yet published, are described here in more details

  7. Estimation for effect of JENDL-3.3 on neutronics characteristics of accelerator-driven system

    The latest version of Japanese Evaluated Nuclear Data Library (JENDL-3.3) was released in last year. Primary purpose of this study was to estimate an effect of a revision of nuclear data library on neutronics characteristics of accelerator-driven subcritical system (ADS). The burnup calculations using both JENDL-3.3 and JENDL-3.2 were performed for JAERI proposed ADS. The detailed contribution of each nuclide and reaction on the difference of the calculation results, such as effective multiplication factor and burnup swing, were investigated. Moreover, to validate the nuclear data of actinides, the burnup analysis for the actinides samples irradiated at the Dounreay Prototype Fast Reactor were carried out. (author)

  8. Neutronic Studies in Support of Accelerator-Driven Systems: The MUSE Experiments in the MASURCA Facility

    The MUSE program (multiplication with an external source) is in progress at the MASURCA critical facility at the Cadarache Research Center of the Commissariat a l'Energie Atomique in France. The program is dedicated to the physics studies of accelerator-driven systems in support of transmutation studies of minor actinides and long-lived fission products. It began in 1995 with the coupling of a Cf source in MASURCA and was followed by a commercial (d,T) source. In 2001, a specially constructed (d,D)/(d,T) neutron generator (GENEPI) was placed in MASURCA and the MUSE-4 program commenced.We describe the first phases of the MUSE-4 program, with data presented that were obtained up to about the summer of 2002. We present some results from the 'reference' configuration, which can operate at critical. We present traverses of measured fission reaction rates, with comparison to calculations. Also in the reference configuration, we performed activation foil measurements and present these results compared to calculations.Because a major objective of the MUSE program is to test and qualify methods of subcritical reactivity measurement, we have devoted a major portion of our studies to this area. We have used classical methods (rod drop, source multiplication) to attempt to measure the subcritical level. In these early phases we studied core configurations of around keff = 0.995. Deeper subcriticality (keff = 0.96) was achieved by inserting a safety rod.In addition to the methods mentioned above, we have devoted a lot of effort to pulse neutron source, fluctuation (Rossi-α and Feynman-α), and transfer function methods (e.g., cross-power spectral density). We present our preliminary results of all the methods, with some discussion regarding cross comparison

  9. Thermal-hydraulic analysis of LBE spallation target for accelerator-driven systems

    Aniseh Ahmed Atef Abdalla; Jiyang Yu; Yongwel Yang

    2013-01-01

    In an accelerator-driven subcritical system (ADS), a high-performance spallation neutron source is used to feed the subcritical reactor. Neutron generation depends on the proton beam intensity. If the beam intensity is increased by a given factor, the number of generated neutrons will increase. The mechanism yielding a high rate of neutron production per energy is the spallation process, and this mechanism produces very high-energy deposition in the spallation target material. Producing a high rate of neutrons is accompanied by creation of problems of decay heat cooling and radiological protection. As a first step in designing a full-scale industrial ADS, a small-scale experimental ADS, which is similar to the European experimental ADS (XADS) is analysed. The analysis presented in this paper is based on lead–bismuth eutectic (LBE) cooled XADS-type experimental reactors, designed during the European experimental (PDS-XADS) project. Computational fluid dynamics analysis has been carried out for the spallation target. Steady-state behaviour and shear stress transport turbulence model with the automatic wall treatment were applied in the present analysis.

  10. Preliminary studies of a new accelerator-driven minor actinide burner in industrial scale

    Highlights: • A new accelerator-driven minor actinide (MA) burner was proposed. • Comprehensive design of spallation target, fuel assembly and subcritical core was performed. • Preliminary safety analyses indicate the inherent safety of the core in the reactivity insertion (500 pcm) and beam overpower (50% increase) transients. - Abstract: Pursuing high transmutation rate of minor actinide (MA), a preliminary conceptual design of a lead-bismuth (LBE) cooled accelerator-driven system (ADS) is proposed in this study. Parametric studies are performed to optimize the neutronics and thermal–hydraulics performances. The proton energy and axial position of the proton beam impact is investigated to obtain high neutron source efficiency and spallation neutron yield. The influences of MA/Pu mixing ratio and the ratio of pin pitch to diameter (P/D) are also optimized to control the burnup reactivity swing and the minimum coolant velocity for adequate cooling. To reduce the power peak, three kinds of power flattening techniques are adopted and compared. The results show that the inert matrix ratio zone loading method seems more versatile. Based on the analyses, an optimized three zone loading pattern is proposed for the 800 MWth subcritical core. The total transmutation rate of MA is 328.8 kg per effective full power year. Preliminary safety analyses based on the balance of power method (BOP) are performed and the results show that in the reactivity insertion and beam overpower transients, the core shows inherent safety, but the scram is necessary by cutting off the beam current to protect the core from possible damages caused by the loss of flow

  11. Preliminary studies of a new accelerator-driven minor actinide burner in industrial scale

    Li, Xunzhao; Zhou, Shengcheng [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Zheng, Youqi, E-mail: yqzheng@mail.xjtu.edu.cn [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China); Wang, Kunpeng [Nuclear and Radiation Safety Center, PO Box 8088, No. 54, Beijing 100082 (China); Wu, Hongchun [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, Shaanxi (China)

    2015-10-15

    Highlights: • A new accelerator-driven minor actinide (MA) burner was proposed. • Comprehensive design of spallation target, fuel assembly and subcritical core was performed. • Preliminary safety analyses indicate the inherent safety of the core in the reactivity insertion (500 pcm) and beam overpower (50% increase) transients. - Abstract: Pursuing high transmutation rate of minor actinide (MA), a preliminary conceptual design of a lead-bismuth (LBE) cooled accelerator-driven system (ADS) is proposed in this study. Parametric studies are performed to optimize the neutronics and thermal–hydraulics performances. The proton energy and axial position of the proton beam impact is investigated to obtain high neutron source efficiency and spallation neutron yield. The influences of MA/Pu mixing ratio and the ratio of pin pitch to diameter (P/D) are also optimized to control the burnup reactivity swing and the minimum coolant velocity for adequate cooling. To reduce the power peak, three kinds of power flattening techniques are adopted and compared. The results show that the inert matrix ratio zone loading method seems more versatile. Based on the analyses, an optimized three zone loading pattern is proposed for the 800 MWth subcritical core. The total transmutation rate of MA is 328.8 kg per effective full power year. Preliminary safety analyses based on the balance of power method (BOP) are performed and the results show that in the reactivity insertion and beam overpower transients, the core shows inherent safety, but the scram is necessary by cutting off the beam current to protect the core from possible damages caused by the loss of flow.

  12. First order Fermi acceleration driven by magnetic reconnection

    Drury, Luke O'C

    2012-01-01

    A box model is used to study first order Fermi acceleration driven by magnetic reconnection. It is shown, at least in this simple model, that the spectral index of the accelerated particles is related to the total compression in the same way as in diffusive shock acceleration and is not, as has been suggested, a universal $E^{-5/2}$ spectrum. The acceleration time-scale is estimated and some comments made about the applicability of the process.

  13. High power radiation guiding systems for laser driven accelerators

    This paper reviews the main problems encountered in the design of an optical system for transmitting high fluence radiation in a laser driven accelerator. Particular attention is devoted to the analysis of mirror and waveguide systems. (orig.)

  14. High intensity laser-driven ion acceleration

    Ion acceleration by intense laser-plasma interactions is a very active field of research whose development can be traced in a large number of publications over the last few years. Past studies were mostly performed irradiating thin foils where protons are predominantly accelerated to energies up to 60 MeV in an exponentially decaying spectrum by a mechanism named target normal sheath acceleration (TNSA). We present our latest experimental advances on acceleration schemes away from TNSA, such as shock acceleration, ion beam generation from relativistically transparent targets and radiation-pressure acceleration. These results are a major step towards highly energetic, mono-chromatic ion beams generated at high conversion efficiencies as demanded by many potential applications. Those include fast ignition inertial confinement fusion (ICF) as well as oncology and radiation therapy of tumors.

