Monte Carlo method in radiation transport problems
International Nuclear Information System (INIS)
Dejonghe, G.; Nimal, J.C.; Vergnaud, T.
1986-11-01
In neutral radiation transport problems (neutrons, photons), two values are important: the flux in the phase space and the density of particles. To solve the problem with Monte Carlo method leads to, among other things, build a statistical process (called the play) and to provide a numerical value to a variable x (this attribution is called score). Sampling techniques are presented. Play biasing necessity is proved. A biased simulation is made. At last, the current developments (rewriting of programs for instance) are presented due to several reasons: two of them are the vectorial calculation apparition and the photon and neutron transport in vacancy media [fr
Renormalization-group approach to nonlinear radiation-transport problems
International Nuclear Information System (INIS)
Chapline, G.F.
1980-01-01
A Monte Carlo method is derived for solving nonlinear radiation-transport problems that allows one to average over the effects of many photon absorptions and emissions at frequencies where the opacity is large. This method should allow one to treat radiation-transport problems with large optical depths, e.g., line-transport problems, with little increase in computational effort over that which is required for optically thin problems
International Nuclear Information System (INIS)
Kong, Rong; Spanier, Jerome
2013-01-01
In this paper we develop novel extensions of collision and track length estimators for the complete space-angle solutions of radiative transport problems. We derive the relevant equations, prove that our new estimators are unbiased, and compare their performance with that of more conventional estimators. Such comparisons based on numerical solutions of simple one dimensional slab problems indicate the the potential superiority of the new estimators for a wide variety of more general transport problems
To the development of numerical methods in problems of radiation transport
International Nuclear Information System (INIS)
Germogenova, T.A.
1990-01-01
Review of studies on the development of numerical methods and the discrete ordinate method in particular, used for solution of radiation protection physics problems is given. Consideration is given to the problems, which arise when calculating fields of penetrating radiation and when studying processes of charged-particle transport and cascade processes, generated by high-energy primary radiation
Energy Technology Data Exchange (ETDEWEB)
Urbatsch, Todd James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-06-15
We present an overview of radiation transport, covering terminology, blackbody raditation, opacities, Boltzmann transport theory, approximations to the transport equation. Next we introduce several transport methods. We present a section on Caseology, observing transport boundary layers. We briefly broach topics of software development, including verification and validation, and we close with a section on high energy-density experiments that highlight and support radiation transport.
Nonlinear radiation transport problems involving widely varying mean free paths
International Nuclear Information System (INIS)
Chapline, G. Jr.; Wood, L.
1976-01-01
In this report a method is given for modifying the Monte-Carlo approach so that one can accurately treat problems that involve both large and small mean free paths. This method purports to offer the advantages of the general Monte Carlo technique as far as relatively great accuracy of simulation of microscopic physical phenomena is concerned, and the advantage of a diffusion theory approach as far as decent time steps in thick problems are concerned; it does suffer from something of the statistical fluctuation problems of the Monte Carlo, although in analytically attenuated and modified form
Introduction to radiation transport
International Nuclear Information System (INIS)
Olson, G.L.
1998-01-01
This lecture will present time-dependent radiation transport where the radiation is coupled to a static medium, i.e., the material is not in motion. In reality, radiation exerts a pressure on the materials it propagates through and will accelerate the material in the direction of the radiation flow. This fully coupled problem with radiation transport and materials in motion is referred to as radiation-hydrodynamics (or in a shorthand notation: rad-hydro) and is beyond the scope of this lecture
C5 Benchmark Problem with Discrete Ordinate Radiation Transport Code DENOVO
Energy Technology Data Exchange (ETDEWEB)
Yesilyurt, Gokhan [ORNL; Clarno, Kevin T [ORNL; Evans, Thomas M [ORNL; Davidson, Gregory G [ORNL; Fox, Patricia B [ORNL
2011-01-01
The C5 benchmark problem proposed by the Organisation for Economic Co-operation and Development/Nuclear Energy Agency was modeled to examine the capabilities of Denovo, a three-dimensional (3-D) parallel discrete ordinates (S{sub N}) radiation transport code, for problems with no spatial homogenization. Denovo uses state-of-the-art numerical methods to obtain accurate solutions to the Boltzmann transport equation. Problems were run in parallel on Jaguar, a high-performance supercomputer located at Oak Ridge National Laboratory. Both the two-dimensional (2-D) and 3-D configurations were analyzed, and the results were compared with the reference MCNP Monte Carlo calculations. For an additional comparison, SCALE/KENO-V.a Monte Carlo solutions were also included. In addition, a sensitivity analysis was performed for the optimal angular quadrature and mesh resolution for both the 2-D and 3-D infinite lattices of UO{sub 2} fuel pin cells. Denovo was verified with the C5 problem. The effective multiplication factors, pin powers, and assembly powers were found to be in good agreement with the reference MCNP and SCALE/KENO-V.a Monte Carlo calculations.
A hopfield-like artificial neural network for solving inverse radiation transport problems
International Nuclear Information System (INIS)
Lee, Sang Hoon
1997-02-01
In this thesis, we solve inverse radiation transport problems by an Artificial Neural Network(ANN) approach. ANNs have many interesting properties such as nonlinear, parallel, and distributed processing. Some of the promising applications of ANNs are optimization, image and signal processing, system control, etc. In some optimization problems, Hopfield Neural Network(HNN) which has one-layered and fully interconnected neurons with feed-back topology showed that it worked well with acceptable fault tolerance and efficiency. The identification of radioactive source in a medium with a limited number of external detectors is treated as an inverse radiation transport problem in this work. This kind of inverse problem is usually ill-posed and severely under-determined; however, its applications are very useful in many fields including medical diagnosis and nondestructive assay of nuclear materials. Therefore, it is desired to develop efficient and robust solution algorithms. Firstly, we study a representative ANN model which has learning ability and fault tolerance, i.e., feed-forward neural network. It has an error backpropagation learning algorithm processed by reducing error in learning patterns that are usually results of test or calculation. Although it has enough fault tolerance and efficiency, a major obstacle is 'curse of dimensionality'--required number of learning patterns and learning time increase exponentially proportional to the problem size. Therefore, in this thesis, this type of ANN is used as benchmarking the reliability of the solution. Secondly, another approach for solving inverse problems, a modified version of HNN is proposed. When diagonal elements of the interconnection matrix are not zero, HNN may become unstable. However, most problems including this identification problem contain non-zero diagonal elements when programmed on neural networks. According to Soulie et al., discrete random iterations could produce the stable minimum state
International Nuclear Information System (INIS)
Ignatovich, V.K.
1989-01-01
The equations. governing the transport of radiation in plane media of finite thickness are formulated and solved in terms reflection and extintion of radiation inthe case of semi infinite media. 13 refs
Present and future problems of radiation shielding for maritime transport of nuclear spent fuels
International Nuclear Information System (INIS)
Ueki, K.; Nariyama, N.; Ohashi, A.
2000-01-01
The transport of spent fuels with casks began in September 1999 by the exclusive spent fuel transport vessel the 'Rokuei Maru'. The casks have been transported to the reprocessing plant at Rokkasho-village in Aomori Prefecture. The 'Rokuei Maru' is approximately 100 m-length, 16.5 m-width and 3,000 gross-tons. The 20 NFT casks can be loaded into 5 holds. At the present time, the NFT casks can carry spent fuels of up to 44,000 MWD/MTU. Serpentine concrete is employed as a neutron shields in the hatch covers, the bulkheads, and the house front of the accommodations except the wheelhouse. Polyethylene covers the side walls in each hold. The neutron shielding ability of serpentine concrete and polyethylene was investigated by a shielding experiment using a 252 Cf-neutron source. The shielding experiment was analyzed with the Monte Carlo code MCNP 4B. In the near future, on-board experiment will be carried out to measure the dose-equivalent rate distributions in the 'Rokuei Maru' and the measured data and the Monte Carlo analysis of it will establish the radiation safety of the ship. (author)
Study of the sensitivity of the radiation transport problem in a scattering medium
International Nuclear Information System (INIS)
Nunes, Rogerio Chaffin
2002-03-01
In this work, the system of differential equations obtained by the angular approach of the two-dimensional transport equation by the discrete ordinates method is solved through the formulation of finite elements with the objective of investigating the sensitivity of the outgoing flux of radiation with the incoming flux and the properties of absorption and scattering of the medium. The variational formulation for the system of differential equations of second order with the generalized boundary conditions of Neumann (third type) allows an easy implementation of the method of the finite elements with triangular mesh and approximation space of first order. The geometry chosen for the simulations is a circle with a non homogeneous circular form in its interior. The mapping of Dirichlet-Neumann is studied through various simulations involving the incoming flux, the outgoing flux and the properties of the medium. (author)
Deterministic methods in radiation transport
International Nuclear Information System (INIS)
Rice, A.F.; Roussin, R.W.
1992-06-01
The Seminar on Deterministic Methods in Radiation Transport was held February 4--5, 1992, in Oak Ridge, Tennessee. Eleven presentations were made and the full papers are published in this report, along with three that were submitted but not given orally. These papers represent a good overview of the state of the art in the deterministic solution of radiation transport problems for a variety of applications of current interest to the Radiation Shielding Information Center user community
Forms of Approximate Radiation Transport
Brunner, G
2002-01-01
Photon radiation transport is described by the Boltzmann equation. Because this equation is difficult to solve, many different approximate forms have been implemented in computer codes. Several of the most common approximations are reviewed, and test problems illustrate the characteristics of each of the approximations. This document is designed as a tutorial so that code users can make an educated choice about which form of approximate radiation transport to use for their particular simulation.
Spent fuel transportation problems
International Nuclear Information System (INIS)
Kondrat'ev, A.N.; Kosarev, Yu.A.; Yulikov, E.A.
1977-01-01
In this paper, problems of transportation of nuclear spent fuel to reprocessing plants are discussed. The solutions proposed are directed toward the achievement of the transportation as economic and safe as possible. The increase of the nuclear power plants number in the USSR and the great distances between these plants and the reprocessing plants involve an intensification of the spent fuel transportation. Higher burnup and holdup time reduction cause the necessity of more bulky casks. In this connection, the economic problems become still more important. One of the ways of the problem solution is the development of rational and cheap cask designs. Also, the enforcement in the world of the environmental and personnel health protection requires to increase the transportation reliability and safety. The paper summarizes safe transportation rules with clarifying the following questions: the increase of the transport unit quantity of the spent fuel; rational shipment organization that minimizes vehicle turnover cycle duration; development of the reliable calculation methods to determine strength, thermal conditions and nuclear safety of transport packaging as applied to the vehicles of high capacity; maximum unification of vehicles, calculation methods and documents; and cask testing on models and in pilot scale on specific test rigs to assure that they meet the international safe fuel shipment rules. Besides, some considerations on the choice and use of structural materials for casks are given, and problems of manufacturing such casks from uranium and lead are considered, as well as problems of the development of fireproof shells, control instrumentation, vehicles decontamination, etc. All the problems are considered from the point of view of normal and accidental shipment conditions. Conclusions are presented [ru
International Nuclear Information System (INIS)
Avery, A.F.; Locke, H.F.
1992-03-01
In 1985 the Reactor Physics Committee of the Nuclear Energy Agency initiated an intercomparison of codes for the calculation of the performance of shielding for the transportation of spent reactor fuel. The results of the application of a range of codes to the prediction of the dose-rates in the four theoretical benchmarks set to examine the attenuation of radiation through a variety of cask geometries are presented in this report. The contributions from neutrons, fission product gamma-rays and secondary gamma-rays are tabulated separately, and grouped according to the type of method of calculation employed. A brief discussion is included for each set of results, and overall comparisons of the methods, codes, and nuclear data are made. A number of conclusions are drawn on the advantages and disadvantages of the various methods of calculation, based upon the results of their application to these four benchmark problems
Radiation transport in numerical astrophysics
International Nuclear Information System (INIS)
Lund, C.M.
1983-02-01
In this article, we discuss some of the numerical techniques developed by Jim Wilson and co-workers for the calculation of time-dependent radiation flow. Difference equations for multifrequency transport are given for both a discrete-angle representation of radiation transport and a Fick's law-like representation. These methods have the important property that they correctly describe both the streaming and diffusion limits of transport theory in problems where the mean free path divided by characteristic distances varies from much less than one to much greater than one. They are also stable for timesteps comparable to the changes in physical variables, rather than being limited by stability requirements
Energy Technology Data Exchange (ETDEWEB)
Wang, C.; Abdel-Khalik, H. S. [Dept. of Nuclear Engineering, North Caroline State Univ., Raleigh, NC 27695 (United States)
2012-07-01
The construction of surrogate models for high fidelity models is now considered an important objective in support of all engineering activities which require repeated execution of the simulation, such as verification studies, validation exercises, and uncertainty quantification. The surrogate must be computationally inexpensive to allow its repeated execution, and must be computationally accurate in order for its predictions to be credible. This manuscript introduces a new surrogate construction approach that reduces the dimensionality of the state solution via a range-finding algorithm from linear algebra. It then employs a proper orthogonal decomposition-like approach to solve for the reduced state. The algorithm provides an upper bound on the error resulting from the reduction. Different from the state-of-the-art, the new approach allows the user to define the desired accuracy a priori which controls the maximum allowable reduction. We demonstrate the utility of this approach using an eigenvalue radiation diffusion model, where the accuracy is selected to match machine precision. Results indicate that significant reduction is possible for typical reactor assembly models, which are currently considered expensive given the need to employ very fine mesh many group calculations to ensure the highest possible fidelity for the downstream core calculations. Given the potential for significant reduction in the computational cost, we believe it is possible to rethink the manner in which homogenization theory is currently employed in reactor design calculations. (authors)
Gupta, S. R. D.; Gupta, Santanu D.
1991-10-01
The flow of laser radiation in a plane-parallel cylindrical slab of active amplifying medium with axial symmetry is treated as a problem in radiative transfer. The appropriate one-dimensional transfer equation describing the transfer of laser radiation has been derived by an appeal to Einstein's A, B coefficients (describing the processes of stimulated line absorption, spontaneous line emission, and stimulated line emission sustained by population inversion in the medium) and considering the 'rate equations' to completely establish the rational of the transfer equation obtained. The equation is then exactly solved and the angular distribution of the emergent laser beam intensity is obtained; its numerically computed values are given in tables and plotted in graphs showing the nature of peaks of the emerging laser beam intensity about the axis of the laser cylinder.
Framework of synchromodal transportation problems
Juncker, M.A.M. de; Huizing, D.; Vecchyo, M.R.O. del; Phillipson, F.; Sangers, A.
2017-01-01
Problem statements and solution methods in mathematical synchromodal transportation problems depend greatly on a set of model choices for which no rule of thumb exists. In this paper, a framework is introduced with which the model choices in synchromodal transportation problems can be classified,
Framework of Synchromodal Transportation Problems
Huncker, M.A.M. de; Huizing, D.; Ortega del Vecchyo, M.R.; Phillipson, F.; Sangers, A.
2017-01-01
Problem statements and solution methods in mathematical synchromodal transportation problems depend greatly on a set of model choices for which no rule of thumb exists. In this paper, a framework is introduced with which the model choices in synchromodal transportation problems can be classified,
Handling and Transport Problems
Energy Technology Data Exchange (ETDEWEB)
Pomarola, J. [Head of Technical Section, Atomic Energy Commission, Saclay (France); Savouyaud, J. [Head of Electro-Mechanical Sub-Division, Atomic Energy Commission, Saclay (France)
1960-07-01
Arrangements for special or dangerous transport operations by road arising out of the activities of the Atomic Energy Commission are made by the Works and Installations Division which acts in concert with the Monitoring and Protection Division (MPD) whenever radioactive substances or appliances are involved. In view of the risk of irradiation and contamination entailed in handling and transporting radioactive substances, including waste, a specialized transport and storage team has been formed as a complement to the emergency and decontamination teams.
International Nuclear Information System (INIS)
Haas, K.F.
1975-01-01
Assuming that very often a long transport route from the factory of the manufacturer to the provided site has to be reckoned with, in general only transport with a ship is possible. As each site is only called by a certain steamship line, at a very early stage of planning the nuclear power plant the possibilities and capacities of the lines and means of transportation under discussion should be investigated. In planning the unloading equipment at the site, due consideration should be given to the fact that at a later time this equipment should also be suitable for the transport of heavy components and spent fuel assemblies. (orig.) [de
International Nuclear Information System (INIS)
Rose, S.J.; Evans, R.G.
1983-09-01
The transport of energy by X-ray photons has been included in the lD Lagrangian hydrodynamics code, MEDUSA. Calculations of the implosion by 0.53 μm laser irradiation of plastic and glass microballoons of current interest at the Central Laser Facility show that radiation preheats the fill gas and alters the temperature and density profiles during the implosion. A lower maximum gas temperature is obtained and this results, for a DT gas fill, in a greatly reduced neutron yield. (author)
International Nuclear Information System (INIS)
Davis, A. B.
2007-01-01
A simple and effective framework is presented for modeling transport processes unfolding at computationally and/or observationally unresolved scales in scattering, absorbing and emitting media. The new approach acts directly on the spatial (i.e., propagation) part of the kernel in the integral formulation of the generic linear transport equation framed for stochastic media with a wide variety of spatial correlations, going far beyond the Markov-Poisson class used in the classic Pomraning-Levermore model. This statistical look at the extinction of un-collided particle beams takes us away from the standard exponential law of transmission. New transmission laws arise that are generally not exponential, often not even for asymptotically large jumps. This means that, from this perspective on random spatial variability, there is no 'effective medium' per se nor homogenization technique that can be used to describe the effects of unresolved fluctuations of the collision coefficient. However, one can still rewrite the transport equation, at least in its integral form, in a manner that looks like its counterpart for uniform media, but with a modified propagation kernel. Implementation in a Monte Carlo scheme is trivially simple and numerical results are presented that illustrate the bulk effect of the new parameterization for plane-parallel geometry. We survey time-domain diagnostics of solar radiative transfer in the Earth's cloudy atmosphere obtained recently from high-resolution ground-based spectroscopy, and it is shown that they are explained comprehensively by the new model. Finally, we discuss possible applications of this modeling framework in nuclear engineering. (authors)
Problems in astrophysical radiation hydrodynamics
International Nuclear Information System (INIS)
Castor, J.I.
1983-01-01
The basic equations of radiation hydrodynamics are discussed in the regime that the radiation is dynamically as well as thermally important. Particular attention is paid to the question of what constitutes an acceptable approximate non-relativistic system of dynamical equations for matter and radiation in this regime. Further discussion is devoted to two classes of application of these ideas. The first class consists of problems dominated by line radiation, which is sensitive to the velocity field through the Doppler effect. The second class is of problems in which the advection of radiation by moving matter dominates radiation diffusion
International Nuclear Information System (INIS)
Lee, E.P.
1977-01-01
In a recent report (UCID 17346, ''Relativistic Particle Beam in a Semi-Infinite Axially Symmetric conducting channel extending from a perfectly conducting plane,'' Dec. 13, 1976) Cooper and Neil demonstrate that the net charge transported by a beam pulse injected into a channel of finite conductivity equals the charge of the beam itself. The channel is taken to be infinite in the positive z direction, has finite radius and is terminated by a conducting ground plane at z =0. This result is not an obvious one, and it is restricted in its applicability by the special model assumed for the channel. It is the purpose to explain the result of Cooper and Neil in more qualitative terms and to make similar calculations using several other channel models. It must be emphasized that these calculations are not concerned with the fate of the transported charge after the pulse has stopped, but rather with how much charge leaves the ground plane assuming the pulse does not stop
Energy Technology Data Exchange (ETDEWEB)
Nunes, Rogerio Chaffin
2002-03-15
In this work, the system of differential equations obtained by the angular approach of the two-dimensional transport equation by the discrete ordinates method is solved through the formulation of finite elements with the objective of investigating the sensitivity of the outgoing flux of radiation with the incoming flux and the properties of absorption and scattering of the medium. The variational formulation for the system of differential equations of second order with the generalized boundary conditions of Neumann (third type) allows an easy implementation of the method of the finite elements with triangular mesh and approximation space of first order. The geometry chosen for the simulations is a circle with a non homogeneous circular form in its interior. The mapping of Dirichlet-Neumann is studied through various simulations involving the incoming flux, the outgoing flux and the properties of the medium. (author)
A Problem on Optimal Transportation
Cechlarova, Katarina
2005-01-01
Mathematical optimization problems are not typical in the classical curriculum of mathematics. In this paper we show how several generalizations of an easy problem on optimal transportation were solved by gifted secondary school pupils in a correspondence mathematical seminar, how they can be used in university courses of linear programming and…
Traveling Salesman Problem with Transportation
Directory of Open Access Journals (Sweden)
Valeriu Ungureanu
2006-09-01
Full Text Available Traveling Salesman Problem (TSP is a generic name that includes diverse practical models. Motivated by applications, a new model of TSP is examined – a synthesis of classical TSP and classical Transportation Problem. Algorithms based on Integer Programming cutting-plane methods and Branch and Bound Techniques are obvious.
A multigroup treatment of radiation transport
International Nuclear Information System (INIS)
Tahir, N.A.; Laing, E.W.; Nicholas, D.J.
1980-12-01
A multi-group radiation package is outlined which will accurately handle radiation transfer problems in laser-produced plasmas. Bremsstrahlung, recombination and line radiation are included as well as fast electron Bremsstrahlung radiation. The entire radiation field is divided into a large number of groups (typically 20), which diffuse radiation energy in real space as well as in energy space, the latter occurring via electron-radiation interaction. Using this model a radiation transport code will be developed to be incorporated into MEDUSA. This modified version of MEDUSA will be used to study radiative preheat effects in laser-compression experiments at the Central Laser Facility, Rutherford Laboratory. The model is also relevant to heavy ion fusion studies. (author)
Problems of radiation protection
International Nuclear Information System (INIS)
Minkova, M.
1991-01-01
A brief review is presented on the dose-dependent radiation injuries and possibilities of the classical chemical radioprotectors. Data are given on different substances of biological origin, including some natural for the body admixtures with a confirmed radioprotective action: biogenic amines (serotonin, mexamine), adenylic nucleotides, amino acids, polyamines, immunomodulators (bacterial endotoxines), prostaglandins, leucotrienes, antioxidants, vitamines (A, E, B 2 , B 6 , P, biotin, flavenoids), natural fats, plant oils and unsaturated fat acids, extracts from green seaweeds and adaptogens. 81 refs
Problems of radiation protection
Energy Technology Data Exchange (ETDEWEB)
Minkova, M [Meditsinska Akademiya, Sofia (Bulgaria). Nauchen Inst. po Rentgenologiya i Radiobiologiya
1991-01-01
A brief review is presented on the dose-dependent radiation injuries and possibilities of the classical chemical radioprotectors. Data are given on different substances of biological origin, including some natural for the body admixtures with a confirmed radioprotective action: biogenic amines (serotonin, mexamine), adenylic nucleotides, amino acids, polyamines, immunomodulators (bacterial endotoxines), prostaglandins, leucotrienes, antioxidants, vitamines (A, E, B{sub 2}, B{sub 6}, P, biotin, flavenoids), natural fats, plant oils and unsaturated fat acids, extracts from green seaweeds and adaptogens. 81 refs.
Transport of radioactivity and radiation
International Nuclear Information System (INIS)
De Beer, G.P.
1988-01-01
The movement of radioactivity and radiation is of prime importance in a wide variety of fields and the present advanced degree of knowledge of transport mechanisms is due largely to the application of sophisticated computer techniques
Problems in practical radiation education
Energy Technology Data Exchange (ETDEWEB)
Turuoka, Moriaki [Hokkaido Sapporo Kaisei Senior High School, Sapporo, Hokkaido (Japan)
1999-09-01
Based on the results of questionnaire survey carried out in 1995 and 1997 and addressed to the same students in a senior high school, Japan, the author arrived at a conclusion that the students had the chance to get information on radiation from the mass media other than at school during two school year. At school they learn through a textbook and also complementary educational materials the teachers provide which will help understanding and improving the interests in radiations. In the practice, some important problems remain unsolved: the student's feeling toward radiations as risky, inadequate descriptions on radiations found in the textbook, and the difficulties in obtaining teaching materials for experiments. These problems must be resolved first of all for the solution of our future energy supply. (S. Ohno)
Parallel thermal radiation transport in two dimensions
International Nuclear Information System (INIS)
Smedley-Stevenson, R.P.; Ball, S.R.
2003-01-01
This paper describes the distributed memory parallel implementation of a deterministic thermal radiation transport algorithm in a 2-dimensional ALE hydrodynamics code. The parallel algorithm consists of a variety of components which are combined in order to produce a state of the art computational capability, capable of solving large thermal radiation transport problems using Blue-Oak, the 3 Tera-Flop MPP (massive parallel processors) computing facility at AWE (United Kingdom). Particular aspects of the parallel algorithm are described together with examples of the performance on some challenging applications. (author)
Parallel thermal radiation transport in two dimensions
Energy Technology Data Exchange (ETDEWEB)
Smedley-Stevenson, R.P.; Ball, S.R. [AWE Aldermaston (United Kingdom)
2003-07-01
This paper describes the distributed memory parallel implementation of a deterministic thermal radiation transport algorithm in a 2-dimensional ALE hydrodynamics code. The parallel algorithm consists of a variety of components which are combined in order to produce a state of the art computational capability, capable of solving large thermal radiation transport problems using Blue-Oak, the 3 Tera-Flop MPP (massive parallel processors) computing facility at AWE (United Kingdom). Particular aspects of the parallel algorithm are described together with examples of the performance on some challenging applications. (author)
International Nuclear Information System (INIS)
Weisbi, C.R.; Oblow, E.M.; Ching, J.; White, J.E.; Wright, R.Q.; Drischler, J.
1975-08-01
Sensitivity analysis is applied to the study of an air transport benchmark calculation to quantify and distinguish between cross-section and method uncertainties. The boundary detector response was converged with respect to spatial and angular mesh size, P/sub l/ expansion of the scattering kernel, and the number and location of energy grid boundaries. The uncertainty in the detector response due to uncertainties in nuclear data is 17.0 percent (one standard deviation, not including uncertainties in energy and angular distribution) based upon the ENDF/B-IV ''error files'' including correlations in energy and reaction type. Differences of approximately 6 percent can be attributed exclusively to differences in processing multigroup transfer matrices. Formal documentation of the PUFF computer program for the generation of multigroup covariance matrices is presented. (47 figures, 14 tables) (U.S.)
Inverse problem in radionuclide transport
International Nuclear Information System (INIS)
Yu, C.
1988-01-01
The disposal of radioactive waste must comply with the performance objectives set forth in 10 CFR 61 for low-level waste (LLW) and 10 CFR 60 for high-level waste (HLW). To determine probable compliance, the proposed disposal system can be modeled to predict its performance. One of the difficulties encountered in such a study is modeling the migration of radionuclides through a complex geologic medium for the long term. Although many radionuclide transport models exist in the literature, the accuracy of the model prediction is highly dependent on the model parameters used. The problem of using known parameters in a radionuclide transport model to predict radionuclide concentrations is a direct problem (DP); whereas the reverse of DP, i.e., the parameter identification problem of determining model parameters from known radionuclide concentrations, is called the inverse problem (IP). In this study, a procedure to solve IP is tested, using the regression technique. Several nonlinear regression programs are examined, and the best one is recommended. 13 refs., 1 tab
Spent nuclear fuel transport problems
International Nuclear Information System (INIS)
Kondrat'ev, A.N.; Kosarev, Yu.A.; Yulikov, E.I.
1977-01-01
The paper considers the problems of shipping spent fuel from nuclear power stations to reprocessing plants and also the principal ways of solving these problems with a view to achieving maximum economy and safety in transport. The increase in the number of nuclear power plants in the USSR will entail an intensification of spent-fuel shipments. Higher burnup and the need to reduce cooling time call for heavier and more complex shipping containers. The problem of shipping spent fuel should be tackled comprehensively, bearing in mind the requirements of safety and economy. One solution to these problems is to develop rational and cheap designs of such containers. In addition, the world-wide trend towards more thorough protection of the environment against pollution and of the health of the population requires the devotion of constant attention to improving the reliability and safety of shipments. The paper considers the prospects for nuclear power development in the USSR and in other member countries of the CMEA (1976-1980), the composition and design of some Soviet packaging assemblies, the appropriate cooling time for spent fuel from thermal reactor power stations, procedures for reducing fuel-shipping costs, some methodological problems of container calculation and design, and finally problems of testing and checking containers on test rigs. (author)
Current problems of radiation hygiene
International Nuclear Information System (INIS)
Krotkov, F.G.; Golikov, V.Ya.
1980-01-01
Present status of radiation hygiene is considered and prospects of its further development are outlined in connection with the expansion of atomic energy use for peaceful purposes. Transfer to the new system of irradiation level reglamentation which is recommended by ICRP presupposes further investigations and data acquisition. Necessity of data acquisition on the frequency of stochastic effects of the doses not exceeding 100 rem, substantiations of methodical approaches to the assessment of the collective radiation doses of large human population groups at low levels of personal irradiation, obtaining of reliable information on the contribution of different sources into collective radiation doses are pointed out. Further investigations on the problems of radiation safety of patients and also prediction assessment of the existing systems of radioactive waste disposal, forecasting and insurance of radioactive wastes, forecasting and insurance of radiation accidents, connected with the injection of radionuclides into the biosphere deserve special attention. Perspective directions of scientific investigations in the field of occupational radiation hygiene are poined out
Problems of radiation protection optimization
International Nuclear Information System (INIS)
Morkunas, G.
2003-01-01
One of the basic principles - optimization of radiation protection - is rather well understood by everybody engaged in protection of humans from ionizing radiation. However, the practical application of this principle is very problematic. This fact can be explained by vagueness of concept of dose constraints, possible legal consequences of any decision based on this principle, traditions of prescriptive system of radiation protection requirements in some countries, insufficiency of qualified expertise. The examples of optimization problems are the different attention given to different kinds of practices, not optimized application of remedial measures, strict requirements for radioactive contamination of imported products, uncertainties in optimization in medical applications of ionizing radiation. Such tools as international co-operation including regional networks of information exchange, training of qualified experts, identification of measurable indicators used for judging about the level of optimization may be the helpful practical means in solving of these problems. It is evident that the principle of optimization can not be replaced by any other alternative despite its complexity. The means for its practical implementation shall be searched for. (author)
Available computer codes and data for radiation transport analysis
International Nuclear Information System (INIS)
Trubey, D.K.; Maskewitz, B.F.; Roussin, R.W.
1975-01-01
The Radiation Shielding Information Center (RSIC), sponsored and supported by the Energy Research and Development Administration (ERDA) and the Defense Nuclear Agency (DNA), is a technical institute serving the radiation transport and shielding community. It acquires, selects, stores, retrieves, evaluates, analyzes, synthesizes, and disseminates information on shielding and ionizing radiation transport. The major activities include: (1) operating a computer-based information system and answering inquiries on radiation analysis, (2) collecting, checking out, packaging, and distributing large computer codes, and evaluated and processed data libraries. The data packages include multigroup coupled neutron-gamma-ray cross sections and kerma coefficients, other nuclear data, and radiation transport benchmark problem results
Photonuclear Physics in Radiation Transport - II: Implementation
International Nuclear Information System (INIS)
White, M.C.; Little, R.C.; Chadwick, M.B.; Young, P.G.; MacFarlane, R.E.
2003-01-01
This is the second of two companion papers. The first paper describes model calculations and nuclear data evaluations of photonuclear reactions on isotopes of C, O, Al, Si, Ca, Fe, Cu, Ta, W, and Pb for incident photon energies up to 150 MeV. This paper describes the steps taken to process these files into transport libraries and to update the Monte Carlo N-Particle (MCNP) and MCNPX radiation transport codes to use tabular photonuclear reaction data. The evaluated photonuclear data files are created in the standard evaluated nuclear data file (ENDF) format. These files must be processed by the NJOY data processing system into A Compact ENDF (ACE) files suitable for radiation transport calculations. MCNP and MCNPX have been modified to use these new data in a self-consistent and fully integrated manner. Verification problems were used at each step along the path to check the integrity of the methodology. The resulting methodology and tools provide a comprehensive system for using photonuclear data in radiation transport calculations. Also described are initial validation simulations used to benchmark several of the photonuclear transport tables
Actual global problems of radiation protection
International Nuclear Information System (INIS)
Ninkovic, M.
1995-01-01
Personal views on some actual problems in radiation protection are given in this paper. Among these problems are: evolution methodology used in radiation protection regulations; radiation protection, nuclear energy and safety, and new approaches to the process of the hazardous substances management. An interesting fact relating to the X-ray, radiation protection and Nikola Tesla are given also. (author)
Induced Compton scattering effects in radiation transport approximations
International Nuclear Information System (INIS)
Gibson, D.R. Jr.
1982-01-01
In this thesis the method of characteristics is used to solve radiation transport problems with induced Compton scattering effects included. The methods used to date have only addressed problems in which either induced Compton scattering is ignored, or problems in which linear scattering is ignored. Also, problems which include both induced Compton scattering and spatial effects have not been considered previously. The introduction of induced scattering into the radiation transport equation results in a quadratic nonlinearity. Methods are developed to solve problems in which both linear and nonlinear Compton scattering are important. Solutions to scattering problems are found for a variety of initial photon energy distributions
Induced Compton-scattering effects in radiation-transport approximations
International Nuclear Information System (INIS)
Gibson, D.R. Jr.
1982-02-01
The method of characteristics is used to solve radiation transport problems with induced Compton scattering effects included. The methods used to date have only addressed problems in which either induced Compton scattering is ignored, or problems in which linear scattering is ignored. Also, problems which include both induced Compton scattering and spatial effects have not been considered previously. The introduction of induced scattering into the radiation transport equation results in a quadratic nonlinearity. Methods are developed to solve problems in which both linear and nonlinear Compton scattering are important. Solutions to scattering problems are found for a variety of initial photon energy distributions
Optimal calculational schemes for solving multigroup photon transport problem
International Nuclear Information System (INIS)
Dubinin, A.A.; Kurachenko, Yu.A.
1987-01-01
A scheme of complex algorithm for solving multigroup equation of radiation transport is suggested. The algorithm is based on using the method of successive collisions, the method of forward scattering and the spherical harmonics method, and is realized in the FORAP program (FORTRAN, BESM-6 computer). As an example the results of calculating reactor photon transport in water are presented. The considered algorithm being modified may be used for solving neutron transport problems
JIT-transportation problem and its algorithm
Bai, Guozhong; Gan, Xiao-Xiong
2011-12-01
This article introduces the (just-in-time) JIT-transportation problem, which requires that all demanded goods be shipped to their destinations on schedule, at a zero or minimal destination-storage cost. The JIT-transportation problem is a special goal programming problem with discrete constraints. This article provides a mathematical model for such a transportation problem and introduces the JIT solution, the deviation solution, the JIT deviation, etc. By introducing the B(λ)-problem, this article establishes the equivalence between the optimal solutions of the B(λ)-problem and the optimal solutions of the JIT-transportation problem, and then provides an algorithm for the JIT-transportation problems. This algorithm is proven mathematically and is also illustrated by an example.
Transport and attenuation of radiations
Nimal, J C
2003-01-01
This article treats of the calculation methods used for the dimensioning of the protections against radiations. The method consists in determining for a given point the flux of particles coming from a source at a given time. A strong attenuation (of about some few mu Sv.h sup - sup 1) is in general expected between the source and the areas accessible to the personnel or the public. The calculation has to take into account a huge number of radiation-matter interactions and to solve the integral-differential transport equation which links the particles flux to the source. Several methods exist from the simplified physical model with numerical developments to the more or less precise resolution of the transport equation. These methods allows also the calculation of the uncertainties of equivalent dose rates, heat sources, structure damages using the data covariances (efficient cross-sections, modeling, etc..): 1 - transport equation; 2 - Monte-Carlo method; 3 - semi-numerical methods S sub N; 4 - methods based o...