  15. Anatomy of a controversy: Application of the Langevin technique to the analysis of the Californium-252 Source-Driven Noise Analysis method for subcriticality determination

    The expressions for the power spectral density of the noise equivalent sources have been calculated explicitly for the (a) stochastic transport equation, (b) the one-speed transport equaton, (c) the one-speed P1 equations, (d) the one-speed diffusion equation and (e) the point kinetic equation. The stochastic nature of Fick's law in (d) has been emphasized. The Langevin technique has been applied at various levels of approximation to the interpretation of the Californium-252 Source-Driven Noise Analysis (CSDNA) experiment for determining the reactivity in subcritical media. The origin of the controversy surrounding this method has been explained. The foundations of the CSDNA method as a viable experimental technique to infer subcriticality from a measured ratio of power spectral densities of the outputs of two neutron detectors and a third external source detector has been examined by solving the one-speed stochastic diffusion equation for a point external Californium-252 source and two detectors in an infinite medium. The expression relating reactivity to the measured ratio of PSDs was found to depend implicitly on k itself. Through a numerical analysis fo this expression, the authors have demonstrated that for a colinear detector-source-detector configuration for neutron detectors far from the source, the expression for the subcritical multiplication factor becomes essentially insensitive to k, hence, demonstrating some possibility for the viability of this technique. However, under more realistic experimental conditions, i.e., for finite systems in which diffusion theroy is not applicable, the measurement of the subcritical multiplication factor from a single measured ratio of PSDs, without extensive transport calculations, remains doubtful

  16. Neutronics Optimization of LiPb-He Dual-Cooled Fuel Breeding Blanket for the Fusion-Driven sub-critical System

    郑善良; 吴宜灿

    2002-01-01

    The concept of the liquid Li17Pb83 and Helium gas dual-cooled Fuel Breeding Blanket (FBB) for the Fusion-Driven sub-critical System (FDS) is presented and analyzed. Taking self-sustaining tritium (TBR >1.05) and annual output of 100 kg or more fissile 239Pu (FBR>0.238) as objective parameters, and based on the three-dimensional Monte Carlo neutron-photon transport code MCNP/4A, a neutronics-optimizated calculation of different cases was carried out and the concept is proved feasible. In addition, the total breeding ratio ( BR = TBR + FBR ) is listed corresponding to different cases.

  17. Neutronics optimization of LiPb-He dual-cooled fuel breeding blanket for the fusion-driven sub-critical system

    The concept of the liquid Li17Pb83 and Helium gas dual-cooled Fuel Breeding Blanket (FBB) for the Fusion-Driven sub-critical System (FDS) is presented and analyzed. Taking self-sustaining tritium (TBR > 1.05) and annual output of 100 kg or more fissile 239Pu (FBR > 0.238) as objective parameters, and based on the three-dimensional Monte Carlo neutron-photon transport code MCNP/4A, a neutronics-optimized calculation of different cases was carried out and the concept is proved feasible. In addition, the total breeding ratio (Br = Tbr + Fbr) is listed corresponding to different cases

  18. Alternative concept for a fast energy amplifier accelerator driven reactor

    Recently Rubbia et al. introduced a conceptual design of a Fast Energy Amplifier (EA) as an advanced innovative reactor which utilizes a neutron spallation source induced by protons as an external source in a subcritical array imbibed a molten lead coolant which, besides being breeder and waste burner, generates energy. This paper introduces some qualitative changes in Rubbia's concept such as more than one point of spallation, in order to reduce the requirement in the energy and current of the accelerator, and mainly to make a more flat neutron distribution. The subcritical core which in Rubbia's concept is an hexagonal array of pins immersed in a molten lead coolant is replaced by a concept of a solid lead calandria with the fuel elements in channels cooled by helium, allowing on line refueling or shuffling, and the utilization of a direct thermodynamic cycle (Brayton), which is more efficient than a vapor cycle. Although the calculations to demonstrate the feasibility of the EA alternative concept are underway and not yet finished, these ideas do not violate the basic physics of the EA, as showed in this paper, with evident advantages in the fuel cycle (on line refueling); reduced requirements in the accelerator complex, which is more realistic and economical in today accelerators technology; and finally the utilization of He as coolant compared with molten Pb is more close to the proved technology given the know how of gas cooled reactors and more efficient from the thermodynamic point of view, allowing simplification and the utilization in other process, besides electricity generation, as hydrogen generation. (author)

  19. Beam-driven, Plasma-based Particle Accelerators

    Muggli, P

    2016-01-01

    We briefly give some of the characteristics of the beam-driven, plasma-based particle accelerator known as the plasma wakefield accelerator (PWFA). We also mention some of the major results that have been obtained since the birth of the concept. We focus on high-energy particle beams where possible.

  20. Startup transients in accelerator driven systems using CINESP-ADS code

    Accelerator Driven Systems (ADS) are subcritical nuclear reactor cores driven by spallation neutron source. These spallation neutrons are provided from the bombardment of a liquid metal flowing in a central region of the core, by a proton beam coming from a linear accelerator. Since neutron source dominates the neutronic of the ADS, its control usually is not related to the delayed neutron fractions as in the critical systems. In this way, ADS kinetics diverges from the former ones. This work presents some results of transients in ADS. Since ADS is to work in a pulsed regime, with time duration of pulse, a parametric result is showed to point out that different pulse durations should be studied in conjunction with pulse intensity, to maintain the ADS power stable. In addition, before generating these results, some transients were used to validate the CINESP-ADS code. It solves numerically the kinetic equations based on the multigroup diffusion theory, in one- or two-dimensional, in the Cartesian or Cylindrical geometries, and for any energy and delayed neutron groups. Three-dimensional simulation is possible using a reactor transversal buckling. The numerical solution is obtained via finite differences for the spatial discretization, using the so-called box integration, and with the use of Alternating Direction Explicit (ADE) methods, for the time discretization. The code application to some transients due to source neutron variations demonstrates its efficiency and accuracy, when compared with analytical techniques, such as one that uses expansion in series of Helmholtz eigenfunctions. (author)

  1. Laser-driven wakefield electron acceleration and associated radiation sources

    The first part of this research thesis introduces the basic concepts needed for the understanding of the laser-driven wakefield acceleration. It describes the properties of the used laser beams and plasmas, presents some notions about laser-plasma interactions for a better understanding of the physics of laser-driven acceleration. The second part deals with the numerical modelling and the presentation of simulation tools needed for the investigation of laser-induced wakefield acceleration. The last part deals with the optical control of the injection, a technique analogous to the impulsion collision scheme

  2. OECD/Nea benchmark calculations for accelerator driven systems

    In order to evaluate the performances of the codes and the nuclear data, the Nuclear Science Committee of the OECD/NEA organised in July 1999 a benchmark exercise on a lead-bismuth cooled sub-critical system driven by a beam of 1 GeV protons. The benchmark model is based on the ALMR reference design and is optimised to burn minor actinides using a 'double strata' fuel cycle strategy. Seven organisations (ANL, CIEMAT, KAERI, JAERI, PSI/CEA, RIT and SCK-CEN) have contributed to this exercise using different basic data libraries (ENDF/B-VI, JEF-2.2 and JENDL-3.2) and various reactor calculation methods. Significant discrepancies are observed in important neutronic parameters, such as keff, reactivity swing with burn-up and neutron flux distributions. (author)

  3. Results from Accelerator Driven TRIGA Reactor Experiments at The University of Texas at Austin

    Accelerator Driven Transmutation of High-Level Waste (ATW) is one possible solution to the fuel reprocessing back-end problem for the disposal of high level waste such as minor actinides (Am, Np or Cm) and long-lived fission products. International programs continue to support research towards the eventual construction and operation of a proton accelerator driven spallation neutron source coupled to a subcritical 'neutron amplifier' for more efficient HLW transmutation. This project was performed under DOE AFCI Reactor-Accelerator Coupling Experiments (RACE). A 20 MeV Electron Linac was installed in the BP no 5 cave placing neutron source adjacent to an offset reactor core to maximize neutron coupling with available systems. Asymmetric neutron injection 'wasted' neutrons due to high leakage but sufficient neutrons were available to raise reactor power to ∼100 watts. The Linac provided approximately 100 mA but only 50% reached target. The Linac cooling system could not prevent overheating at frequencies over 200 Hz. The Linac electron beam had harmonics of primary frequency and periodic low frequency pulse intensity changes. Neutron detection using fission chambers in current mode eliminated saturation dead time and produced better sensitivity. The Operation of 'dual shielded' fission chambers reduced electron noise from linac. Benchmark criticality calculation using start-up data showed that the MCNPX model overestimates reactivity. TRIGA core was loaded to just slightly supercritical by adding graphite elements and measuring reactivity of $0.037. MCNPX modeled TRIGA core with and without graphite to arrive at 'true' measured subcritical multiplication of 0.998733± 0.00069. Thus, Alpha for the UT-RACE TRIGA core was approximately 155.99 s-1. The Stochastic Feynman-Alpha Method (SFM) accuracy was evaluated during transients and reactivity changes. SFM was shown to be a potential real-time method of reactivity determination in future ADSS but requires stable

  4. Investigation of Lead Target Nuclei Used on Accelerator-Driven Systems for Tritium Production

    Tel, E.; Aydin, A.