Coordinated Transportation: Problems and Promise?
Fickes, Michael
1998-01-01
Examines the legal, administrative, and logistical barriers that have prevented the wide acceptance of coordinating community and school transportation services and why these barriers may be breaking down. Two examples of successful implementation of coordinated transportation are examined: employing a single system to serve all transportation…
Handling and transport problems (1960)
International Nuclear Information System (INIS)
Pomarola, J.; Savouyaud, J.
1960-01-01
I. The handling and transport of radioactive wastes involves the danger of irradiation and contamination. It is indispensable: - to lay down a special set of rules governing the removal and transport of wastes within centres or from one centre to another; - to give charge of this transportation to a group containing teams of specialists. The organisation, equipment and output of these teams is being examined. II. Certain materials are particularly dangerous to transport, and for these special vehicles and fixed installations are necessary. This is the case especially for the evacuation of very active liquids. A transport vehicle is described, consisting of a trailer tractor and a recipient holding 500 litres of liquid of which the activity can reach 1000 C/l; the decanting operation, the route to be followed by the vehicle, and the precautions taken are also described. (author) [fr
Radiation transport calculation methods in BNCT
International Nuclear Information System (INIS)
Koivunoro, H.; Seppaelae, T.; Savolainen, S.
2000-01-01
Boron neutron capture therapy (BNCT) is used as a radiotherapy for malignant brain tumours. Radiation dose distribution is necessary to determine individually for each patient. Radiation transport and dose distribution calculations in BNCT are more complicated than in conventional radiotherapy. Total dose in BNCT consists of several different dose components. The most important dose component for tumour control is therapeutic boron dose D B . The other dose components are gamma dose D g , incident fast neutron dose D f ast n and nitrogen dose D N . Total dose is a weighted sum of the dose components. Calculation of neutron and photon flux is a complex problem and requires numerical methods, i.e. deterministic or stochastic simulation methods. Deterministic methods are based on the numerical solution of Boltzmann transport equation. Such are discrete ordinates (SN) and spherical harmonics (PN) methods. The stochastic simulation method for calculation of radiation transport is known as Monte Carlo method. In the deterministic methods the spatial geometry is partitioned into mesh elements. In SN method angular integrals of the transport equation are replaced with weighted sums over a set of discrete angular directions. Flux is calculated iteratively for all these mesh elements and for each discrete direction. Discrete ordinates transport codes used in the dosimetric calculations are ANISN, DORT and TORT. In PN method a Legendre expansion for angular flux is used instead of discrete direction fluxes, land the angular dependency comes a property of vector function space itself. Thus, only spatial iterations are required for resulting equations. A novel radiation transport code based on PN method and tree-multigrid technique (TMG) has been developed at VTT (Technical Research Centre of Finland). Monte Carlo method solves the radiation transport by randomly selecting neutrons and photons from a prespecified boundary source and following the histories of selected particles
Intelligent transportation systems problems and perspectives
Pamuła, Wiesław
2016-01-01
This book presents a discussion of problems encountered in the deployment of Intelligent Transport Systems (ITS). It puts emphasis on the early tasks of designing and proofing the concept of integration of technologies in Intelligent Transport Systems. In its first part the book concentrates on the design problems of urban ITS. The second part of the book features case studies representative for the different modes of transport. These are freight transport, rail transport and aerospace transport encompassing also space stations. The book provides ideas for deployment which may be developed by scientists and engineers engaged in the design of Intelligent Transport Systems. It can also be used in the training of specialists, students and post-graduate students in universities and transport high schools. .
Implementation and testing of a multivariate inverse radiation transport solver
International Nuclear Information System (INIS)
Mattingly, John; Mitchell, Dean J.
2012-01-01
Detection, identification, and characterization of special nuclear materials (SNM) all face the same basic challenge: to varying degrees, each must infer the presence, composition, and configuration of the SNM by analyzing a set of measured radiation signatures. Solutions to this problem implement inverse radiation transport methods. Given a set of measured radiation signatures, inverse radiation transport estimates properties of the source terms and transport media that are consistent with those signatures. This paper describes one implementation of a multivariate inverse radiation transport solver. The solver simultaneously analyzes gamma spectrometry and neutron multiplicity measurements to fit a one-dimensional radiation transport model with variable layer thicknesses using nonlinear regression. The solver's essential components are described, and its performance is illustrated by application to benchmark experiments conducted with plutonium metal. - Highlights: ► Inverse problems, specifically applied to identifying and characterizing radiation sources . ► Radiation transport. ► Analysis of gamma spectroscopy and neutron multiplicity counting measurements. ► Experimental testing of the inverse solver against measurements of plutonium.
Collection of problems in transport theory
International Nuclear Information System (INIS)
Kaper, H.G.
1975-01-01
Problems presented are: (1) definition of transport operators; (2) relation between the integro-differential and integral form of the transport equation; (3) asymptotic behavior of the scalar density near curved boundaries and interfaces; (4) singularities at a corner; (5) regularity of the solution of the transport equation; (7) transport equations on a manifold; (8) numerical analysis; (9) cubature; (10) point spectrum of the transport operator; (11) convergence of the multigroup approximation; (12) convergence of discrete ordinates approximations; (13) the finite double-norm property; (14) convergence of discrete ordinates approximation. The presentation of the problems is intended to direct attention to gaps in the existing knowledge of transport theory and to stimulate research into new areas of transport theory
Application of nonlinear Krylov acceleration to radiative transfer problems
International Nuclear Information System (INIS)
Till, A. T.; Adams, M. L.; Morel, J. E.
2013-01-01
The iterative solution technique used for radiative transfer is normally nested, with outer thermal iterations and inner transport iterations. We implement a nonlinear Krylov acceleration (NKA) method in the PDT code for radiative transfer problems that breaks nesting, resulting in more thermal iterations but significantly fewer total inner transport iterations. Using the metric of total inner transport iterations, we investigate a crooked-pipe-like problem and a pseudo-shock-tube problem. Using only sweep preconditioning, we compare NKA against a typical inner / outer method employing GMRES / Newton and find NKA to be comparable or superior. Finally, we demonstrate the efficacy of applying diffusion-based preconditioning to grey problems in conjunction with NKA. (authors)
Ethical problems in radiation protection
Energy Technology Data Exchange (ETDEWEB)
Shrader-Frechette, K.; Persson, Lars
2001-05-01
In this report the authors survey existing international radiation-protection recommendations and standards of the ICRP, the IAEA, and the ILO. After outlining previous work on the ethics of radiation protection, professional ethics, and the ethics of human radiation experiments, the authors review ethical thinking on seven key issues related to radiation protection and ethics. They formulate each of these seven issues in terms of alternative ethical stances: (1) equity versus efficiency, (2) health versus economics, (3) individual rights versus societal benefits, (4) due process versus necessary sacrifice, (5) uniform versus double standards, (6) stake holder consent versus management decisions, and (7) environmental stewardship versus anthropocentric standards.
Ethical problems in radiation protection
International Nuclear Information System (INIS)
Shrader-Frechette, K.; Persson, Lars
2001-05-01
In this report the authors survey existing international radiation-protection recommendations and standards of the ICRP, the IAEA, and the ILO. After outlining previous work on the ethics of radiation protection, professional ethics, and the ethics of human radiation experiments, the authors review ethical thinking on seven key issues related to radiation protection and ethics. They formulate each of these seven issues in terms of alternative ethical stances: (1) equity versus efficiency, (2) health versus economics, (3) individual rights versus societal benefits, (4) due process versus necessary sacrifice, (5) uniform versus double standards, (6) stake holder consent versus management decisions, and (7) environmental stewardship versus anthropocentric standards
Main problems of modern radiation hygiene
International Nuclear Information System (INIS)
Il'in, L.A.; Buldakov, L.A.; Knizhnikov, V.A.
1982-01-01
The results of investigations carried out in 1980-81 in the field of radiation hygiene as well as plans for 1981-85 are considered. Three main groups of problems which the radiation hygiene is facing at the present time are discussed. The determination of levels and study of regularities of ionizing radiation dose formation in the population and personnel working with ionizing radiation sources in one of the promissing directions of the investigations. Delayed irradiation aftereffects andcontaminant action ofirradiation and chemical substances are no less important. The third important problem lies in the development of protective measures and arrangements on improving state sanitary inspection in the field of radiation hygiene
Terminological problems in radiation diagnosis
International Nuclear Information System (INIS)
Rozenfel'd, L.G.
1991-01-01
It was noted the necessity of regulation of medical termonilogy. The introduction of terms radiation diagnosis, radiation therapy was justified, usage of terms xeroroentgenography, reconstructive tomography was recommended. In author's opinion it was expedient to exclude from utilization the terms diagnostic radiology, skiagraphy, electroroentgenography, computerized tomography
Directions in Radiation Transport Modelling
Directory of Open Access Journals (Sweden)
P Nicholas Smith
2016-12-01
More exciting advances are on the horizon to increase the power of simulation tools. The advent of high performance computers is allowing bigger, higher fidelity models to be created, if the challenges of parallelization and memory management can be met. 3D whole core transport modelling is becoming possible. Uncertainty quantification is improving with large benefits to be gained from more accurate, less pessimistic estimates of uncertainty. Advanced graphical displays allow the user to assimilate and make sense of the vast amounts of data produced by modern modelling tools. Numerical solvers are being developed that use goal-based adaptivity to adjust the nodalisation of the system to provide the optimum scheme to achieve the user requested accuracy on the results, thus removing the need to perform costly convergence studies in space and angle etc. More use is being made of multi-physics methods in which radiation transport is coupled with other phenomena, such as thermal-hydraulics, structural response, fuel performance and/or chemistry in order to better understand their interplay in reactor cores.
Parallel processing Monte Carlo radiation transport codes
International Nuclear Information System (INIS)
McKinney, G.W.
1994-01-01
Issues related to distributed-memory multiprocessing as applied to Monte Carlo radiation transport are discussed. Measurements of communication overhead are presented for the radiation transport code MCNP which employs the communication software package PVM, and average efficiency curves are provided for a homogeneous virtual machine
Multi-Stage Transportation Problem With Capacity Limit
I. Brezina; Z. Čičková; J. Pekár; M. Reiff
2010-01-01
The classical transportation problem can be applied in a more general way in practice. Related problems as Multi-commodity transportation problem, Transportation problems with different kind of vehicles, Multi-stage transportation problems, Transportation problem with capacity limit is an extension of the classical transportation problem considering the additional special condition. For solving such problems many optimization techniques (dynamic programming, linear programming, special algor...
Algorithm for the Stochastic Generalized Transportation Problem
Directory of Open Access Journals (Sweden)
Marcin Anholcer
2012-01-01
Full Text Available The equalization method for the stochastic generalized transportation problem has been presented. The algorithm allows us to find the optimal solution to the problem of minimizing the expected total cost in the generalized transportation problem with random demand. After a short introduction and literature review, the algorithm is presented. It is a version of the method proposed by the author for the nonlinear generalized transportation problem. It is shown that this version of the method generates a sequence of solutions convergent to the KKT point. This guarantees the global optimality of the obtained solution, as the expected cost functions are convex and twice differentiable. The computational experiments performed for test problems of reasonable size show that the method is fast. (original abstract
Problems in radiation shielding calculations with Monte Carlo methods
International Nuclear Information System (INIS)
Ueki, Kohtaro
1985-01-01
The Monte Carlo method is a very useful tool for solving a large class of radiation transport problem. In contrast with deterministic method, geometric complexity is a much less significant problem for Monte Carlo calculations. However, the accuracy of Monte Carlo calculations is of course, limited by statistical error of the quantities to be estimated. In this report, we point out some typical problems to solve a large shielding system including radiation streaming. The Monte Carlo coupling technique was developed to settle such a shielding problem accurately. However, the variance of the Monte Carlo results using the coupling technique of which detectors were located outside the radiation streaming, was still not enough. So as to bring on more accurate results for the detectors located outside the streaming and also for a multi-legged-duct streaming problem, a practicable way of ''Prism Scattering technique'' is proposed in the study. (author)
Rare event simulation in radiation transport
International Nuclear Information System (INIS)
Kollman, C.
1993-10-01
This dissertation studies methods for estimating extremely small probabilities by Monte Carlo simulation. Problems in radiation transport typically involve estimating very rare events or the expected value of a random variable which is with overwhelming probability equal to zero. These problems often have high dimensional state spaces and irregular geometries so that analytic solutions are not possible. Monte Carlo simulation must be used to estimate the radiation dosage being transported to a particular location. If the area is well shielded the probability of any one particular particle getting through is very small. Because of the large number of particles involved, even a tiny fraction penetrating the shield may represent an unacceptable level of radiation. It therefore becomes critical to be able to accurately estimate this extremely small probability. Importance sampling is a well known technique for improving the efficiency of rare event calculations. Here, a new set of probabilities is used in the simulation runs. The results are multiple by the likelihood ratio between the true and simulated probabilities so as to keep the estimator unbiased. The variance of the resulting estimator is very sensitive to which new set of transition probabilities are chosen. It is shown that a zero variance estimator does exist, but that its computation requires exact knowledge of the solution. A simple random walk with an associated killing model for the scatter of neutrons is introduced. Large deviation results for optimal importance sampling in random walks are extended to the case where killing is present. An adaptive ''learning'' algorithm for implementing importance sampling is given for more general Markov chain models of neutron scatter. For finite state spaces this algorithm is shown to give with probability one, a sequence of estimates converging exponentially fast to the true solution
Coupled electron-photon radiation transport
International Nuclear Information System (INIS)
Lorence, L.; Kensek, R.P.; Valdez, G.D.; Drumm, C.R.; Fan, W.C.; Powell, J.L.
2000-01-01
Massively-parallel computers allow detailed 3D radiation transport simulations to be performed to analyze the response of complex systems to radiation. This has been recently been demonstrated with the coupled electron-photon Monte Carlo code, ITS. To enable such calculations, the combinatorial geometry capability of ITS was improved. For greater geometrical flexibility, a version of ITS is under development that can track particles in CAD geometries. Deterministic radiation transport codes that utilize an unstructured spatial mesh are also being devised. For electron transport, the authors are investigating second-order forms of the transport equations which, when discretized, yield symmetric positive definite matrices. A novel parallelization strategy, simultaneously solving for spatial and angular unknowns, has been applied to the even- and odd-parity forms of the transport equation on a 2D unstructured spatial mesh. Another second-order form, the self-adjoint angular flux transport equation, also shows promise for electron transport
Survey of radiation protection programmes for transport
International Nuclear Information System (INIS)
Lizot, M.T.; Perrin, M.L.; Sert, G.; Lange, F.; Schwarz, G.; Feet, H.J.; Christ, R.; Shaw, K.B.; Hughes, J.S.; Gelder, R.
2001-07-01
The survey of radiation protection programmes for transport has been jointly performed by three scientific organisations I.P.S.N. (France), G.R.S. ( Germany), and N.R.P.B. (United kingdom) on behalf of the European Commission and the pertaining documentation summarises the findings and conclusions of the work that was undertaken with the principal objectives to provide guidance on the establishment, implementation and application of radiation protection programmes for the transport of radioactive materials by operators and the assessment and evaluation of such programmes by the competent authority and to review currently existing radiation protection programmes for the transport of radioactive materials. (N.C.)
ipole: Semianalytic scheme for relativistic polarized radiative transport
Moscibrodzka, Monika; Gammie, Charles F.
2018-04-01
ipole is a ray-tracing code for covariant, polarized radiative transport particularly useful for modeling Event Horizon Telescope sources, though may also be used for other relativistic transport problems. The code extends the ibothros scheme for covariant, unpolarized transport using two representations of the polarized radiation field: in the coordinate frame, it parallel transports the coherency tensor, and in the frame of the plasma, it evolves the Stokes parameters under emission, absorption, and Faraday conversion. The transport step is as spacetime- and coordinate- independent as possible; the emission, absorption, and Faraday conversion step is implemented using an analytic solution to the polarized transport equation with constant coefficients. As a result, ipole is stable, efficient, and produces a physically reasonable solution even for a step with high optical depth and Faraday depth.
Integrating routing decisions in public transportation problems
Schmidt, Marie E
2014-01-01
This book treats three planning problems arising in public railway transportation planning: line planning, timetabling, and delay management, with the objective to minimize passengers’ travel time. While many optimization approaches simplify these problems by assuming that passengers’ route choice is independent of the solution, this book focuses on models which take into account that passengers will adapt their travel route to the implemented planning solution. That is, a planning solution and passengers’ routes are determined and evaluated simultaneously. This work is technically deep, with insightful findings regarding complexity and algorithmic approaches to public transportation problems with integrated passenger routing. It is intended for researchers in the fields of mathematics, computer science, or operations research, working in the field of public transportation from an optimization standpoint. It is also ideal for students who want to gain intuition and experience in doing complexity proofs ...
Radiation protection problems with sealed Pu radiation sources
International Nuclear Information System (INIS)
Naumann, M.; Wels, C.
1982-01-01
A brief outline of the production methods and most important properties of Pu-238 and Pu-239 is given, followed by an overview of possibilities for utilizing the different types of radiation emitted, a description of problems involved in the safe handling of Pu radiation sources, and an assessment of the design principles for Pu-containing alpha, photon, neutron and energy sources from the radiation protection point of view. (author)
Inverse problems in linear transport theory
International Nuclear Information System (INIS)
Dressler, K.
1988-01-01
Inverse problems for a class of linear kinetic equations are investigated. The aim is to identify the scattering kernel of a transport equation (corresponding to the structure of a background medium) by observing the 'albedo' part of the solution operator for the corresponding direct initial boundary value problem. This means to get information on some integral operator in an integrodifferential equation through on overdetermined boundary value problem. We first derive a constructive method for solving direct halfspace problems and prove a new factorization theorem for the solutions. Using this result we investigate stationary inverse problems with respect to well posedness (e.g. reduce them to classical ill-posed problems, such as integral equations of first kind). In the time-dependent case we show that a quite general inverse problem is well posed and solve it constructively. (orig.)
Problems of photo-radiative action
International Nuclear Information System (INIS)
Milinchuk, V.K.
1985-01-01
The most interesting photo-radiation effects observed in the last few years are discussed, in particular, considerable reduction ip material radiation resistance under the combined effect of ionizing and visible radiation. Intermediate active particles are shown to absorb the light according to the mechanism of ''direct'' absorption and as a result of photo-sensibilization reactions as well. Channels of absorbed light energy dissipation depend on the nature and structure of the intermediate active particles, temperature, light radiation frequency and other parameters. Problems are considered which solution promotes further development of photo-radiation chemistry and that are important for such branches of modern physical chemistry as kinetics and mechanism of elementary processes in organic solids, radiation resistance and ageing of organic polymers
Hub location problems in transportation networks
DEFF Research Database (Denmark)
Gelareh, Shahin; Nickel, Stefan
2011-01-01
In this paper we propose a 4-index formulation for the uncapacitated multiple allocation hub location problem tailored for urban transport and liner shipping network design. This formulation is very tight and most of the tractable instances for MIP solvers are optimally solvable at the root node....... also introduce fixed cost values for Australian Post (AP) dataset....
Resolving beam transport problems in electrostatic accelerators
International Nuclear Information System (INIS)
Larson, J.D.
1977-01-01
A review is given of problem areas in beam transmission which are frequently encountered during the design, operation and upgrading of electrostatic accelerators. Examples are provided of analytic procedures that clarify accelerator ion optics and lead to more effective beam transport. Suggestions are made for evaluating accelerator design with the goal of improved performance
Resolving beam transport problems in electrostatic accelerators
International Nuclear Information System (INIS)
Larson, J.D.
1977-01-01
This paper reviews problem areas in beam transmission which are frequently encountered during the design, operation and upgrading of electrostatic accelerators. Examples are provided of analytic procedures that clarify accelerator ion optics and lead to more effective beam transport. Suggestions are made for evaluating accelerator design with the goal of improved performance
Pressing problems of measurement of ionizing radiations
International Nuclear Information System (INIS)
Fominykh, V.I.; Yudin, M.F.
1993-01-01
The current system for ensuring the unity of measurements in the Russian Federation and countries of the former Soviet Union ensures a high quality of dosimetric, radiometric, and spectrometric measurements in accordance with the recommendations of the Consulative Committee on Standards for Measurements of Ionizing Radiations of the International Bureau of Weights and Measures (IBWM), International Organization on Radiological Units (ICRU), International Commission on Radiological Protection (ICRP), International Organization on Legislative Metrology (IOLM), International Atomic Energy Agency (IAEA), World Health Organization (WHO), etc. Frequent collation of the national primary and secondary standards of Russia with those of IBWM and the leading national laboratories of the world facilitate mutual verification of the measurements of ionizing radiations. The scope of scientific and scientific-technical problems that can be solved by using ionizing radiations has expanded significantly in recent years. In this paper the authors consider some pressing problems of the metrology of ionizing radiations which have arisen as a result of this expansion. These include the need for unity and reliability of measurements involved in radiation protection, the measurement of low doses involving low dose rates, ensuring the unity of measurements when monitoring the radiological security of the population, the need for more uniformity on an international scale regarding the basic physical quantities and their units for characterizing radiation fields, determination of the accuracy of measurement of the radiation dose absorbed by an irradiated tissue or organ, and the development of complex standards for ionizing radiations. 5 refs., 1 tab
Rare Event Simulation in Radiation Transport
Kollman, Craig
This dissertation studies methods for estimating extremely small probabilities by Monte Carlo simulation. Problems in radiation transport typically involve estimating very rare events or the expected value of a random variable which is with overwhelming probability equal to zero. These problems often have high dimensional state spaces and irregular geometries so that analytic solutions are not possible. Monte Carlo simulation must be used to estimate the radiation dosage being transported to a particular location. If the area is well shielded the probability of any one particular particle getting through is very small. Because of the large number of particles involved, even a tiny fraction penetrating the shield may represent an unacceptable level of radiation. It therefore becomes critical to be able to accurately estimate this extremely small probability. Importance sampling is a well known technique for improving the efficiency of rare event calculations. Here, a new set of probabilities is used in the simulation runs. The results are multiplied by the likelihood ratio between the true and simulated probabilities so as to keep our estimator unbiased. The variance of the resulting estimator is very sensitive to which new set of transition probabilities are chosen. It is shown that a zero variance estimator does exist, but that its computation requires exact knowledge of the solution. A simple random walk with an associated killing model for the scatter of neutrons is introduced. Large deviation results for optimal importance sampling in random walks are extended to the case where killing is present. An adaptive "learning" algorithm for implementing importance sampling is given for more general Markov chain models of neutron scatter. For finite state spaces this algorithm is shown to give, with probability one, a sequence of estimates converging exponentially fast to the true solution. In the final chapter, an attempt to generalize this algorithm to a continuous
Multi-Stage Transportation Problem With Capacity Limit
Directory of Open Access Journals (Sweden)
I. Brezina
2010-06-01
Full Text Available The classical transportation problem can be applied in a more general way in practice. Related problems as Multi-commodity transportation problem, Transportation problems with different kind of vehicles, Multi-stage transportation problems, Transportation problem with capacity limit is an extension of the classical transportation problem considering the additional special condition. For solving such problems many optimization techniques (dynamic programming, linear programming, special algorithms for transportation problem etc. and heuristics approaches (e.g. evolutionary techniques were developed. This article considers Multi-stage transportation problem with capacity limit that reflects limits of transported materials (commodity quantity. Discussed issues are: theoretical base, problem formulation as way as new proposed algorithm for that problem.
Radiation protection problems by nonionizing electromagnetic radiation in Austria
International Nuclear Information System (INIS)
Duftschmid, K.E.
1984-03-01
Since about one year an interdisciplinary study group has been established to investigate possible radiation protection problems caused by nonionizing electromagnetic radiation in this country. The aim of this project is to identify major fields of concern, to establish appropriate techniques of measurement and control and eventually develop a sound basis for future legislation. The paper gives a summary on the present results of this study. (Author)
Problems of radiation protection at medical use of radiation equipment
International Nuclear Information System (INIS)
Larwin, K.
1979-01-01
For medical use of radiation equipment man is not only operator, but also object (patient). The question, if or how much it is necessary to expose the patient, is a medical problem and therefore not to be discussed here. For the user of medical equipments we have often special conditions. For many diagnostic applications the physician has to stay in the application room in contact with the patient. As a typical example for the problems of radiation protection there is discussed the situation on a well known fluoroscopic unit for lung and stomach examinations. (author)
Hybrid Predictive Control for Dynamic Transport Problems
Núñez, Alfredo A; Cortés, Cristián E
2013-01-01
Hybrid Predictive Control for Dynamic Transport Problems develops methods for the design of predictive control strategies for nonlinear-dynamic hybrid discrete-/continuous-variable systems. The methodology is designed for real-time applications, particularly the study of dynamic transport systems. Operational and service policies are considered, as well as cost reduction. The control structure is based on a sound definition of the key variables and their evolution. A flexible objective function able to capture the predictive behaviour of the system variables is described. Coupled with efficient algorithms, mainly drawn from the area of computational intelligence, this is shown to optimize performance indices for real-time applications. The framework of the proposed predictive control methodology is generic and, being able to solve nonlinear mixed-integer optimization problems dynamically, is readily extendable to other industrial processes. The main topics of this book are: ●hybrid predictive control (HPC) ...
A method for unbalanced transportation problems in fuzzy ...
Indian Academy of Sciences (India)
Among linear programming problems, the transportation problem is very popular. ... Therefore, Zadeh (1965) introduced the concept of fuzzy numbers. ... While solving unbalanced transportation problems we come across two type of cases.
Recent developments in the Los Alamos radiation transport code system
International Nuclear Information System (INIS)
Forster, R.A.; Parsons, K.
1997-01-01
A brief progress report on updates to the Los Alamos Radiation Transport Code System (LARTCS) for solving criticality and fixed-source problems is provided. LARTCS integrates the Diffusion Accelerated Neutral Transport (DANT) discrete ordinates codes with the Monte Carlo N-Particle (MCNP) code. The LARCTS code is being developed with a graphical user interface for problem setup and analysis. Progress in the DANT system for criticality applications include a two-dimensional module which can be linked to a mesh-generation code and a faster iteration scheme. Updates to MCNP Version 4A allow statistical checks of calculated Monte Carlo results
IONIZING RADIATION AS AN INDUSTRIAL HEALTH PROBLEM.
TREWIN, R B
1964-01-04
Ionizing radiation, first as x-rays, later in natural form, was discovered in Europe in the late 1890's. Immediate practical uses were found for these discoveries, particularly in medicine. Unfortunately, because of the crude early equipment and ignorance of the harmful effects of radiation, many people were injured, some fatally. Because of these experiences, committees and regulatory bodies were set up to study the problem. These have built up an impressive fund of knowledge useful in radiation protection.With the recent development of the peaceful uses of atomic energy, sources of radioactivity have appeared cheaply and in abundance. A rapidly growing number are finding industrial application. Because of their potential risk to humans, the industrial physician must acquire new knowledge and skills so that he may give proper guidance in this new realm of preventive medicine.The Radiation Protection Program of one such industry, the Hydro-Electric Power Commission of Ontario, is summarized.
Ionizing Radiation as an Industrial Health Problem
Trewin, R. B.
1964-01-01
Ionizing radiation, first as x-rays, later in natural form, was discovered in Europe in the late 1890's. Immediate practical uses were found for these discoveries, particularly in medicine. Unfortunately, because of the crude early equipment and ignorance of the harmful effects of radiation, many people were injured, some fatally. Because of these experiences, committees and regulatory bodies were set up to study the problem. These have built up an impressive fund of knowledge useful in radiation protection. With the recent development of the peaceful uses of atomic energy, sources of radioactivity have appeared cheaply and in abundance. A rapidly growing number are finding industrial application. Because of their potential risk to humans, the industrial physician must acquire new knowledge and skills so that he may give proper guidance in this new realm of preventive medicine. The Radiation Protection Program of one such industry, the Hydro-Electric Power Commission of Ontario, is summarized. PMID:14105012
Calculation of neutron and gamma transport at the FOA:type of problems and calculation methods
International Nuclear Information System (INIS)
Lefvert, T.
1975-11-01
Protection against the effects of nuclear warfare involves the analysis of the forms of results of a nuclear charge explosion producing neutron and gamma radiation. It brings out problems leading to the calculation of criticality, leakage, and deep transmission. Methods have been developed for various kinds of particle transport problems. Applications to radiation therapy, storage of fissile materials, and fast reactors are discussed. A list (with brief description) of all neutron and gamma transport programmes of the FOA is given. (J.S.)
IPOLE - semi-analytic scheme for relativistic polarized radiative transport
Mościbrodzka, M.; Gammie, C. F.
2018-03-01
We describe IPOLE, a new public ray-tracing code for covariant, polarized radiative transport. The code extends the IBOTHROS scheme for covariant, unpolarized transport using two representations of the polarized radiation field: In the coordinate frame, it parallel transports the coherency tensor; in the frame of the plasma it evolves the Stokes parameters under emission, absorption, and Faraday conversion. The transport step is implemented to be as spacetime- and coordinate- independent as possible. The emission, absorption, and Faraday conversion step is implemented using an analytic solution to the polarized transport equation with constant coefficients. As a result, IPOLE is stable, efficient, and produces a physically reasonable solution even for a step with high optical depth and Faraday depth. We show that the code matches analytic results in flat space, and that it produces results that converge to those produced by Dexter's GRTRANS polarized transport code on a complicated model problem. We expect IPOLE will mainly find applications in modelling Event Horizon Telescope sources, but it may also be useful in other relativistic transport problems such as modelling for the IXPE mission.
Radiation transformation studies: are they relevant to radiation protection problems?
International Nuclear Information System (INIS)
Seymour, C.B.; Mothersill, C.
1988-01-01
Because of the difficulties of studying radio-carcinogenesis in humans, several in vitro systems are utilised. These cell transformation systems are reviewed, with particular emphasis on their relevance to human radiological protection problems. Most available systems use rodent fibroblasts. These are discussed in detail. Attention is drawn to certain artefacts which can cause problems with interpretation of such data. The relevance of these systems is questionable because of species differences, particularly concerning life span and because most human tumours are derived from epithelial cells. New epithelial culture systems and three-dimensional tissue culture methods becoming available are discussed in the light of their potential for addressing radiation protection problems. (author)
Sharp fronts within geochemical transport problems
International Nuclear Information System (INIS)
Grindrod, P.
1995-01-01
The authors consider some reactive geochemical transport problems in groundwater systems. When incoming fluid is in disequilibrium with the mineralogy sharp transition fronts may develop. They show that this is a generic property for a class of systems where the timescales associated with reaction and diffusion phenomena are much shorter than those associated with advective transport. Such multiple timescale problems are relevant to a variety of processes in natural systems: mathematically methods of singular perturbation theory reduce the dimension of the problems to be solved locally. Furthermore, they consider how spatial heterogeneous mineralogy can impact upon the propagation of sharp geochemical fronts. The authors developed an asymptotic approach in which they solve equations for the evolving geometry of the front and indicate how the non-smooth perturbations due to natural heterogeneity of the mineralogy on underlying ground water flow field are balanced against the smoothing effect of diffusion/dispersive processes. Fronts are curvature damped, and the results here indicate the generic nature of separate front propagation within both model (idealized) and natural (heterogeneous) geochemical systems
Problems of radiation medicine and radiobiology
International Nuclear Information System (INIS)
Bazyka, D.A.
2014-01-01
Research activities and scientific advance achieved in 2013 at the State Institution 'National Research Center for Radiation Medicine of the National Academy of Medical Sciences of Ukraine' (NRCRM) concerning medical problems of the Chornobyl disaster, radiation medicine, radiobiology, radiation hygiene and epidemiology in collaboration with the WHO network of medical preparedness and assistance in radiation accidents are outlined in the annual report. Key points include the research results of XRCC1 and XPD gene polymorphism in thyroid cancer patients, CD38 gene GG genotype as a risk factor for chronic lymphocytic leukemia, frequency of 185delAG and 5382insC mutations in BRCA1 gene in women with breast cancer, cognitive function and TERF1, TERF2, TERT gene expression both with telomere length in human under the low dose radiation exposure. The 'source-scattering/shielding structures-man' models for calculation of partial dose values to the eye lens and new methods for radiation risk assessment were developed and adapted. Radiation risks of leukemia including chronic lymphocytic leukemia in the cohort of liquidators were published according to the 'case-control' study results after 20 years of survey. Increase of non-tumor morbidity in liquidators during the 1988-2011 with the maximum level 12-21 years upon irradiation was found. Incidence in evacuees appeared being of two-peak pattern i.e. in the first years after the accident and 12 years later. Experimental studies have concerned the impact of radio-modifiers on cellular systems, reproductive function in the population, features of the child nutrition in radiation contamination area were studied. Report also shows the results of scientific and organizational, medical and preventive work, staff training, and implementation of innovations. The NRCRM Annual Report was approved at the Scientific Council meeting of NAMS on March 3, 201
Trade and transport of radiation sources
International Nuclear Information System (INIS)
1996-01-01
The guide specifies the obligations pertaining to the trade in and transport of radiation sources and other matters to be taken into account in safety supervision. It also specifies obligations and procedures relating to transfrontier movements of radioactive waste contained in the EU Council Directive 92/3/Euratom. (7 refs.)
LDRD Final Review: Radiation Transport Calculations
Energy Technology Data Exchange (ETDEWEB)
Goorley, John Timothy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Morgan, George Lake [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lestone, John Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-06-22
Both high-fidelity & toy simulations are being used to understand measured signals and improve the Area 11 NDSE diagnostic. We continue to gain more and more confidence in the ability for MCNP to simulate neutron and photon transport from source to radiation detector.
Nonlinear acceleration of transport criticality problems
International Nuclear Information System (INIS)
Park, H.; Knoll, D.A.; Newman, C.K.
2011-01-01
We present a nonlinear acceleration algorithm for the transport criticality problem. The algorithm combines the well-known nonlinear diffusion acceleration (NDA) with a recently developed, Newton-based, nonlinear criticality acceleration (NCA) algorithm. The algorithm first employs the NDA to reduce the system to scalar flux, then the NCA is applied to the resulting drift-diffusion system. We apply a nonlinear elimination technique to eliminate the eigenvalue from the Jacobian matrix. Numerical results show that the algorithm reduces the CPU time a factor of 400 in a very diffusive system, and a factor of 5 in a non-diffusive system. (author)
Radiation transport between concentric spheres
International Nuclear Information System (INIS)
Haan, S.W.
1994-01-01
This is a note originally distributed in 1983. I am re-releasing it now, with a couple of words changed, so that it can be used for test problems, distributed more openly, and so forth. One could argue that it should be published, but I do not have time to reshape it into something I would regard as suitable for journal publication. A different derivation of the same result is being published in an appendix in D.W. Phillion and S.M. Pollaine, ''Dynamical Compensation of Irradiation Nonuniformities in a Spherical Hohlraum Illuminated with Tetrahedral Symmetry by Laser Beams,'' submitted to Phys. Plasmas
Spatial domain decomposition for neutron transport problems
International Nuclear Information System (INIS)
Yavuz, M.; Larsen, E.W.