    2012-02-01

    High-current proton accelerators are being researched at Los Alamos National Laboratory and other laboratories for accelerator production of tritium, transmuting long-lived radioactive waste into shorter-lived products, converting excess plutonium, and producing energy. These technologies make use of spallation neutrons produced in ( p,xn) and ( n,xn) nuclear reactions on high-Z targets. Through ( p,xn) and ( n,xn) nuclear reactions, neutrons are produced and are moderated by heavy water. These moderated neutrons are subsequently captured on 3He to produce tritium via the ( n,p) reaction. Tritium self-sufficiency must be maintained for a commercial fusion power plant. Rubbia succeeded in a proposal of a full scale demonstration plant of the Energy Amplifier. This plant is to be known the accelerator-driven system (ADS). The ADS can be used for production of neutrons in spallation neutron source and they can act as an intense neutron source in accelerator-driven subcritical reactors, capable of incinerating nuclear waste and of producing energy. Thorium and Uranium are nuclear fuels and Lead, Bismuth, Tungsten are the target nuclei in these reactor systems. The spallation targets can be Pb, Bi, W, etc. isotopes and these target material can be liquid or solid. Naturally Lead includes the 204Pb (%1.42), 206Pb (%24.1), 207Pb (%22.1) and 208Pb (%52.3) isotopes. The design of ADS systems and also a fusion-fission hybrid reactor systems require the knowledge of a wide range of better data. In this study, by using Hartree-Fock method with an effective nucleon-nucleon Skyrme interactions rms nuclear charge radii, rms nuclear mass radii, rms nuclear proton, neutron radii and neutron skin thickness were calculated for the 204, 206, 208Pb isotopes . The calculated results have been compared with those of the compiled experimental and theoretical values of other studies.

  5. A study of physics of sub-critical multiplicative systems driven by sources and the utilization of deterministic codes in calculation of this systems

    This work presents the Physics of Source Driven Systems (ADS). It shows some statics and Kinetics parameters of the reactor Physics and when it is sub critical, that are important in evaluation and definition of these systems. The objective is to demonstrate that there are differences in parameters when the reactor is critical. Moreover, the work shows the differences observed in the parameters for different calculation models. Two calculation methodologies are shown In this dissertation: Gandini and Salvatores and Dulla, and some parameters are calculated. The ANISN deterministic transport code is used in calculation in order to compare these parameters. In a subcritical configuration of IPEN-MB-01 Reactor driven by an external source some parameters are calculated. The conclusions about calculation realized are presented in end of work. (author)

  6. A study of calculation methodology and experimental measurements of the kinetic parameters for source driven subcritical systems

    This work presents a theoretical study of reactor kinetics focusing on the methodology of calculation and the experimental measurements of the so-called kinetic parameters. A comparison between the methodology based on the Dulla's formalism and the classical method is made. The objective is to exhibit the dependence of the parameters on subcriticality level and perturbation. Two different slab type systems were considered: thermal one and fast one, both with homogeneous media. One group diffusion model was used for the fast reactor, and for the thermal system, two groups diffusion model, considering, in both case, only one precursor's family. The solutions were obtained using the expansion method. Also, descriptions of the main experimental methods of measurements of the kinetic parameters are presented in order to put a question about the compatibility of these methods in subcritical region. (author)

  7. Superpower linear proton accelerator for neutron generator and accelerator-driven system

    The perspectives of development of superpower linear proton accelerators for high-intensive neutron generators and accelerator-driven systems are discussed. The main technical characteristics of the projects on neutron generators based on linear accelerators are presented. These projects are developed in USA, Japan, Italy and Russia. The RFQ structures are used in all projects for the initial acceleration of protons up to 5-7 MeV. The different modifications of drift tubes are applied for acceleration up to 100 MeV. The main acceleration (up to 1 GeV) is supposed to perform in superconducting resonators

  8. Evaluation of subcritical hybrid systems loaded with reprocessed fuel

    Highlights: • Accelerator driven systems (ADS) and fusion–fission systems are investigated for transmutation and fuel regeneration. • The calculations were performed using Monteburns code. • The results indicate the most suitable system for achieve transmutation. - Abstract: Two subcritical hybrid systems containing spent fuel reprocessed by Ganex technique and spiked with thorium were submitted to neutron irradiation of two different sources: ADS (Accelerator-driven subcritical) and Fusion. The aim is to investigate the nuclear fuel evolution using reprocessed fuel and the neutronic parameters under neutron irradiation. The source multiplication factor and fuel depletion for both systems were analysed during 10 years. The simulations were performed using MONTEBURNS code (MCNP/ORIGEN). The results indicate the main differences when irradiating the fuel with different neutron sources as well as the most suitable system for achieving transmutation

  9. Preliminary report on the promise of accelerator-driven natural-uranium-fueled light-water-moderated breeding power reactors

    A new concept for a power breeder reactor that consists of an accelerator-driven subcritical thermal fission system is proposed. In this system an accelerator provides a high-energy proton beam which interacts with a heavy-element target to produce, via spallation reactions, an intense source of neutrons. This source then drives a natural-uranium-fueled, light-water-moderated and -cooled subcritical blanket which both breeds new fuel and generates heat that can be converted to electrical power. The report given presents a general layout of the resulting Accelerator Driven Light Water Reactor (ADLWR), evaluates its performance, discusses its fuel cycle characteristics, and identifies the potential contributions to the nuclear energy economy this type of power reactor might make. A light-water thermal fission system is found to provide an attractive feature when designed to be source-driven. The equilibrium fissile fuel content that gives the highest energy multiplication is approximately equal to the content of 235U in natural uranium. Consequently, natural-uranium-fueled ADLWRs that are designed to have the highest energy generation per source neutron are also fuel-self-sufficient; that is, their fissile fuel content remains constant with burnup. This feature allows the development of a nuclear energy system that is based on the most highly developed fission technology available (the light water reactor technology) and yet has a simple and safe fuel cycle. ADLWRs will breed on natural uranium, have no doubling time limitation, and be free from the need for uranium enrichment or for the separation of plutonium. It appears that ADLWRs could also be efficiently operated with thorium fuel cycles and with denatured fuel cycles

  10. Photonic crystal laser-driven accelerator structures

    Cowan, Benjamin

    2005-01-01

    We discuss simulated photonic crystal structure designs, including two- and three-dimensional planar structures and fibers. The discussion of 2D structures demonstrates guiding of a speed-of-light accelerating mode by a defect in a photonic crystal lattice and reveals design considerations and trade-offs. With a three-dimensional lattice, we introduce a candidate geometry and discuss beam dynamics, coupling, and manufacturing techniques for that structure. In addition we discuss W-band scale tests of photonic crystal structures. The computational methods are also discussed.

  11. An overview of accelerator-driven transmutation technology

    Accelerator-Driven Transmutation Technology, or ADT2, is a collection of programs that share a common theme - they each have at their heart an intense source of neutrons generated by a high-energy proton beam striking a heavy metal target. The beam energy, typically 1000 MeV, is enough for a single proton to smash a target atom into atomic fragments. This so-called spallation process generates large numbers of neutrons (around 20 to 30 per proton) amid the atomic debris. These neutrons are of high value because they can be used to transmute neighboring atoms by neutron capture. Three distinct ADT2 program elements will be described. These are ADEP - accelerator-driven energy production, ABC - accelerator based conversion (of plutonium) and ATW - accelerator transmutation of waste

  12. Compact Couplers for Photonic Crystal Laser-Driven Accelerator Structures

    Photonic crystal waveguides are promising candidates for laser-driven accelerator structures because of their ability to confine a speed-of-light mode in an all-dielectric structure. Because of the difference between the group velocity of the waveguide mode and the particle bunch velocity, fields must be coupled into the accelerating waveguide at frequent intervals. Therefore efficient, compact couplers are critical to overall accelerator efficiency. We present designs and simulations of high-efficiency coupling to the accelerating mode in a three-dimensional photonic crystal waveguide from a waveguide adjoining it at 90o. We discuss details of the computation and the resulting transmission. We include some background on the accelerator structure and photonic crystal-based optical acceleration in general.