1989-01-01
A spatial Domain Decomposition method is proposed for modifying the Source Iteration (SI) and Diffusion Synthetic Acceleration (DSA) algorithms for solving discrete ordinates problems. The method, which consists of subdividing the spatial domain of the problem and performing the transport sweeps independently on each subdomain, has the advantage of being parallelizable because the calculations in each subdomain can be performed on separate processors. In this paper we describe the details of this spatial decomposition and study, by numerical experimentation, the effect of this decomposition on the SI and DSA algorithms. Our results show that the spatial decomposition has little effect on the convergence rates until the subdomains become optically thin (less than about a mean free path in thickness)
K. Schwarzschild's problem in radiation transfer theory
International Nuclear Information System (INIS)
Rutily, B.; Chevallier, L.; Pelkowski, J.
2006-01-01
We solve exactly the problem of a finite slab receiving an isotropic radiation on one side and no radiation on the other side. This problem-to be more precise the calculation of the source function within the slab-was first formulated by K. Schwarzschild in 1914. We first solve it for unspecified albedos and optical thicknesses of the atmosphere, in particular for an albedo very close to 1 and a very large optical thickness in view of some astrophysical applications. Then we focus on the conservative case (albedo=1), which is of great interest for the modeling of grey atmospheres in radiative equilibrium. Ten-figure tables of the conservative source function are given. From the analytical expression of this function, we deduce (1) a simple relation between the effective temperature of a grey atmosphere in radiative equilibrium and the temperature of the black body that irradiates it (2) the temperature at any point of the atmosphere when it is in local thermodynamical equilibrium. This temperature distribution is the counterpart, for a finite slab, of Hopf's distribution in a half-space. Its graphical representation is given for various optical thicknesses of the atmosphere
THE PROBLEMS OF PASSENGER TRANSPORTATIONS IN AN INTERNATIONAL COMMUNICATION
Directory of Open Access Journals (Sweden)
Yu. S. Barash
2010-05-01
Full Text Available The basic aspects of international passenger transportations in Ukraine are represented. The analysis of present situation in these transportations is carried out. Some variants of solving the problems of passenger transportations in an international communication are considered.
International Nuclear Information System (INIS)
Cartier, J.
2006-04-01
This thesis focuses on mathematical analysis, numerical resolution and modelling of the transport equations. First of all, we deal with numerical approximation of the solution of the transport equations by using a mixed-hybrid scheme. We derive and study a mixed formulation of the transport equation, then we analyse the related variational problem and present the discretization and the main properties of the scheme. We particularly pay attention to the behavior of the scheme and we show its efficiency in the diffusion limit (when the mean free path is small in comparison with the characteristic length of the physical domain). We present academical benchmarks in order to compare our scheme with other methods in many physical configurations and validate our method on analytical test cases. Unstructured and very distorted meshes are used to validate our scheme. The second part of this thesis deals with two transport problems. The first one is devoted to the study of diffusion due to boundary conditions in a transport problem between two plane plates. The second one consists in modelling and simulating radiative transfer phenomenon in case of the industrial context of inertial confinement fusion. (author)
The quasidiffusion method for transport problems on unstructured meshes
Wieselquist, William A.
2009-06-01
In this work, we develop a quasidiffusion (QD) method for solving radiation transport problems on unstructured quadrilateral meshes in 2D Cartesian geometry, for example hanging-node meshes from adaptive mesh refinement (AMR) applications or skewed quadrilateral meshes from radiation hydrodynamics with Lagrangian meshing. The main result of the work is a new low-order quasidiffusion (LOQD) discretization on arbitrary quadrilaterals and a strategy for the efficient iterative solution which uses Krylov methods and incomplete LU factorization (ILU) preconditioning. The LOQD equations are a non-symmetric set of first-order PDEs that in second-order form resembles convection- diffusion with a diffusion tensor, with the difference that the LOQD equations contain extra cross-derivative terms. Our finite volume (FV) discretization of the LOQD equations is compared with three LOQD discretizations from literature. We then present a conservative, short characteristics discretization based on subcell balances (SCSB) that uses polynomial exponential moments to achieve robust behavior in various limits (e.g. small cells and voids) and is second- order accurate in space. A linear representation of the isotropic component of the scattering source based on face-average and cell-average scalar fluxes is also proposed and shown to be effective in some problems. In numerical tests, our QD method with linear scattering source representation shows some advantages compared to other transport methods. We conclude with avenues for future research and note that this QD method may easily be extended to arbitrary meshes in 3D Cartesian geometry.
Problems with models of the radiation belts
International Nuclear Information System (INIS)
Daly, E.J.; Lemaire, J.; Heynderickx, D.; Rodgers, D.J.
1996-01-01
The current standard models of the radiation-belt environment have many shortcomings, not the least of which is their extreme age. Most of the data used for them were acquired in the 1960's and early 1970's. Problems with the present models, and the ways in which data from more recent missions are being or can be used to create new models with improved functionality, are described. The phenomenology of the radiation belts, the effects on space systems, and geomagnetic coordinates and modeling are discussed. Errors found in present models, their functional limitations, and problems with their implementation and use are detailed. New modeling must address problems at low altitudes with the south Atlantic anomaly, east-west asymmetries and solar cycle variations and at high altitudes with the highly dynamic electron environment. The important issues in space environment modeling from the point of view of usability and relationship with effects evaluation are presented. New sources of data are discussed. Future requirements in the data, models, and analysis tools areas are presented
Monte Carlo applications to radiation shielding problems
International Nuclear Information System (INIS)
Subbaiah, K.V.
2009-01-01
Monte Carlo methods are a class of computational algorithms that rely on repeated random sampling of physical and mathematical systems to compute their results. However, basic concepts of MC are both simple and straightforward and can be learned by using a personal computer. Uses of Monte Carlo methods require large amounts of random numbers, and it was their use that spurred the development of pseudorandom number generators, which were far quicker to use than the tables of random numbers which had been previously used for statistical sampling. In Monte Carlo simulation of radiation transport, the history (track) of a particle is viewed as a random sequence of free flights that end with an interaction event where the particle changes its direction of movement, loses energy and, occasionally, produces secondary particles. The Monte Carlo simulation of a given experimental arrangement (e.g., an electron beam, coming from an accelerator and impinging on a water phantom) consists of the numerical generation of random histories. To simulate these histories we need an interaction model, i.e., a set of differential cross sections (DCS) for the relevant interaction mechanisms. The DCSs determine the probability distribution functions (pdf) of the random variables that characterize a track; 1) free path between successive interaction events, 2) type of interaction taking place and 3) energy loss and angular deflection in a particular event (and initial state of emitted secondary particles, if any). Once these pdfs are known, random histories can be generated by using appropriate sampling methods. If the number of generated histories is large enough, quantitative information on the transport process may be obtained by simply averaging over the simulated histories. The Monte Carlo method yields the same information as the solution of the Boltzmann transport equation, with the same interaction model, but is easier to implement. In particular, the simulation of radiation
Radiation transport: Progress report, July 1, 1987-September 30, 1987
International Nuclear Information System (INIS)
O'Dell, R.D.; Nagy, A.
1988-05-01
Research and development progress in radiation transport for the Los Alamos National Laboratory's Group S-6 for the fourth quarter of FY 87 is reported. Included are unclassified tasks in the areas of Deterministic Radiation Transport, Monte Carlo Radiation Transport, and Cross Sections and Physics. 23 refs., 9 figs
Radiation transport methods for nuclear log assessment - an overview
International Nuclear Information System (INIS)
Badruzzaman, A.
1996-01-01
Methods of radiation transport have been applied to well-logging problems with nuclear sources since the early 1960s. Nuclear sondes are used in identifying rock compositions and fluid properties in reservoirs to predict the porosity and oil saturation. Early computational effort in nuclear logging used diffusion techniques. As computers became more powerful, deterministic transport methods and, finally, Monte Carlo methods were applied to solve these problems in three dimensions. Recently, the application has been extended to problems with a new generation of devices, including spectroscopic sondes that measure such quantities as the carbon/oxygen ratio to predict oil saturation and logging-while-drilling (LWD) sondes that take neutron and gamma measurements as they rotate in the borehole. These measurements present conditions that will be difficult to calibrate in the laboratory
Fallout radiation protection provided by transportation vehicles
Energy Technology Data Exchange (ETDEWEB)
Burson, Z.G.
1972-10-20
Fallout radiation protection factors (PF's) were estimated for a variety of civilian transportation vehicles using measurements of the natural terrain radiation as a source. The PF values are below 2 in light vehicles, truck beds, or trailers; from 2.5 to 3 in the cabs of heavy trucks and in a railway guard car; and from 3.0 to 3.5 in the engineer's seat of heavy locomotives. This information can be useful in planning the possible movement of personnel from or through areas contaminated either by a wartime incident or a peacetime accident. The information may also be useful for studying the reduction of exposure to the natural terrestrial radiation environment provided by vehicles.
Deterministic methods in radiation transport. A compilation of papers presented February 4--5, 1992
Energy Technology Data Exchange (ETDEWEB)
Rice, A.F.; Roussin, R.W. [eds.
1992-06-01
The Seminar on Deterministic Methods in Radiation Transport was held February 4--5, 1992, in Oak Ridge, Tennessee. Eleven presentations were made and the full papers are published in this report, along with three that were submitted but not given orally. These papers represent a good overview of the state of the art in the deterministic solution of radiation transport problems for a variety of applications of current interest to the Radiation Shielding Information Center user community.
Deterministic methods in radiation transport. A compilation of papers presented February 4-5, 1992
Energy Technology Data Exchange (ETDEWEB)
Rice, A. F.; Roussin, R. W. [eds.
1992-06-01
The Seminar on Deterministic Methods in Radiation Transport was held February 4--5, 1992, in Oak Ridge, Tennessee. Eleven presentations were made and the full papers are published in this report, along with three that were submitted but not given orally. These papers represent a good overview of the state of the art in the deterministic solution of radiation transport problems for a variety of applications of current interest to the Radiation Shielding Information Center user community.
NASA space radiation transport code development consortium
International Nuclear Information System (INIS)
Townsend, L. W.
2005-01-01
Recently, NASA established a consortium involving the Univ. of Tennessee (lead institution), the Univ. of Houston, Roanoke College and various government and national laboratories, to accelerate the development of a standard set of radiation transport computer codes for NASA human exploration applications. This effort involves further improvements of the Monte Carlo codes HETC and FLUKA and the deterministic code HZETRN, including developing nuclear reaction databases necessary to extend the Monte Carlo codes to carry out heavy ion transport, and extending HZETRN to three dimensions. The improved codes will be validated by comparing predictions with measured laboratory transport data, provided by an experimental measurements consortium, and measurements in the upper atmosphere on the balloon-borne Deep Space Test Bed (DSTB). In this paper, we present an overview of the consortium members and the current status and future plans of consortium efforts to meet the research goals and objectives of this extensive undertaking. (authors)
A class of ejecta transport test problems
International Nuclear Information System (INIS)
Hammerberg, James E.; Buttler, William T.; Oro, David M.; Rousculp, Christopher L.; Morris, Christopher; Mariam, Fesseha G.
2011-01-01
Hydro code implementations of ejecta dynamics at shocked interfaces presume a source distribution function ofparticulate masses and velocities, f 0 (m, v;t). Some of the properties of this source distribution function have been determined from extensive Taylor and supported wave experiments on shock loaded Sn interfaces of varying surface and subsurface morphology. Such experiments measure the mass moment of f o under vacuum conditions assuming weak particle-particle interaction and, usually, fully inelastic capture by piezo-electric diagnostic probes. Recently, planar Sn experiments in He, Ar, and Kr gas atmospheres have been carried out to provide transport data both for machined surfaces and for coated surfaces. A hydro code model of ejecta transport usually specifies a criterion for the instantaneous temporal appearance of ejecta with source distribution f 0 (m, v;t 0 ). Under the further assumption of separability, f 0 (m,v;t 0 ) = f 1 (m)f 2 (v), the motion of particles under the influence of gas dynamic forces is calculated. For the situation of non-interacting particulates, interacting with a gas via drag forces, with the assumption of separability and simplified approximations to the Reynolds number dependence of the drag coefficient, the dynamical equation for the time evolution of the distribution function, f(r,v,m;t), can be resolved as a one-dimensional integral which can be compared to a direct hydro simulation as a test problem. Such solutions can also be used for preliminary analysis of experimental data. We report solutions for several shape dependent drag coefficients and analyze the results of recent planar dsh experiments in Ar and Xe.
Dispersive effects in radiation transport and radiation hydrodynamics in matter at high density
International Nuclear Information System (INIS)
Crowley, B.J.B.
1983-01-01
In a recent research program (reported in AWRE 0 20/82) I have investigated the generalisation of the equations of radiation hydrodynamics when electromagnetic radiation is assumed to obey a linear-response dispersion relation of the form nω=kc where the refractive index n depends on the frequency ω and/or wave number k. From the application of the Boltzmann-Liouville transport theory to photons in the short-wavelength (geometrical optics) limit, I derive the energy and momentum equations which, when combined with a classical (Euler-Lagrange-Navier-Stokes) treatment of a fluid material medium in LTE, yield a complete dynamical theory of linear interactions (+ stimulated processes) between incoherent (thermal) radiation and dense, locally isotropic matter. The theory includes an account of pondero-motive forces and electro (magneto) striction. Moreover, it is apparently capable of being generalised to non-linear interactions in which the refractive index depends on the local specific intensity of the radiation field, and, to some extent, to the treatment of high-frequency coherent radiation. The generalisation of various approximated forms of radiation-transport theory (esp. diffusion) has been considered in detail. Some problems remain however. One such is the treatment of anomalous dispersion. Current research work is concentrating on the interesting atomic physics aspects of electromagnetic (esp. radiative) properties of a dispersive material medium
Condensed history Monte Carlo methods for photon transport problems
International Nuclear Information System (INIS)
Bhan, Katherine; Spanier, Jerome
2007-01-01
We study methods for accelerating Monte Carlo simulations that retain most of the accuracy of conventional Monte Carlo algorithms. These methods - called Condensed History (CH) methods - have been very successfully used to model the transport of ionizing radiation in turbid systems. Our primary objective is to determine whether or not such methods might apply equally well to the transport of photons in biological tissue. In an attempt to unify the derivations, we invoke results obtained first by Lewis, Goudsmit and Saunderson and later improved by Larsen and Tolar. We outline how two of the most promising of the CH models - one based on satisfying certain similarity relations and the second making use of a scattering phase function that permits only discrete directional changes - can be developed using these approaches. The main idea is to exploit the connection between the space-angle moments of the radiance and the angular moments of the scattering phase function. We compare the results obtained when the two CH models studied are used to simulate an idealized tissue transport problem. The numerical results support our findings based on the theoretical derivations and suggest that CH models should play a useful role in modeling light-tissue interactions
Current problems of prevention diagnosis and treatment of radiation sickness
International Nuclear Information System (INIS)
Gus'kova, A.K.
1986-01-01
Causes of increasing interest to the problems of prevention, diagnosis and treatment of radiation sickness are presented. On the basis of recent publications some new aspects as quantitative criteria in radiobiology, organization problems of medical aid at radiation incidents estimation of efficiency of preventive medicine and radiation sickness therapy, theoretical development of radiotherapy of different organs et al., are characterized
Problems Of Transport Energetics In Lithuania
International Nuclear Information System (INIS)
Ambrazevicius, A.; Baublys, J.
2001-01-01
Lithuania has more than one million of transport means, the thermal capacity of which is about 50 mill. kW, i.e. 10 times more than the capacity of all thermal power stations. In the 21st century electrical energy will be used for transport means instead of petrol, and new capacities of electric stations in Lithuania will be necessary. All perspective transport means are described and conclusions for Lithuanian energetics are presented. (author)
Radiation transport. Progress report, April 1-December 31, 1983
International Nuclear Information System (INIS)
O'Dell, R.D.
1984-10-01
Research and development progress in radiation transport by the Los Alamos National Laboratory's Group X-6 for the last nine months of CY 83 is reported. Included are unclassified tasks in the areas of Fission Reactor Neutronics, Deterministic Transport Methods, Monte Carlo Radiation Transport, and Cross Sections and Physics
The problem of creation of radiation monitoring system
International Nuclear Information System (INIS)
Pilipchak, S.I.
1990-01-01
The review of problem of radiation monitoring system (RMS) in the territory of the country is presented. Unsolved problems are discussed which are divided into three groups: the organization of structures in RMS; implementation of automated RMS; the solution of scientific problems of global monitoring of radiation situation. 12 refs.; 1 tab
Ship Block Transportation Scheduling Problem Based on Greedy Algorithm
Directory of Open Access Journals (Sweden)
Chong Wang
2016-05-01
Full Text Available Ship block transportation problems are crucial issues to address in reducing the construction cost and improving the productivity of shipyards. Shipyards aim to maximize the workload balance of transporters with time constraint such that all blocks should be transported during the planning horizon. This process leads to three types of penalty time: empty transporter travel time, delay time, and tardy time. This study aims to minimize the sum of the penalty time. First, this study presents the problem of ship block transportation with the generalization of the block transportation restriction on the multi-type transporter. Second, the problem is transformed into the classical traveling salesman problem and assignment problem through a reasonable model simplification and by adding a virtual node to the proposed directed graph. Then, a heuristic algorithm based on greedy algorithm is proposed to assign blocks to available transporters and sequencing blocks for each transporter simultaneously. Finally, the numerical experiment method is used to validate the model, and its result shows that the proposed algorithm is effective in realizing the efficient use of the transporters in shipyards. Numerical simulation results demonstrate the promising application of the proposed method to efficiently improve the utilization of transporters and to reduce the cost of ship block logistics for shipyards.
An inverse method for radiation transport
Energy Technology Data Exchange (ETDEWEB)
Favorite, J. A. (Jeffrey A.); Sanchez, R. (Richard)
2004-01-01
Adjoint functions have been used with forward functions to compute gradients in implicit (iterative) solution methods for inverse problems in optical tomography, geoscience, thermal science, and other fields, but only once has this approach been used for inverse solutions to the Boltzmann transport equation. In this paper, this approach is used to develop an inverse method that requires only angle-independent flux measurements, rather than angle-dependent measurements as was done previously. The method is applied to a simplified form of the transport equation that does not include scattering. The resulting procedure uses measured values of gamma-ray fluxes of discrete, characteristic energies to determine interface locations in a multilayer shield. The method was implemented with a Newton-Raphson optimization algorithm, and it worked very well in numerical one-dimensional spherical test cases. A more sophisticated optimization method would better exploit the potential of the inverse method.
Manual for medical problems of radiation protection
International Nuclear Information System (INIS)
Anon.
1979-01-01
The manual deals comprehensively and topically with the theoretical and practical fundamentals of radiation protection of the population considering the present knowledge in the fields of radiobiology and radiation protection medicine. The subject is covered under the following headings: (1) physics of ionizing radiations, (2) biological radiation effects, (3) the acute radiation syndrome, (4) medical treatment of the acute radiation syndrome, (5) combined radiation injuries, and (6) prophylaxis and therapy of injuries caused by fission products of nuclear explosions. The book is of interest to medical doctors, medical scientists, and students in medicine who have to acquire special knowledge in the field of radiation protection and it is of value as a reference book in daily routine
Exponential convergence on a continuous Monte Carlo transport problem
International Nuclear Information System (INIS)
Booth, T.E.
1997-01-01
For more than a decade, it has been known that exponential convergence on discrete transport problems was possible using adaptive Monte Carlo techniques. An adaptive Monte Carlo method that empirically produces exponential convergence on a simple continuous transport problem is described
Paradox in a non-linear capacitated transportation problem
Directory of Open Access Journals (Sweden)
Dahiya Kalpana
2006-01-01
Full Text Available This paper discusses a paradox in fixed charge capacitated transportation problem where the objective function is the sum of two linear fractional functions consisting of variables costs and fixed charges respectively. A paradox arises when the transportation problem admits of an objective function value which is lower than the optimal objective function value, by transporting larger quantities of goods over the same route. A sufficient condition for the existence of a paradox is established. Paradoxical range of flow is obtained for any given flow in which the corresponding objective function value is less than the optimum value of the given transportation problem. Numerical illustration is included in support of theory.
Distributed Graphs for Solving Co-modal Transport Problems
Karama , Jeribi; Hinda , Mejri; Hayfa , Zgaya; Slim , Hammadi
2011-01-01
International audience; The paper presents a new approach based on a special distributed graphs in order to solve co-modal transport problems. The co-modal transport system consists on combining different transport modes effectively in terms of economic, environmental, service and financial efficiency, etc. However, the problem is that these systems must deal with different distributed information sources stored in different locations and provided by different public and private companies. In...
Solving fully fuzzy transportation problem using pentagonal fuzzy numbers
Maheswari, P. Uma; Ganesan, K.
2018-04-01
In this paper, we propose a simple approach for the solution of fuzzy transportation problem under fuzzy environment in which the transportation costs, supplies at sources and demands at destinations are represented by pentagonal fuzzy numbers. The fuzzy transportation problem is solved without converting to its equivalent crisp form using a robust ranking technique and a new fuzzy arithmetic on pentagonal fuzzy numbers. To illustrate the proposed approach a numerical example is provided.
grmonty: A MONTE CARLO CODE FOR RELATIVISTIC RADIATIVE TRANSPORT
International Nuclear Information System (INIS)
Dolence, Joshua C.; Gammie, Charles F.; Leung, Po Kin; Moscibrodzka, Monika
2009-01-01
We describe a Monte Carlo radiative transport code intended for calculating spectra of hot, optically thin plasmas in full general relativity. The version we describe here is designed to model hot accretion flows in the Kerr metric and therefore incorporates synchrotron emission and absorption, and Compton scattering. The code can be readily generalized, however, to account for other radiative processes and an arbitrary spacetime. We describe a suite of test problems, and demonstrate the expected N -1/2 convergence rate, where N is the number of Monte Carlo samples. Finally, we illustrate the capabilities of the code with a model calculation, a spectrum of the slowly accreting black hole Sgr A* based on data provided by a numerical general relativistic MHD model of the accreting plasma.
Compendium of Material Composition Data for Radiation Transport Modeling
International Nuclear Information System (INIS)
Williams, Ralph G.; Gesh, Christopher J.; Pagh, Richard T.
2006-01-01
Computational modeling of radiation transport problems including homeland security, radiation shielding and protection, and criticality safety all depend upon material definitions. This document has been created to serve two purposes: (1) to provide a quick reference of material compositions for analysts and (2) a standardized reference to reduce the differences between results from two independent analysts. Analysts are always encountering a variety of materials for which elemental definitions are not readily available or densities are not defined. This document provides a location where unique or hard to define materials will be located to reduce duplication in research for modeling purposes. Additionally, having a common set of material definitions helps to standardize modeling across PNNL and provide two separate researchers the ability to compare different modeling results from a common materials basis.
Validation of comprehensive space radiation transport code
International Nuclear Information System (INIS)
Shinn, J.L.; Simonsen, L.C.; Cucinotta, F.A.
1998-01-01
The HZETRN code has been developed over the past decade to evaluate the local radiation fields within sensitive materials on spacecraft in the space environment. Most of the more important nuclear and atomic processes are now modeled and evaluation within a complex spacecraft geometry with differing material components, including transition effects across boundaries of dissimilar materials, are included. The atomic/nuclear database and transport procedures have received limited validation in laboratory testing with high energy ion beams. The codes have been applied in design of the SAGE-III instrument resulting in material changes to control injurious neutron production, in the study of the Space Shuttle single event upsets, and in validation with space measurements (particle telescopes, tissue equivalent proportional counters, CR-39) on Shuttle and Mir. The present paper reviews the code development and presents recent results in laboratory and space flight validation
Density control problems in large stellarators with neoclassical transport
International Nuclear Information System (INIS)
Maassberg, H.; Beidler, C.D.; Simmet, E.E.
1999-01-01
With respect to the particle flux, the off-diagonal term in the neoclassical transport matrix becomes crucial in the stellarator long-mean-free-path regime. Central heating with peaked temperature profiles can make an active density profile control by central particle refuelling mandatory. The neoclassical particle confinement can significantly exceed the energy confinement at the outer radii. As a consequence, the required central refuelling may be larger than the neoclassical particle fluxes at outer radii leading to the loss of the global density control. Radiative losses as well as additional 'anomalous' electron heat diffusivities further exacerbate this problem. In addition to the analytical formulation of the neoclassical link of particle and energy fluxes, simplified model simulations as well as time-dependent ASTRA code simulations are described. In particular, the 'low-' and 'high-mirror' W7-X configurations are compared. For the W7-X 'high-mirror' configuration especially, the appearance of the neoclassical particle transport barrier is predicted at higher densities. (author)
TOPICAL PROBLEMS AND DEVELOPMENT PERSPECTIVES OF INTERNATIONAL FREIGHT TRANSPORT
Sulce, Anastasija
2014-01-01
The title of thesis is Typical Problems and Development Perspectives of International Freight Transport. This work is dedicated to different modes of international transportation, freight and logistics their advantages and disadvantages. Another essential part of the work related to different way for transport development and its efficient usage The objective is to explore modes of freight transport and logistics in details and, thereof, reveal advantages and disadvantages. On the basis ...
Problems of linear electron (polaron) transport theory in semiconductors
Klinger, M I
1979-01-01
Problems of Linear Electron (Polaron) Transport Theory in Semiconductors summarizes and discusses the development of areas in electron transport theory in semiconductors, with emphasis on the fundamental aspects of the theory and the essential physical nature of the transport processes. The book is organized into three parts. Part I focuses on some general topics in the theory of transport phenomena: the general dynamical theory of linear transport in dissipative systems (Kubo formulae) and the phenomenological theory. Part II deals with the theory of polaron transport in a crystalline semicon
Department of Environmental and Radiation Transport Physics - Overview
International Nuclear Information System (INIS)
Woznicka, U.
2001-01-01
Full text: We deal with environmental physics and the radiation transport physics, both theoretically and experimentally. Some results find their way to practical applications. Our environmental physics research encompasses hydrogeological problems as well as measurements of trace elements in the atmosphere and in the water. Theoretical (analytical and numerical) and experimental issues of the radiation transport and radiation fields are our main field of research. The interest in radiation transport phenomena is stimulated by their importance for the environmental physics, industrial and nuclear facilities and methods of geophysical. Environmental isotopes and noble gases are used in the investigation of water-bearing geological formations in order to determine the origin and age of groundwater. The papers listed below and three ''Reports on research'' present recent achievements in this field. The gas chromatography methods are used for monitoring the anthropogenic trace gases (SF 6 and freons), which participate in the Earth green-house effect. A very high detection level of SF 6 in water, 0.0028 fg/cm 3 H 2 0, has been reached as required for hydrogeological purposes. A preliminary verification of the SF 6 tracer method for dating young groundwaters by the tritium method has been carried out. We carried on the work on a method of radon measurement in soil in connection with geological conditions. The national seminar ''Radon in Environment'' organized at the INP aroused an interest of Polish scientific centres in that field. The seminar gathered 60 participants who presented 24 oral reports and 8 posters. Within the scope of the radiation transport physics we studied thermal neutron transport in finite hydrogenous media. Advantages and limitations of a Monte Carlo code (MCNP) in thermal neutron transport simulations have been examined by both the analytical solution and the experiment on the INP pulsed neutron generator. An interesting contribution to the
Radiation transport phenomena and modeling. Part A: Codes; Part B: Applications with examples
International Nuclear Information System (INIS)
Lorence, L.J. Jr.; Beutler, D.E.
1997-09-01
This report contains the notes from the second session of the 1997 IEEE Nuclear and Space Radiation Effects Conference Short Course on Applying Computer Simulation Tools to Radiation Effects Problems. Part A discusses the physical phenomena modeled in radiation transport codes and various types of algorithmic implementations. Part B gives examples of how these codes can be used to design experiments whose results can be easily analyzed and describes how to calculate quantities of interest for electronic devices
Dynamic Flow Management Problems in Air Transportation
Patterson, Sarah Stock
1997-01-01
In 1995, over six hundred thousand licensed pilots flew nearly thirty-five million flights into over eighteen thousand U.S. airports, logging more than 519 billion passenger miles. Since demand for air travel has increased by more than 50% in the last decade while capacity has stagnated, congestion is a problem of undeniable practical significance. In this thesis, we will develop optimization techniques that reduce the impact of congestion on the national airspace. We start by determining the optimal release times for flights into the airspace and the optimal speed adjustment while airborne taking into account the capacitated airspace. This is called the Air Traffic Flow Management Problem (TFMP). We address the complexity, showing that it is NP-hard. We build an integer programming formulation that is quite strong as some of the proposed inequalities are facet defining for the convex hull of solutions. For practical problems, the solutions of the LP relaxation of the TFMP are very often integral. In essence, we reduce the problem to efficiently solving large scale linear programming problems. Thus, the computation times are reasonably small for large scale, practical problems involving thousands of flights. Next, we address the problem of determining how to reroute aircraft in the airspace system when faced with dynamically changing weather conditions. This is called the Air Traffic Flow Management Rerouting Problem (TFMRP) We present an integrated mathematical programming approach for the TFMRP, which utilizes several methodologies, in order to minimize delay costs. In order to address the high dimensionality, we present an aggregate model, in which we formulate the TFMRP as a multicommodity, integer, dynamic network flow problem with certain side constraints. Using Lagrangian relaxation, we generate aggregate flows that are decomposed into a collection of flight paths using a randomized rounding heuristic. This collection of paths is used in a packing integer
Problems of medical personnel deontology during radiation emergency response
International Nuclear Information System (INIS)
Poplavskij, K.K.; Popov, A.O.
1990-01-01
Problems of deontology in the process of liquidation of radiation accident consequences are considered in the article. It is noted, that shortages of ethical nature in the activities of physicians are related to insufficient qualification of medical personnel in the area of radiation medicine. Problems of medical personnel participation in the large scale propaganda activities among various groups of population are considered. 5 refs
Problems of radiation genetics. [In Russian
Energy Technology Data Exchange (ETDEWEB)
Dubinin, N P
1956-01-01
A general review is presented of recent experiments in genetics. Mutant and hereditary effects of the increase in natural radiation and that released by atomic and hydrogen tests were analyzed. Achievements and the possibilities of applying radiation in the induction of selective plant mutations are discussed.
Some human-related problems in radiation protection
International Nuclear Information System (INIS)
Yoshizawa, Yasuo
1980-01-01
Radiation protection includes both human and source-related problems. The human problems have not only medical but also social aspects, such as labor management. Special attention should be paid to the fact that the subject of radiation protection is not a human being as living thing but as member of society. ICRP recommended that conditions of work can be divided into two classed, working condition A and B, according to annual exposure. This application is of great value to radiation protection practice. Nevertheless the legal regulations do not adopt it yet. The present condition of the medical surveillance of radiation workers is not appropriate from the scientific standpoint. This is the difficult problem which is caused by the delay of the legal application of ICRP recommendation. Compensation for occupational radiation hazards should be overlooked. This problem have been investigated by an authorized committee, but a number of unsolved problems still remain. (author)
Statistics of Monte Carlo methods used in radiation transport calculation
International Nuclear Information System (INIS)
Datta, D.
2009-01-01
Radiation transport calculation can be carried out by using either deterministic or statistical methods. Radiation transport calculation based on statistical methods is basic theme of the Monte Carlo methods. The aim of this lecture is to describe the fundamental statistics required to build the foundations of Monte Carlo technique for radiation transport calculation. Lecture note is organized in the following way. Section (1) will describe the introduction of Basic Monte Carlo and its classification towards the respective field. Section (2) will describe the random sampling methods, a key component of Monte Carlo radiation transport calculation, Section (3) will provide the statistical uncertainty of Monte Carlo estimates, Section (4) will describe in brief the importance of variance reduction techniques while sampling particles such as photon, or neutron in the process of radiation transport
ATR, Radiation Transport Models in Atmosphere at Various Altitudes
International Nuclear Information System (INIS)
1981-01-01
1 - Description of problem or function: ATR is a user-oriented code for calculating quickly and simply radiation environment problems at all altitudes in the atmosphere. The code is based on parametric models of a comprehensive data base of air transport results which were generated using discrete ordinates transport techniques for infinite homogeneous air. The effects of air-ground interface and non-uniform air density are treated as perturbation corrections on homogeneous air results. ATR includes parametric models for neutrons and secondary gamma rays as a function of space, energy and source- target angle out to angles of 550 g/cm 2 of air. ATR contains parameterizations of infinite medium air transport of neutrons and secondary gamma rays and correction factors for the air-ground interface and high altitude exponential air. It responds to a series of user-oriented commands which specify the source, geometry and print options to output a variety of useful air transport information, including energy-angle dependent fluence, dose, current, and isodose ranges. 2 - Method of solution: The version 3 differs from earlier versions in that version 3 contains the parameterization of the new neutron and secondary gamma rays data base that was calculated using the latest DNA approved cross sections for air. Other improvements to the ATR code include: parameterization and inclusion into ATR of new air- over-ground correction factors, low energy x-rays calculations, new fission source, and new convenience options. 3 - Restrictions on the complexity of the problem: ATR takes approximately 36,000 decimal words of storage. This can be lessened by overlaying different parts of the code
ASYMPTOTICS OF a PARTICLES TRANSPORT PROBLEM
Directory of Open Access Journals (Sweden)
Kuzmina Ludmila Ivanovna
2017-11-01
Full Text Available Subject: a groundwater filtration affects the strength and stability of underground and hydro-technical constructions. Research objectives: the study of one-dimensional problem of displacement of suspension by the flow of pure water in a porous medium. Materials and methods: when filtering a suspension some particles pass through the porous medium, and some of them are stuck in the pores. It is assumed that size distributions of the solid particles and the pores overlap. In this case, the main mechanism of particle retention is a size-exclusion: the particles pass freely through the large pores and get stuck at the inlet of the tiny pores that are smaller than the particle diameter. The concentrations of suspended and retained particles satisfy two quasi-linear differential equations of the first order. To solve the filtration problem, methods of nonlinear asymptotic analysis are used. Results: in a mathematical model of filtration of suspensions, which takes into account the dependence of the porosity and permeability of the porous medium on concentration of retained particles, the boundary between two phases is moving with variable velocity. The asymptotic solution to the problem is constructed for a small filtration coefficient. The theorem of existence of the asymptotics is proved. Analytical expressions for the principal asymptotic terms are presented for the case of linear coefficients and initial conditions. The asymptotics of the boundary of two phases is given in explicit form. Conclusions: the filtration problem under study can be solved analytically.
Solving radiation problems at particle accelerators
Energy Technology Data Exchange (ETDEWEB)
Nikolai V. Mokhov
2001-12-11
At high-intensity high-energy particle accelerators, consequences of a beam-induced radiation impact on machine and detector components, people, environment and complex performance can range from negligible to severe. The specifics, general approach and tools used at such machines for radiation analysis are described. In particular, the world leader Fermilab accelerator complex is considered, with its fixed target and collider experiments, as well as new challenging projects such as LHC, VLHC, muon collider and neutrino factory. The emphasis is on mitigation of deleterious beam-induced radiation effects and on the key role of effective computer simulations.
Solving radiation problems at particle accelerators
International Nuclear Information System (INIS)
Mokhov, N.V.
2001-01-01
At high-intensity high-energy particle accelerators, consequences of a beam-induced radiation impact on machine and detector components, people, environment and complex performance can range from negligible to severe. The specifics, general approach and tools used at such machines for radiation analysis are described. In particular, the world leader Fermilab accelerator complex is considered, with its fixed target and collider experiments, as well as new challenging projects such as LHC, VLHC, muon collider and neutrino factory. The emphasis is on mitigation of deleterious beam-induced radiation effects and on the key role of effective computer simulations
Integral and Lagrangian simulations of particle and radiation transport in plasma
International Nuclear Information System (INIS)
Christlieb, A J; Hitchon, W N G; Lawler, J E; Lister, G G
2009-01-01
Accurate integral and Lagrangian models of transport in plasmas, in which the models reflect the actual physical behaviour as closely as possible, are presented. These methods are applied to the behaviour of particles and photons in plasmas. First, to show how these types of models arise in a wide range of plasma physics applications, an application to radiation transport in a lighting discharge is given. The radiation transport is solved self-consistently with a model of the discharge to provide what are believed to be very accurate 1D simulations of fluorescent lamps. To extend these integral methods to higher dimensions is computationally very costly. The wide utility of 'treecodes' in solving massive integral problems in plasma physics is discussed, and illustrated in modelling vortex formation in a Penning trap, where a remarkably detailed simulation of vortex formation in the trap is obtained. Extension of treecode methods to other integral problems such as radiation transport is under consideration.
To the problem of superfluous cosmic radiation
International Nuclear Information System (INIS)
Savenko, I.A.; Saraeva, M.A.; Shavrin, P.I.
1979-01-01
From consideration of a number of basic works on the excessive cosmic radiation given is the most probable composition (electron, proton, and nuclear components) of this radiation in equatorial regions at altitudes corresponding to minimum altitudes of the drift trajectories hsub(min) <= 0, in case of detecting by detector on the artificial satellite of the Earth (ASE) with the mass up to 1t and of the heavier ASE. The disagreement in spectra of solar cosmic rays obtained along the latitude effect on the ASE. ''Molniya-1'' and in the experiments out of the magnetosphere on the ASE ''Explorer-41'' is explained by excessive radiation production of solar cosmic rays. The comparison of readings of the neutron channel with those of the charged particle channels of the apparatus on the ASE ''Molniya-1'' during the proton event on 25.01.1971 does not contradict to the supposition on the similarity of excessive cosmic radiation production of galactic and solar cosmic rays
Monte Carlo method for neutron transport problems
International Nuclear Information System (INIS)
Asaoka, Takumi
1977-01-01
Some methods for decreasing variances in Monte Carlo neutron transport calculations are presented together with the results of sample calculations. A general purpose neutron transport Monte Carlo code ''MORSE'' was used for the purpose. The first method discussed in this report is the method of statistical estimation. As an example of this method, the application of the coarse-mesh rebalance acceleration method to the criticality calculation of a cylindrical fast reactor is presented. Effective multiplication factor and its standard deviation are presented as a function of the number of histories and comparisons are made between the coarse-mesh rebalance method and the standard method. Five-group neutron fluxes at core center are also compared with the result of S4 calculation. The second method is the method of correlated sampling. This method was applied to the perturbation calculation of control rod worths in a fast critical assembly (FCA-V-3) Two methods of sampling (similar flight paths and identical flight paths) are tested and compared with experimental results. For every cases the experimental value lies within the standard deviation of the Monte Carlo calculations. The third method is the importance sampling. In this report a biased selection of particle flight directions discussed. This method was applied to the flux calculation in a spherical fast neutron system surrounded by a 10.16 cm iron reflector. Result-direction biasing, path-length stretching, and no biasing are compared with S8 calculation. (Aoki, K.)
Study and application of Dot 3.5 computer code in radiation shielding problems
International Nuclear Information System (INIS)
Otto, A.C.; Mendonca, A.G.; Maiorino, J.R.
1983-01-01
The application of nuclear transportation code S sub(N), Dot 3.5, to radiation shielding problems is revised. Aiming to study the better available option (convergence scheme, calculation mode), of DOT 3.5 computer code to be applied in radiation shielding problems, a standard model from 'Argonne Code Center' was selected and a combination of several calculation options to evaluate the accuracy of the results and the computational time was used, for then to select the more efficient option. To illustrate the versatility and efficacy in the application of the code for tipical shielding problems, the streaming neutrons calculation along a sodium coolant channel is ilustrated. (E.G.) [pt
Efficient decomposition and linearization methods for the stochastic transportation problem
International Nuclear Information System (INIS)
Holmberg, K.
1993-01-01
The stochastic transportation problem can be formulated as a convex transportation problem with nonlinear objective function and linear constraints. We compare several different methods based on decomposition techniques and linearization techniques for this problem, trying to find the most efficient method or combination of methods. We discuss and test a separable programming approach, the Frank-Wolfe method with and without modifications, the new technique of mean value cross decomposition and the more well known Lagrangian relaxation with subgradient optimization, as well as combinations of these approaches. Computational tests are presented, indicating that some new combination methods are quite efficient for large scale problems. (authors) (27 refs.)
Fundaments of transport equation splitting and the eigenvalue problem
International Nuclear Information System (INIS)
Stancic, V.
2000-01-01
In order to remove some singularities concerning the boundary conditions of one dimensional transport equation, a split form of transport equation describing the forward i.e. μ≥0, and a backward μ<0 directed neutrons is being proposed here. The eigenvalue problem has also been considered here (author)
Problem Sets: Fundamentals Of Transportation And Traffic Operations
Daganzo, Carlos F.
1998-01-01
These problem sets comprise a supplement to Fundamentals of Transportation and Traffic Operations (C. Daganzo, Pergamon, 1997). Academicians can also obtain a companion set of solutions by writing to "Institute of Transportation Studies, Publications Office, 109 McLaughlin Hall, University of California, Berkeley, CA 94720" or by sending e-mail to .
Transport of infrared radiation in cuboidal clouds
Harshvardhan, MR.; Weinman, J. A.; Davies, R.
1981-01-01
The transport of infrared radiation in a single cuboidal cloud is modeled using a variable azimuth two-stream approximation. Computations are made at 10 microns for a Deirmendjian (1969) C-1 water cloud where the single scattering albedo is equal to 0.638 and the asymmetry parameter is 0.865. The results indicate that the emittance of the top face of the model cloud is always less than that for a plane parallel cloud of the same optical depth. The hemispheric flux escaping from the cloud top possesses a gradient from the center to the edges which are warmer when the cloud is over warmer ground. Cooling rate calculations in the 8-13.6 micron region demonstrate that there is cooling out of the sides of the cloud at all levels even when there is heating of the core from the ground below. The radiances exiting from model cuboidal clouds are computed by path integration over the source function obtained with the two-stream approximation. Results indicate that the brightness temperature measured from finite clouds will overestimate the cloud-top temperature.
Some problems in the acceptability of implementing radiation protection programs
International Nuclear Information System (INIS)
Neill, R.H.
1997-01-01
The three fundamentals that radiation protection programs are based upon are; 1) establishing a quantitative correlation between radiation exposure and biological effects in people; 2) determining a level of acceptable risk of exposure; and 3) establishing systems to measure the radiation dose to insure compliance with the regulations or criteria. The paper discusses the interrelationship of these fundamentals, difficulties in obtaining a consensus of acceptable risk and gives some examples of problems in identifying the most critical population-at-risk and in measuring dose. Despite such problems, it is recommended that we proceed with the existing conservative structure of radiation protection programs based upon a linear no threshold model for low radiation doses to insure public acceptability of various potential radiation risks. Voluntary compliance as well as regulatory requirements should continue to be pursued to maintain minimal exposure to ionizing radiation. (author)
International Nuclear Information System (INIS)
Dmitriy Y. Anistratov; Adrian Constantinescu; Loren Roberts; William Wieselquist
2007-01-01
This is a project in the field of fundamental research on numerical methods for solving the particle transport equation. Numerous practical problems require to use unstructured meshes, for example, detailed nuclear reactor assembly-level calculations, large-scale reactor core calculations, radiative hydrodynamics problems, where the mesh is determined by hydrodynamic processes, and well-logging problems in which the media structure has very complicated geometry. Currently this is an area of very active research in numerical transport theory. main issues in developing numerical methods for solving the transport equation are the accuracy of the numerical solution and effectiveness of iteration procedure. The problem in case of unstructured grids is that it is very difficult to derive an iteration algorithm that will be unconditionally stable
Compendium of Material Composition Data for Radiation Transport Modeling
Energy Technology Data Exchange (ETDEWEB)
McConn, Ronald J.; Gesh, Christopher J.; Pagh, Richard T.; Rucker, Robert A.; Williams III, Robert
2011-03-04
Introduction Meaningful simulations of radiation transport applications require realistic definitions of material composition and densities. When seeking that information for applications in fields such as homeland security, radiation shielding and protection, and criticality safety, researchers usually encounter a variety of materials for which elemental compositions are not readily available or densities are not defined. Publication of the Compendium of Material Composition Data for Radiation Transport Modeling, Revision 0, in 2006 was the first step toward mitigating this problem. Revision 0 of this document listed 121 materials, selected mostly from the combined personal libraries of staff at the Pacific Northwest National Laboratory (PNNL), and thus had a scope that was recognized at the time to be limited. Nevertheless, its creation did provide a well-referenced source of some unique or hard-to-define material data in a format that could be used directly in radiation transport calculations being performed at PNNL. Moreover, having a single common set of material definitions also helped to standardize at least one aspect of the various modeling efforts across the laboratory by providing separate researchers the ability to compare different model results using a common basis of materials. The authors of the 2006 compendium understood that, depending on its use and feedback, the compendium would need to be revised to correct errors or inconsistencies in the data for the original 121 materials, as well as to increase (per users suggestions) the number of materials listed. This 2010 revision of the compendium has accomplished both of those objectives. The most obvious change is the increased number of materials from 121 to 372. The not-so-obvious change is the mechanism used to produce the data listed here. The data listed in the 2006 document were compiled, evaluated, entered, and error-checked by a group of individuals essentially by hand, providing no library
International Nuclear Information System (INIS)
Olson, Gordon L.
2016-01-01
One-dimensional models for the transport of radiation through binary stochastic media do not work in multi-dimensions. Authors have attempted to modify or extend the 1D models to work in multidimensions without success. Analytic one-dimensional models are successful in 1D only when assuming greatly simplified physics. State of the art theories for stochastic media radiation transport do not address multi-dimensions and temperature-dependent physics coefficients. Here, the concept of effective opacities and effective heat capacities is found to well represent the ensemble averaged transport solutions in cases with gray or multigroup temperature-dependent opacities and constant or temperature-dependent heat capacities. In every case analyzed here, effective physics coefficients fit the transport solutions over a useful range of parameter space. The transport equation is solved with the spherical harmonics method with angle orders of n=1 and 5. Although the details depend on what order of solution is used, the general results are similar, independent of angular order. - Highlights: • Gray and multigroup radiation transport is done through 2D stochastic media. • Approximate models for the mean radiation field are found for all test problems. • Effective opacities are adjusted to fit the means of stochastic media transport. • Test problems include temperature dependent opacities and heat capacities • Transport solutions are done with angle orders n=1 and 5.
Radiation interaction with substance and simulation of the nuclear geophysical problems
International Nuclear Information System (INIS)
Pshenichnyj, G.A.
1982-01-01
Main processes of interaction of various types of nuclear radiation (NR) with substance, NR transport theory and physical- mathematical simulation of basic problems of nuclear geophysics (NG) are considered. General classification of NG methods according to the type of the detected radiation with a more detailed division according to the physical essence of the interaction process employed is given. Direct NG problems are related to the study of space- energy radiation distribution in substance under certain cross sections of elementary interaction processes, substance properties and specified geometric conditions. The theoretical solution of the direct problems is based on using mathematical models of radiation transport in specified media. The NG inverse problems consist in determining element composition and other medium properties by data of integral or spectral characteristics of NR fields measurements. The NR in the course of its transport in substance can experience dozens of elementary interaction processes, the predominance of this or that process depending on NR energy, medium properties and geometric measurement conditions. This explains a wide NG method diversity. The Monte Carlo method application in the NR transport theory and various methods of decreasing calculations labour input are considered [ru
Numerical simulations for radiation hydrodynamics. 2: Transport limit
International Nuclear Information System (INIS)
Dai, W.W.; Woodward, P.R.
2000-01-01
A finite difference scheme is proposed for two-dimensional radiation hydrodynamical equations in the transport limit. The scheme is of Godunov-type, in which the set of time-averaged flux needed in the scheme is calculated through Riemann problems solved. In the scheme, flow signals are explicitly treated, while radiation signals are implicitly treated. Flow fields and radiation fields are updated simultaneously. An iterative approach is proposed to solve the set of nonlinear algebraic equations arising from the implicitness of the scheme. The sweeping method used in the scheme significantly reduces the number of iterations or computer CPU time needed. A new approach to further accelerate the convergence is proposed, which further reduces the number of iterations needed by more than one order. No matter how many cells radiation signals propagate in one time step, only an extremely small number of iterations are needed in the scheme, and each iteration costs only about 0.8% of computer CPU time which is needed for one time step of a second order accurate and fully explicit scheme. Two-dimensional problems are treated through a dimensionally split technique. Therefore, iterations for solving the set of algebraic equations are carried out only in each one-dimensional sweep. Through numerical examples it is shown that the scheme keeps the principle advantages of Godunov schemes for flow motion. In the time scale of flow motion numerical results are the same as those obtained from a second order accurate and fully explicit scheme. The acceleration of the convergence proposed in this paper may be directly applied to other hyperbolic systems. This study is important for laser fusion and astrophysics
The gender problem in radiation protection
Energy Technology Data Exchange (ETDEWEB)
Persson, Lars [Nobel Inst. of Physics, Stockholm (Sweden)
2012-07-01
Gender is a range of characteristics used to distinguish between males and females, particularly in the cases of men and women and the masculine and feminine attributes assigned to them. While the social sciences sometimes approach gender as a social construct, and some gender studies particularly do, research in the natural and medical sciences investigates whether biological differences in males and females influence the development of gender in humans. Radiation protection regulations also take into account the possibly different radiation risks of males and females. The following contribution investigates how far this is justified, and what are the consequences. (orig.)
The gender problem in radiation protection
International Nuclear Information System (INIS)
Persson, Lars
2012-01-01
Gender is a range of characteristics used to distinguish between males and females, particularly in the cases of men and women and the masculine and feminine attributes assigned to them. While the social sciences sometimes approach gender as a social construct, and some gender studies particularly do, research in the natural and medical sciences investigates whether biological differences in males and females influence the development of gender in humans. Radiation protection regulations also take into account the possibly different radiation risks of males and females. The following contribution investigates how far this is justified, and what are the consequences. (orig.)
Los Alamos radiation transport code system on desktop computing platforms
International Nuclear Information System (INIS)
Briesmeister, J.F.; Brinkley, F.W.; Clark, B.A.; West, J.T.
1990-01-01
The Los Alamos Radiation Transport Code System (LARTCS) consists of state-of-the-art Monte Carlo and discrete ordinates transport codes and data libraries. These codes were originally developed many years ago and have undergone continual improvement. With a large initial effort and continued vigilance, the codes are easily portable from one type of hardware to another. The performance of scientific work-stations (SWS) has evolved to the point that such platforms can be used routinely to perform sophisticated radiation transport calculations. As the personal computer (PC) performance approaches that of the SWS, the hardware options for desk-top radiation transport calculations expands considerably. The current status of the radiation transport codes within the LARTCS is described: MCNP, SABRINA, LAHET, ONEDANT, TWODANT, TWOHEX, and ONELD. Specifically, the authors discuss hardware systems on which the codes run and present code performance comparisons for various machines
Astronaut radiation. Will it become a problem?
International Nuclear Information System (INIS)
Parker, I.
1988-01-01
The U.S. NRCP recommendations to NASA for astronauts' dose limits to deep-body, eyes and skin are discussed in outline in relation to the longer space flights (e.g. space station duties and a manned Mars mission). Cosmic rays, solar flares and trapped Van Allen belt radiation are considered. (U.K.)
Status and problems of radiation education in Taiwan
International Nuclear Information System (INIS)
Huang Chin-Wang
1999-01-01
In Taiwan, there are few numbers of radiation education, courses this fact makes an impression of insufficiency. This matter is thinkable to be an important problem. There are sets of atomic power stations and 6 atomic reactors are now operating. The electric power production is about 50144 MW, which comprises 20 % of total electric power in the country. The knowledge for the related to the radiation is not diffuse and there is only frightened impression. The radiation education should be spread to the ordinary citizen, and essential qualities a risk of the radiation should be instructed sufficiently. The radiation literacy of the ordinary citizen is needed to raise the level. (author)
On the Structure of the Fixed Charge Transportation Problem
Kowalski, K.
2005-01-01
This work extends the theory of the fixed charge transportation problem (FCTP), currently based mostly on a forty-year-old publication by Hirsch and Danzig. This paper presents novel properties that need to be considered by those using existing, or those developing new methods for optimizing FCTP. It also defines the problem in an easier way,…
Chernobyl accident: Causes, consequences and problems of radiation measurements
International Nuclear Information System (INIS)
Kortov, V.; Ustyantsev, Yu.
2013-01-01
General description of Chernobyl accident is given in the review. The accident causes are briefly described. Special attention is paid to radiation situation after the accident and radiation measurements problems. Some data on Chernobyl disaster are compared with the corresponding data on Fukushima accident. It is noted that Chernobyl and Fukushima lessons should be taken into account while developing further measures on raising nuclear industry safety. -- Highlights: ► The short comparative analysis of accidents at Chernobyl and Fukushima is given. ► We note the great effect of β-radiation on the radiation situation at Chernobyl. ► We discuss the problems of radiation measurements under these conditions. ► The impact of shelter on the radiation situation near Chernobyl NPS is described
Radiation proctitis and its surgical problems
Energy Technology Data Exchange (ETDEWEB)
Ichikawa, Hideyuki; Hayashi, Shiro; Yasuna, Osamu; Yamaura, Yoshinori
1985-01-01
Radiation proctitis was investigated in terms of clinico-pathological findings, the method of treatment and therapeutic results in 11 patients (7 with cervical cancer, 1 with ovarian cancer, and 3 with cancer of the bladder). Four of the patients with cervical cancer were treated with 4,136-5,000 rad of WCo combined with brachytherapy of WCo or TXCs, one patient with 6,000 rad of WCo alone, one with 3,000 rad of x-ray alone, and one with 4,900 rad of x-ray combined with brachytherapy of TXCs. A patient with ovarian cancer was treated with 6,000 rad of x-ray and three patients with cancer of the bladder were treated with 4,200-6,330 rad of x-ray. Radiation proctitis developed early (4 months to 1 year after therapy) in 8 patients and late (4 years to 19 years after therapy) in the other 3 patients. Common symptoms were melena, constipation and sensation of gastric fullness. According to the Sherman's classification, proctitis was grade III or IV (showing constriction, ulcer or fistula) in all patients. Although the lesion could be resected in one patient, only colostomy was performed in the other 10 patients. It is recommended that care should be taken in deciding the method of exposure to the pelvic viscera and exposure doses for the prevention of radiation proctitis, and that intestinal lesions should be resected before far-advanced intestinal disturbance developes. (Namekawa, K.).
Radiation doses from the transport of radioactive materials
International Nuclear Information System (INIS)
Shaw, K.B.; Holyoak, B.
1983-01-01
A summary is given of a study on radiation exposure resulting from the transport of radioactive materials within the United Kingdom. It was concluded that the transport of technetium generators for hospital use accounts for about 49% of the occupational exposure for the normal transport of radioactive materials. Other isotopes for medical and industrial use contribute about 38% of the occupational exposure and the remainder can be attributed to transportation as a result of the nuclear fuel cycle including the transport of irradiated nuclear fuel. The occupational collective dose for all modes of transport is estimated at 1 man Sv y -1 . (UK)
Resonance in the restricted problem caused by solar radiation pressure
International Nuclear Information System (INIS)
Bhatnagar, K.B.; Gupta, B.
1977-01-01
Resonance is discussed in the motion of an artificial Earth satellite caused by solar radiation pressure. The Hamiltonian and the generating functions occurring in the problem are expanded in the power series of small parameter β, which depends on solar radiation pressure. Also the perturbations in the osculating elements are obtained up to O(βsup(1/2)). (author)
Radiation safety in sea transport of radioactive material in Japan
International Nuclear Information System (INIS)
Odano, N.; Yanagi, H.
2004-01-01
Radiation safety for sea transport of radioactive material in Japan has been discussed based on records of the exposed dose of sea transport workers and measured data of dose rate equivalents distribution inboard exclusive radioactive material shipping vessels. Recent surveyed records of the exposed doses of workers who engaged in sea transport operation indicate that exposed doses of transport workers are significantly low. Measured distribution of the exposed dose equivalents inboard those vessels indicates that dose rate equivalents inside those vessels are lower than levels regulated by the transport regulations of Japan. These facts clarify that radiation safety of inboard environment and handling of transport casks in sea transport of radioactive material in Japan are assured
Radiation safety in sea transport of radioactive material in Japan
Energy Technology Data Exchange (ETDEWEB)
Odano, N. [National Maritime Research Inst., Tokyo (Japan); Yanagi, H. [Nuclear Fuel Transport Co., Ltd., Tokyo (Japan)
2004-07-01
Radiation safety for sea transport of radioactive material in Japan has been discussed based on records of the exposed dose of sea transport workers and measured data of dose rate equivalents distribution inboard exclusive radioactive material shipping vessels. Recent surveyed records of the exposed doses of workers who engaged in sea transport operation indicate that exposed doses of transport workers are significantly low. Measured distribution of the exposed dose equivalents inboard those vessels indicates that dose rate equivalents inside those vessels are lower than levels regulated by the transport regulations of Japan. These facts clarify that radiation safety of inboard environment and handling of transport casks in sea transport of radioactive material in Japan are assured.
Radiation transport phenomena and modeling - part A: Codes
International Nuclear Information System (INIS)
Lorence, L.J.
1997-01-01
The need to understand how particle radiation (high-energy photons and electrons) from a variety of sources affects materials and electronics has motivated the development of sophisticated computer codes that describe how radiation with energies from 1.0 keV to 100.0 GeV propagates through matter. Predicting radiation transport is the necessary first step in predicting radiation effects. The radiation transport codes that are described here are general-purpose codes capable of analyzing a variety of radiation environments including those produced by nuclear weapons (x-rays, gamma rays, and neutrons), by sources in space (electrons and ions) and by accelerators (x-rays, gamma rays, and electrons). Applications of these codes include the study of radiation effects on electronics, nuclear medicine (imaging and cancer treatment), and industrial processes (food disinfestation, waste sterilization, manufacturing.) The primary focus will be on coupled electron-photon transport codes, with some brief discussion of proton transport. These codes model a radiation cascade in which electrons produce photons and vice versa. This coupling between particles of different types is important for radiation effects. For instance, in an x-ray environment, electrons are produced that drive the response in electronics. In an electron environment, dose due to bremsstrahlung photons can be significant once the source electrons have been stopped
Kapteyn series arising in radiation problems
International Nuclear Information System (INIS)
Lerche, I; Tautz, R C
2008-01-01
In discussing radiation from multiple point charges or magnetic dipoles, moving in circles or ellipses, a variety of Kapteyn series of the second kind arises. Some of the series have been known in closed form for a hundred years or more, others appear not to be available to analytic persuasion. This paper shows how 12 such generic series can be developed to produce either closed analytic expressions or integrals that are not analytically tractable. In addition, the method presented here may be of benefit when one has other Kapteyn series of the second kind to consider, thereby providing an additional reason to consider such series anew
Radiation quality and radiation risks - some current problems
International Nuclear Information System (INIS)
Kellerer, A.M.; Hahn, K.
1989-01-01
The newly evaluated cancer mortality data of the atomic bomb survivors suggest substantially enhanced risk estimates, and the various factors that are involved in the change are considered. The enhanced risk estimates have already led to added restrictions in the dose limits for radiation workers, and there may be a further tightening of regulations in the future. The impending revision of the quality factors in radiation protection may, therefore, lead to practical difficulties, and a careful consideration of the various aspects involved in a revision is required. A liaison group of ICRU and ICRP has proposed a reformulation of the quality factor that is related not to the LET, but to the microdosimetric variably y. The relation leads to increased quality factors for neutrons, but also to a quality factor for γ rays of only 0.5. Alternatives are presented that relate the quality factor to LET and that retain γ- rays as the reference radiation. One option corresponds to different quality factors for γ rays and X-rays, the other option sets the quality factor for photons approximately equal to unity, irrespective of energy. (author)
Transport of radioactive sources-an environmental problem
International Nuclear Information System (INIS)
Merckaert, G.
1996-01-01
Full text: The transport of dangerous goods is submitted to various regulations. These can be international, national or regional and they can differ from country to country. The basis for the regulations for dangerous goods can be found in the recommendations on the transport of dangerous goods, issued by the United Nations committee of experts on the transport of dangerous goods (orange book). For radioactive material the regulations for the safe transport of radioactive material, issued by the International Atomic Energy Agency (IAEA), are applied. The UN recommendations provide for 9 classes of dangerous goods. With regard to class 7, specifically related to the transport of radioactive material special recommendation relating to class 70, the IAEA regulations are referred to. These IAEA regulations for their part provide for 13 schedules, varying between weakly and highly radioactive. The radioactive sources which are used for non-destructive testing or for medical purposes are mostly sealed sources, i.e. the radioactive material is contained in a metallic shell. According to the nature of the isotope and their activity, the sources are transported either in industrial packagings, type A or type B packagings. According to the mode of transport, either air, sea, rail or road, various specific rules are applied, which however, are fortunately nearly completely harmonized. Special attention is paid to radiation protection, heat removal and the testing and fabrication of packagings. As a general rule, the safety of transport is based on the safety of the packagings, i.e. their ability to maintain, even in accident conditions, their capacity of tightness, shielding against radiation and removing the heat generated by the transported material
The use of symbolic computation in radiative, energy, and neutron transport calculations
Frankel, J. I.
This investigation uses symbolic computation in developing analytical methods and general computational strategies for solving both linear and nonlinear, regular and singular, integral and integro-differential equations which appear in radiative and combined mode energy transport. This technical report summarizes the research conducted during the first nine months of the present investigation. The use of Chebyshev polynomials augmented with symbolic computation has clearly been demonstrated in problems involving radiative (or neutron) transport, and mixed-mode energy transport. Theoretical issues related to convergence, errors, and accuracy have also been pursued. Three manuscripts have resulted from the funded research. These manuscripts have been submitted to archival journals. At the present time, an investigation involving a conductive and radiative medium is underway. The mathematical formulation leads to a system of nonlinear, weakly-singular integral equations involving the unknown temperature and various Legendre moments of the radiative intensity in a participating medium. Some preliminary results are presented illustrating the direction of the proposed research.
Path Toward a Unified Geometry for Radiation Transport
Lee, Kerry
The Direct Accelerated Geometry for Radiation Analysis and Design (DAGRAD) element of the RadWorks Project under Advanced Exploration Systems (AES) within the Space Technology Mission Directorate (STMD) of NASA will enable new designs and concepts of operation for radiation risk assessment, mitigation and protection. This element is designed to produce a solution that will allow NASA to calculate the transport of space radiation through complex CAD models using the state-of-the-art analytic and Monte Carlo radiation transport codes. Due to the inherent hazard of astronaut and spacecraft exposure to ionizing radiation in low-Earth orbit (LEO) or in deep space, risk analyses must be performed for all crew vehicles and habitats. Incorporating these analyses into the design process can minimize the mass needed solely for radiation protection. Transport of the radiation fields as they pass through shielding and body materials can be simulated using Monte Carlo techniques or described by the Boltzmann equation, which is obtained by balancing changes in particle fluxes as they traverse a small volume of material with the gains and losses caused by atomic and nuclear collisions. Deterministic codes that solve the Boltzmann transport equation, such as HZETRN (high charge and energy transport code developed by NASA LaRC), are generally computationally faster than Monte Carlo codes such as FLUKA, GEANT4, MCNP(X) or PHITS; however, they are currently limited to transport in one dimension, which poorly represents the secondary light ion and neutron radiation fields. NASA currently uses HZETRN space radiation transport software, both because it is computationally efficient and because proven methods have been developed for using this software to analyze complex geometries. Although Monte Carlo codes describe the relevant physics in a fully three-dimensional manner, their computational costs have thus far prevented their widespread use for analysis of complex CAD models, leading
Radiation protection problems with dental radiological equipment
International Nuclear Information System (INIS)
Cooney, P.; Rajan, J.; Malone, J.F.; Gavin, G.
1995-01-01
With the advent of the EC Patient Directive, the importance of surveying and optimising patient exposure for diagnostic imaging procedures is paramount. In the field of dentistry there has been a heightened interest in areas of equipment performance and patient exposure. This interest, coupled with a number of dental radiation safety incidents investigated by our department, and the issuing of a Code of Practice for Radiological Protection in Dentistry by the Department of Health, led to the establishment in our department, of an evaluation protocol for the performance and operation of dental X ray equipment. The protocol was used to perform a survey on over 100 dental X ray units in use in the Public Sector in Ireland. This presentation will report on the radiation incidents mentioned above. It will detail the protocol and furnish the results and conclusions of the survey. The survey has made it possible to establish clearly the necessary steps required to ensure compliance with requirements. In addition, the corrective steps taken by the dental authorities will be presented and the overall impact of the regulations and the programme consequent on them will be reviewed. (Author)
Intense radiative heat transport across a nano-scale gap
International Nuclear Information System (INIS)
Budaev, Bair V.; Ghafari, Amin; Bogy, David B.
2016-01-01
In this paper, we analyze the radiative heat transport in layered structures. The analysis is based on our prior description of the spectrum of thermally excited waves in systems with a heat flux. The developed method correctly predicts results for all known special cases for both large and closing gaps. Numerical examples demonstrate the applicability of our approach to the calculation of the radiative heat transport coefficient across various layered structures.
Handling and transport problems (1960); Problemes de manipulation et de transport (1960)
Energy Technology Data Exchange (ETDEWEB)
Pomarola, J; Savouyaud, J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires
1960-07-01
I. The handling and transport of radioactive wastes involves the danger of irradiation and contamination. It is indispensable: - to lay down a special set of rules governing the removal and transport of wastes within centres or from one centre to another; - to give charge of this transportation to a group containing teams of specialists. The organisation, equipment and output of these teams is being examined. II. Certain materials are particularly dangerous to transport, and for these special vehicles and fixed installations are necessary. This is the case especially for the evacuation of very active liquids. A transport vehicle is described, consisting of a trailer tractor and a recipient holding 500 litres of liquid of which the activity can reach 1000 C/l; the decanting operation, the route to be followed by the vehicle, and the precautions taken are also described. (author) [French] I. La manipulation et le transport des dechets radioactifs presentent des dangers d'irradiation et de contamination. Il est necessaire: - d'edicter des consignes speciales applicables a l'enlevement et au transport des dechets dans les centres ou de centre a centre; - de confier les transports a un groupe dont relevent des equipes specialisees; - on examine l'organisation, les moyens, le rendement de ces equipes. II. Certains transports sont particulierement dangereux et necessitent des engins speciaux et des installations fixes. C'est le cas, notamment de l'evacuation des liquides tres actifs. On decrit: - un engin de transport compose d'un ensemble a tracteur semi-remorque et d'un recipient qui contient 500 litres de liquide dont l'activite peut atteindre 1000 C/l; - les operations de transvasement, l'acheminement de l'engin, les precautions prises. (auteur)
International Nuclear Information System (INIS)
Goncalves, G.A.; Bogado Leite, S.Q.; Vilhena, M.T. de
2009-01-01
An analytical solution has been obtained for the one-speed stationary neutron transport problem, in an infinitely long cylinder with anisotropic scattering by the decomposition method. Series expansions of the angular flux distribution are proposed in terms of suitably constructed functions, recursively obtainable from the isotropic solution, to take into account anisotropy. As for the isotropic problem, an accurate closed-form solution was chosen for the problem with internal source and constant incident radiation, obtained from an integral transformation technique and the F N method
On the Use of Importance Sampling in Particle Transport Problems
International Nuclear Information System (INIS)
Eriksson, B.
1965-06-01
The idea of importance sampling is applied to the problem of solving integral equations of Fredholm's type. Especially Bolzmann's neutron transport equation is taken into consideration. For the solution of the latter equation, an importance sampling technique is derived from some simple transformations at the original transport equation into a similar equation. Examples of transformations are given, which have been used with great success in practice
On the Use of Importance Sampling in Particle Transport Problems
Energy Technology Data Exchange (ETDEWEB)
Eriksson, B
1965-06-15
The idea of importance sampling is applied to the problem of solving integral equations of Fredholm's type. Especially Bolzmann's neutron transport equation is taken into consideration. For the solution of the latter equation, an importance sampling technique is derived from some simple transformations at the original transport equation into a similar equation. Examples of transformations are given, which have been used with great success in practice.
Transport casks help solve spent fuel interim storage problems
International Nuclear Information System (INIS)
Dierkes, P.; Janberg, K.; Baatz, H.; Weinhold, G.
1980-01-01
Transport casks can be used as storage modules, combining the inherent safety of passive cooling with the absence of secondary radioactive waste and the flexibility to build up storage capacity according to actual requirements. In the Federal Republic of Germany, transport casks are being developed as a solution to its interim storage problems. Criteria for their design and licensing are outlined. Details are given of the casks and the storage facility. Tests are illustrated. (U.K.)
International Nuclear Information System (INIS)
Zhao, J.M.; Tan, J.Y.; Liu, L.H.
2012-01-01
Light transport in graded index media follows a curved trajectory determined by Fermat's principle. Besides the effect of variation of the refractive index on the transport of radiative intensity, the curved ray trajectory will induce geometrical effects on the transport of polarization ellipse. This paper presents a complete derivation of vector radiative transfer equation for polarized radiation transport in absorption, emission and scattering graded index media. The derivation is based on the analysis of the conserved quantities for polarized light transport along curved trajectory and a novel approach. The obtained transfer equation can be considered as a generalization of the classic vector radiative transfer equation that is only valid for uniform refractive index media. Several variant forms of the transport equation are also presented, which include the form for Stokes parameters defined with a fixed reference and the Eulerian forms in the ray coordinate and in several common orthogonal coordinate systems.
Multiple Choice Knapsack Problem: example of planning choice in transportation.
Zhong, Tao; Young, Rhonda
2010-05-01
Transportation programming, a process of selecting projects for funding given budget and other constraints, is becoming more complex as a result of new federal laws, local planning regulations, and increased public involvement. This article describes the use of an integer programming tool, Multiple Choice Knapsack Problem (MCKP), to provide optimal solutions to transportation programming problems in cases where alternative versions of projects are under consideration. In this paper, optimization methods for use in the transportation programming process are compared and then the process of building and solving the optimization problems is discussed. The concepts about the use of MCKP are presented and a real-world transportation programming example at various budget levels is provided. This article illustrates how the use of MCKP addresses the modern complexities and provides timely solutions in transportation programming practice. While the article uses transportation programming as a case study, MCKP can be useful in other fields where a similar decision among a subset of the alternatives is required. Copyright 2009 Elsevier Ltd. All rights reserved.
Is radioactive mixed waste packaging and transportation really a problem
International Nuclear Information System (INIS)
McCall, D.L.; Calihan, T.W. III.