  13. The GUINEVERE project for Accelerator Driven System physics

    Billebaud, A.; Baylac, M.; Bondoux, D.; Bouvier, J.; Chabod, S.; De Conto, J.M.; Nuttin, A. [LPSC-CNRS-IN2P3/UJF/INPG, 53 Avenue des Martyrs. 38026 Grenoble cedex (France); Baeten, P.; Ait Abderrahim, H.; Bergmans, G.; Chetnitkov, A.; Kochetkov, A.; Vandeplassche, D.; Vermeersch, F.; Vittiglio, G. [SCK.CEN, Boeretang 200, 2400 Mol (Belgium); Ban, G.; Gautier, J.M.; Lecolley, F.R.; Lecouey, J.L.; Marie, N.; Merrer, Y.; Steckmeyer, J.C. [LPC Caen, ENSICAEN/Universite de Caen/CNRS-IN2P3, 14050 Caen (France); Dessagne, P.; Gaudiot, G.; Heitz, G.; Kerveno, M. [IPHC-DRS/UdS/CNRS-IN2P3, 67037 Strasbourg (France); Granget, G.; Mellier, F. [CEA-Cadarache, 13108 Saint Paul-lez-Durance (France); Laune, B.; Reynet, D. [IPNO, CNRS-IN2P3/UPS, 91406 Orsay (France)

    2009-06-15

    The GUINEVERE project is part of the EUROTRANS Integrated Project of the 6. EURATOM Framework Programme. It is mainly devoted to ADS on-line reactivity monitoring validation, subcriticality determination and operational procedures (loading, start-up, shut-down,..) in follow-up of the MUSE experiments. The project consists in coupling a fast lead core, set-up in the VENUS reactor at SCK.CEN Mol (B), with a GENEPI neutron source under construction by CNRS. To accommodate the accelerator in a vertical coupling configuration, the VENUS building is being heightened. The fast core will be loaded with enriched Uranium and will be moderated and reflected with solid lead (zero power experiment). For the purpose of the experimental programme, the neutron source has to be operated not only in pulsed mode but also in continuous mode to investigate the current-to-flux reactivity indicator in representative conditions of a powerful ADS. In this latter mode it is also required to make short beam interruptions to have access to the neutron population decrease as a function of time: from this spectrum it will be possible to apply different analysis techniques such as 'prompt decay' fitting techniques and 'source jerk' techniques. Beam interruptions will be repeated at a programmable frequency to improve time spectra statistics. Different sub-criticality levels (k{sub eff}=0.99, 0.97, 0.95,..) will be investigated in order to obtain a full set of data points for the final overall validation of the methodology. This paper describes the status of the experimental facility assembling, and the foreseen experimental programme to be started. (authors)

  14. OECD/NEA Benchmark Calculations for an Accelerator-Driven Minor Actinide Burner

    Noticing the current interest in accelerator-driven systems as actinide waste burners, the OECD/NEA has organised an international benchmark exercise for evaluating the performance of computational tools and nuclear data for this type of system. The benchmark model simulates a lead-bismuth cooled sub-critical system driven by a beam of 1 GeV protons. The core design is similar to that of an ALMR, and the fuel composition is typical for a minor actinide burner in a 'double strata' fuel cycle. Lead-bismuth was chosen as target material. Since the intention was to validate data and codes in the energy region below 20 MeV, a predefined spallation neutron source was provided to the benchmark participants. The solutions from seven organisations (ANL, CIEMAT, KAERI, JAERI, PSI/CEA, RIT and SCK-CEN) are based on three different basic data libraries (ENDF/B-VI, JEF-2.2 and JENDL-3.2) and both deterministic and Monte Carlo reactor codes. Significant discrepancies are observed for important neutronic parameters such as initial keff, burn-up reactivity swing and flux distribution. Additional investigations of the basic nuclear data, the data processing methods and the approximations for the reactor simulation will be necessary to understand the origin of all observed discrepancies. (authors)

  15. Monte-Carlo Simulation of the Features of Bi-Reactior Accelerator Driven Systems

    Bznuni, S A; Khudaverdian, A G; Barashenkov, V S; Sosnin, A N; Polyanskii, A A

    2002-01-01

    Parameters of accelerator-driven systems containing two "cascade" subcritical assemblies (liquid metal fast reactor, used as a neutron booster, and a thermal reactor, where main heat production is taking place) are investigated. Three main reactor cores analogous to VVER-1000, MSBR-1000 and CANDU-6 reactors are considered. Functioning in a safe mode (k_{eff}=0.94-0.98) these systems under consideration demonstrate much larger capacity in the wide range of k_{eff} in comparison with analogous systems without intermediate fast booster reactor and simultaneously having the density of thermal neutron flux equal to Phi^{max}=10^{14} cm^{-2}c^{-1} and operating with the fast and thermal zones they are capable to transmute the whole scope of nuclear waste reducing the requirements on the beam current of the accelerator by one order of magnitude. It seems to be the most important in case when molten salt thermal breeder reactor cores are considered as a main heat generating zone.

  16. Lead-bismuth spallation target design of the accelerator-driven test facility (ADTF)

    A design methodology for the lead-bismuth eutectic (LBE) spallation target has been developed and applied for the accelerator-driven test facility (ADTF) target. This methodology includes the target interface with the subcritical multiplier (SCM) of the ADTF and the different engineering aspects of the target design, physics, heat-transfer, hydraulics, structural, radiological, and safety analyses. Several design constrains were defined and utilised for the target design process to satisfy different engineering requirements and to minimise the time and the cost of the design development. Interface requirements with the subcritical multiplier were defined based on target performance parameters and material damage issues to enhance the lifetime of the target structure. Different structural materials were considered to define the most promising candidate based on the current database including radiation effects. The developed target design has a coaxial geometrical configuration to minimise the target footprint and it is installed vertically along the SCM axis. LBE is the target material and the target coolant with ferritic steel (HT-9 Alloy) structural material. The proton beam has 8.33 mA current uniformly distributed and 8.14 cm beam radius resulting in a current density of 40 μA/cm2. The beam power is 5 MW and the proton energy is 600 MeV. The beam tube has 10 cm radius to accommodate the halo current. A hemi-spherical geometry is used for the target window, which is connected to the beam tube. The beam tube is enclosed inside two coaxial tubes to provide inlet and outlet manifolds for the LBE coolant. The inlet and the outlet coolant manifolds and the proton beam are entered from the top above the SCM. The paper describes the design criteria, engineering constraints, and the developed target design for the ADTF. (authors)

  17. Implementation and training methodology of subcritical reactors neutronic calculations triggered by external neutron source and applications

    This works had as goal to investigate calculational methodologies on subcritical source driven reactor, such as Accelerator Driven Subcritical Reactor (ADSR) and Fusion Driven Subcritical Reactor (FDSR). Intense R and D has been done about these subcritical concepts, mainly due to Minor Actinides (MA) and Long Lived Fission Products (LLFP) transmutation possibilities. In this work, particular emphasis has been given to: (1) complement and improve calculation methodology with neutronic transmutation and decay capabilities and implement it computationally, (2) utilization of this methodology in the Coordinated Research Project (CRP) of the International Atomic Energy Agency Analytical and Experimental Benchmark Analysis of ADS and in the Collaborative Work on Use of Low Enriched Uranium in ADS, especially in the reproduction of the experimental results of the Yalina Booster subcritical assembly and study of a subcritical core of IPEN / MB-01 reactor, (3) to compare different nuclear data libraries calculation of integral parameters, such as keff and ksrc, and differential distributions, such as spectrum and flux, and nuclides inventories and (4) apply the develop methodology in a study that may help future choices about dedicated transmutation system. The following tools have been used in this work: MCNP (Monte Carlo N particle transport code), MCB (enhanced version of MCNP that allows burnup calculation) and NJOY to process nuclear data from evaluated nuclear data files. (author)

  18. System and safety studies of accelerator driven transmutation. Annual Report 2003

    The research on safety of Accelerator-Driven Transmutation Systems (ADS) at the Dept. of Nuclear and Reactor Physics reported here has been focused on different aspects of safety of the Accelerator-Driven Transmutation Systems and on Transmutation research in more general terms. An overview of the topics of our research is given in the Summary which is followed by detailed reports as separate chapters or subchapters. Some of the research topics reported in this report are referred to appendices, which have been published in the open literature. Topics, which are not yet published, are described with more details in the main part of this report. Main focus has been, as before, largely determined by the programme of the European projects of the 5th Framework Programme in which KTH is actively participating. In particular: a) ADS core design and development of advanced nuclear fuel optimised for high transmutation rates and good safety features. This activity includes even computer modeling of nuclear fuel production. Three different ADS-core concept are being investigated: Conceptual design of Pb-Bi cooled core with nitride fuel so called Sing-Sing Core developed at KTH; Pb-Bi cooled core with oxide fuel so called ANSALDO design for the European Project PDS-XADS; Gas cooled core with oxide fuel a design investigated for the European Project PDS-XADS. b) analysis of potential of advance fuels, in particular nitrides with high content of minor actinides; c) analysis of ADS-dynamics and assessment of major reactivity feedbacks; d) emergency heat removal from ADS; e) participation in ADS: MUSE (CEA-Cadarache), YALINA subcritical experiment in Minsk and designing of the subcritical experiment SAD in Dubna; f) theoretical and simulation studies of radiation damage in high neutron (and/or proton) fluxes; g) computer code and nuclear data development relevant for simulation and optimization of ADS, validation of the MCB code and sensitivity analysis; h) studies of