1992-01-01
Recently, there has been significant concern expressed in the nuclear community over the packaging and transportation of radioactive mixed waste under US Department of Transportation regulation. This concern has grown more intense over the last 5 to 10 years. Generators and regulators have realized that much of the waste shipped as ''low-level radioactive waste'' was in fact ''radioactive mixed waste'' and that these wastes pose unique transportation and disposal problems. Radioactive mixed wastes must, therefore, be correctly identified and classed for shipment. If must also be packaged, marked, labeled, and otherwise prepared to ensure safe transportation and meet applicable storage and disposal requirements, when established. This paper discusses regulations applicable to the packaging and transportation of radioactive mixed waste and identifies effective methods that waste shippers can adopt to meet the current transportation requirements. This paper will include a characterization and description of the waste, authorized packaging, and hazard communication requirements during transportation. Case studies will be sued to assist generators in understanding mixed waste shipment requirements and clarify the requirements necessary to establish a waste shipment program. Although management and disposal of radioactive mixed waste is clearly a critical issue, packaging and transportation of these waste materials is well defined in existing US Department of Transportation hazardous material regulations
Particle swarm optimization - Genetic algorithm (PSOGA) on linear transportation problem
Rahmalia, Dinita
2017-08-01
Linear Transportation Problem (LTP) is the case of constrained optimization where we want to minimize cost subject to the balance of the number of supply and the number of demand. The exact method such as northwest corner, vogel, russel, minimal cost have been applied at approaching optimal solution. In this paper, we use heurisitic like Particle Swarm Optimization (PSO) for solving linear transportation problem at any size of decision variable. In addition, we combine mutation operator of Genetic Algorithm (GA) at PSO to improve optimal solution. This method is called Particle Swarm Optimization - Genetic Algorithm (PSOGA). The simulations show that PSOGA can improve optimal solution resulted by PSO.
Nonrelativistic grey Sn-transport radiative-shock solutions
International Nuclear Information System (INIS)
Ferguson, J. M.; Morel, J. E.; Lowrie, R. B.
2017-01-01
We present semi-analytic radiative-shock solutions in which grey Sn-transport is used to model the radiation, and we include both constant cross sections and cross sections that depend on temperature and density. These new solutions solve for a variable Eddington factor (VEF) across the shock domain, which allows for interesting physics not seen before in radiative-shock solutions. Comparisons are made with the grey nonequilibrium-diffusion radiative-shock solutions of Lowrie and Edwards [1], which assumed that the Eddington factor is constant across the shock domain. It is our experience that the local Mach number is monotonic when producing nonequilibrium-diffusion solutions, but that this monotonicity may disappear while integrating the precursor region to produce Sn-transport solutions. For temperature- and density-dependent cross sections we show evidence of a spike in the VEF in the far upstream portion of the radiative-shock precursor. We show evidence of an adaptation zone in the precursor region, adjacent to the embedded hydrodynamic shock, as conjectured by Drake [2, 3], and also confirm his expectation that the precursor temperatures adjacent to the Zel’dovich spike take values that are greater than the downstream post-shock equilibrium temperature. We also show evidence that the radiation energy density can be nonmonotonic under the Zel’dovich spike, which is indicative of anti-diffusive radiation flow as predicted by McClarren and Drake [4]. We compare the angle dependence of the radiation flow for the Sn-transport and nonequilibriumdiffusion radiation solutions, and show that there are considerable differences in the radiation flow between these models across the shock structure. Lastly, we analyze the radiation flow to understand the cause of the adaptation zone, as well as the structure of the Sn-transport radiation-intensity solutions across the shock structure.
2D deterministic radiation transport with the discontinuous finite element method
International Nuclear Information System (INIS)
Kershaw, D.; Harte, J.
1993-01-01
This report provides a complete description of the analytic and discretized equations for 2D deterministic radiation transport. This computational model has been checked against a wide variety of analytic test problems and found to give excellent results. We make extensive use of the discontinuous finite element method
Discontinuous Galerkin for the Radiative Transport Equation
Guermond, Jean-Luc; Kanschat, Guido; Ragusa, Jean C.
2013-01-01
This note presents some recent results regarding the approximation of the linear radiative transfer equation using discontinuous Galerkin methods. The locking effect occurring in the diffusion limit with the upwind numerical flux is investigated and a correction technique is proposed.
Discontinuous Galerkin for the Radiative Transport Equation
Guermond, Jean-Luc
2013-10-11
This note presents some recent results regarding the approximation of the linear radiative transfer equation using discontinuous Galerkin methods. The locking effect occurring in the diffusion limit with the upwind numerical flux is investigated and a correction technique is proposed.
Nature and magnitude of the problem of spent radiation sources
International Nuclear Information System (INIS)
1991-09-01
Various types of sealed radiation sources are widely used in industry, medicine and research. Virtually all countries have some sealed sources. The activity in the sources varies from kilobecquerels in consumer products to hundreds of pentabecquerels in facilities for food irradiation. Loss or misuse of sealed sources can give rise to accidents resulting in radiation exposure of workers and members of the general public, and can also give rise to extensive contamination of land, equipment and buildings. In extreme cases the exposure can be lethal. Problems of safety relating to spent radiation sources have been under consideration within the Agency for some years. The first objective of the project has been to prepare a comprehensive report reviewing the nature and background of the problem, also giving an overview of existing practices for the management of spent radiation sources. This report is the fulfilment of this first objective. The safe management of spent radiation sources cannot be studied in isolation from their normal use, so it has been necessary to include some details which are relevant to the use of radiation sources in general, although that area is outside the scope of this report. The report is limited to radiation sources made up of radioactive material. The Agency is implementing a comprehensive action plan for assistance to Member States, especially the developing countries, in all aspects of the safe management of spent radiation sources. The Agency is further seeking to establish regional or global solutions to the problems of long-term storage of spent radiation sources, as well as finding routes for the disposal of sources when it is not feasible to set up safe national solutions. The cost of remedial actions after an accident with radiation sources can be very high indeed: millions of dollars. If the Agency can help to prevent even one such single accident, the cost of its whole programme in this field would be more than covered. Refs
Two-stage optimization in a transportation problem
CSIR Research Space (South Africa)
Stewart, TJ
1979-01-01
Full Text Available A study of the economic distribution of maize throughout South Africa is reported. Although the problem of minimizing total transportation costs in such a situation is a classical one, and its solution is well known, there was in this case a high...
Finite element method for solving neutron transport problems
International Nuclear Information System (INIS)
Ferguson, J.M.; Greenbaum, A.
1984-01-01
A finite element method is introduced for solving the neutron transport equations. Our method falls into the category of Petrov-Galerkin solution, since the trial space differs from the test space. The close relationship between this method and the discrete ordinate method is discussed, and the methods are compared for simple test problems
A numerical study for global atmospheric transport-chemistry problems
E.J. Spee (Edwin); J.G. Verwer (Jan); P.M. de Zeeuw (Paul); J.G. Blom (Joke); W. Hundsdorfer (Willem)
1998-01-01
htmlabstractAtmospheric air quality modeling relies in part on numerical simulation. Required numerical simulations are often hampered by lack of computer capacity and computational speed. This problem is most severe in the field of global modeling where transport and exchange of trace constituents
A numerical study for global atmospheric transport-chemistry problems
E.J. Spee (Edwin); J.G. Verwer (Jan); P.M. de Zeeuw (Paul); J.G. Blom (Joke); W. Hundsdorfer (Willem)
1997-01-01
textabstractAtmospheric air quality modeling relies in part on numerical simulation. Required numerical simulations are often hampered by lack of computer capacity and computational speed. This problem is most severe in the field of global modeling where transport and exchange of trace constituents
Selecting The Best Initial Method For A Transportation Problem ...
African Journals Online (AJOL)
This paper is concerned with determining the best initial method for a transportation problem. Seven initial methods are considered and compared. One is a new method that has not been reported in the literature. Comparison is done on the basis of the number of iterations required to reach the final solution if the concerned ...
Radiation transport Part B: Applications with examples
International Nuclear Information System (INIS)
Beutler, D.E.
1997-01-01
In the previous sections Len Lorence has described the need, theory, and types of radiation codes that can be applied to model the results of radiation effects tests or working environments for electronics. For the rest of this segment, the author will concentrate on the specific ways the codes can be used to predict device response or analyze radiation test results. Regardless of whether one is predicting responses in a working or test environment, the procedures are virtually the same. The same can be said for the use of 1-, 2-, or 3-dimensional codes and Monte Carlo or discrete ordinates codes. No attempt is made to instruct the student on the specifics of the code. For example, the author will not discuss the details, such as the number of meshes, energy groups, etc. that are appropriate for a discrete ordinates code. For the sake of simplicity, he will restrict himself to the 1-dimensional code CEPXS/ONELD. This code along with a wide variety of other radiation codes can be obtained form the Radiation Safety Information Computational Center (RSICC) for a nominal handling fee
A discrete-ordinates solution for a radiation therapy problem
International Nuclear Information System (INIS)
Goldschmidt, Gustavo Brun; Reichert, Janice Teresinha; Barichello, Liliane Basso
2008-01-01
A concise and accurate procedure for evaluating dose distribution, in a radiation therapy planning, is presented. The analytical discrete-ordinates method (ADO method) is used to develop a complete solution for a spectral dependent radiative transfer equation, in a one-dimensional medium, according to a multigroup scheme. Numerical results are presented for test problems, where the Klein-Nishina scattering kernel was used to describe the interaction processes. (author)
Overview. Department of Environmental and Radiation Transport Physics. Section 6
Energy Technology Data Exchange (ETDEWEB)
Loskiewicz, J. [Institute of Nuclear Physics, Cracow (Poland)
1995-12-31
Research activities in the Department of Environmental and Radiation Transport Physics are carried out by three Laboratories: Laboratory of Environmental Physics, Laboratory of Neutron Transport Physics and Laboratory of Physics and Modeling of Radiation Transport. The researches provided in 1994 cover: tracer transport and flows in porous media, studies on pollution in atmospheric air, physics of molecular phenomena in chromatographic detectors, studies on neutron transport in heterogenous media, studies on evaluation of neutron cross-section in the thermal region, studies on theory and utilization of neural network in data evaluation, numerical modelling of particle cascades for particle accelerator shielding purpose. In this section the description of mentioned activities as well as the information about personnel employed in the Department, papers and reports published in 1994, contribution to conferences and grants is also given.
Overview. Department of Environmental and Radiation Transport Physics. Section 6
Energy Technology Data Exchange (ETDEWEB)
Loskiewicz, J [Institute of Nuclear Physics, Cracow (Poland)
1996-12-31
Research activities in the Department of Environmental and Radiation Transport Physics are carried out by three Laboratories: Laboratory of Environmental Physics, Laboratory of Neutron Transport Physics and Laboratory of Physics and Modeling of Radiation Transport. The researches provided in 1994 cover: tracer transport and flows in porous media, studies on pollution in atmospheric air, physics of molecular phenomena in chromatographic detectors, studies on neutron transport in heterogenous media, studies on evaluation of neutron cross-section in the thermal region, studies on theory and utilization of neural network in data evaluation, numerical modelling of particle cascades for particle accelerator shielding purpose. In this section the description of mentioned activities as well as the information about personnel employed in the Department, papers and reports published in 1994, contribution to conferences and grants is also given.
Numerical investigation of the inverse blackbody radiation problem
International Nuclear Information System (INIS)
Xin Tan, Guo-zhen Yang, Ben-yuan Gu
1994-01-01
A numerical algorithm for the inverse blackbody radiation problem, which is the determination of the temperature distribution of a thermal radiator (TDTR) from its total radiated power spectrum (TRPS), is presented, based on the general theory of amplitude-phase retrieval. With application of this new algorithm, the ill-posed nature of the Fredholm equation of the first kind can be largely overcome and a convergent solution to high accuracy can be obtained. By incorporation of the hybrid input-output algorithm into our algorithm, the convergent process can be substantially expedited and the stagnation problem of the solution can be averted. From model calculations it is found that the new algorithm can also provide a robust reconstruction of the TDTR from the noise-corrupted data of the TRPS. Therefore the new algorithm may offer a useful approach to solving the ill-posed inverse problem. 18 refs., 9 figs
Development and preliminary verification of 2-D transport module of radiation shielding code ARES
International Nuclear Information System (INIS)
Zhang Penghe; Chen Yixue; Zhang Bin; Zang Qiyong; Yuan Longjun; Chen Mengteng
2013-01-01
The 2-D transport module of radiation shielding code ARES is two-dimensional neutron and radiation shielding code. The theory model was based on the first-order steady state neutron transport equation, adopting the discrete ordinates method to disperse direction variables. Then a set of differential equations can be obtained and solved with the source iteration method. The 2-D transport module of ARES was capable of calculating k eff and fixed source problem with isotropic or anisotropic scattering in x-y geometry. The theoretical model was briefly introduced and series of benchmark problems were verified in this paper. Compared with the results given by the benchmark, the maximum relative deviation of k eff is 0.09% and the average relative deviation of flux density is about 0.60% in the BWR cells benchmark problem. As for the fixed source problem with isotropic and anisotropic scattering, the results of the 2-D transport module of ARES conform with DORT very well. These numerical results of benchmark problems preliminarily demonstrate that the development process of the 2-D transport module of ARES is right and it is able to provide high precision result. (authors)
The isotope density inverse problem in multigroup neutron transport
International Nuclear Information System (INIS)
Zazula, J.M.
1981-01-01
The inverse problem for stationary multigroup anisotropic neutron transport is discussed in order to search for isotope densities in multielement medium. The spatial- and angular-integrated form of neutron transport equation, in terms of the flux in a group - density of an element spatial correlation, leads to a set of integral functionals for the densities weighted by the group fluxes. Some methods of approximation to make the problem uniquently solvable are proposed. Particularly P 0 angular flux information and the spherically-symetrical geometry of an infinite medium are considered. The numerical calculation using this method related to sooner evaluated direct problem data gives promising agreement with primary densities. This approach would be the basis for further application in an elemental analysis of a medium, using an isotopic neutron source and a moving, energy-dependent neutron detector. (author)
Кіхтенко, Ігор Миколайович
2016-01-01
Subject of research – the relevance of radiation damage at modern development of industry and medicine. In the world of radiation sources used in different fields of practice and their application in the future will increase, which greatly increases the likelihood of injury in a significant contingent of people.Research topic – the definition of the role of nuclear energy and the industrial use of ionizing radiation sources in the problem of radiation damage. The purpose of research – identif...
Radiation problems expected for the German spallation neutron source
International Nuclear Information System (INIS)
Goebel, K.
1981-01-01
The German project for the construction of a Spallation Neutron Source with high proton beam power (5.5 MW) will have to cope with a number of radiation problems. The present report describes these problems and proposes solutions for keeping exposures for the staff and release of activity and radiation into the environment as low as reasonably achievable. It is shown that the strict requirements of the German radiation protection regulations can be met. The main problem will be the exposure of maintenance personnel to remanent gamma radiation, as is the case at existing proton accelerators. Closed ventilation and cooling systems will reduce the release of (mainly short-lived) activity to acceptable levels. Shielding requirements for different sections are discussed, and it is demonstrated by calculations and extrapolations from experiments that fence-post doses well below 150 mrem/y can be obtained at distances of the order of 100 metres from the principal source points. The radiation protection system proposed for the Spallation Neutron Source is discussed, in particular the needs for monitor systems and a central radiation protection data base and alarm system. (orig.)
Problems of radiation protection during SIP implementation on the Shelter
International Nuclear Information System (INIS)
Bogorad, V.I.; Litvinskaya, T.V.; Nikonov, D.A.
2001-01-01
One of the most urgent problems for today, during the SIP plans implementation of the Shelter transformation, is personnel radiation safety. The first of them assumes that a worker can be exposed to permitted annual dose during a short period of time with subsequent withdrawal of the person from radiation-hazardous activities. The second approach is based on the determination of derived dose limits that would provide for non-excess of the main limits on the assumption that a person is involved in radiation-hazardous work during the whole year. Radiation protection during practical activity should be formed on the basis of optimization principle. The optimization, in this case, implies that activities in the fields of ionizing radiation should be planned and performed in such way that, during their performance, the levels of individual doses and/or the quantity of exposed persons be as low as possible with taking into account the economic and social factors
International Nuclear Information System (INIS)
Kim, Jong Woo; Woo, Myeong Hyeon; Kim, Jae Hyun; Kim, Do Hyun; Shin, Chang Ho; Kim, Jong Kyung
2017-01-01
In this study hybrid Monte Carlo/Deterministic method is explained for radiation transport analysis in global system. FW-CADIS methodology construct the weight window parameter and it useful at most global MC calculation. However, Due to the assumption that a particle is scored at a tally, less particles are transported to the periphery of mesh tallies. For compensation this space-dependency, we modified the module in the ADVANTG code to add the proposed method. We solved the simple test problem for comparing with result from FW-CADIS methodology, it was confirmed that a uniform statistical error was secured as intended. In the future, it will be added more practical problems. It might be useful to perform radiation transport analysis using the Hybrid Monte Carlo/Deterministic method in global transport problems.
Radiation hygiene problems of radiopharmaceutical preparation at nuclear medicine units
International Nuclear Information System (INIS)
Pekarek, J.; Kukacka, R.
1977-01-01
The problems of magistral radiopharmaceuticals preparation are indicated and the layout of a unit for the magistral preparation of radiopharmaceuticals is described. The results are briefly reported of a study of radiation load of laboratory personnel preparing radiopharmaceuticals as against doctors actually applying them. It was found that the exposure of hands to ionizing radiation represents the highest hazard for the laboratory personnel. The most important radiation protection principles are pointed out, such as the use of protective clothing, regular preventive medical examinations, appropriately shielded radionuclides and radionuclide generators to be supplied by manufacturers, and a more frequent rotation of personnel working with active and nonactive preparations. (L.O.)
Problems of dose rate in radiation protection regulation
International Nuclear Information System (INIS)
Osmachkin, V.S.
2001-01-01
Some modern problems of Radiation Safety Standards are discussed. It is known that Standards are based on the Linear-Non-Threshold Concept (LNTC) of radiation risk, which is now called by many experts as conservative. It is thought it is necessary to include in the Standards such factor as dose rate or duration of irradiation. Some model of effects of radiation exposure with taking into account the reparation of cell damage is presented. The practical method for assessment of effects of duration of irradiation on detriments is proposed.(author)
International Nuclear Information System (INIS)
Palta, J.R.
1981-01-01
A versatile computer program MORSE, based on neutron and photon transport theory has been utilzed to investigate radiation therapy treatment planning quantities and techniques. A multi-energy group representation of transport equation provides a concise approach in utilizing Monte Carlo numerical techniques to multiple radiation therapy treatment planning problems. Central axis total and scattered dose distributions for homogeneous and inhomogeneous water phantoms are calculated and the correction factor for lung and bone inhomogeneities are also evaluated. Results show that Monte Carlo calculations based on multi-energy group tansport theory predict the depth dose distributions that are in good agreement with available experimental data. Central axis depth dose distributions for a bremsstrahlung spectrum from a linear accelerator is also calculated to exhibit the versatility of the computer program in handling multiple radiation therapy problems. A novel approach is undertaken to study the dosimetric properties of brachytherapy sources
Radiological emergency: road map for radiation accident victim transport
International Nuclear Information System (INIS)
Costa, V.S.G.; Alcantara, Y.P.; Lima, C.M.A.; Silva, F. C. A. da
2017-01-01
During a radiological or nuclear emergency, a number of necessary actions are taken, both within the radiation protection of individuals and the environment, involving many institutions and highly specialized personnel. Among them it is possible to emphasize the air transportation of radiation accident victims.The procedures and measures for the safe transport of these radiation accident victims are generally the responsibility of the armed forces, specifically the Aeronautics, with the action denominated 'Aeromedical Military Evacuation of Radiation Accident Victims'. The experience with the Radiological Accident of Goiânia demonstrated the importance of adequate preparation and response during a radiological emergency and the need for procedures and measures with regard to the transport of radiation victims are clearly defined and clearly presented for the effectiveness of the actions. This work presents the necessary actions for the transport of radiation accident victim during a radiological emergency, through the road map technique, which has been widely used in scientific technical area to facilitate understanding and show the way to be followed to reach the proposed objectives
Problems with ink skin markings for radiation field setups
International Nuclear Information System (INIS)
Endoh, Masaru; Saeki, Mituaki; Ishida, Yusei
1982-01-01
Ink skin markings are used in radiation therapy to aid in reproduction of treatment field setups or to indelibly outline field markings or tumors. We reported two cases of indelible ink skin for radiation field septa with minimal discomfort and dermatitis have been experienced for 6 months and above since end of radiotherapy. These indelible ink skin markings look like tattoo that will be big problems in the case of young female. We improved these problems by using of 10 percent silver nitrate instead of habitual skin ink. (author)
Transport of cobalt-60 industrial radiation sources
Kunstadt, Peter; Gibson, Wayne
This paper will deal with safety aspects of the handling of Cobalt-60, the most widely used industrial radio-isotope. Cobalt-60 is a man-made radioisotope of Cobalt-59, a naturally occurring non radioactive element, that is made to order for radiation therapy and a wide range of industrial processing applications including sterilization of medical disposables, food irradiation, etc.
Implicit Monte Carlo methods and non-equilibrium Marshak wave radiative transport
International Nuclear Information System (INIS)
Lynch, J.E.
1985-01-01
Two enhancements to the Fleck implicit Monte Carlo method for radiative transport are described, for use in transparent and opaque media respectively. The first introduces a spectral mean cross section, which applies to pseudoscattering in transparent regions with a high frequency incident spectrum. The second provides a simple Monte Carlo random walk method for opaque regions, without the need for a supplementary diffusion equation formulation. A time-dependent transport Marshak wave problem of radiative transfer, in which a non-equilibrium condition exists between the radiation and material energy fields, is then solved. These results are compared to published benchmark solutions and to new discrete ordinate S-N results, for both spatially integrated radiation-material energies versus time and to new spatially dependent temperature profiles. Multigroup opacities, which are independent of both temperature and frequency, are used in addition to a material specific heat which is proportional to the cube of the temperature. 7 refs., 4 figs
Approximation of scalar and vector transport problems on polyhedral meshes
International Nuclear Information System (INIS)
Cantin, Pierre
2016-01-01
This thesis analyzes, at the continuous and at the discrete level on polyhedral meshes, the scalar and the vector transport problems in three-dimensional domains. These problems are composed of a diffusive term, an advective term, and a reactive term. In the context of Friedrichs systems, the continuous problems are analyzed in Lebesgue graph spaces. The classical positivity assumption on the Friedrichs tensor is generalized so as to consider the case of practical interest where this tensor takes null or slightly negative values. A new scheme converging at the order 3/2 is devised for the scalar advection-reaction problem using scalar degrees of freedom attached to mesh vertices. Two new schemes considering as well scalar degrees of freedom attached to mesh vertices are devised for the scalar transport problem and are robust with respect to the dominant regime. The first scheme converges at the order 1/2 when advection effects are dominant and at the order 1 when diffusion effects are dominant. The second scheme improves the accuracy by converging at the order 3/2 when advection effects are dominant. Finally, a new scheme converging at the order 1/2 is devised for the vector advection-reaction problem considering only one scalar degree of freedom per mesh edge. The accuracy and the efficiency of all these schemes are assessed on various test cases using three-dimensional polyhedral meshes. (author)
bhlight: GENERAL RELATIVISTIC RADIATION MAGNETOHYDRODYNAMICS WITH MONTE CARLO TRANSPORT
International Nuclear Information System (INIS)
Ryan, B. R.; Gammie, C. F.; Dolence, J. C.
2015-01-01
We present bhlight, a numerical scheme for solving the equations of general relativistic radiation magnetohydrodynamics using a direct Monte Carlo solution of the frequency-dependent radiative transport equation. bhlight is designed to evolve black hole accretion flows at intermediate accretion rate, in the regime between the classical radiatively efficient disk and the radiatively inefficient accretion flow (RIAF), in which global radiative effects play a sub-dominant but non-negligible role in disk dynamics. We describe the governing equations, numerical method, idiosyncrasies of our implementation, and a suite of test and convergence results. We also describe example applications to radiative Bondi accretion and to a slowly accreting Kerr black hole in axisymmetry
Modified Monte Carlo procedure for particle transport problems
International Nuclear Information System (INIS)
Matthes, W.
1978-01-01
The simulation of photon transport in the atmosphere with the Monte Carlo method forms part of the EURASEP-programme. The specifications for the problems posed for a solution were such, that the direct application of the analogue Monte Carlo method was not feasible. For this reason the standard Monte Carlo procedure was modified in the sense that additional properly weighted branchings at each collision and transport process in a photon history were introduced. This modified Monte Carlo procedure leads to a clear and logical separation of the essential parts of a problem and offers a large flexibility for variance reducing techniques. More complex problems, as foreseen in the EURASEP-programme (e.g. clouds in the atmosphere, rough ocean-surface and chlorophyl-distribution in the ocean) can be handled by recoding some subroutines. This collision- and transport-splitting procedure can of course be performed differently in different space- and energy regions. It is applied here only for a homogeneous problem
Advantages of Analytical Transformations in Monte Carlo Methods for Radiation Transport
International Nuclear Information System (INIS)
McKinley, M S; Brooks III, E D; Daffin, F
2004-01-01
Monte Carlo methods for radiation transport typically attempt to solve an integral by directly sampling analog or weighted particles, which are treated as physical entities. Improvements to the methods involve better sampling, probability games or physical intuition about the problem. We show that significant improvements can be achieved by recasting the equations with an analytical transform to solve for new, non-physical entities or fields. This paper looks at one such transform, the difference formulation for thermal photon transport, showing a significant advantage for Monte Carlo solution of the equations for time dependent transport. Other related areas are discussed that may also realize significant benefits from similar analytical transformations
Radiation transport in statistically inhomogeneous rocks
International Nuclear Information System (INIS)
Lukhminskij, B.E.
1975-01-01
A study has been made of radiation transfer in statistically inhomogeneous rocks. Account has been taken of the statistical character of rock composition through randomization of density. Formulas are summarized for sigma-distribution, homogeneous density, the Simpson and Cauchy distributions. Consideration is given to the statistics of mean square ranges in a medium, simulated by the jump Markov random function. A quantitative criterion of rock heterogeneity is proposed
International Nuclear Information System (INIS)
Zazula, J.M.
1984-01-01
This work concerns calculation of a neutron response, caused by a neutron field perturbed by materials surrounding the source or the detector. Solution of a problem is obtained using coupling of the Monte Carlo radiation transport computation for the perturbed region and the discrete ordinates transport computation for the unperturbed system. (author). 62 refs
The transportation management division institutional program: Networking and problem solving
International Nuclear Information System (INIS)
McGinnis, K.A.; Peterson, J.M.
1989-06-01
The US Department of Energy (DOE) has several programs related to transportation. While these programs may have differing missions and legislative authority, the required activities are frequently similar. To ensure a DOE-wide perspective in developing transportation policies and procedures, a DOE Transportation Institutional Task Force (Task Force) has been formed, which is the primary focus of this paper. The Task Force, composed of representatives from each of the major DOE transportation programs, meets periodically to exchange experiences and insights on institutional issues related to Departmental shipping. The primary purpose of the group is to identify opportunities for productive interactions with the transportation community, including interested and affected members of the public. This paper will also focus sharply on the networking of DOE with the State, Tribal, and local officials in fostering better understanding and in solving problems. An example of such activity is the DOE's cooperative agreement with the Energy Task Force of the Urban Consortium. A major effort is to encourage cooperative action in identifying, addressing, and resolving issues that could impede the transportation of radioactive materials
Transport synthetic acceleration for long-characteristics assembly-level transport problems
Energy Technology Data Exchange (ETDEWEB)
Zika, M R; Adams, M L
2000-02-01
The authors apply the transport synthetic acceleration (TSA) scheme to the long-characteristics spatial discretization for the two-dimensional assembly-level transport problem. This synthetic method employs a simplified transport operator as its low-order approximation. Thus, in the acceleration step, the authors take advantage of features of the long-characteristics discretization that make it particularly well suited to assembly-level transport problems. The main contribution is to address difficulties unique to the long-characteristics discretization and produce a computationally efficient acceleration scheme. The combination of the long-characteristics discretization, opposing reflecting boundary conditions (which are present in assembly-level transport problems), and TSA presents several challenges. The authors devise methods for overcoming each of them in a computationally efficient way. Since the boundary angular data exist on different grids in the high- and low-order problems, they define restriction and prolongation operations specific to the method of long characteristics to map between the two grids. They implement the conjugate gradient (CG) method in the presence of opposing reflection boundary conditions to solve the TSA low-order equations. The CG iteration may be applied only to symmetric positive definite (SPD) matrices; they prove that the long-characteristics discretization yields an SPD matrix. They present results of the acceleration scheme on a simple test problem, a typical pressurized water reactor assembly, and a typical boiling water reactor assembly.
Transport synthetic acceleration for long-characteristics assembly-level transport problems
International Nuclear Information System (INIS)
Zika, M.R.; Adams, M.L.
2000-01-01
The authors apply the transport synthetic acceleration (TSA) scheme to the long-characteristics spatial discretization for the two-dimensional assembly-level transport problem. This synthetic method employs a simplified transport operator as its low-order approximation. Thus, in the acceleration step, the authors take advantage of features of the long-characteristics discretization that make it particularly well suited to assembly-level transport problems. The main contribution is to address difficulties unique to the long-characteristics discretization and produce a computationally efficient acceleration scheme. The combination of the long-characteristics discretization, opposing reflecting boundary conditions (which are present in assembly-level transport problems), and TSA presents several challenges. The authors devise methods for overcoming each of them in a computationally efficient way. Since the boundary angular data exist on different grids in the high- and low-order problems, they define restriction and prolongation operations specific to the method of long characteristics to map between the two grids. They implement the conjugate gradient (CG) method in the presence of opposing reflection boundary conditions to solve the TSA low-order equations. The CG iteration may be applied only to symmetric positive definite (SPD) matrices; they prove that the long-characteristics discretization yields an SPD matrix. They present results of the acceleration scheme on a simple test problem, a typical pressurized water reactor assembly, and a typical boiling water reactor assembly
Transport Synthetic Acceleration for Long-Characteristics Assembly-Level Transport Problems
International Nuclear Information System (INIS)
Zika, Michael R.; Adams, Marvin L.
2000-01-01
We apply the transport synthetic acceleration (TSA) scheme to the long-characteristics spatial discretization for the two-dimensional assembly-level transport problem. This synthetic method employs a simplified transport operator as its low-order approximation. Thus, in the acceleration step, we take advantage of features of the long-characteristics discretization that make it particularly well suited to assembly-level transport problems. Our main contribution is to address difficulties unique to the long-characteristics discretization and produce a computationally efficient acceleration scheme.The combination of the long-characteristics discretization, opposing reflecting boundary conditions (which are present in assembly-level transport problems), and TSA presents several challenges. We devise methods for overcoming each of them in a computationally efficient way. Since the boundary angular data exist on different grids in the high- and low-order problems, we define restriction and prolongation operations specific to the method of long characteristics to map between the two grids. We implement the conjugate gradient (CG) method in the presence of opposing reflection boundary conditions to solve the TSA low-order equations. The CG iteration may be applied only to symmetric positive definite (SPD) matrices; we prove that the long-characteristics discretization yields an SPD matrix. We present results of our acceleration scheme on a simple test problem, a typical pressurized water reactor assembly, and a typical boiling water reactor assembly
Radiative transport-based frequency-domain fluorescence tomography
International Nuclear Information System (INIS)
Joshi, Amit; Rasmussen, John C; Sevick-Muraca, Eva M; Wareing, Todd A; McGhee, John
2008-01-01
We report the development of radiative transport model-based fluorescence optical tomography from frequency-domain boundary measurements. The coupled radiative transport model for describing NIR fluorescence propagation in tissue is solved by a novel software based on the established Attila(TM) particle transport simulation platform. The proposed scheme enables the prediction of fluorescence measurements with non-contact sources and detectors at a minimal computational cost. An adjoint transport solution-based fluorescence tomography algorithm is implemented on dual grids to efficiently assemble the measurement sensitivity Jacobian matrix. Finally, we demonstrate fluorescence tomography on a realistic computational mouse model to locate nM to μM fluorophore concentration distributions in simulated mouse organs
Some problems for natural radiation impact assessment in road construction
International Nuclear Information System (INIS)
Li Xutong; Chen Xiaoqiu; Li Yuanxin
2002-01-01
Some instances have occurred for that road constructions were likely to meet with some high grade uranium mine in some provinces with abundant uranium resource and developed economy. Some of the constructions have made assessment for the radiation risk. The author discusses the problems existent in the assessments
A Monte Carlo transport code study of the space radiation environment using FLUKA and ROOT
Wilson, T; Carminati, F; Brun, R; Ferrari, A; Sala, P; Empl, A; MacGibbon, J
2001-01-01
We report on the progress of a current study aimed at developing a state-of-the-art Monte-Carlo computer simulation of the space radiation environment using advanced computer software techniques recently available at CERN, the European Laboratory for Particle Physics in Geneva, Switzerland. By taking the next-generation computer software appearing at CERN and adapting it to known problems in the implementation of space exploration strategies, this research is identifying changes necessary to bring these two advanced technologies together. The radiation transport tool being developed is tailored to the problem of taking measured space radiation fluxes impinging on the geometry of any particular spacecraft or planetary habitat and simulating the evolution of that flux through an accurate model of the spacecraft material. The simulation uses the latest known results in low-energy and high-energy physics. The output is a prediction of the detailed nature of the radiation environment experienced in space as well a...
Organic radiation chemistry--the present state and problems
International Nuclear Information System (INIS)
Sareava, V.V.; Kalyazin, E.P.
1985-01-01
The authors pose the principal problems to be solved in organic radiation chemistry: 1) to derive from the structural formula of a given organic compound the composition of the products from its radiolysis under standard conditions; 2) to use a number of physicochemical properties of a given compound at the molecular and material levels to predict the variation in composition and fraction of products from the radiolysis of the compounds with a change in irradiation conditions, i.e., the parameters of the acting radiation and the state of the substance, to indicate the direction of the principal radiation chemical processes in complex mixtures of natural or technical origin. Having stated the problems, the authors attempt to show the level of understanding of the radiolysis of organic compounds, using aliphatic hydrocarbons as principal discussion subjects
Criticality problems in energy dependent neutron transport theory
International Nuclear Information System (INIS)
Victory, H.D. Jr.
1979-01-01
The criticality problem is considered for energy dependent neutron transport in an isotropically scattering, homogeneous slab. Under a positivity assumption on the scattering kernel, an expression can be found relating the thickness of the slab to a parameter characterizing production by fission. This is accomplished by exploiting the Perron-Frobenius-Jentsch characterization of positive operators (i.e. those leaving invariant a normal, reproducing cone in a Banach space). It is pointed out that those techniques work for classes of multigroup problems were the Case singular eigenfunction approach is not as feasible as in the one-group theory, which is also analyzed
A contribution to problems of clean transport of bulk materials
Directory of Open Access Journals (Sweden)
Fedora Jaroslav
1996-03-01
Full Text Available The lecture analyses the problem of development of the pipe conveyor with a rubber belt, the facitities of its application in the practice and environmental aspects resulting from its application. The pipe conveyor is a new perspective transport system. It enables ransporting bulk materials (coal, crushed, rock, coke, plant ash, fertilisers, limestones, time in a specific operations (power plants, heating plants.cellulose, salt, sugar, wheat and other materials with a minimum effect on the environment. The transported material is enclosed in the pipeline so that there is no escape of dust, smell or of the transported material itself. The lecture is aimed at: - the short description of the operating principle and design of the pipe conveyor which was developed in the firm Matador Púchov in cooperation with the firm TEDO, - the analysis of experiencie in working some pipe conveyors which were under operation for a certain
The spectral volume method as applied to transport problems
International Nuclear Information System (INIS)
McClarren, Ryan G.