  19. System and safety studies of accelerator driven transmutation. Annual Report 2003

    Gudowski, Waclaw; Wallenius, Jan; Tucek, Kamil [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Nuclear and Reactor Physics] [and others

    2004-12-01

    The research on safety of Accelerator-Driven Transmutation Systems (ADS) at the Dept. of Nuclear and Reactor Physics reported here has been focused on different aspects of safety of the Accelerator-Driven Transmutation Systems and on Transmutation research in more general terms. An overview of the topics of our research is given in the Summary which is followed by detailed reports as separate chapters or subchapters. Some of the research topics reported in this report are referred to appendices, which have been published in the open literature. Topics, which are not yet published, are described with more details in the main part of this report. Main focus has been, as before, largely determined by the programme of the European projects of the 5th Framework Programme in which KTH is actively participating. In particular: a) ADS core design and development of advanced nuclear fuel optimised for high transmutation rates and good safety features. This activity includes even computer modeling of nuclear fuel production. Three different ADS-core concept are being investigated: Conceptual design of Pb-Bi cooled core with nitride fuel so called Sing-Sing Core developed at KTH; Pb-Bi cooled core with oxide fuel so called ANSALDO design for the European Project PDS-XADS; Gas cooled core with oxide fuel a design investigated for the European Project PDS-XADS. b) analysis of potential of advance fuels, in particular nitrides with high content of minor actinides; c) analysis of ADS-dynamics and assessment of major reactivity feedbacks; d) emergency heat removal from ADS; e) participation in ADS: MUSE (CEA-Cadarache), YALINA subcritical experiment in Minsk and designing of the subcritical experiment SAD in Dubna; f) theoretical and simulation studies of radiation damage in high neutron (and/or proton) fluxes; g) computer code and nuclear data development relevant for simulation and optimization of ADS, validation of the MCB code and sensitivity analysis; h) studies of

  20. OECD/NEA comparison calculations for an accelerator-driven minor actinide burner: analysis of preliminary results

    In the framework of the NEA Nuclear Science Committee, an international benchmark exercise for an accelerator-driven system is being undertaken. A model of a lead-bismuth cooled subcritical system driven by a beam of 1 GeV protons was chosen for the exercise. Except for the subassembly geometry, the design of the subcritical core is based on the ALMR reference design of a sodium-cooled actinide burner. To reduce the high pumping power for the lead-bismuth coolant, the reference subassembly was replaced by a subassembly with a smaller number of pins, and the fission power of the system was proportionally reduced. Lead-bismuth was chosen as target material to reflect the generally increased interest in this material for high-power spallation target applications. An interesting role of accelerator-driven systems is to burn actinide waste from reactors with conventional fuel cycles. The benchmark reactor is assumed to operate as a minor actinide burner in a 'double strata' fuel cycle scheme, featuring a fully closed fuel cycle with a top-up of pure minor actinides. Two fuel compositions for a start-up and an equilibrium core are considered, both differing considerably from normal U-Pu mixed oxide fuel compositions. Six organisations (ANL, CIEMAT, JAERI, KAERI, PSI/CEA and RIT) have contributed preliminary results for inclusion in this paper. The results are based on deterministic transport as well as Monte Carlo calculations using data from ENDF/B-VI, JENDL3.2 and JEF2.2. Significant difference in important neutronic parameters are observed. (authors)

  1. Technology and Components of Accelerator-driven Systems. Second International Workshop Proceedings, Nantes, France, 21-23 May 2013

    The accelerator-driven system (ADS) is a potential transmutation system option as part of partitioning and transmutation strategies for radioactive waste in advanced nuclear fuel cycles. Following the success of the workshop series on the utilisation and reliability of the High Power Proton Accelerators (HPPA), the scope of this new workshop series on Technology and Components of Accelerator-driven Systems has been extended to cover subcritical systems as well as the use of neutron sources. The workshop organised by the OECD Nuclear Energy Agency provided experts with a forum to present and discuss state-of-the-art developments in the field of ADS and neutron sources. A total of 40 papers were presented during the oral and poster sessions. Four technical sessions were organised addressing ADS experiments and test facilities, accelerators, simulation, safety, data, neutron sources that were opportunity to present the status of projects like the MYRRHA facility, the MEGAPIE target, FREYA and GUINEVERE experiments, the KIPT neutron source, and the FAIR linac. These proceedings include all the papers presented at the workshop

  2. Conceptual design of a commercial accelerator driven thorium reactor

    This paper describes the substantial work done in underpinning and developing the concept design for a commercial 600 MWe, accelerator driven, thorium fuelled, lead cooled, power producing, fast reactor. The Accelerator Driven Thorium Reactor (ADTR TM) has been derived from original work by Carlo Rubbia. Over the period 2007 to 2009 Aker Solutions commissioned this concept design work and, in close collaboration with Rubbia, developed the physics, engineering and business model. Much has been published about the Energy Amplifier concept and accelerator driven systems. This paper concentrates on the unique physics developed during the concept study of the ADTR TM power station and the progress made in engineering and design of the system. Particular attention is paid to where the concept design has moved significantly beyond published material. Description of challenges presented for the engineering and safety of a commercial system and how they will be addressed is included. This covers the defining system parameters, accelerator sizing, core and fuel design issues and, perhaps most importantly, reactivity control. The paper concludes that the work undertaken supports the technical viability of the ADTR TM power station. Several unique features of the reactor mean that it can be deployed in countries with aspirations to gain benefit from nuclear power and, at 600 MWe, it fits a size gap for less mature grid systems. It can provide a useful complement to Generation III, III+ and IV systems through its ability to consume actinides whilst at the same time providing useful power. (authors)

  3. Proliferation Potential of Accelerator-Drive Systems: Feasibility Calculations

    Riendeau, C.D.; Moses, D.L.; Olson, A.P.

    1998-11-01

    Accelerator-driven systems for fissile materials production have been proposed and studied since the early 1950s. Recent advances in beam power levels for small accelerators have raised the possibility that such use could be feasible for a potential proliferator. The objective of this study is to review the state of technology development for accelerator-driven spallation neutron sources and subcritical reactors. Energy and power requirements were calculated for a proton accelerator-driven neutron spallation source and subcritical reactors to produce a significant amount of fissile material--plutonium.

  4. Nonlinear Laser Driven Donut Wakefields for Positron and Electron Acceleration

    Vieira, J.; Mendonça, J. T.

    2014-05-01

    We show analytically and through three-dimensional particle-in-cell simulations that nonlinear wakefields driven by Laguerre-Gaussian laser pulses can lead to hollow electron self-injection and positron acceleration. We find that higher order lasers can drive donut shaped blowout wakefields with strong positron accelerating gradients comparable to those of a spherical bubble. Corresponding positron focusing forces can be more than an order of magnitude stronger than electron focusing forces in a spherical bubble. Required laser intensities and energies to reach the nonlinear donut shaped blowout are within state-of-the-art experimental conditions.

  5. Subcriticality determination in ADS: Valina-Booster experiments

    A major problem in operating a full-scale subcritical accelerator-driven system (ADS) is to ensure sufficient margin to criticality. Therefore, reliable techniques for subcriticality monitoring are required. In order to develop such techniques, a full understanding of existing reactivity determination methods is essential. In this work, reactivity determination methods, such as pulsed neutron source methods and noise methods, are studied experimentally in the subcritical facility YALINA-Booster. YALINA-Booster: The subcritical assembly YALINA-Booster: recently constructed at the Joint Institute for Power and Nuclear Research - Sosny, consists of a subcritical core driven by an external neutron source. The neutron source is a powerful neutron generator consisting of a deuteron accelerator and a target of deuterium or tritium embedded in titanium. Through (d, d) - or (d, t)-reactions neutrons are created with energy around 2.5 MeV and 14.1 MeV respectively. Neutrons are born in the centre of the core and multiply through a lead matrix fuelled with highly enriched uranium (90% and 36%). This zone is referred to as the booster zone and is surrounded by a thermal zone, moderated by polyethylene. In order to reach sufficient high effective multiplication factor, the thermal zone is fuelled by approximately one thousand rods of 10% enriched uranium dioxide in cylindrical geometry. To prevent thermal neutrons from diffusing into the fast booster zone, an interface, consisting of boron carbide and natural uranium rods, is located between the zones. YALINA-Booster has a radial graphite reflector of thickness 24 cm. Experiments: Experiments using the neutron source in pulsed mode will be presented, relying on methods such as the area method and the method of prompt neutron decay rate determination. Moreover, results from noise analysis using for instance the Feynman-α method will be presented

  6. Laser-driven particle acceleration towards radiobiology and medicine

    2016-01-01

    This book deals with the new method of laser-driven acceleration for application to radiation biophysics and medicine. It provides multidisciplinary contributions from world leading scientist in order to assess the state of the art of innovative tools for radiation biology research and medical applications of ionizing radiation. The book contains insightful contributions on highly topical aspects of spatio-temporal radiation biophysics, evolving over several orders of magnitude, typically from femtosecond and sub-micrometer scales. Particular attention is devoted to the emerging technology of laser-driven particle accelerators and their applicatio to spatio-temporal radiation biology and medical physics, customization of non-conventional and selective radiotherapy and optimized radioprotection protocols.

  7. System and safety studies of accelerator driven transmutation. Annual Report 2005

    The results of the research activities on System and Safety of Accelerator-Driven Transmutation (ADS) at the Department of Nuclear and Reactor Physics are described in this report followed by the Appendices of the relevant scientific papers published in 2005. PhD and Licentiate dissertations of Marcus Ericsson, Per Seltborg, Christina Lagerstedt and Daniel Westlen (see Appendices) reflect the research mainstream of 2005. Year 2005 was also very rich in international activities with ADS in focus. Summary of conferences, seminars and lecturing activities is given in Chapter 9 Research activities of 2005 have been focused on several areas: system and safety studies of ADS; subcritical experiments; ADS source efficiency studies; nuclear fuel cycle analysis; potential of reactor based transmutation; ADS fuel development; simulation of radiation damage; and development of codes and methods. Large part of the research activities has been well integrated with the European projects of the 5th and 6th Framework Programmes of the European Commission in which KTH is actively participating. In particular European projects: RED-IMPACT, CONFIRM, FUTURE, EUROTRANS and NURESIM

  8. MCNPX simulations of fast neutron diagnostics for accelerator-driven systems

    In accelerator-driven systems, the neutron spectrum will extend all the way up to the incident beam energy, i.e., several hundred MeV or even up to GeV energies. The high neutron energy allows novel diagnostics with a set of measurement techniques that can be used in a sub-critical reactor environment. Such measurements are primarily connected to system safety and validation. This report shows that in-core fast-neutron diagnostics can be employed to monitor changes in the position of incidence of the primary proton beam onto the neutron production target. It has also been shown that fast neutrons can be used to detect temperature-dependent density changes in a liquid lead-bismuth target. Fast neutrons can escape the system via the beam pipe for the incident proton beam. Out-of-core monitoring of these so called back-streaming neutrons could potentially be used to monitor beam changes if the target has a suitable shape. Moreover, diagnostics of back-streaming neutrons might be used for validation of the system design

  9. System and safety studies of accelerator driven transmutation Annual Report 2005

    Gudowski, Waclaw; Wallenius, Jan; Arzhanov, Vasily; Jolkkonen, Mikael; Eriksson, Marcus; Seltborg, Per; Westlen, Daniel; Lagerstedt, Christina; Isaksson, Patrick; Persson, Carl-Magnus; Aalander, Alexandra [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Nuclear and Reactor Physics

    2006-11-15

    The results of the research activities on System and Safety of Accelerator-Driven Transmutation (ADS) at the Department of Nuclear and Reactor Physics are described in this report followed by the Appendices of the relevant scientific papers published in 2005. PhD and Licentiate dissertations of Marcus Ericsson, Per Seltborg, Christina Lagerstedt and Daniel Westlen (see Appendices) reflect the research mainstream of 2005. Year 2005 was also very rich in international activities with ADS in focus. Summary of conferences, seminars and lecturing activities is given in Chapter 9 Research activities of 2005 have been focused on several areas: system and safety studies of ADS; subcritical experiments; ADS source efficiency studies; nuclear fuel cycle analysis; potential of reactor based transmutation; ADS fuel development; simulation of radiation damage; and development of codes and methods. Large part of the research activities has been well integrated with the European projects of the 5th and 6th Framework Programmes of the European Commission in which KTH is actively participating. In particular European projects: RED-IMPACT, CONFIRM, FUTURE, EUROTRANS and NURESIM.

  10. Accelerator-driven systems (ADS) and fast reactors (FR) in advanced nuclear fuel cycles

    The long-term hazard of radioactive waste arising from nuclear energy production is a matter of continued discussion and public concern in many countries. Through partitioning and transmutation (P and T) of the actinides and some of the long-lived fission products, the radiotoxicity of high-level waste (HLW) can be reduced by a factor of 100 compared with the current once-through fuel cycle. This requires very effective reactor and fuel cycle strategies, including fast reactors (FR) and/or accelerator-driven, sub-critical systems (ADS). The present study compares FR- and ADS-based actinide transmutation systems with respect to reactor properties, fuel cycle requirements, safety, economic aspects and (R and D) needs. Several advanced fuel cycle strategies are analysed in a consistent manner to provide insight into the essential differences between the various systems in which the role of ADS is emphasised. The report includes a summary aimed at policy makers and research managers as well as a detailed technical section for experts in this domain. (authors)

  11. Numerical simulations of subcritical reactor kinetics in thermal hydraulic transient phases

    Yoo, J.; Park, W. S. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    A subcritical reactor driven by a linear proton accelerator has been considered as a nuclear waste incinerator at Korea Atomic Energy Research Institute (KAERI). Since the multiplication factor of a subcritical reactor is less than unity, to compensate exponentially decreasing fission neutrons, external neutrons form spallation reactions are essentially required for operating the reactor in its steady state. Furthermore, the profile of accelerator beam currents is very important in controlling a subcritical reactor, because the reactor power varies in accordance to the profile of external neutrons. We have developed a code system to find numerical solutions of reactor kinetics equations, which are the simplest dynamic model for controlling reactors. In a due course of our previous numerical study of point kinetics equations for critical reactors, however, we learned that the same code system can be used in studying dynamic behavior of the subcritical reactor. Our major motivation of this paper is to investigate responses of subcritical reactors for small changes in thermal hydraulic parameters. Building a thermal hydraulic model for the subcritical reactor dynamics, we performed numerical simulations for dynamic responses of the reactor based on point kinetics equations with a source term. Linearizing a set of coupled differential equations for reactor responses, we focus our research interest on dynamic responses of the reactor to variations of the thermal hydraulic parameters in transient phases. 5 refs., 8 figs. (Author)

  12. Advanced Approaches to High Intensity Laser-Driven Ion Acceleration

    Henig, Andreas

    2010-01-01

    Since the pioneering work that was carried out 10 years ago, the generation of highly energetic ion beams from laser-plasma interactions has been investigated in much detail in the regime of target normal sheath acceleration (TNSA). Creation of ion beams with small longitudinal and transverse emittance and energies extending up to tens of MeV fueled visions of compact, laser-driven ion sources for applications such as ion beam therapy of tumors or fast ignition inertial confinement fusion. Ho...

  13. Reactivity Monitoring of Accelerator-Driven Nuclear Reactor Systems

    Uyttenhove, W.

    2016-01-01

    This thesis provides a methodology and set-up of a reactivity monitoring tool for Accelerator-Driven Systems (ADS). The reactivity monitoring tool should guarantee the operation of an ADS at a safe margin from criticality. Robustness is assured in different aspects of the monitoring tool: the choice of the measurement techniques, the evaluation methods to derive the reactivity from experimental data, and the detector type and positioning. In the first chapter of the work, the experience from ...

  14. Assessment of the transmutation capability an accelerator driven system cooled by lead bismuth eutectic alloy

    1. PURPOSE The reduction of long-lived fission products (LLFP) and minor actinides (MA) is a key point for the public acceptability and economy of nuclear energy. In principle, any nuclear fast reactor is able to burn and transmute MA, but the amount of MA content has to be limited a few percent, having unfavourable consequences on the coolant void reactivity, Doppler effect, and delayed neutron fraction, and therefore on the dynamic behaviour and control. Accelerator Driven Systems (ADS) are instead able to safely burn and/or transmute a large quantity of actinides and LLFP, as they do not rely on delayed neutrons for control or power change and the reactivity feedbacks have very little importance during accidents. Such systems are very innovative being based on the coupling of an accelerator with a subcritical system by means of a target system, where the neutronic source needed to maintain the neutron reaction chain is produced by spallation reactions. To this end the PDS-XADS (Preliminary Design Studies on an experimental Accelerator Driven System) project was funded by the European Community in the 5th Framework Program in order both to demonstrate the feasibility of the coupling between an accelerator and a sub-critical core loaded with standard MOX fuel and to investigate the transmutation capability in order to achieve values suitable for an Industrial Scale Transmuter. This paper summarizes and compares the results of neutronic calculations aimed at evaluating the transmutation capability of cores cooled by Lead-Bismuth Eutectic alloy and loaded with assemblies based on (Pu, Am, Cm) oxide dispersed in a molybdenum metal (CERMET) or magnesia (CERCER) matrices. It also describes the constraints considered in the design of such cores and describes the thermo-mechanical behaviour of these innovative fuels along the cycle. 2. DESCRIPTION OF THE WORK: The U-free composite fuels (CERMET and CERCER) were selected for this study, being considered at European level

  15. Intense tera-hertz laser driven proton acceleration in plasmas

    Sharma, A.; Tibai, Z.; Hebling, J.