2011-01-01
We present a new spatial discretization for transport problems: the spectral volume method. This method, rst developed by Wang for computational fluid dynamics, divides each computational cell into several sub-cells and enforces particle balance on each of these sub-cells. Also, these sub-cells are used to build a polynomial reconstruction in the cell. The idea of dividing cells into many cells is a generalization of the simple corner balance and other similar schemes. The spectral volume method preserves particle conservation and preserves the asymptotic diffusion limit. We present results from the method on two transport problems in slab geometry using discrete ordinates and second through sixth order spectral volume schemes. The numerical results demonstrate the accuracy and preservation of the diffusion limit of the spectral volume method. Future work will explore possible bene ts of the scheme for high-performance computing and for resolving diffusive boundary layers. (author)
Engineering solutions of traffic safety problems of road transport
Directory of Open Access Journals (Sweden)
M. Bogdevičius
2004-02-01
Full Text Available The authors of this paper focus on the simulation of the motor vehicle movement (taking into consideration motor vehicle dynamics, motor vehicle hydraulic brake system influence on motor vehicle movement, interaction between its wheels with road pavements, road guardrail characteristics, interaction between motor vehicle and road guardrail on a certain road section and propose their specific solution of this problem. The presented results, illustrating the motor vehicle movement trajectories (motor vehicle braking and interaction between motor vehicle and road guardrail at various initial conditions and at various certain pavement surface of the road section under investigation and work of a motor vehicle hydraulic brake system. Taking into consideration the presented general mathematical model and computer aided test results it is possible to investigate various road transport traffic situations as well as to investigate various transport traffic safety problems.
A review on fuzzy and stochastic extensions of the multi index transportation problem
Directory of Open Access Journals (Sweden)
Singh Sungeeta
2017-01-01
Full Text Available The classical transportation problem (having source and destination as indices deals with the objective of minimizing a single criterion, i.e. cost of transporting a commodity. Additional indices such as commodities and modes of transport led to the Multi Index transportation problem. An additional fixed cost, independent of the units transported, led to the Multi Index Fixed Charge transportation problem. Criteria other than cost (such as time, profit etc. led to the Multi Index Bi-criteria transportation problem. The application of fuzzy and stochastic concept in the above transportation problems would enable researchers to not only introduce real life uncertainties but also obtain solutions of these transportation problems. The review article presents an organized study of the Multi Index transportation problem and its fuzzy and stochastic extensions till today, and aims to help researchers working with complex transportation problems.
Efficient solution of a multi objective fuzzy transportation problem
Vidhya, V.; Ganesan, K.
2018-04-01
In this paper we present a methodology for the solution of multi-objective fuzzy transportation problem when all the cost and time coefficients are trapezoidal fuzzy numbers and the supply and demand are crisp numbers. Using a new fuzzy arithmetic on parametric form of trapezoidal fuzzy numbers and a new ranking method all efficient solutions are obtained. The proposed method is illustrated with an example.
Radiation exposure during air and ground transportation
International Nuclear Information System (INIS)
Hsu, P.C.; Weng, P.S.
1976-01-01
The results of a one year study program of radiation exposure experienced on both domestic and international flights of the China Airline and the Far East Airline in the Pacific, Southeast Asia and Taiwan areas and on trains and buses on Taiwan island are reported. CaSO 4 :Dy thermoluminescent dosimeters were used. It has been shown that transit exposures may amount to 10 times that on the ground with an altitude varying from 3,050 to 12,200 m. (U.K.)
Regulatory practices of radiation safety of SNF transportation in Russia
International Nuclear Information System (INIS)
Kuryndina, Lidia; Kuryndin, Anton; Stroganov, Anatoly
2008-01-01
This paper overviews current regulatory practices for the assurance of nuclear and radiation safety during railway transportation of SNF on the territory of Russian Federation from NPPs to longterm-storage of reprocessing sites. The legal and regulatory requirements (mostly compliant with IAEA ST-1), licensing procedure for NM transportation are discussed. The current procedure does not require a regulatory approval for each particular shipment if the SNF fully comply with the Rosatom's branch standard and is transported in approved casks. It has been demonstrated that SNF packages compliant with the branch standard, which is knowingly provide sufficient safety margin, will conform to the federal level regulations. The regulatory approval is required if a particular shipment does not comply with the branch standard. In this case, the shipment can be approved only after regulatory review of Applicant's documents to demonstrate that the shipment still conformant to the higher level (federal) regulations. The regulatory review frequently needs a full calculation test of the radiation safety assurance. This test can take a lot of time. That's why the special calculation tools were created in SEC NRS. These tools aimed for precision calculation of the radiation safety parameters by SNF transportation use preliminary calculated Green's functions. Such approach allows quickly simulate any source distribution and optimize spent fuel assemblies placement in cask due to the transport equation property of linearity relatively the source. The short description of calculation tools are presented. Also, the paper discusses foreseen implications related to transportation of mixed-oxide SNF. (author)
Development of the Contiguous-cells Transportation Problem
Directory of Open Access Journals (Sweden)
O. E. Charles-Owaba
2015-08-01
Full Text Available The issue of scheduling a long string of multi-period activities which have to be completed without interruption has always been an industrial challenge. The existing production/maintenance scheduling algorithms can only handle situations where activities can be split into two or more sets of activities carried out in non-contiguous sets of work periods. This study proposes a contiguous-periods production/maintenance scheduling approach using the Transportation Model. Relevant variables and parameters of contiguous-cells scheduling problem were taken from the literature. A scheduling optimization problem was defined and solved using a contiguous-cells transportation algorithm (CCTA which was applied in order to determine the optimal maintenance schedule of a fleet of ships at a dockyard in South-Western Nigeria. Fifteen different problems were solved. It is concluded that the contiguous-cells transportation approach to production/ maintenance scheduling is feasible. The model will be a useful decision support tool for scheduling maintenance operations.
Chemical and kinetic equilibrations via radiative parton transport
International Nuclear Information System (INIS)
Zhang Bin; Wortman, Warner A
2011-01-01
A hot and dense partonic system can be produced in the early stage of a relativistic heavy ion collision. How it equilibrates is important for the extraction of Quark-Gluon Plasma properties. We study the chemical and kinetic equilibrations of the Quark-Gluon Plasma using a radiative transport model. Thermal and Color-Glass-Condensate motivated initial conditions are used. We observe that screened parton interactions always lead to partial pressure isotropization. Different initial pressure anisotropies result in the same asymptotic evolution. Comparison of evolutions with and without radiative processes shows that chemical equilibration interacts with kinetic equilibration and radiative processes can contribute significantly to pressure isotropization.
An Algorithm for the Mixed Transportation Network Design Problem.
Liu, Xinyu; Chen, Qun
2016-01-01
This paper proposes an optimization algorithm, the dimension-down iterative algorithm (DDIA), for solving a mixed transportation network design problem (MNDP), which is generally expressed as a mathematical programming with equilibrium constraint (MPEC). The upper level of the MNDP aims to optimize the network performance via both the expansion of the existing links and the addition of new candidate links, whereas the lower level is a traditional Wardrop user equilibrium (UE) problem. The idea of the proposed solution algorithm (DDIA) is to reduce the dimensions of the problem. A group of variables (discrete/continuous) is fixed to optimize another group of variables (continuous/discrete) alternately; then, the problem is transformed into solving a series of CNDPs (continuous network design problems) and DNDPs (discrete network design problems) repeatedly until the problem converges to the optimal solution. The advantage of the proposed algorithm is that its solution process is very simple and easy to apply. Numerical examples show that for the MNDP without budget constraint, the optimal solution can be found within a few iterations with DDIA. For the MNDP with budget constraint, however, the result depends on the selection of initial values, which leads to different optimal solutions (i.e., different local optimal solutions). Some thoughts are given on how to derive meaningful initial values, such as by considering the budgets of new and reconstruction projects separately.
An Algorithm for the Mixed Transportation Network Design Problem.
Directory of Open Access Journals (Sweden)
Xinyu Liu
Full Text Available This paper proposes an optimization algorithm, the dimension-down iterative algorithm (DDIA, for solving a mixed transportation network design problem (MNDP, which is generally expressed as a mathematical programming with equilibrium constraint (MPEC. The upper level of the MNDP aims to optimize the network performance via both the expansion of the existing links and the addition of new candidate links, whereas the lower level is a traditional Wardrop user equilibrium (UE problem. The idea of the proposed solution algorithm (DDIA is to reduce the dimensions of the problem. A group of variables (discrete/continuous is fixed to optimize another group of variables (continuous/discrete alternately; then, the problem is transformed into solving a series of CNDPs (continuous network design problems and DNDPs (discrete network design problems repeatedly until the problem converges to the optimal solution. The advantage of the proposed algorithm is that its solution process is very simple and easy to apply. Numerical examples show that for the MNDP without budget constraint, the optimal solution can be found within a few iterations with DDIA. For the MNDP with budget constraint, however, the result depends on the selection of initial values, which leads to different optimal solutions (i.e., different local optimal solutions. Some thoughts are given on how to derive meaningful initial values, such as by considering the budgets of new and reconstruction projects separately.
Teaching effective problem solving skills to radiation protection students
International Nuclear Information System (INIS)
Waller, Edward
2008-01-01
Full text: Problem solving skills are essential for all radiation protection personnel. Although some students have more natural problem solving skills than others, all students require practice to become comfortable using these skills. At the University of Ontario Institute of Technology (UOIT), a unique one-semester course was developed as part of the core curriculum to teach students problem solving skills and elements of modelling and simulation. The underlying emphasis of the course was to allow students to develop their own problem solving strategies, both individually and in groups. Direction was provided on how to examine problems from different perspectives, and how to determine the proper root problem statement. A five-point problem solving strategy was presented as: 1) Problem definition; 2) Solution generation; 3) Decision; 4) Implementation; 5) Evaluation. Within the strategy, problem solving techniques were integrated from diverse areas such as: De Bono 's six thinking hats, Kepner-Tregoe decision analysis, Covey's seven habits of highly effective people, Reason's swiss cheese theory of complex failure, and Howlett's common failure modes. As part of the evaluation step, students critically explore areas such as ethics and environmental responsibility. In addition to exploring problem solving methods, students learn the usefulness of simulation methods, and how to model and simulate complex phenomena of relevance to radiation protection. Computational aspects of problem solving are explored using the commercially available MATLAB computer code. A number of case studies are presented as both examples and problems to the students. Emphasis was placed on solutions to problems of interest to radiation protection, health physics and nuclear engineering. A group project, pertaining to an accident or event related to the nuclear industry is a course requirement. Students learn to utilize common time and project management tools such as flowcharting, Pareto
Signal Processing Model for Radiation Transport
Energy Technology Data Exchange (ETDEWEB)
Chambers, D H
2008-07-28
This note describes the design of a simplified gamma ray transport model for use in designing a sequential Bayesian signal processor for low-count detection and classification. It uses a simple one-dimensional geometry to describe the emitting source, shield effects, and detector (see Fig. 1). At present, only Compton scattering and photoelectric absorption are implemented for the shield and the detector. Other effects may be incorporated in the future by revising the expressions for the probabilities of escape and absorption. Pair production would require a redesign of the simulator to incorporate photon correlation effects. The initial design incorporates the physical effects that were present in the previous event mode sequence simulator created by Alan Meyer. The main difference is that this simulator transports the rate distributions instead of single photons. Event mode sequences and other time-dependent photon flux sequences are assumed to be marked Poisson processes that are entirely described by their rate distributions. Individual realizations can be constructed from the rate distribution using a random Poisson point sequence generator.
The problem of the detection threshold in radiation measurement
International Nuclear Information System (INIS)
Rose, E.; Wueneke, C.D.
1983-01-01
In all cases encountered in practical radiation measurement, the basic problem is to differentiate between the lowest measured value and the zero value (background, natural background radiation, etc.). For this purpose, on the mathematical side, tests based on hypotheses are to be applied. These will show the probability of differentiation between two values having the same random spread. By means of these tests and the corresponding error theory, a uniform treatment of the subject, applicable to all problems relating to measuring technique alike, can be found. Two basic concepts are found in this process, which have to be defined in terms of semantics and nomenclature: Decision threshold and detection threshold, or 'minimum detectable mean value'. At the decision threshold, one has to decide (with a given statistical error probability) whether a measured value is to be attributed to the background radiation, accepting the zero hypothesis, or whether this value differs significantly from the background radiation (error of 1rst kind). The minimum detectable mean value is the value which, with a given decision threshold, can be determined with sufficient significance to be a measured value and thus cannot be mistaken as background radiation (alternative hypothesis, error of 2nd kind). Normally, the two error types are of equal importance. It may happen, however, that one type of error gains more importance, depending on the approach. (orig.) [de
On the use of antithetic variates in particle transport problems
International Nuclear Information System (INIS)
Milgram, M.S.
2001-01-01
The possible use of antithetic variates as a method of variance reduction in particle transport problems is investigated, by performing some numerical experiments. It is found that if variance reduction is not very carefully defined, it is possible, with antithetic variates, to spuriously detect reduction, or not detect true reduction. Once such subtleties are overcome, it is shown that antithetic variates can reduce variance in multidimensional integration up to a point. The phenomenon of spontaneous correlation is defined and identified as the cause of failure. The surprising result that it sometimes pays to track non-contributing particle histories is demonstrated by means of a zero variance integration analogue. The principles developed in the investigation of multi-variable integration are then employed in a simple calculation of energy deposition using the EGS4 computer code. Promising results are obtained for the total energy deposition problem, but the depth/dose problem remains unsolved. Possible means of overcoming the difficulties are suggested
The adaptive collision source method for discrete ordinates radiation transport
International Nuclear Information System (INIS)
Walters, William J.; Haghighat, Alireza
2017-01-01
Highlights: • A new adaptive quadrature method to solve the discrete ordinates transport equation. • The adaptive collision source (ACS) method splits the flux into n’th collided components. • Uncollided flux requires high quadrature; this is lowered with number of collisions. • ACS automatically applies appropriate quadrature order each collided component. • The adaptive quadrature is 1.5–4 times more efficient than uniform quadrature. - Abstract: A novel collision source method has been developed to solve the Linear Boltzmann Equation (LBE) more efficiently by adaptation of the angular quadrature order. The angular adaptation method is unique in that the flux from each scattering source iteration is obtained, with potentially a different quadrature order used for each. Traditionally, the flux from every iteration is combined, with the same quadrature applied to the combined flux. Since the scattering process tends to distribute the radiation more evenly over angles (i.e., make it more isotropic), the quadrature requirements generally decrease with each iteration. This method allows for an optimal use of processing power, by using a high order quadrature for the first iterations that need it, before shifting to lower order quadratures for the remaining iterations. This is essentially an extension of the first collision source method, and is referred to as the adaptive collision source (ACS) method. The ACS methodology has been implemented in the 3-D, parallel, multigroup discrete ordinates code TITAN. This code was tested on a several simple and complex fixed-source problems. The ACS implementation in TITAN has shown a reduction in computation time by a factor of 1.5–4 on the fixed-source test problems, for the same desired level of accuracy, as compared to the standard TITAN code.
Foucart, Francois
2018-04-01
General relativistic radiation hydrodynamic simulations are necessary to accurately model a number of astrophysical systems involving black holes and neutron stars. Photon transport plays a crucial role in radiatively dominated accretion discs, while neutrino transport is critical to core-collapse supernovae and to the modelling of electromagnetic transients and nucleosynthesis in neutron star mergers. However, evolving the full Boltzmann equations of radiative transport is extremely expensive. Here, we describe the implementation in the general relativistic SPEC code of a cheaper radiation hydrodynamic method that theoretically converges to a solution of Boltzmann's equation in the limit of infinite numerical resources. The algorithm is based on a grey two-moment scheme, in which we evolve the energy density and momentum density of the radiation. Two-moment schemes require a closure that fills in missing information about the energy spectrum and higher order moments of the radiation. Instead of the approximate analytical closure currently used in core-collapse and merger simulations, we complement the two-moment scheme with a low-accuracy Monte Carlo evolution. The Monte Carlo results can provide any or all of the missing information in the evolution of the moments, as desired by the user. As a first test of our methods, we study a set of idealized problems demonstrating that our algorithm performs significantly better than existing analytical closures. We also discuss the current limitations of our method, in particular open questions regarding the stability of the fully coupled scheme.
DIAPHANE: A portable radiation transport library for astrophysical applications
Reed, Darren S.; Dykes, Tim; Cabezón, Rubén; Gheller, Claudio; Mayer, Lucio
2018-05-01
One of the most computationally demanding aspects of the hydrodynamical modelingof Astrophysical phenomena is the transport of energy by radiation or relativistic particles. Physical processes involving energy transport are ubiquitous and of capital importance in many scenarios ranging from planet formation to cosmic structure evolution, including explosive events like core collapse supernova or gamma-ray bursts. Moreover, the ability to model and hence understand these processes has often been limited by the approximations and incompleteness in the treatment of radiation and relativistic particles. The DIAPHANE project has focused on developing a portable and scalable library that handles the transport of radiation and particles (in particular neutrinos) independently of the underlying hydrodynamic code. In this work, we present the computational framework and the functionalities of the first version of the DIAPHANE library, which has been successfully ported to three different smoothed-particle hydrodynamic codes, GADGET2, GASOLINE and SPHYNX. We also present validation of different modules solving the equations of radiation and neutrino transport using different numerical schemes.
Françoise Benz
2006-01-01
2005-2006 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 27, 28, 29 June 11:00-12:00 - TH Conference Room, bldg. 4 The use of Monte Carlo radiation transport codes in radiation physics and dosimetry F. Salvat Gavalda,Univ. de Barcelona, A. FERRARI, CERN-AB, M. SILARI, CERN-SC Lecture 1. Transport and interaction of electromagnetic radiation F. Salvat Gavalda,Univ. de Barcelona Interaction models and simulation schemes implemented in modern Monte Carlo codes for the simulation of coupled electron-photon transport will be briefly reviewed. Different schemes for simulating electron transport will be discussed. Condensed algorithms, which rely on multiple-scattering theories, are comparatively fast, but less accurate than mixed algorithms, in which hard interactions (with energy loss or angular deflection larger than certain cut-off values) are simulated individually. The reliability, and limitations, of electron-interaction models and multiple-scattering theories will be analyzed. Benchmark comparisons of simu...
Dark radiation from the axino solution of the gravitino problem
International Nuclear Information System (INIS)
Hasenkamp, Jasper
2012-01-01
Current observations of the cosmic microwave background could confirm an increase in the radiation energy density after primordial nucleosynthesis but before photon decoupling. We show that, if the gravitino problem is solved by a light axino, dark (decoupled) radiation emerges naturally in this period leading to a new upper bound on the reheating temperature T R ≤10 11 GeV. In turn, successful thermal leptogenesis might predict such an increase. The Large Hadron Collider could endorse this opportunity. At the same time, axion and axino can naturally form the observed dark matter.
Predicting Behavioral Problems in Craniopharyngioma Survivors after Conformal Radiation Therapy
Dolson, Eugenia P.; Conklin, Heather M.; Li, Chenghong; Xiong, Xiaoping; Merchant, Thomas E.
2009-01-01
Background Although radiation therapy is a primary treatment for craniopharyngioma, it can exacerbate existing problems related to the tumor and pre-irradiation management. Survival is often marked by neurologic deficits, panhypopituitarism, diabetes insipidus, cognitive deficiencies and behavioral and social problems. Procedure The Achenbach Child Behavior Checklist (CBCL) was used to evaluate behavioral and social problems during the first five years of follow-up in 27 patients with craniopharyngioma treated with conformal radiation therapy. Results All group averages for the CBCL scales were within the age-typical range at pre-irradiation baseline. Extent of surgical resection was implicated in baseline differences for the Internalizing, Externalizing, Behavior Problem and Social scores. Significant longitudinal changes were found in Internalizing, Externalizing, Behavior Problem and School scores that correlated with tumor and treatment related factors. Conclusions The most common variables implicated in post-irradiation behavioral and social problems were CSF shunting, presence of an Ommaya reservoir, diabetes insipidus, and low pre-irradiation growth hormone levels. PMID:19191345
Some factors affecting radiative heat transport in PWR cores
International Nuclear Information System (INIS)
Hall, A.N.
1989-04-01
This report discusses radiative heat transport in Pressurized Water Reactor cores, using simple models to illustrate basic features of the transport process. Heat transport by conduction and convection is ignored in order to focus attention on the restrictions on radiative heat transport imposed by the geometry of the heat emitting and absorbing structures. The importance of the spacing of the emitting and absorbing structures is emphasised. Steady state temperature distributions are found for models of cores which are uniformly heated by fission product decay. In all of the models, a steady state temperature distribution can only be obtained if the central core temperature is in excess of the melting point of UO 2 . It has recently been reported that the MIMAS computer code, which takes into account radiative heat transport, has been used to model the heat-up of the Three Mile Island-2 reactor core, and the computations indicate that the core could not have reached the melting point of UO 2 at any time or any place. We discuss this result in the light of the calculations presented in this paper. It appears that the predicted stabilisation of the core temperatures at ∼ 2200 0 C may be a consequence of the artificially large spacing between the radial rings employed in the MIMAS code, rather than a result of physical significance. (author)
The intelligence of dual simplex method to solve linear fractional fuzzy transportation problem.
Narayanamoorthy, S; Kalyani, S
2015-01-01
An approach is presented to solve a fuzzy transportation problem with linear fractional fuzzy objective function. In this proposed approach the fractional fuzzy transportation problem is decomposed into two linear fuzzy transportation problems. The optimal solution of the two linear fuzzy transportations is solved by dual simplex method and the optimal solution of the fractional fuzzy transportation problem is obtained. The proposed method is explained in detail with an example.
The Intelligence of Dual Simplex Method to Solve Linear Fractional Fuzzy Transportation Problem
Directory of Open Access Journals (Sweden)
S. Narayanamoorthy
2015-01-01
Full Text Available An approach is presented to solve a fuzzy transportation problem with linear fractional fuzzy objective function. In this proposed approach the fractional fuzzy transportation problem is decomposed into two linear fuzzy transportation problems. The optimal solution of the two linear fuzzy transportations is solved by dual simplex method and the optimal solution of the fractional fuzzy transportation problem is obtained. The proposed method is explained in detail with an example.
Monte Carlo methods for flux expansion solutions of transport problems
International Nuclear Information System (INIS)
Spanier, J.
1999-01-01
Adaptive Monte Carlo methods, based on the use of either correlated sampling or importance sampling, to obtain global solutions to certain transport problems have recently been described. The resulting learning algorithms are capable of achieving geometric convergence when applied to the estimation of a finite number of coefficients in a flux expansion representation of the global solution. However, because of the nonphysical nature of the random walk simulations needed to perform importance sampling, conventional transport estimators and source sampling techniques require modification to be used successfully in conjunction with such flux expansion methods. It is shown how these problems can be overcome. First, the traditional path length estimators in wide use in particle transport simulations are generalized to include rather general detector functions (which, in this application, are the individual basis functions chosen for the flus expansion). Second, it is shown how to sample from the signed probabilities that arise as source density functions in these applications, without destroying the zero variance property needed to ensure geometric convergence to zero error
Radiation Belt Transport Driven by Solar Wind Dynamic Pressure Fluctuations
Kress, B. T.; Hudson, M. K.; Ukhorskiy, A. Y.; Mueller, H.
2012-12-01
The creation of the Earth's outer zone radiation belts is attributed to earthward transport and adiabatic acceleration of electrons by drift-resonant interactions with electromagnetic fluctuations in the magnetosphere. Three types of radial transport driven by solar wind dynamic pressure fluctuations that have been identified are: (1) radial diffusion [Falthammer, 1965], (2) significant changes in the phase space density radial profile due to a single or few ULF drift-resonant interactions [Ukhorskiy et al., 2006; Degeling et al., 2008], and (3) shock associated injections of radiation belt electrons occurring in less than a drift period [Li et al., 1993]. A progress report will be given on work to fully characterize different forms of radial transport and their effect on the Earth's radiation belts. The work is being carried out by computing test-particle trajectories in electric and magnetic fields from a simple analytic ULF field model and from global MHD simulations of the magnetosphere. Degeling, A. W., L. G. Ozeke, R. Rankin, I. R. Mann, and K. Kabin (2008), Drift resonant generation of peaked relativistic electron distributions by Pc 5 ULF waves, textit{J. Geophys. Res., 113}, A02208, doi:10.1029/2007JA012411. Fälthammar, C.-G. (1965), Effects of Time-Dependent Electric Fields on Geomagnetically Trapped Radiation, J. Geophys. Res., 70(11), 2503-2516, doi:10.1029/JZ070i011p02503. Li, X., I. Roth, M. Temerin, J. R. Wygant, M. K. Hudson, and J. B. Blake (1993), Simulation of the prompt energization and transport of radiation belt particles during the March 24, 1991 SSC, textit{Geophys. Res. Lett., 20}(22), 2423-2426, doi:10.1029/93GL02701. Ukhorskiy, A. Y., B. J. Anderson, K. Takahashi, and N. A. Tsyganenko (2006), Impact of ULF oscillations in solar wind dynamic pressure on the outer radiation belt electrons, textit{Geophys. Res. Lett., 33}(6), L06111, doi:10.1029/2005GL024380.
Mathematical and numerical analysis of PN models for photons transport problems
International Nuclear Information System (INIS)
Valentin, Xavier
2015-01-01
Computational costs for direct numerical simulations of photon transport problems are very high in terms of CPU time and memory. One way to tackle this issue is to develop reduced models that a cheaper to solve numerically. There exists number of these models: moments models, discrete ordinates models (S N ), diffusion-like models... In this thesis, we focus on P N models in which the transport operator is approached by mean of a truncated development on the spherical harmonics basis. These models are arbitrary accurate in the angular dimension and are rotationally invariants (in multiple space dimensions). The latter point is fundamental when one wants to simulate inertial confinement fusion (ICF) experiments where the spherical symmetry plays an important part in the accuracy of the numerical solutions. We study the mathematical structure of the PN models and construct a new numerical method in the special case of a one dimensional space dimension with spherical symmetry photon transport problems. We first focus on a linear transport problem in the vacuum. Even in this simple case, it appears in the P N equations geometrical source terms that are stiff in the neighborhood of r = 0 and thus hard to discretize. Existing numerical methods are not satisfactory for multiple reasons: (1) inaccuracy in the neighborhood of r = 0 ('flux-dip'), (2) do not capture steady states (well-balanced scheme), (3) no stability proof. Following recent works, we develop a new well-balanced scheme for which we show the L 2 stability. We then extend the scheme for photon transport problems within a no moving media, the linear Boltzmann equation, and interest ourselves on its behavior in the diffusion limit (asymptotic-preserving property). In a second part, we consider radiation hydrodynamics problems. Since modelization of these problems is still under discussion in the literature, we compare a set of existing models by mean of mathematical analysis and establish a hierarchy
ON PROBLEM OF REGIONAL WAREHOUSE AND TRANSPORT INFRASTRUCTURE OPTIMIZATION
Directory of Open Access Journals (Sweden)
I. Yu. Miretskiy
2017-01-01
Full Text Available The article suggests an approach of solving the problem of warehouse and transport infrastructure optimization in a region. The task is to determine the optimal capacity and location of the support network of warehouses in the region, as well as power, composition and location of motor fleets. Optimization is carried out using mathematical models of a regional warehouse network and a network of motor fleets. These models are presented as mathematical programming problems with separable functions. The process of finding the optimal solution of problems is complicated due to high dimensionality, non-linearity of functions, and the fact that a part of variables are constrained to integer, and some variables can take values only from a discrete set. Given the mentioned above complications search for an exact solution was rejected. The article suggests an approximate approach to solving problems. This approach employs effective computational schemes for solving multidimensional optimization problems. We use the continuous relaxation of the original problem to obtain its approximate solution. An approximately optimal solution of continuous relaxation is taken as an approximate solution of the original problem. The suggested solution method implies linearization of the obtained continuous relaxation and use of the separable programming scheme and the scheme of branches and bounds. We describe the use of the simplex method for solving the linearized continuous relaxation of the original problem and the specific moments of the branches and bounds method implementation. The paper shows the finiteness of the algorithm and recommends how to accelerate process of finding a solution.
PROBLEMS OF CLASSIFICATION AND FORMATION LAND OF AVIATION TRANSPORT
Directory of Open Access Journals (Sweden)
Novakovska I. O.
2017-08-01
territories. Land-use restrictions on aviation transport on adjacent airport territories cover large areas of land. Formation of aviation land-use and ecologically safe use of land of aviation transport is an extremely topical subject of scientific research in modern conditions. The main task is the development of scientific bases and methodological provisions for the formation, operation and regulation of the use of land potential of the aviation industry and methodological recommendations of land management of objects of aviation transport. The indicated problems were almost not investigated by Ukrainian scientists. The separation of land and property of airports of state, communal and private property is the serious problem in modern time. Due to the violation of the principle that an aerodrome is a strategic object that is not able to privatized, and a terminal is an investment object, including private property, only in 5 years it was possible to return the communal property to the Odessa airport, which in 2011 was transferred to offshore investors. The registration of land occupied has not been completed by other airports, and the corresponding legal documents have been issued to them. In accordance with the State Target Program for the Development of Airports, it is planned to implement a range of appropriate measures to ensure the construction, reconstruction and modernization of facilities. It is necessary to reflect in the State Land Cadastre the data on the registration of aerodrome territories as restrictions on land use associated with the operation of aviation transport, to make necessary changes to the Law of Ukraine "On State Land Cadastre" and the Procedure for State Land Cadastre.
Novel Parallel Numerical Methods for Radiation and Neutron Transport
International Nuclear Information System (INIS)
Brown, P N
2001-01-01
In many of the multiphysics simulations performed at LLNL, transport calculations can take up 30 to 50% of the total run time. If Monte Carlo methods are used, the percentage can be as high as 80%. Thus, a significant core competence in the formulation, software implementation, and solution of the numerical problems arising in transport modeling is essential to Laboratory and DOE research. In this project, we worked on developing scalable solution methods for the equations that model the transport of photons and neutrons through materials. Our goal was to reduce the transport solve time in these simulations by means of more advanced numerical methods and their parallel implementations. These methods must be scalable, that is, the time to solution must remain constant as the problem size grows and additional computer resources are used. For iterative methods, scalability requires that (1) the number of iterations to reach convergence is independent of problem size, and (2) that the computational cost grows linearly with problem size. We focused on deterministic approaches to transport, building on our earlier work in which we performed a new, detailed analysis of some existing transport methods and developed new approaches. The Boltzmann equation (the underlying equation to be solved) and various solution methods have been developed over many years. Consequently, many laboratory codes are based on these methods, which are in some cases decades old. For the transport of x-rays through partially ionized plasmas in local thermodynamic equilibrium, the transport equation is coupled to nonlinear diffusion equations for the electron and ion temperatures via the highly nonlinear Planck function. We investigated the suitability of traditional-solution approaches to transport on terascale architectures and also designed new scalable algorithms; in some cases, we investigated hybrid approaches that combined both
Problems and progress in radiation physics of semiconductors
International Nuclear Information System (INIS)
Vinetskij, V.L.
1982-01-01
A survey of the current status of radiation physics of semiconductors comprises the analysis of some new problems and poses the statement of concern. The essential difference between the probability of interstitial-vacancy pair occurrence W(T) in elastic collisions and the generally accepted step distribution with a typical ''threshold'' energy Tsub(d) is indicated. The role of diffusion and reaction evolution of primary defects leading to specific properties of the cluster formation process is shown. Special features of defect formation in spatially inhomogeneous semiconductors, in particular for elastic stresses present, are described. Among most important advances in the radiation physics of semiconductors there are the discovery of non-activation motion of the ''extra'' atom in silicon, the observation of a low activation energy value for the vacancy diffusion, the understanding of subthreshold mechanism of defect formation and radiation-induced diffusion, the effects of laser annealing of defects and oriented crystallization
Krylov Techniques for 3D Problems in Transport Theory
International Nuclear Information System (INIS)
Ruben Panta Pazos
2006-01-01
When solving integral-differential equations by means of numerical methods one has to deal with large systems of linear equations, such as happens in transport theory [10]. Many iterative techniques are now used in Transport Theory in order to solve problems of 2D and 3D dimensions. In this paper, we choose two problems to solve the following transport equation, [Equation] where x: represents the spatial variable, μ: the cosine of the angle, ψ: the angular flux, h(x, μ): is the collision frequency, k(x, μ, μ'): the scattering kernel, q(x, μ): the source. The aim of this work is the straightforward application of the Krylov spaces technique [2] to the governing equation or to its discretizations derived of the discrete ordinates method (choosing a finite number of directions and then approximating the integral term by means of a proper sum). The equation (1) can be written in functional form as [Equation] with ψ in the Hilbert space L 2 ([0,a] x [-1,1])., and q is the source function. The operator derived from a discrete ordinates scheme that approximates the operator [Equation] generates the following subspace [Equation] i.e. the subspace generated by the iterations of order 0, 1, 2,..., m-1 of the source function q. Two methods are specially outstanding, the Lanczos method to solve the problem given by equation (2) with certain boundary conditions, and the conjugate gradient method to solve the same problem with identical boundary conditions. We discuss and accelerate the basic iterative method [8]. An important conclusion is the generation of these methods to solve linear systems in Hilbert spaces, if verify the convergence conditions, which are outlined in this work. The first problem is a cubic domain with two regions, one with a source near the vertex at the origin and the shield region. In this case, the Cartesian planes (specifically 0 < x < L, 0 < y < L, 0 < z < L) are reflexive boundaries and the rest faces of the cube are vacuum boundaries. The
Computer codes for problems of isotope and radiation research
International Nuclear Information System (INIS)
Remer, M.
1986-12-01
A survey is given of computer codes for problems in isotope and radiation research. Altogether 44 codes are described as titles with abstracts. 17 of them are in the INIS scope and are processed individually. The subjects are indicated in the chapter headings: 1) analysis of tracer experiments, 2) spectrum calculations, 3) calculations of ion and electron trajectories, 4) evaluation of gamma irradiation plants, and 5) general software
Directory of Open Access Journals (Sweden)
A.M. Shendrik
2014-03-01
Full Text Available The container gas transportation for low and medium level consumers as an alternative to pipelines is considered. The options for gas supply schemes, based on road and rail transport are given. The advantages and disadvantages of both types of gas transporting are described, the areas of their effective using are separated in the article. Promising implementations of technology in environment of economic crisis and also considering world trends of energy development are presented. The most advanced organization of compressed gas condensate transportation of unprepared gas fields in large diameter universal cylindrical balloons (up to 1000 mm are reasoned. The problem of compressed gas sea transportation are well disclosed, but the alternative ways of gas transportation by land are not investigated enough. Compressed Natural Gas (CNG Technology - is new promising technology for natural gas transportation by specially designed vessels – CNG-vessels. The feature of this technology is that natural gas can be downloaded directly near gas deposits and unloaded - directly into the customer's network. This eliminates significant capital investments in underwater pipelining or gas liquefaction plants. The main objects of investment are CNG-vessels themselves. The most attractive places for implementation of CNG-technology are sea (offshore natural gas deposits. Numerous international experts estimate the natural gas transportation by CNG-vessels in 1.5-2.0 times more cost-beneficial in comparison with offshore pipelines transportation, or in comparison with LNG (Liquefied Natural Gas shipping with natural gas transportation volume between 0.5 and 4.0 billion cubic meters per year on the route from 250 to 2,500 sea miles. This technology makes possible to provide gas supplement to the mountain and abounding in water areas, remote and weakly gasified regions. Described technology deserves special attention in the case of depleted and low-power oil and
Transport of radioactive materials: the need for radiation protection programmes
International Nuclear Information System (INIS)
Masinza, S.A.