    2016-06-01

    We investigate the acceleration of a proton beam driven by intense tera-hertz (THz) laser field from a near critical density hydrogen plasma. Two-dimension-in-space and three-dimension-in-velocity particle-in-cell simulation results show that a relatively long wavelength and an intense THz laser can be employed for proton acceleration to high energies from near critical density plasmas. We adopt here the electromagnetic field in a long wavelength (0.33 THz) regime in contrast to the optical and/or near infrared wavelength regime, which offers distinct advantages due to their long wavelength ( λ = 350 μ m ), such as the λ 2 scaling of the electron ponderomotive energy. Simulation study delineates the evolution of THz laser field in a near critical plasma reflecting the enhancement in the electric field of laser, which can be of high relevance for staged or post ion acceleration.

  16. First-Order Particle Acceleration in Magnetically-driven Flows

    Beresnyak, Andrey; Li, Hui

    2016-03-01

    We demonstrate that particles are regularly accelerated while experiencing curvature drift in flows driven by magnetic tension. Some examples of such flows include spontaneous turbulent reconnection and decaying magnetohydrodynamic turbulence, where a magnetic field relaxes to a lower-energy configuration and transfers part of its energy to kinetic motions of the fluid. We show that this energy transfer, which normally causes turbulent cascade and heating of the fluid, also results in a first-order acceleration of non-thermal particles. Since it is generic, this acceleration mechanism is likely to play a role in the production of non-thermal particle distribution in magnetically dominant environments such as the solar chromosphere, pulsar magnetospheres, jets from supermassive black holes, and γ-ray bursts.

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

    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

  18. Accelerated Ions from a Laser Driven Z-pinch

    Helle, Michael H; Kaganovich, Dmitri; Chen, Yu-hsin; Palastro, John P; Ting, Antonio

    2015-01-01

    Intense laser acceleration of ions is inherently difficult due to the velocity mismatch between laser pulses moving at the speed of light and slowly moving massive ions. Instead of directly accelerating the ions, current approaches rely on TV/m laser fields to ionize and drive out electrons. The ions are then accelerated by the resulting electrostatic fields from charge separation. Here we report experimental and numerical acceleration of ions by means of laser driven Z-pinch exiting a sharp plasma interface. This is achieved by first driving a plasma wakefield in the self-modulated bubble regime. Cold return currents are generated to maintain quasi-neutrality of the plasma. The opposite current repel and form an axial fast current and a cylindrical-shell cold return current with a large (100 MG) azithmuthal field in between. These conditions produce a Z-pinch that compresses the fast electrons and ions on axis. If this process is terminated at a sharp plasma interface, a beam of ions are then accelerated in ...

  19. MUSE-1: A first experiment at MASURCA to validate the physics of sub-critical multiplying systems relevant to ADS

    In the framework of CEA programme ISAAC, devoted to Accelerator-Driven Systems, several experiments activities have been launched. A significant experimental programme is underway in MASURCA experimental reactor in Cadarache to validate the physics of subcritical multiplying media. The first experiment MUSE-1 performed in December 1995 is described in the present paper, and a first analysis of the result obtained is given

  20. Advanced approaches to high intensity laser-driven ion acceleration

    Since the pioneering work that was carried out 10 years ago, the generation of highly energetic ion beams from laser-plasma interactions has been investigated in much detail in the regime of target normal sheath acceleration (TNSA). Creation of ion beams with small longitudinal and transverse emittance and energies extending up to tens of MeV fueled visions of compact, laser-driven ion sources for applications such as ion beam therapy of tumors or fast ignition inertial con finement fusion. However, new pathways are of crucial importance to push the current limits of laser-generated ion beams further towards parameters necessary for those applications. The presented PhD work was intended to develop and explore advanced approaches to high intensity laser-driven ion acceleration that reach beyond TNSA. In this spirit, ion acceleration from two novel target systems was investigated, namely mass-limited microspheres and nm-thin, free-standing diamond-like carbon (DLC) foils. Using such ultrathin foils, a new regime of ion acceleration was found where the laser transfers energy to all electrons located within the focal volume. While for TNSA the accelerating electric field is stationary and ion acceleration is spatially separated from laser absorption into electrons, now a localized longitudinal field enhancement is present that co-propagates with the ions as the accompanying laser pulse pushes the electrons forward. Unprecedented maximum ion energies were obtained, reaching beyond 0.5 GeV for carbon C6+ and thus exceeding previous TNSA results by about one order of magnitude. When changing the laser polarization to circular, electron heating and expansion were shown to be efficiently suppressed, resulting for the first time in a phase-stable acceleration that is dominated by the laser radiation pressure which led to the observation of a peaked C6+ spectrum. Compared to quasi-monoenergetic ion beam generation within the TNSA regime, a more than 40 times increase in

  1. Advanced approaches to high intensity laser-driven ion acceleration

    Henig, Andreas

    2010-04-26

    Since the pioneering work that was carried out 10 years ago, the generation of highly energetic ion beams from laser-plasma interactions has been investigated in much detail in the regime of target normal sheath acceleration (TNSA). Creation of ion beams with small longitudinal and transverse emittance and energies extending up to tens of MeV fueled visions of compact, laser-driven ion sources for applications such as ion beam therapy of tumors or fast ignition inertial con finement fusion. However, new pathways are of crucial importance to push the current limits of laser-generated ion beams further towards parameters necessary for those applications. The presented PhD work was intended to develop and explore advanced approaches to high intensity laser-driven ion acceleration that reach beyond TNSA. In this spirit, ion acceleration from two novel target systems was investigated, namely mass-limited microspheres and nm-thin, free-standing diamond-like carbon (DLC) foils. Using such ultrathin foils, a new regime of ion acceleration was found where the laser transfers energy to all electrons located within the focal volume. While for TNSA the accelerating electric field is stationary and ion acceleration is spatially separated from laser absorption into electrons, now a localized longitudinal field enhancement is present that co-propagates with the ions as the accompanying laser pulse pushes the electrons forward. Unprecedented maximum ion energies were obtained, reaching beyond 0.5 GeV for carbon C{sup 6+} and thus exceeding previous TNSA results by about one order of magnitude. When changing the laser polarization to circular, electron heating and expansion were shown to be efficiently suppressed, resulting for the first time in a phase-stable acceleration that is dominated by the laser radiation pressure which led to the observation of a peaked C{sup 6+} spectrum. Compared to quasi-monoenergetic ion beam generation within the TNSA regime, a more than 40 times

  2. Development of an accelerating-piston implosion-driven launcher

    Huneault, Justin; Loiseau, Jason; Higgins, Andrew

    2013-06-01

    The ability to soft-launch projectiles at velocities exceeding 10 km/s is of interest to several scientific fields, including orbital debris impact testing and equation of state research. Current soft-launch technologies have reached a performance plateau below this operating range. The energy and power density of high explosives provides a possible avenue to reach this velocity if used to dynamically compress a light driver gas to significantly higher pressures and temperatures compared to light-gas guns. In the implosion-driven launcher (IDL), linear implosion of a pressurized tube drives a strong shock into the gas ahead of the tube pinch, thereby forming an increasingly long column of compressed gas which can be used to propel a projectile. The McGill IDL has demonstrated the ability to launch a 0.1-g projectile to 9.1 km/s. This study focuses on the implementation of a novel launch cycle wherein the explosively driven pinch is accelerated down the length of the tube in order to maintain a relatively constant projectile base pressure early in the launch cycle. The experimental development of an accelerating driver which utilizes an explosive lens to phase the detonation wave is presented. The design and experimental performance of an accelerating-piston IDL is also discussed.

  3. Reactivity determination in accelerator driven nuclear reactors by statistics from neutron detectors (Feynman-Alpha Method)

    The Feynman-alpha method is used in traditional nuclear reactors to determine the subcritical reactivity of a system. The method is based on the measurement of the mean number and the variance of detector counts for different measurement times. The measurement is performed while a steady-state neutron flux is maintained in the reactor by an external neutron source, as a rule a radioactive source. From a plot of the variance-to-mean ratio as a function of measurement time ('gate length'), the reactivity can be determined by fitting the measured curve to the analytical solution. A new situation arises in the planned accelerator driven systems (ADS). An ADS will be run in a subcritical mode, and the steady flux will be maintained by an accelerator based source. Such a source has statistical properties that are different from those of a steady radioactive source. As one example, in a currently running European Community project for ADS research, the MUSE project, the source will be a periodically pulsed neutron generator. The theory of Feynman-alpha method needs to be extended to such nonstationary sources. There are two ways of performing and evaluating such pulsed source experiments. One is to synchronise the detector time gate start with the beginning of an incoming pulse. The Feynman-alpha method has been elaborated for such a case recently. The other method can be called stochastic pulsing. It means that there is no synchronisation between the detector time gate start and the source pulsing, i.e. the start of each measurement is chosen at a random time. The analytical solution to the Feynman-alpha formula from this latter method is the subject of this report. We have obtained an analytical Feynman-alpha formula for the case of stochastic pulsing by two different methods. One is completely based on the use of the symbolic algebra code Mathematica, whereas the other is based on complex function techniques. Closed form solutions could be obtained by both methods

  4. Monte Carlo Alpha Iteration Algorithm for a Subcritical System Analysis

    Hyung Jin Shim

    2015-01-01

    Full Text Available The α-k iteration method which searches the fundamental mode alpha-eigenvalue via iterative updates of the fission source distribution has been successfully used for the Monte Carlo (MC alpha-static calculations of supercritical systems. However, the α-k iteration method for the deep subcritical system analysis suffers from a gigantic number of neutron generations or a huge neutron weight, which leads to an abnormal termination of the MC calculations. In order to stably estimate the prompt neutron decay constant (α of prompt subcritical systems regardless of subcriticality, we propose a new MC alpha-static calculation method named as the α iteration algorithm. The new method is derived by directly applying the power method for the α-mode eigenvalue equation and its calculation stability is achieved by controlling the number of time source neutrons which are generated in proportion to α divided by neutron speed in MC neutron transport simulations. The effectiveness of the α iteration algorithm is demonstrated for two-group homogeneous problems with varying the subcriticality by comparisons with analytic solutions. The applicability of the proposed method is evaluated for an experimental benchmark of the thorium-loaded accelerator-driven system.

  5. Transformer ratio saturation in a beam-driven wakefield accelerator

    Farmer, J. P.; Martorelli, R.; Pukhov, A. [Institut für Theoretische Physik I, Heinrich Heine Universität, 40225 Düsseldorf (Germany)

    2015-12-15

    We show that for beam-driven wakefield acceleration, the linearly ramped, equally spaced train of bunches typically considered to optimise the transformer ratio only works for flat-top bunches. Through theory and simulation, we explain that this behaviour is due to the unique properties of the plasma response to a flat-top density profile. Calculations of the optimal scaling for a train of Gaussian bunches show diminishing returns with increasing bunch number, tending towards saturation. For a periodic bunch train, a transformer ratio of 23 was achieved for 50 bunches, rising to 40 for a fully optimised beam.

  6. Stochastic acceleration of ions driven by Pc1 wave packets

    The stochastic motion of protons and He+ ions driven by Pc1 wave packets is studied in the context of resonant particle heating. Resonant ion cyclotron heating typically occurs when wave powers exceed 10−4 nT2/Hz. Gyroresonance breaks the first adiabatic invariant and energizes keV ions. Cherenkov resonances with the electrostatic component of wave packets can also accelerate ions. The main effect of this interaction is to accelerate thermal protons to the local Alfven speed. The dependencies of observable quantities on the wave power and plasma parameters are determined, and estimates for the heating extent and rate of particle heating in these wave-particle interactions are shown to be in reasonable agreement with known empirical data

  7. Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams

    Schroeder, C. B.

    2011-01-01

    Plasma accelerators may be driven by the ponderomotive force of an intense laser or the space-charge force of a charged particle beam. The implications for accelerator design and the different physical mechanisms of laser-driven and beam-driven plasma acceleration are discussed. Driver propagation is examined, as well as the effects of the excited plasma wave phase velocity. The driver coupling to subsequent plasma accelerator stages for high-energy physics applications is addressed.

  8. Super- and Sub-critical Regions in Shocks driven by Radio-Loud and Radio-Quiet CMEs

    Alessandro Bemporad; Salvatore Mancuso

    2012-01-01

    White-light coronagraphic images of Coronal Mass Ejections (CMEs) observed by SOHO/LASCO C2 have been used to estimate the density jump along the whole front of two CME-driven shocks. The two events are different in that the first one was a “radio-loud” fast CME, while the second one was a “radio quiet” slow CME. From the compression ratios inferred along the shock fronts, we estimated the Alfvén Mach numbers for the general case of an oblique shock. It turns out that the “radio-loud” CME sho...

  9. Editorial: Focus on Laser- and Beam-Driven Plasma Accelerators

    Joshi, Chan; Malka, Victor

    2010-04-01

    The ability of short but intense laser pulses to generate high-energy electrons and ions from gaseous and solid targets has been well known since the early days of the laser fusion program. However, during the past decade there has been an explosion of experimental and theoretical activity in this area of laser-matter interaction, driven by the prospect of realizing table-top plasma accelerators for research, medical and industrial uses, and also relatively small and inexpensive plasma accelerators for high-energy physics at the frontier of particle physics. In this focus issue on laser- and beam-driven plasma accelerators, the latest advances in this field are described. Focus on Laser- and Beam-Driven Plasma Accelerators Contents Slow wave plasma structures for direct electron acceleration B D Layer, J P Palastro, A G York, T M Antonsen and H M Milchberg Cold injection for electron wakefield acceleration X Davoine, A Beck, A Lifschitz, V Malka and E Lefebvre Enhanced proton flux in the MeV range by defocused laser irradiation J S Green, D C Carroll, C Brenner, B Dromey, P S Foster, S Kar, Y T Li, K Markey, P McKenna, D Neely, A P L Robinson, M J V Streeter, M Tolley, C-G Wahlström, M H Xu and M Zepf Dose-dependent biological damage of tumour cells by laser-accelerated proton beams S D Kraft, C Richter, K Zeil, M Baumann, E Beyreuther, S Bock, M Bussmann, T E Cowan, Y Dammene, W Enghardt, U Helbig, L Karsch, T Kluge, L Laschinsky, E Lessmann, J Metzkes, D Naumburger, R Sauerbrey, M. Scḧrer, M Sobiella, J Woithe, U Schramm and J Pawelke The optimum plasma density for plasma wakefield excitation in the blowout regime W Lu, W An, M Zhou, C Joshi, C Huang and W B Mori Plasma wakefield acceleration experiments at FACET M J Hogan, T O Raubenheimer, A Seryi, P Muggli, T Katsouleas, C Huang, W Lu, W An, K A Marsh, W B Mori, C E Clayton and C Joshi Electron trapping and acceleration on a downward density ramp: a two-stage approach R M G M Trines, R Bingham, Z Najmudin

  10. A regulated power supply for accelerator driven system

    This paper discusses a regulated high voltage power supply (RHVPS) developed for accelerator driven systems to drive a klystron. The RHVPS uses a large no. of small voltage choppers. These choppers are switched in tandem by a novel technique to regulate output voltage. Various parts of the system are novel. The front end is a pair of transformer with 40 secondaries each. Each secondary feeds a switched power module (SPM) which has a rectifier-filter unit followed by an IGBT switch to get 1.3 kV. All 80 SPMs are connected in series. The final output is taken from the two end SPMs. A central controller uses voltage sample from each SPM and generates switching pulses for each IGBT switch. IGBTs of all SPMs are switched with a fixed phase lag from each other, resulting in purely constant voltage with ripple limited to one SPM voltage. The frequency of ripple is high and can be filtered out with a simpler filter. The system can turn off for protection of the load in less than 2 microseconds, the essential attribute for a power supply to be used with klystrons. The results of wire burn tests measure the low stored energy at fault turn off (less than10 J). The power supply (rated for 100 kV at 2.5 MW) will be used for a continuous duty with the klystron for accelerator driven system at BARC (India). A power supply giving 80 kV, 75A is being used with an accelerator system for extraction of beam along with a Neutral Beam Injector. This paper discusses the technology and experimental results of the system. It also discusses various other options with similar power supply. (author)