2004-01-01
The increase in the use of radioactive materials worldwide requires that these materials be moved from production sites to the end user or in the case of radioactive waste, from the waste generator to the repository. Tens of millions of packages containing radioactive material are consigned for transport each year throughout the world. The amount of radioactive material in these packages varies from negligible quantities in shipments of consumer products to very large quantities of shipments of irradiated nuclear fuel. Transport is the main way in which the radioactive materials being moved get into the public domain. The public is generally unaware of the lurking danger when transporting these hazardous goods. Thus radiation protection programmes are important to assure the public of the certainty of their safety during conveyance of these materials. Radioactive material is transported by land (road and rail), inland waterways, sea/ocean and air. These modes of transport are regulated by international 'modal' regulations. The international community has formulated controls to reduce the number of accidents and mitigate their consequences should they happen. When accidents involving the transport of radioactive material occur, it could result in injury, loss of life and pollution of the environment. In order to ensure the safety of people, property and the environment, national and international transport regulations have been developed. The appropriate authorities in each state utilise them to control the transport of radioactive material. Stringent measures are required in these regulations to ensure adequate containment, shielding and the prevention of criticality in all spheres of transport, i.e. routine, minor incidents and accident conditions. Despite the extensive application of these stringent safety controls, transport accidents involving packages containing radioactive material have occurred and will continue to occur. When a transport accident occurs, it
Application of radiation protection programmes to transport of radioactive material
International Nuclear Information System (INIS)
Lopez Vietri, Jorge; Capadona, Nancy; Barenghi, Leonardo
2008-01-01
Full text: The principles for implementing radiation protection programmes (RPP) are detailed in the draft IAEA safety guide TS-G-1.5 'Radiation protection programmes for transport of radioactive material'. The document is described in this paper and analysis is made for typical applications to current operations carried out by consignors, carriers and consignees. Systematic establishment and application of RPPs is a way to control radiological protection during different steps of transport activity. The most widely transported packages in the world are radiopharmaceuticals by road. It is described an application of RPP for an organization involved in road transport of Type A packages containing radiopharmaceuticals. Considerations based on the radionuclides, quantities and activities transported are the basis to design and establish the scope of the RPP for the organizations involved in transport. Next stage is the determination of roles and responsibilities for each activity related to transport of radioactive materials. An approach to the dose received by workers is evaluated considering the type, category and quantity of packages, the radionuclides, the frequency of consignments and how long are the storages. The average of transports made in the last years must be taken into account and special measures intended to optimize the protection are evaluated. Tasks like monitoring, control of surface contamination and segregation measures, are designed based on the dose evaluation and optimization. The RPP also indicates main measures to follow in case of emergency during transport taking account of radionuclides, activities and category of packages for different accident scenarios. Basis for training personnel involved in handling of radioactive materials to insure they have appropriate knowledge about preparing packages, measuring dose rates, calculating transport index, labelling, marking and placarding, transport documents, etc, are considered. The RPP is a part
Inverse problem for extragalactic transport of ultra-high energy cosmic rays
International Nuclear Information System (INIS)
Ptuskin, V.S.; Rogovaya, S.I.; Zirakashvili, V.N.
2015-01-01
The energy spectra and composition of ultra-high energy cosmic rays are changing in a course of propagation in the expanding Universe filled with background radiation. We developed a numerical code for solution of inverse problem for cosmic-ray transport equations that allows the determination of average source spectra of different nuclei from the cosmic ray spectra observed at the Earth. Employing this approach, the injection spectra of protons and Iron nuclei in extragalactic sources are found assuming that only these species are accelerated at the source. The data from the Auger experiment and the combined data from the Telescope Array + HiRes experiments are used to illustrate the method
Inverse problem for extragalactic transport of ultra-high energy cosmic rays
Energy Technology Data Exchange (ETDEWEB)
Ptuskin, V.S.; Rogovaya, S.I.; Zirakashvili, V.N., E-mail: vptuskin@izmiran.ru, E-mail: rogovaya@izmiran.ru, E-mail: zirak@izmiran.ru [Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation of the Russian Academy of Sciences (IZMIRAN), Troitsk, Moscow, 142190 (Russian Federation)
2015-03-01
The energy spectra and composition of ultra-high energy cosmic rays are changing in a course of propagation in the expanding Universe filled with background radiation. We developed a numerical code for solution of inverse problem for cosmic-ray transport equations that allows the determination of average source spectra of different nuclei from the cosmic ray spectra observed at the Earth. Employing this approach, the injection spectra of protons and Iron nuclei in extragalactic sources are found assuming that only these species are accelerated at the source. The data from the Auger experiment and the combined data from the Telescope Array + HiRes experiments are used to illustrate the method.
International Nuclear Information System (INIS)
Mishra, Subhash C.; Vernekar, Rohan Ranganath
2012-01-01
Application of the lattice Boltzmann method (LBM) recently proposed by Asinari et al. [Asinari P, Mishra SC, Borchiellini R. A lattice Boltzmann formulation to the analysis of radiative heat transfer problems in a participating medium. Numer Heat Transfer B 2010; 57:126–146] is extended to the analysis of transport of collimated radiation in a planar participating medium. To deal with azimuthally symmetric radiation in planar medium, a new lattice structure for the LBM is used. The transport of the collimated component in the medium is analysed by two different, viz., flux splitting and direct approaches. For different angles of incidence of the collimated radiation, the LBM formulation is tested for the effects of the extinction coefficient, the anisotropy factor, and the boundary emissivities on heat flux and emissive power distributions. Results are compared with the benchmark results obtained using the finite volume method. Both the approaches in LBM provide accurate results. -- Highlights: ► Transport of collimated radiation in participating media is studied. ► Usage of Lattice Boltzmann method (LBM) is extended in this study. ► In LBM, flux splitting and direct approaches are proposed. ► Effects of various parameters are studied on heat flux and temperature profiles. ► In all cases, LBM provides correct results.
Nodal methods for problems in fluid mechanics and neutron transport
International Nuclear Information System (INIS)
Azmy, Y.Y.
1985-01-01
A new high-accuracy, coarse-mesh, nodal integral approach is developed for the efficient numerical solution of linear partial differential equations. It is shown that various special cases of this general nodal integral approach correspond to several high efficiency nodal methods developed recently for the numerical solution of neutron diffusion and neutron transport problems. The new approach is extended to the nonlinear Navier-Stokes equations of fluid mechanics; its extension to these equations leads to a new computational method, the nodal integral method which is implemented for the numerical solution of these equations. Application to several test problems demonstrates the superior computational efficiency of this new method over previously developed methods. The solutions obtained for several driven cavity problems are compared with the available experimental data and are shown to be in very good agreement with experiment. Additional comparisons also show that the coarse-mesh, nodal integral method results agree very well with the results of definitive ultra-fine-mesh, finite-difference calculations for the driven cavity problem up to fairly high Reynolds numbers
Discontinuous finite element treatment of duct problems in transport calculations
International Nuclear Information System (INIS)
Mirza, A. M.; Qamar, S.
1998-01-01
A discontinuous finite element approach is presented to solve the even-parity Boltzmann transport equation for duct problems. Presence of ducts in a system results in the streaming of particles and hence requires the employment of higher order angular approximations to model the angular flux. Conventional schemes based on the use of continuous trial functions require the same order of angular approximations to be used everywhere in the system, resulting in wastage of computational resources. Numerical investigations for the test problems presented in this paper indicate that the discontinuous finite elements eliminate the above problems and leads to computationally efficient and economical methods. They are also found to be more suitable for treating the sharp changes in the angular flux at duct-observer interfaces. The new approach provides a single-pass alternate to extrapolation and interactive schemes which need multiple passes of the solution strategy to acquire convergence. The method has been tested with the help of two case studies, namely straight and dog-leg duct problems. All results have been verified against those obtained from Monte Carlo simulations and K/sup +/ continuous finite element method. (author)
Transport synthetic acceleration scheme for multi-dimensional neutron transport problems
Energy Technology Data Exchange (ETDEWEB)
Modak, R S; Kumar, Vinod; Menon, S V.G. [Theoretical Physics Div., Bhabha Atomic Research Centre, Mumbai (India); Gupta, Anurag [Reactor Physics Design Div., Bhabha Atomic Research Centre, Mumbai (India)
2005-09-15
The numerical solution of linear multi-energy-group neutron transport equation is required in several analyses in nuclear reactor physics and allied areas. Computer codes based on the discrete ordinates (Sn) method are commonly used for this purpose. These codes solve external source problem and K-eigenvalue problem. The overall solution technique involves solution of source problem in each energy group as intermediate procedures. Such a single-group source problem is solved by the so-called Source Iteration (SI) method. As is well-known, the SI-method converges very slowly for optically thick and highly scattering regions, leading to large CPU times. Over last three decades, many schemes have been tried to accelerate the SI; the most prominent being the Diffusion Synthetic Acceleration (DSA) scheme. The DSA scheme, however, often fails and is also rather difficult to implement. In view of this, in 1997, Ramone and others have developed a new acceleration scheme called Transport Synthetic Acceleration (TSA) which is much more robust and easy to implement. This scheme has been recently incorporated in 2-D and 3-D in-house codes at BARC. This report presents studies on the utility of TSA scheme for fairly general test problems involving many energy groups and anisotropic scattering. The scheme is found to be useful for problems in Cartesian as well as Cylindrical geometry. (author)
Transport synthetic acceleration scheme for multi-dimensional neutron transport problems
International Nuclear Information System (INIS)
Modak, R.S.; Vinod Kumar; Menon, S.V.G.; Gupta, Anurag
2005-09-01
The numerical solution of linear multi-energy-group neutron transport equation is required in several analyses in nuclear reactor physics and allied areas. Computer codes based on the discrete ordinates (Sn) method are commonly used for this purpose. These codes solve external source problem and K-eigenvalue problem. The overall solution technique involves solution of source problem in each energy group as intermediate procedures. Such a single-group source problem is solved by the so-called Source Iteration (SI) method. As is well-known, the SI-method converges very slowly for optically thick and highly scattering regions, leading to large CPU times. Over last three decades, many schemes have been tried to accelerate the SI; the most prominent being the Diffusion Synthetic Acceleration (DSA) scheme. The DSA scheme, however, often fails and is also rather difficult to implement. In view of this, in 1997, Ramone and others have developed a new acceleration scheme called Transport Synthetic Acceleration (TSA) which is much more robust and easy to implement. This scheme has been recently incorporated in 2-D and 3-D in-house codes at BARC. This report presents studies on the utility of TSA scheme for fairly general test problems involving many energy groups and anisotropic scattering. The scheme is found to be useful for problems in Cartesian as well as Cylindrical geometry. (author)
Computer codes in nuclear safety, radiation transport and dosimetry
International Nuclear Information System (INIS)
Bordy, J.M.; Kodeli, I.; Menard, St.; Bouchet, J.L.; Renard, F.; Martin, E.; Blazy, L.; Voros, S.; Bochud, F.; Laedermann, J.P.; Beaugelin, K.; Makovicka, L.; Quiot, A.; Vermeersch, F.; Roche, H.; Perrin, M.C.; Laye, F.; Bardies, M.; Struelens, L.; Vanhavere, F.; Gschwind, R.; Fernandez, F.; Quesne, B.; Fritsch, P.; Lamart, St.; Crovisier, Ph.; Leservot, A.; Antoni, R.; Huet, Ch.; Thiam, Ch.; Donadille, L.; Monfort, M.; Diop, Ch.; Ricard, M.
2006-01-01
The purpose of this conference was to describe the present state of computer codes dedicated to radiation transport or radiation source assessment or dosimetry. The presentations have been parted into 2 sessions: 1) methodology and 2) uses in industrial or medical or research domains. It appears that 2 different calculation strategies are prevailing, both are based on preliminary Monte-Carlo calculations with data storage. First, quick simulations made from a database of particle histories built though a previous Monte-Carlo simulation and secondly, a neuronal approach involving a learning platform generated through a previous Monte-Carlo simulation. This document gathers the slides of the presentations
Radiation transport modelling for the interpretation of oblique ECE measurements
Directory of Open Access Journals (Sweden)
Denk Severin S.
2017-01-01
Since radiation transport modelling is required for the interpretation of oblique ECE diagnostics we present in this paper an extended forward model that supports oblique lines of sight. To account for the refraction of the line of sight, ray tracing in the cold plasma approximation was added to the model. Furthermore, an absorption coefficient valid for arbitrary propagation was implemented. Using the revised model it is shown that for the oblique ECE Imaging diagnostic at ASDEX Upgrade there can be a significant difference between the cold resonance position and the point from which most of the observed radiation originates.
Second order time evolution of the multigroup diffusion and P1 equations for radiation transport
International Nuclear Information System (INIS)
Olson, Gordon L.
2011-01-01
Highlights: → An existing multigroup transport algorithm is extended to be second-order in time. → A new algorithm is presented that does not require a grey acceleration solution. → The two algorithms are tested with 2D, multi-material problems. → The two algorithms have comparable computational requirements. - Abstract: An existing solution method for solving the multigroup radiation equations, linear multifrequency-grey acceleration, is here extended to be second order in time. This method works for simple diffusion and for flux-limited diffusion, with or without material conduction. A new method is developed that does not require the solution of an averaged grey transport equation. It is effective solving both the diffusion and P 1 forms of the transport equation. Two dimensional, multi-material test problems are used to compare the solution methods.
A model problem concerning ionic transport in microstructured solid electrolytes
Curto Sillamoni, Ignacio J.; Idiart, Martín I.
2015-11-01
We consider ionic transport by diffusion and migration through microstructured solid electrolytes. The assumed constitutive relations for the constituent phases follow from convex energy and dissipation potentials which guarantee thermodynamic consistency. The effective response is determined by homogenizing the relevant field equations via the notion ofmulti-scale convergence. The resulting homogenized response involves several effective tensors, but they all require the solution of just one standard conductivity problem over the representative volume element. A multi-scale model for semicrystalline polymer electrolytes with spherulitic morphologies is derived by applying the theory to a specific class of two-dimensional microgeometries for which the effective response can be computed exactly. An enriched model accounting for a random dispersion of filler particles with interphases is also derived. In both cases, explicit expressions for the effective material parameters are provided. The models are used to explore the effect of crystallinity and filler content on the overall response. Predictions support recent experimental observations on doped poly-ethylene-oxide systems which suggest that the anisotropic crystalline phase can actually support faster ion transport than the amorphous phase along certain directions dictated by the morphology of the polymeric chains. Predictions also support the viewpoint that ceramic fillers improve ionic conductivity and cation transport number via interphasial effects.
Impacts of Transportation Cost on Distribution-Free Newsboy Problems
Directory of Open Access Journals (Sweden)
Ming-Hung Shu
2014-01-01
Full Text Available A distribution-free newsboy problem (DFNP has been launched for a vendor to decide a product’s stock quantity in a single-period inventory system to sustain its least maximum-expected profits when combating fierce and diverse market circumstances. Nowadays, impacts of transportation cost on determination of optimal inventory quantity have become attentive, where its influence on the DFNP has not been fully investigated. By borrowing an economic theory from transportation disciplines, in this paper the DFNP is tackled in consideration of the transportation cost formulated as a function of shipping quantity and modeled as a nonlinear regression form from UPS’s on-site shipping-rate data. An optimal solution of the order quantity is computed on the basis of Newton’s approach to ameliorating its complexity of computation. As a result of comparative studies, lower bounds of the maximal expected profit of our proposed methodologies surpass those of existing work. Finally, we extend the analysis to several practical inventory cases including fixed ordering cost, random yield, and a multiproduct condition.
International Nuclear Information System (INIS)
Wang, Yaqi
2012-01-01
The Method of Manufactured Solutions (MMS) is an accepted technique to verify that a numerical discretization for the radiation transport equation has been implemented correctly. This technique offers a few advantages over other methods such as benchmark problems or analytical solutions. The solution can be manufactured such that properties for the angular flux are either stressed or preserved. For radiation transport, these properties can include desired smoothness, positiveness and arbitrary order of anisotropy in angle. Another advantage is that the angular flux solution can be manufactured for multidimensional problems where analytical solutions are difficult to obtain in general.
A transportronic solution to the problem of interorbital transportation
Brown, William C.
1992-01-01
An all-electronic transportation system described by the term 'transportronics' is examined as a means of solving the current problem of the high cost of transporting material from low-Earth orbit (LEO) to geostationary orbit (GEO). In this transportation system, low cost electric energy at the surface of the Earth is efficiently converted into microwave power which is then efficiently formed into a narrow beam which is kept incident upon the orbital transfer vehicles (OTV's) by electronic tracking. The incident beam is efficiently captured and converted into DC power by a device which has a very high ratio of DC power output to its mass. Because the mass of the electric thruster is also low, the resulting acceleration is unprecedented for electric-propelled vehicles. However, the performance of the system in terms of transit times from LEO to GEO is penalized by the short time of contact between the beam and the vehicle in low-Earth orbits. This makes it necessary to place the Earth based transmitters and the vehicles in the equatorial plane thus introducing many geopolitical factors. Technically, however, such a system as described in the report may out-perform any other approach to transportation in the LEO to GEO regime. The report describes and analyzes all portions of the beamed microwave power transmission system in considerable detail. An economic analysis of the operating and capital costs is made with the aid of a reference system capable of placing about 130,000 kilograms of payload into GEO each year. More mature states of the system are then examined, to a level in which 60,000 metric tons per year could be placed into GEO.
Davis, Anthony B.; Marshak, Alexander
2010-01-01
The interplay of sunlight with clouds is a ubiquitous and often pleasant visual experience, but it conjures up major challenges for weather, climate, environmental science and beyond. Those engaged in the characterization of clouds (and the clear air nearby) by remote sensing methods are even more confronted. The problem comes, on the one hand, from the spatial complexity of real clouds and, on the other hand, from the dominance of multiple scattering in the radiation transport. The former ingredient contrasts sharply with the still popular representation of clouds as homogeneous plane-parallel slabs for the purposes of radiative transfer computations. In typical cloud scenes the opposite asymptotic transport regimes of diffusion and ballistic propagation coexist. We survey the three-dimensional (3D) atmospheric radiative transfer literature over the past 50 years and identify three concurrent and intertwining thrusts: first, how to assess the damage (bias) caused by 3D effects in the operational 1D radiative transfer models? Second, how to mitigate this damage? Finally, can we exploit 3D radiative transfer phenomena to innovate observation methods and technologies? We quickly realize that the smallest scale resolved computationally or observationally may be artificial but is nonetheless a key quantity that separates the 3D radiative transfer solutions into two broad and complementary classes: stochastic and deterministic. Both approaches draw on classic and contemporary statistical, mathematical and computational physics.
Radiation forces and the Abraham-Minkowski problem
Brevik, Iver
2018-04-01
Recent years have witnessed a number of beautiful experiments in radiation optics. Our purpose with this paper is to highlight some developments of radiation pressure physics in general, and thereafter to focus on the importance of the mentioned experiments in regard to the classic Abraham-Minkowski problem. That means, what is the “correct” expression for electromagnetic momentum density in continuous matter. In our opinion, one often sees that authors over-interpret the importance of their experimental findings with respect to the momentum problem. Most of these experiments are actually unable to discriminate between these energy-momentum tensors at all, since they can be easily described in terms of force expressions that are common for Abraham and Minkowski. Moreover, we emphasize the inherent ambiguity in applying the formal conservation principles to the radiation field in a dielectric, the reason being that the electromagnetic field in matter is only a subsystem which has to be supplemented by the mechanical subsystem to be closed. Finally, we make some suggestions regarding the connection between macroscopic electrodynamics and the Casimir effect, suggesting that there is a limit for the magnitudes of the cutoff parameters in QFT related to surface tension in ordinary hydromechanics.
OGRE, Monte-Carlo System for Gamma Transport Problems
International Nuclear Information System (INIS)
1984-01-01
1 - Nature of physical problem solved: The OGRE programme system was designed to calculate, by Monte Carlo methods, any quantity related to gamma-ray transport. The system is represented by two examples - OGRE-P1 and OGRE-G. The OGRE-P1 programme is a simple prototype which calculates dose rate on one side of a slab due to a plane source on the other side. The OGRE-G programme, a prototype of a programme utilizing a general-geometry routine, calculates dose rate at arbitrary points. A very general source description in OGRE-G may be employed by reading a tape prepared by the user. 2 - Method of solution: Case histories of gamma rays in the prescribed geometry are generated and analyzed to produce averages of any desired quantity which, in the case of the prototypes, are gamma-ray dose rates. The system is designed to achieve generality by ease of modification. No importance sampling is built into the prototypes, a very general geometry subroutine permits the treatment of complicated geometries. This is essentially the same routine used in the O5R neutron transport system. Boundaries may be either planes or quadratic surfaces, arbitrarily oriented and intersecting in arbitrary fashion. Cross section data is prepared by the auxiliary master cross section programme XSECT which may be used to originate, update, or edit the master cross section tape. The master cross section tape is utilized in the OGRE programmes to produce detailed tables of macroscopic cross sections which are used during the Monte Carlo calculations. 3 - Restrictions on the complexity of the problem: Maximum cross-section array information may be estimated by a given formula for a specific problem. The number of regions must be less than or equal to 50
Problem and future of radiation hazard in IVR
International Nuclear Information System (INIS)
Chida, Koichi; Maruoka, Shin; Saito, Haruo; Ishibashi, Tadashi; Takai, Yoshihiro
2008-01-01
This paper describes problems of radiation exposure to patients and operators, their dose assessment and future in the radio-protection at IVR (interventional radiology) like percutaneous coronary intervention. Patients who undergo the IVR operation are usually faced to dying risk and thereby the actually still occurring radiation injury is often justified. However, effort must be taken based on measurement and dose assessment of the radiation to reduce the exposure dose in patients, which, authors comment, leads to the decrease of dose also to the operators derived mainly from scattering. Presently in IVR, however, there are scarce methods to directly measure and assess the maximal exposure dose of patient's skin in a real time, and therefore which are tasks remained in future. Practically used is the evaluation of the overall dose by parameters like exposing hours and area dose values (International Commission of Radiological Protection (ICRP), 2001 and Food and Drug Administration (FDA), 1995), and/or by IVR-reference point method (International Electrotechnical Commission, 2000). The latter is on the defined point 15-cm distant from the isocenter toward X-ray tube focus and the concept is already incorporated in Japan Industrial Standard. Those evaluations are conceivably helpful for future assessment of IVR radiation effects involving carcinogenesis. (R.T.)
Some Current Problems in Optimisation of Radiation Protection System
International Nuclear Information System (INIS)
Franic, Z.; Prlic, I.
2001-01-01
Full text: The current system of radiation protection is generally based on recommendations promulgated in the International Commission on Radiological Protection (ICRP) publication 60. These principles and recommendations were subsequently adopted by the International Atomic Energy Agency (IAEA) in International Basic Safety Standards for Protection against Ionising Radiation and for the Safety of Radiation Sources (BSS). However, in recent years certain problems have arisen such as application of risk factors at low doses, use and interpretation of a collective dose, concept of dose commitment, optimisation of all types of occupational exposure and practices, implementation of ALARA approach in the common occupational as well as in quite complex situations etc. In this paper are presented some of the issues that have to be addressed in the development of the new ICRP Recommendations that are planned to be developed in next four or five years. As the new radiation protection philosophy shifts from society-based control of stochastic risks to an individual-based policy, consequently it will require introduction of modified approach to optimisation process and probably introduction of some new dosimetric quantities. (author)
Radiation protection problems by the operation of the cyclotron facility
International Nuclear Information System (INIS)
Durcik, M.; Nikodemova, D.
1998-01-01
The Cyclotron Center in Bratislava will consist of two cyclotrons. First - cyclotron DC-72 with maximal energy of 72 MV for protons for making experiments, for teaching process, for radioisotope production as 123 I and for neutron and proton therapy. Second - compact cyclotron with maximal proton energy of 18 MeV will be used for radioisotopes production for medical diagnosis as 1 *F (fluorodeoxyglucose), 81 Rb/ 81 Kr generator. This paper deals with the radiation protection problems by the operation of tis cyclotron facility as radiation protection of workers, monitoring plan, ventilation, safety lock and limitation and radiation monitoring. For proposed and continuing practices at the accelerator facility, the following general principles have to be fulfilled: (1) practices should produce sufficient benefit to offset the radiation detriment they case (justification); (2) the magnitude of the individual doses should be kept as low as achievable (optimization of protection); (3) individual exposures are subject to dose limits and some control of risk from potential exposures (dose and risk limits)
Hybrid formulation of radiation transport in optically thick divertor plasmas
Energy Technology Data Exchange (ETDEWEB)
Rosato, J.; Marandet, Y.; Bufferand, H.; Stamm, R. [PIIM, UMR 7345 Aix-Marseille Universite / CNRS, Centre de St-Jerome, Marseille (France); Reiter, D. [IEK-4 Plasmaphysik, Forschungszentrum Juelich GmbH, Juelich (Germany)
2016-08-15
Kinetic Monte Carlo simulations of coupled atom-radiation transport in optically thick divertor plasmas can be computationally very demanding, in particular in ITER relevant conditions or even larger devices, e.g. for power plant divertor studies. At high (∝ 10{sup 15} cm{sup -3}) atomic densities, it can be shown that sufficiently large divertors behave in certain areas like a black body near the first resonance line of hydrogen (Lyman α). This suggests that, at least in part, the use of continuum model (radiation hydrodynamics) can be sufficiently accurate, while being less time consuming. In this work, we report on the development of a hybrid model devoted to switch automatically between a kinetic and a continuum description according to the plasma conditions. Calculations of the photo-excitation rate in a homogeneous slab are performed as an illustration. The outlined hybrid concept might be also applicable to neutral atom transport, due to mathematical analogy of transport equations for neutrals and radiation. (copyright 2016 The Authors. Contributions to Plasma Physics published by Wiley-VCH Verlag GmbH and Co. KGaA Weinheim. This)
Finite element based composite solution for neutron transport problems
International Nuclear Information System (INIS)
Mirza, A.N.; Mirza, N.M.
1995-01-01
A finite element treatment for solving neutron transport problems is presented. The employs region-wise discontinuous finite elements for the spatial representation of the neutron angular flux, while spherical harmonics are used for directional dependence. Composite solutions has been obtained by using different orders of angular approximations in different parts of a system. The method has been successfully implemented for one dimensional slab and two dimensional rectangular geometry problems. An overall reduction in the number of nodal coefficients (more than 60% in some cases as compared to conventional schemes) has been achieved without loss of accuracy with better utilization of computational resources. The method also provides an efficient way of handling physically difficult situations such as treatment of voids in duct problems and sharply changing angular flux. It is observed that a great wealth of information about the spatial and directional dependence of the angular flux is obtained much more quickly as compared to Monte Carlo method, where most of the information in restricted to the locality of immediate interest. (author)
Radiation doses arising from the air transport of radioactive materials
International Nuclear Information System (INIS)
Gelder, R.; Shaw, K.B.; Wilson, C.K.
1989-01-01
There is a compelling need for the transport of radioactive material by air because of the requirement by hospitals throughout the world for urgent delivery for medical purposes. Many countries have no radionuclide-producing capabilities and depend on imports: a range of such products is supplied from the United Kingdom. Many of these are short lived, which explains the need for urgent delivery. The only satisfactory method of delivery on a particular day to a particular destination is often by the use of scheduled passenger air service. The International Civil Aviation Organization's Technical Instructions for the Safe Transport of Dangerous Goods by Air (ICAO 1987-1988), prescribe the detailed requirements applicable to the international transport of dangerous goods by air. Radioactive materials are required to be separated from persons and from undeveloped photographic films or plates: minimum distances as a function of the total sum of transport indexes are given in the Instructions. A study, which included the measurement and assessment of the radiation doses resulting from the transport of radioactive materials by air from the UK, has been performed by the National Radiological Protection Board (NRPB) on behalf of the Civil Aviation Authority (CAA) and the Department of Transport (DTp)
Directory of Open Access Journals (Sweden)
Liyang Xiao
2018-03-01
Full Text Available Many government agencies and business organizations have realized that it is necessary to consider not only the economic cost but also the road transport emissions when they determine the transport policies and operations. In this study, a patient transportation problem with the aim of reducing transport emissions has been formulated by implementing CVRP model. In order to determine the routes of patient transportation with optimized emissions for targeted hospital, an improved Cuckoo Search (ICS algorithm is proposed. In this study, a ‘split’ procedure has been implemented to simplify the individual’s representation. A new category of cuckoos has been introduced to improve the ICS’s search ability. Two heuristics have been applied to improve the quality of initial population. A local search mechanism has been embedded in the search procedure to improve the quality of solutions obtained at the end of each iteration. The computational results were encouraging and demonstrated the effectiveness of the proposed solution method.
Atmospheric transport, clouds and the Arctic longwave radiation paradox
Sedlar, Joseph
2016-04-01
Clouds interact with radiation, causing variations in the amount of electromagnetic energy reaching the Earth's surface, or escaping the climate system to space. While globally clouds lead to an overall cooling radiative effect at the surface, over the Arctic, where annual cloud fractions are high, the surface cloud radiative effect generally results in a warming. The additional energy input from absorption and re-emission of longwave radiation by the clouds to the surface can have a profound effect on the sea ice state. Anomalous atmospheric transport of heat and moisture into the Arctic, promoting cloud formation and enhancing surface longwave radiation anomalies, has been identified as an important mechanism in preconditioning Arctic sea ice for melt. Longwave radiation is emitted equally in all directions, and changes in the atmospheric infrared emission temperature and emissivity associated with advection of heat and moisture over the Arctic should correspondingly lead to an anomalous signal in longwave radiation at the top of the atmosphere (TOA). To examine the role of atmospheric heat and moisture transport into the Arctic on TOA longwave radiation, infrared satellite sounder observations from AIRS during 2003-2014 are analyzed for summer (JJAS). Thermodynamic metrics are developed to identify months characterized by a high frequency of warm and moist advection into the Arctic, and segregate the 2003-14 time period into climatological and anomalously warm, moist summer months. We find that anomalously warm, moist months result in a significant TOA longwave radiative cooling, which is opposite the forcing signal that the surface experiences during these months. At the timescale of the advective events, 3-10 days, the TOA cooling can be as large as the net surface energy budget during summer. When averaged on the monthly time scale, and over the full Arctic basin (poleward of 75°N), summer months experiencing frequent warm, moist advection events are
The use of Monte Carlo radiation transport codes in radiation physics and dosimetry
CERN. Geneva; Ferrari, Alfredo; Silari, Marco
2006-01-01
Transport and interaction of electromagnetic radiation Interaction models and simulation schemes implemented in modern Monte Carlo codes for the simulation of coupled electron-photon transport will be briefly reviewed. In these codes, photon transport is simulated by using the detailed scheme, i.e., interaction by interaction. Detailed simulation is easy to implement, and the reliability of the results is only limited by the accuracy of the adopted cross sections. Simulations of electron and positron transport are more difficult, because these particles undergo a large number of interactions in the course of their slowing down. Different schemes for simulating electron transport will be discussed. Condensed algorithms, which rely on multiple-scattering theories, are comparatively fast, but less accurate than mixed algorithms, in which hard interactions (with energy loss or angular deflection larger than certain cut-off values) are simulated individually. The reliability, and limitations, of electron-interacti...
Radiation protection and dosimetry problems around medium energy accelerators
Energy Technology Data Exchange (ETDEWEB)
Pavlovic, R; Pavlovic, S; Markovic, S [Inst. of Nuclear Sciences Vinca, Belgrade (Yugoslavia); Boreli, F [Fac. of Electrical Engineering, Belgrade (Yugoslavia)
1996-12-31
In the Institute of Nuclear Sciences `VINCA`, the Accelerator Installation `TESLA`, which is an ion accelerator facility consisting of an isochronous cyclotron `VINCY`, a heavy ion source, a D{sup -} / H{sup -} ion source, three low energy and five high energy experimental channels is now under construction. The Tesla Accelerator Installation should by the principal facility for basic and applied research in physics, chemistry, biology, and material science, as well as for production of radioisotopes, medical diagnostics and therapy with radioisotopes and accelerated particle beams. Some problems in defining radiation protection and safety programme, particularly problems in construction appropriate shielding barriers at the Accelerator Installation `TESLA` are discussed in this paper. (author) 1 fig., 9 refs.
The problems of civil defense at the radiation accidents
International Nuclear Information System (INIS)
Ojagov, H.O.
2003-01-01
Full text: A decrease of risk to a possible low level (optimization) is carried out due to the following two circumstances. A lime it of risk of a potential irradiation from all possible sources of radiation is regulated and for each source the boundary of risk is established; under a decrease of potential radiation risk there is the minimum level of risk, below which a risk is considered as negligible and further decrease of risk is inexpedient. The persons attracted for realization of emergency and saving work, are considered on the same footing as the personnel working with ethnogeny sources of ionizing radiation or those who work in conditions under the influence of latter. Main problems and measures of radioprotection are outlined in the appropriate normative documents of the Republic. At different stages of an accident the interference is regulated by zoning of the polluted territories which is based on the value of annual ED which can be received by the inhabitants in absence of measures of irradiation protection. On the territories where an annual ED does not exceed 1 mSv the usual control of radioactive pollution of objects of an environment and agricultural production is made and by its results an irradiation dose of the population on this territory is not restricted by the radiation factor. This territory is not considered as a zone of a radioactive pollution. Applying the security system in all cases the limits are applied to a sum of all appropriate doses from external radiation for an established period of time and half - century doses from receipts for the same time. Based on the stated above principles which are used as guidance at acceptance of the decisions about character of an interference (protective measures) at planning protective measures on a case of radiation accidence the derivative levels of interference: doses and power of radiation doses levels of radioactive pollution and other characteristics RP with reference to concrete radio
International Nuclear Information System (INIS)
Pandya, Tara M.; Johnson, Seth R.; Evans, Thomas M.; Davidson, Gregory G.; Hamilton, Steven P.; Godfrey, Andrew T.
2015-01-01
This paper discusses the implementation, capabilities, and validation of Shift, a massively parallel Monte Carlo radiation transport package developed and maintained at Oak Ridge National Laboratory. It has been developed to scale well from laptop to small computing clusters to advanced supercomputers. Special features of Shift include hybrid capabilities for variance reduction such as CADIS and FW-CADIS, and advanced parallel decomposition and tally methods optimized for scalability on supercomputing architectures. Shift has been validated and verified against various reactor physics benchmarks and compares well to other state-of-the-art Monte Carlo radiation transport codes such as MCNP5, CE KENO-VI, and OpenMC. Some specific benchmarks used for verification and validation include the CASL VERA criticality test suite and several Westinghouse AP1000 ® problems. These benchmark and scaling studies show promising results
International Nuclear Information System (INIS)
Vaz, Solange dos Reis e; Andrade, Fernando de Menezes; Aleixo, Luiz Claudio Martins
2007-01-01
The heavy transportation in Brazil is generally done by highways. The radioactive material transportation follow this same rule. Whenever a radioactive material is carried by the road, by the sea or by the air, in some cases, a kind of combination of those transportation ways, the transport manager has to create a Transportation Plan and submit it to CNEN. Only after CNEN's approval, the transportation can be done. The plan must have the main action on Radiation Protection, giving responsibilities and showing all the directing that will be take. Although, the Brazilian's highways are not in good conditions, one could say that some of them are not good enough for any kind of transportation. But we are facing radioactive material use increase but the hospitals and industries, that the reason it's much more common that kind of transportation nowadays. So, because of that, a special attention by the governments must be provide to those activities. This paper goal is to show the real conditions of some important highways in Brazil in a radioactive protection's perspective and give some suggestions to adjust some of those roads to this new reality. (author)
Bayesian Mars for uncertainty quantification in stochastic transport problems
International Nuclear Information System (INIS)
Stripling, Hayes F.; McClarren, Ryan G.
2011-01-01
We present a method for estimating solutions to partial differential equations with uncertain parameters using a modification of the Bayesian Multivariate Adaptive Regression Splines (BMARS) emulator. The BMARS algorithm uses Markov chain Monte Carlo (MCMC) to construct a basis function composed of polynomial spline functions, for which derivatives and integrals are straightforward to compute. We use these calculations and a modification of the curve-fitting BMARS algorithm to search for a basis function (response surface) which, in combination with its derivatives/integrals, satisfies a governing differential equation and specified boundary condition. We further show that this fit can be improved by enforcing a conservation or other physics-based constraint. Our results indicate that estimates to solutions of simple first order partial differential equations (without uncertainty) can be efficiently computed with very little regression error. We then extend the method to estimate uncertainties in the solution to a pure absorber transport problem in a medium with uncertain cross-section. We describe and compare two strategies for propagating the uncertain cross-section through the BMARS algorithm; the results from each method are in close comparison with analytic results. We discuss the scalability of the algorithm to parallel architectures and the applicability of the two strategies to larger problems with more degrees of uncertainty. (author)
Adaptive sampling method in deep-penetration particle transport problem
International Nuclear Information System (INIS)
Wang Ruihong; Ji Zhicheng; Pei Lucheng
2012-01-01
Deep-penetration problem has been one of the difficult problems in shielding calculation with Monte Carlo method for several decades. In this paper, a kind of particle transport random walking system under the emission point as a sampling station is built. Then, an adaptive sampling scheme is derived for better solution with the achieved information. The main advantage of the adaptive scheme is to choose the most suitable sampling number from the emission point station to obtain the minimum value of the total cost in the process of the random walk. Further, the related importance sampling method is introduced. Its main principle is to define the importance function due to the particle state and to ensure the sampling number of the emission particle is proportional to the importance function. The numerical results show that the adaptive scheme under the emission point as a station could overcome the difficulty of underestimation of the result in some degree, and the adaptive importance sampling method gets satisfied results as well. (authors)
Homogenization of a Conductive-Radiative Heat Transfer Problem
Directory of Open Access Journals (Sweden)
Habibi Zakaria
2012-04-01
Full Text Available This paper focuses on the contribution of the second order corrector in periodic homogenization applied to a conductive-radiative heat transfer problem. Especially, for a heat conduction problem in a periodically perforated domain with a non-local boundary condition modelling the radiative heat transfer, if this model contains an oscillating thermal source and a thermal exchange with the perforations, the second order corrector helps us to model the gradients which appear between the source area and the perforations. Ce papier est consacré à montrer l’influence du correcteur de second ordre en homogénéisation périodique. Dans l’homogénéisation d’un problème de conduction rayonnement dans un domaine périodiquement perforé par plusieurs trous, on peut voir une contribution non négligeable de ce correcteur lors de la présence d’une source thermique oscillante et d’un échange thermique dans les perforations. Ce correcteur nous permet de modéliser les gradients qui apparaissent entre la zone de la source thermique et les perforations.
Non-ionizing radiation and health protection problems
International Nuclear Information System (INIS)
Jammet, Henri.
1979-01-01
Wavelength and frequency are two closely related properties which determine the characteristics of any particular type of electromagnetic radiation and which can be used interchangeably to describe it. For protection purposes the determination of the energy absorbed (absorbed dose) and of its distribution within living systems, whatever the radiation concerned, is still one of the chief problems to be solved. Therefore, although thermal effects are often prevailing, no appropriate dose-effect relationships could be established in most cases and more particularly as far as non-thermal effects are concerned. The problems associated with the different types of NIR are briefly reviewed. An increasing number of countries is promulgating regulatory measures for limiting exposure to NIR of occupationally exposed individuals and of the general population. Harmonization of basic concepts and internationally acceptable protection standards are therefore urgently needed. IRPA is probably the only international, non-governmental scientific organization able to promote wide international and interdisciplinary cooperation in the field of health protection against NIR. Therefore, after having carefully considered the situation, IRPA felt that it was its responsibility to produce guidance on basic protection criteria and standards and created the International NIR-Committee with the objective of developing background documents and internationally accepted recommendations
Aksenov, A. F.; Burnazyan, A. I.
1985-01-01
The purpose and application of the provisional standards for radiation safety of crew and passengers in civil aviation are given. The radiation effect of cosmic radiation in flight on civil aviation air transport is described. Standard levels of radiation and conditions of radiation safety are discussed.
International Nuclear Information System (INIS)
Schneider, K.J.; Smith, R.I.; Daling, P.M.; Ross, W.A.; McNair, G.W.
1988-01-01
The federal system for the management of spent fuel and high-level radioactive waste includes the acceptance by the US Department of Energy (DOE) of the spent fuel or waste loaded in casks at the reactor or other waste generators, its transportation to a repository, and its handling and final emplacement in the repository. The DOE plans to implement a transportation system that is safe, secure, efficient, and cost-effective and will meet applicable regulatory safety and security requirements. The DOE commissioned the Pacific Northwest Laboratory (PNL) to develop estimates of the routine radiation doses that would result from the operation of a system postulated using current designs and practices. From that evaluation, PNL identified activities/operations that result in the higher fraction of doses, proposed conceptual alternatives that would effectively reduce such exposures, and evaluated the cost-effectiveness of such alternatives. The study is one of a series used in making overall system design and operational decisions in the development of the DOE's spent-fuel/high-level waste transportation system. This paper contains the highlights from the PNL study of the estimated radiation doses to the transportation workers in a postulated reference transportation system and potential alternatives to that system
International Nuclear Information System (INIS)
Rexer, G.
1978-12-01
Computer-aided design of nuclear shielding and irradiation facilities is characterized by studies of different design variants in order to determine which facilities are safe and still economicol. The design engineer has a very complex task including the formulation of calculation models, data linking of programs and data, and the management of large data stores. Integrated modular program systems with centralized module and data management make it possible to treat these problems in a more simplified and automatic manner. The paper describes a system of this type for the field of radiation transport and radiation shielding. The basis is the modular system RSYST II which has a dynamic hierarchical scheme for the structuring of problem data in a central data base. (orig./RW) [de
A FORMALISM FOR COVARIANT POLARIZED RADIATIVE TRANSPORT BY RAY TRACING
International Nuclear Information System (INIS)
Gammie, Charles F.; Leung, Po Kin
2012-01-01
We write down a covariant formalism for polarized radiative transfer appropriate for ray tracing through a turbulent plasma. The polarized radiation field is represented by the polarization tensor (coherency matrix) N αβ ≡ (a α k a* β k ), where a k is a Fourier coefficient for the vector potential. Using Maxwell's equations, the Liouville-Vlasov equation, and the WKB approximation, we show that the transport equation in vacuo is k μ ∇ μ N αβ = 0. We show that this is equivalent to Broderick and Blandford's formalism based on invariant Stokes parameters and a rotation coefficient, and suggest a modification that may reduce truncation error in some situations. Finally, we write down several alternative approaches to integrating the transfer equation.
Radiation transport in high-level waste form
International Nuclear Information System (INIS)
Arakali, V.S.; Barnes, S.M.
1992-01-01
The waste form selected for vitrifying high-level nuclear waste stored in underground tanks at West Valley, NY is borosilicate glass. The maximum radiation level at the surface of a canister filled with the high-level waste form is prescribed by repository design criteria for handling and disposition of the vitrified waste. This paper presents an evaluation of the radiation transport characteristics for the vitreous waste form expected to be produced at West Valley and the resulting neutron and gamma dose rates. The maximum gamma and neutron dose rates are estimated to be less than 7500 R/h and 10 mRem/h respectively at the surface of a West Valley canister filled with borosilicate waste glass
Interface methods for hybrid Monte Carlo-diffusion radiation-transport simulations
International Nuclear Information System (INIS)
Densmore, Jeffery D.
2006-01-01
Discrete diffusion Monte Carlo (DDMC) is a technique for increasing the efficiency of Monte Carlo simulations in diffusive media. An important aspect of DDMC is the treatment of interfaces between diffusive regions, where DDMC is used, and transport regions, where standard Monte Carlo is employed. Three previously developed methods exist for treating transport-diffusion interfaces: the Marshak interface method, based on the Marshak boundary condition, the asymptotic interface method, based on the asymptotic diffusion-limit boundary condition, and the Nth-collided source technique, a scheme that allows Monte Carlo particles to undergo several collisions in a diffusive region before DDMC is used. Numerical calculations have shown that each of these interface methods gives reasonable results as part of larger radiation-transport simulations. In this paper, we use both analytic and numerical examples to compare the ability of these three interface techniques to treat simpler, transport-diffusion interface problems outside of a more complex radiation-transport calculation. We find that the asymptotic interface method is accurate regardless of the angular distribution of Monte Carlo particles incident on the interface surface. In contrast, the Marshak boundary condition only produces correct solutions if the incident particles are isotropic. We also show that the Nth-collided source technique has the capacity to yield accurate results if spatial cells are optically small and Monte Carlo particles are allowed to undergo many collisions within a diffusive region before DDMC is employed. These requirements make the Nth-collided source technique impractical for realistic radiation-transport calculations
Problems is applying new internal dose coefficients to radiation control
Energy Technology Data Exchange (ETDEWEB)
Sato, Yuichi [Oarai Laboratory, Chiyoda Technol Corporation, Ibaraki (Japan)
1998-06-01
The author discussed problems concerning the conceivable influence in the radiation control and those newly developing when the new internal dose coefficients are applied in the law in the future. For the conceivable influence, the occupational and public exposure was discussed: In the former, the effective dose equivalent limit (at present, 50 mSv/y) was thought to be reduced and in the latter, the limit to be obscure although it might be more greatly influenced by the new coefficients. For newly developing problems, since the new biological model which is more realistic was introduced for calculation of the internal dose and made the calculation more complicated, use of computer is requisite. The effective dose of the internal exposure in the individual monitoring should be conveniently calculated as done at present even after application of the new coefficients. For calculation of the effective dose of the internal exposure, there are such problems as correction of the inhaled particle size and of the individual personal parameter. A model calculation of residual rate in the chest where the respiratory tract alone participated was presented as an example but for the whole body, more complicated functions were pointed out necessary. The concept was concluded to be incorporated in the law in a convenient and easy manner and a software for calculation of internal dose using the new coefficients was wanted. (K.H.)
Modified Approach for Optimization of Real Life Transportation Problem in Neutrosophic Environment
Directory of Open Access Journals (Sweden)
Akanksha Singh
2017-01-01
Full Text Available To the best of our knowledge, there is only one approach for solving neutrosophic cost minimization transportation problems. Since neutrosophic transportation problems are a new area of research, other researchers may be attracted to extend this approach for solving other types of neutrosophic transportation problems like neutrosophic solid transportation problems, neutrosophic time minimization transportation problems, neutrosophic transshipment problems, and so on. However, after a deep study of the existing approach, it is noticed that a mathematical incorrect assumption has been used in these existing approaches; therefore there is a need to modify these existing approaches. Keeping the same in mind, in this paper, the existing approach is modified. Furthermore, the exact results of some existing transportation problems are obtained by the modified approach.
International Nuclear Information System (INIS)
Martin, William R.; Brown, Forrest B.
2001-01-01
We present an alternative Monte Carlo method for solving the coupled equations of radiation transport and material energy. This method is based on incorporating the analytical solution to the material energy equation directly into the Monte Carlo simulation for the radiation intensity. This method, which we call the Analytical Monte Carlo (AMC) method, differs from the well known Implicit Monte Carlo (IMC) method of Fleck and Cummings because there is no discretization of the material energy equation since it is solved as a by-product of the Monte Carlo simulation of the transport equation. Our method also differs from the method recently proposed by Ahrens and Larsen since they use Monte Carlo to solve both equations, while we are solving only the radiation transport equation with Monte Carlo, albeit with effective sources and cross sections to represent the emission sources. Our method bears some similarity to a method developed and implemented by Carter and Forest nearly three decades ago, but there are substantive differences. We have implemented our method in a simple zero-dimensional Monte Carlo code to test the feasibility of the method, and the preliminary results are very promising, justifying further extension to more realistic geometries. (authors)
International Nuclear Information System (INIS)
1986-05-01
The document provides guidance on one of the components of the system of dose limitation as it applies to the transport of radioactive material, namely the optimization of radiation protection. It focuses on the following parts of the transport system: design, maintenance, preparation for transport, transport, storage-in-transit and handling and it considers occupational and public exposures. The application is intended mainly for those transport situations within the regulatory requirements where potential radiation exposures could be beneficially reduced
Radiation protection programmes for the transport of radioactive material. Safety guide
International Nuclear Information System (INIS)
2007-01-01
This Safety Guide provides guidance on meeting the requirements for the establishment of radiation protection programmes (RPPs) for the transport of radioactive material, to optimize radiation protection in order to meet the requirements for radiation protection that underlie the Regulations for the Safe Transport of Radioactive Material. This Guide covers general aspects of meeting the requirements for radiation protection, but does not cover criticality safety or other possible hazardous properties of radioactive material. The annexes of this Guide include examples of RPPs, relevant excerpts from the Transport Regulations, examples of total dose per transport index handled, a checklist for road transport, specific segregation distances and emergency instructions for vehicle operators
On Tamm's problem in the Vavilov-Cherenkov radiation theory
International Nuclear Information System (INIS)
Afanas'ev, G.N.; Kartavenko, V.G.; Stepanovskij, Yu.P.
1999-01-01
We analyze the well-known Tamm's problem treating the charge motion on a finite space interval with the velocity exceeding light velocity in medium. By comparing Tamm's approximate formulae with the exact ones we prove that the former do not properly describe Cherenkov radiation terms. We also investigate Tamm's formula cos θ T = 1/βn defining the position of the maximum of the field strengths in the Fourier representation. Numerical analysis of the Fourier components of field strengths shows that they have a well pronounced maximum at θ = θ T only for the charge motion on the sufficiently small interval. As an interval grows, many maxima appear. For the charge motion on an infinite interval there is infinite number of maxima of the same amplitude. The quantum analysis of Tamm's formula leads to the same results
One-dimensional central-force problem, including radiation reaction
International Nuclear Information System (INIS)
Kasher, J.C.
1976-01-01
Two equal masses of equal charge magnitude (either attractive or repulsive) are held a certain distance apart for their entire past history. AT t = 0 one of them is either started from rest or given an initial velocity toward or away from the other charge. When the Dirac radiation-reaction force is included in the force equation, our Taylor-series numerical calculations lead to two types of nonphysical results for both the attractive and repulsive cases. In the attractive case, the moving charge either stops and moves back out to infinity, or violates energy conservation as it nears collision with the fixed charge. For the repulsive charges, the moving particle either eventually approaches and collides with the fixed one, or violates energy conservation as it goes out to infinity. These results lead us to conclude that the Lorentz-Dirac equation is not valid for the one-dimensional central-force problem
Problems relating to international transport of nuclear fuels
International Nuclear Information System (INIS)
Timm, U.E.
1985-01-01
Owing to the tremendous geographic distances between uranium deposits of interest, to the various degrees of sophistication of nuclear industry in industrialized countries and to the close international cooperation in the field of nuclear energy, safe international transports, physical protection and transport handling play an important role. It is suggested to better coordinate the activities of nuclear power plant operators, the nuclear industry and specialized transport companies with respect to all national and international issues of nuclear fuel transports. (DG) [de
3D-TRANS-2003, Workshop on Common Tools and Interfaces for Radiation Transport Codes
International Nuclear Information System (INIS)
2004-01-01
Description: Contents proceedings of Workshop on Common Tools and Interfaces for Deterministic Radiation Transport, for Monte Carlo and Hybrid Codes with a proposal to develop the following: GERALD - A General Environment for Radiation Analysis and Design. GERALD intends to create a unifying software environment where the user can define, solve and analyse a nuclear radiation transport problem using available numerical tools seamlessly. This environment will serve many purposes: teaching, research, industrial needs. It will also help to preserve the existing analytical and numerical knowledge base. This could represent a significant step towards solving the legacy problem. This activity should contribute to attracting young engineers to nuclear science and engineering and contribute to competence and knowledge preservation and management. This proposal was made at the on Workshop on C ommon Tools and Interfaces for Deterministic Radiation Transport, for Monte Carlo and Hybrid Codes , held from 25-26 September 2003 in connection with the conference SNA-2003. A first success with the development of such tools was achieved with the BOT3P2.0 and 3.0 codes providing an easy procedure and mechanism for defining and displaying 3D geometries and materials both in the form of refineable meshes for deterministic codes or Monte Carlo geometries consistent with deterministic models. Advanced SUSD: Improved tools for Sensitivity/Uncertainty Analysis. The development of tools for the analysis and estimation of sensitivities and uncertainties in calculations, or their propagation through complex computational schemes, in the field of neutronics, thermal hydraulics and also thermo-mechanics is of increasing importance for research and engineering applications. These tools allow establishing better margins for engineering designs and for the safe operation of nuclear facilities. Such tools are not sufficiently developed, but their need is increasingly evident in many activities
Study of Radiation Shielding Analysis for Low-Intermediate Level Waste Transport Ship
Energy Technology Data Exchange (ETDEWEB)
Kim, Dohyung; Lee, Unjang; Song, Yangsoo; Kim, Sukhoon; Ko, Jaehoon [Korea Nuclear Engineering and Service Corporation, Seoul (Korea, Republic of)
2007-07-01
In Korea, it is planed to transport Low-Intermediate Level Radioactive Waste (LILW) from each nuclear power plant site to Kyongju LILW repository after 2009. Transport through the sea using ship is one of the most prospective ways of LILW transport for current situation in Korea. There are domestic and international regulations for radiation dose limit for radioactive material transport. In this article, radiation shielding analysis for LILW transport ship is performed using 3-D computer simulation code, MCNP. As a result, the thickness and materials for radiation shielding walls next to cargo in the LILW transport ship are determined.
Global aerosol transport and consequences for the radiation budget
International Nuclear Information System (INIS)
Newiger, M.; Grassl, H.; Schussel, P.; Rehkopf, J.
1984-01-01
Man's activities may influence global climate by changing the atmospheric composition and surface characteristics and by waste heat. Most prominent within this discussion is the increase or decrease of radiatively active trace gases like CO/sub 2/, N/sub 2/O, O/sub 3/, and others. The general opinion is converging towards a greenhouse effect as a combined action of all trace gases, whose exact magnitude is uncertain mainly because of the unknown reaction of water cycle. The aim of our global 2-D (resolving latitude and height) aerosol transport model is the calculation of aerosol particle number density profiles as a function of latitude for present natural plus anthropogenic emissions. The aerosol transport model uses prescribed meridonal circulation, diffusivity factors and cloud climatology for January as well as July. All these latitude and height dependent input parameters were taken from well known sources. The fixed climatology excludes the feedback of aerosol particle parameter changes on mean circulation. However, the radiative parameters of six clouds types are modified, although they possess by adoption of the Telegadas and London (1954) cloud climatology prescribed amount and height. The inclusion of the feedback on mean circulation seems premature at present. Adding particles either accounting for natural emissions or natural anthropogenic emission and removing particles by all known sinks outside and within clouds gives us - for the stationary state - vertical profiles of aerosol number density in three sizes classes as a function of latitude. These profiles in turn are input for radiation flux calculations in clear and cloudy areas in order to assess net flux changes caused by the present aerosol load in comparison to a scenario without anthropogenic emissions. The net flux changes finally are compared to those calculated for increased CO/sub 2/ levels
International Nuclear Information System (INIS)
Verdu, G.; Capilla, M.; Talavera, C. F.; Ginestar, D.
2012-01-01
PL equations are classical high order approximations to the transport equations which are based on the expansion of the angular dependence of the angular neutron flux and the nuclear cross sections in terms of spherical harmonics. A nodal collocation method is used to discretize the PL equations associated with a neutron source transport problem. The performance of the method is tested solving two 1D problems with analytical solution for the transport equation and a classical 2D problem. (authors)
Energy Technology Data Exchange (ETDEWEB)
Verdu, G. [Departamento de Ingenieria Quimica Y Nuclear, Universitat Politecnica de Valencia, Cami de Vera, 14, 46022. Valencia (Spain); Capilla, M.; Talavera, C. F.; Ginestar, D. [Dept. of Nuclear Engineering, Departamento de Matematica Aplicada, Universitat Politecnica de Valencia, Cami de Vera, 14, 46022. Valencia (Spain)
2012-07-01
PL equations are classical high order approximations to the transport equations which are based on the expansion of the angular dependence of the angular neutron flux and the nuclear cross sections in terms of spherical harmonics. A nodal collocation method is used to discretize the PL equations associated with a neutron source transport problem. The performance of the method is tested solving two 1D problems with analytical solution for the transport equation and a classical 2D problem. (authors)
Inorganic and organic radiation chemistry: state and problems
International Nuclear Information System (INIS)
Kalyazin, E.P.; Bugaenko, L.T.
1990-01-01
Radiation inorganic and organic chemistry is presented on the basis of the general scheme and classification of radiolysis products and elementary processes, by which evolution of radiation-affected substances up to the final radiolysis products takes place. The evolution is traced for the representatives of inorganic and organic compounds. The contribution of radiation inorganic and organic chemistry to radiation technology, radiation materials technology, radiation ecology and medicine, is shown. Tendencies in the development of radiation chemistry and prediction of its certain directions are considered
On bi-criteria two-stage transportation problem: a case study
Directory of Open Access Journals (Sweden)
Ahmad MURAD
2010-01-01
Full Text Available The study of the optimum distribution of goods between sources and destinations is one of the important topics in projects economics. This importance comes as a result of minimizing the transportation cost, deterioration, time, etc. The classical transportation problem constitutes one of the major areas of application for linear programming. The aim of this problem is to obtain the optimum distribution of goods from different sources to different destinations which minimizes the total transportation cost. From the practical point of view, the transportation problems may differ from the classical form. It may contain one or more objective function, one or more stage to transport, one or more type of commodity with one or more means of transport. The aim of this paper is to construct an optimization model for transportation problem for one of mill-stones companies. The model is formulated as a bi-criteria two-stage transportation problem with a special structure depending on the capacities of suppliers, warehouses and requirements of the destinations. A solution algorithm is introduced to solve this class of bi-criteria two-stage transportation problem to obtain the set of non-dominated extreme points and the efficient solutions accompanied with each one that enables the decision maker to choose the best one. The solution algorithm mainly based on the fruitful application of the methods for treating transportation problems, theory of duality of linear programming and the methods of solving bi-criteria linear programming problems.
Exposure to cosmic radiation: a developing major problem in radiation protection
International Nuclear Information System (INIS)
Lowder, W.M.; Hajnal, F.
1992-01-01
'Full Text:' Cosmic radiation at ground altitudes is usually a relatively minor contributor to human radiation exposure, producing a global collective dose equivalent that is about 10 percent of the total from all natural sources. However, more than a million people living at high altitudes receive annual dose equivalents in excess of 5 mSv. In recent years, there has been increasing concern about the exposure of aircraft flight crews and passengers, for whom annual dose equivalents of up to several mSv have been estimated. Recent EML results indicate the presence of an important high-energy neutron component at jet aircraft altitudes, perhaps producing dose equivalents of the order of 0.1. mSv/h at high latitudes. Finally, space agencies have been long concerned with the potential exposures of astronauts, especially from the rare massive solar flare events. As more people venture into space, this source of human radiation exposure will become increasingly important. Available date on those aspects of cosmic radiation exposure will be reviewed, along with current and anticipated future research activities that may yield and improve assessment of the problem. The question of how such exposures might be controlled will be addressed, but not answered. (author)
The EGS4 Code System: Solution of gamma-ray and electron transport problems
International Nuclear Information System (INIS)
Nelson, W.R.; Namito, Yoshihito.
1990-01-01
In this paper we present an overview of the EGS4 Code System -- a general purpose package for the Monte Carlo simulation of the transport of electrons and photons. During the last 10-15 years EGS has been widely used to design accelerators and detectors for high-energy physics. More recently the code has been found to be of tremendous use in medical radiation physics and dosimetry. The problem-solving capabilities of EGS4 will be demonstrated by means of a variety of practical examples. To facilitate this review, we will take advantage of a new add-on package, called SHOWGRAF, to display particle trajectories in complicated geometries. These are shown as 2-D laser pictures in the written paper and as photographic slides of a 3-D high-resolution color monitor during the oral presentation. 11 refs., 15 figs
The EGS4 Code System: Solution of Gamma-ray and Electron Transport Problems
Nelson, W. R.; Namito, Yoshihito
1990-03-01
In this paper we present an overview of the EGS4 Code System -- a general purpose package for the Monte Carlo simulation of the transport of electrons and photons. During the last 10-15 years EGS has been widely used to design accelerators and detectors for high-energy physics. More recently the code has been found to be of tremendous use in medical radiation physics and dosimetry. The problem-solving capabilities of EGS4 will be demonstrated by means of a variety of practical examples. To facilitate this review, we will take advantage of a new add-on package, called SHOWGRAF, to display particle trajectories in complicated geometries. These are shown as 2-D laser pictures in the written paper and as photographic slides of a 3-D high-resolution color monitor during the oral presentation. 11 refs., 15 figs.
The new deterministic 3-D radiation transport code Multitrans: C5G7 MOX fuel assembly benchmark
International Nuclear Information System (INIS)
Kotiluoto, P.
2003-01-01
The novel deterministic three-dimensional radiation transport code MultiTrans is based on combination of the advanced tree multigrid technique and the simplified P3 (SP3) radiation transport approximation. In the tree multigrid technique, an automatic mesh refinement is performed on material surfaces. The tree multigrid is generated directly from stereo-lithography (STL) files exported by computer-aided design (CAD) systems, thus allowing an easy interface for construction and upgrading of the geometry. The deterministic MultiTrans code allows fast solution of complicated three-dimensional transport problems in detail, offering a new tool for nuclear applications in reactor physics. In order to determine the feasibility of a new code, computational benchmarks need to be carried out. In this work, MultiTrans code is tested for a seven-group three-dimensional MOX fuel assembly transport benchmark without spatial homogenization (NEA C5G7 MOX). (author)
Energy Technology Data Exchange (ETDEWEB)
Lizot, M.T.; Perrin, M.L.; Sert, G. [CEA Fontenay-aux-Roses, Inst. de Protection et de Surete Nucleaire, Dept. de Protection et de Surete Nucleaire, 92 (France); Lange, F.; Schwarz, G.; Feet, H.J.; Christ, R. [Gesellschaft fur Anlagen-und Reaktorsicherheit, GRS, mbH, Cologne (Germany); Shaw, K.B.; Hughes, J.S.; Gelder, R. [National Radiological Protection Board (NRPB), Oxon, OX (United Kingdom)
2001-07-01
The survey of radiation protection programmes for transport has been jointly performed by three scientific organisations I.P.S.N. (France), G.R.S. ( Germany), and N.R.P.B. (United kingdom) on behalf of the European Commission and the pertaining documentation summarises the findings and conclusions of the work that was undertaken with the principal objectives to provide guidance on the establishment, implementation and application of radiation protection programmes for the transport of radioactive materials by operators and the assessment and evaluation of such programmes by the competent authority and to review currently existing radiation protection programmes for the transport of radioactive materials. (N.C.)
Discussion on some problems in evolution of radiation protection system
International Nuclear Information System (INIS)
Pan Ziqiang
2003-01-01
In radiation protection practice in China, the appropriate simplification and better coordination for the existing radiation protection system are necessary. The human-based protective measures alone could not meet the requirements of the environmental protection in many circumstances. Protecting the environment from ionizing radiation would be implicated in radiation protection. Collective dose is an useful index, its applicable scope should be well defined. Using such an quantity can help increase radiation protection level, but applicable conditions should be defined, such as time and space. Natural radiation is the largest contributor of the radiation exposure to human. Occupational exposure from natural radiation should be controlled, such as to underground miners and air crew. Controlling both man-made and natural radiation exposure to pregnant women and children needs to be enhanced, especially radiological diagnosis and therapy
Use of implicit Monte Carlo radiation transport with hydrodynamics and compton scattering
International Nuclear Information System (INIS)
Fleck, J.A. Jr.
1971-03-01
It is shown that the combination of implicit radiation transport and hydrodynamics, Compton scattering, and any other energy transport can be simply carried out by a ''splitting'' procedure. Contributions to material energy exchange can be reckoned separately for hydrodynamics, radiation transport without scattering, Compton scattering, plus any other possible energy exchange mechanism. The radiation transport phase of the calculation would be implicit, but the hydrodynamics and Compton portions would not, leading to possible time step controls. The time step restrictions which occur on radiation transfer due to large Planck mean absorption cross-sections would not occur
High-Fidelity Kinetics and Radiation Transport for NLTE Hypersonic Flows, Phase I
National Aeronautics and Space Administration — The modeling of NLTE hypersonic flows combines several disciplines: chemistry, kinetics, radiation transport, fluid mechanics, and surface science. No single code or...
Solving wood chip transport problems with computer simulation.
Dennis P. Bradley; Sharon A. Winsauer
1976-01-01
Efficient chip transport operations are difficult to achieve due to frequent and often unpredictable changes in distance to market, chipping rate, time spent at the mill, and equipment costs. This paper describes a computer simulation model that allows a logger to design an efficient transport system in response to these changing factors.
Utilizing Problem Structure in Optimization of Radiation Therapy
International Nuclear Information System (INIS)
Carlsson, Fredrik
2008-04-01
In this thesis, optimization approaches for intensity-modulated radiation therapy are developed and evaluated with focus on numerical efficiency and treatment delivery aspects. The first two papers deal with strategies for solving fluence map optimization problems efficiently while avoiding solutions with jagged fluence profiles. The last two papers concern optimization of step-and-shoot parameters with emphasis on generating treatment plans that can be delivered efficiently and accurately. In the first paper, the problem dimension of a fluence map optimization problem is reduced through a spectral decomposition of the Hessian of the objective function. The weights of the eigenvectors corresponding to the p largest eigenvalues are introduced as optimization variables, and the impact on the solution of varying p is studied. Including only a few eigenvector weights results in faster initial decrease of the objective value, but with an inferior solution, compared to optimization of the bixel weights. An approach combining eigenvector weights and bixel weights produces improved solutions, but at the expense of the pre-computational time for the spectral decomposition. So-called iterative regularization is performed on fluence map optimization problems in the second paper. The idea is to find regular solutions by utilizing an optimization method that is able to find near-optimal solutions with non-jagged fluence profiles in few iterations. The suitability of a quasi-Newton sequential quadratic programming method is demonstrated by comparing the treatment quality of deliverable step-and-shoot plans, generated through leaf sequencing with a fixed number of segments, for different number of bixel-weight iterations. A conclusion is that over-optimization of the fluence map optimization problem prior to leaf sequencing should be avoided. An approach for dynamically generating multileaf collimator segments using a column generation approach combined with optimization of
ETRAN, Electron Transport and Gamma Transport with Secondary Radiation in Slab by Monte-Carlo
International Nuclear Information System (INIS)
1992-01-01
A - Nature of physical problem solved: ETRAN computes the transport of electrons and photons through plane-parallel slab targets that have a finite thickness in one dimension and are unbound in the other two-dimensions. The incident radiation can consist of a beam of either electrons or photons with specified spectral and directional distribution. Options are available by which all orders of the electron-photon cascade can be included in the calculation. Thus electrons are allowed to give rise to secondary knock-on electrons, continuous Bremsstrahlung and characteristic x-rays; and photons are allowed to produce photo-electrons, Compton electrons, and electron- positron pairs. Annihilation quanta, fluorescence radiation, and Auger electrons are also taken into account. If desired, the Monte- Carlo histories of all generations of secondary radiations are followed. The information produced by ETRAN includes the following items: 1) reflection and transmission of electrons or photons, differential in energy and direction; 2) the production of continuous Bremsstrahlung and characteristic x-rays by electrons and the emergence of such radiations from the target (differential in photon energy and direction); 3) the spectrum of the amounts of energy left behind in a thick target by an incident electron beam; 4) the deposition of energy and charge by an electron beam as function of the depth in the target; 5) the flux of electrons, differential in energy, as function of the depth in the target. B - Method of solution: A programme called DATAPAC-4 takes data for a particular material from a library tape and further processes them. The function of DATAPAC-4 is to produce single-scattering and multiple-scattering data in the form of tabular arrays (again stored on magnetic tape) which facilitate the rapid sampling of electron and photon Monte Carlo histories in ETRAN. The photon component of the electron-photon cascade is calculated by conventional random sampling that imitates
X-radiation effect on water transport in ascite cells of Ehrlich carcinoma
International Nuclear Information System (INIS)
Barnov, V.A.; Ajvazishvili, M.A.; Kartvelishvili, I.I.; Tushishvili, D.I.
1988-01-01
Effect of local X radiation with doses 0.05 and 0.15 C/kg on water transport in ascitic cells of Erlich carcinoma is studied in rats. To study water transport through cell membranes, tritium mark was used. It is concluded that radiation effect on water transport in cells of Erlich carcinoma may be related to change in ionic permittivity of the membrane, because small changes in transmembrane ion transport affect immediately the osmotic motion of water. 5 refs
International Nuclear Information System (INIS)
Densmore, Jeffery D.; Thompson, Kelly G.; Urbatsch, Todd J.
2012-01-01
Discrete Diffusion Monte Carlo (DDMC) is a technique for increasing the efficiency of Implicit Monte Carlo radiative-transfer simulations in optically thick media. In DDMC, particles take discrete steps between spatial cells according to a discretized diffusion equation. Each discrete step replaces many smaller Monte Carlo steps, thus improving the efficiency of the simulation. In this paper, we present an extension of DDMC for frequency-dependent radiative transfer. We base our new DDMC method on a frequency-integrated diffusion equation for frequencies below a specified threshold, as optical thickness is typically a decreasing function of frequency. Above this threshold we employ standard Monte Carlo, which results in a hybrid transport-diffusion scheme. With a set of frequency-dependent test problems, we confirm the accuracy and increased efficiency of our new DDMC method.
Acceleration of a Monte Carlo radiation transport code
International Nuclear Information System (INIS)
Hochstedler, R.D.; Smith, L.M.
1996-01-01
Execution time for the Integrated TIGER Series (ITS) Monte Carlo radiation transport code has been reduced by careful re-coding of computationally intensive subroutines. Three test cases for the TIGER (1-D slab geometry), CYLTRAN (2-D cylindrical geometry), and ACCEPT (3-D arbitrary geometry) codes were identified and used to benchmark and profile program execution. Based upon these results, sixteen top time-consuming subroutines were examined and nine of them modified to accelerate computations with equivalent numerical output to the original. The results obtained via this study indicate that speedup factors of 1.90 for the TIGER code, 1.67 for the CYLTRAN code, and 1.11 for the ACCEPT code are achievable. copyright 1996 American Institute of Physics
Charge transport properties of CdMnTe radiation detectors
Energy Technology Data Exchange (ETDEWEB)
Kim K.; Rafiel, R.; Boardman, M.; Reinhard, I.; Sarbutt, A.; Watt, G.; Watt, C.; Uxa, S.; Prokopovich, D.A.; Belas, E.; Bolotnikov, A.E.; James, R.B.
2012-04-11
Growth, fabrication and characterization of indium-doped cadmium manganese telluride (CdMnTe)radiation detectors have been described. Alpha-particle spectroscopy measurements and time resolved current transient measurements have yielded an average charge collection efficiency approaching 100 %. Spatially resolved charge collection efficiency maps have been produced for a range of detector bias voltages. Inhomogeneities in the charge transport of the CdMnTe crystals have been associated with chains of tellurium inclusions within the detector bulk. Further, it has been shown that the role of tellurium inclusions in degrading chargecollection is reduced with increasing values of bias voltage. The electron transit time was determined from time of flight measurements. From the dependence of drift velocity on applied electric field the electron mobility was found to be n = (718 55) cm2/Vs at room temperature.
Charge transport properties of CdMnTe radiation detectors
Directory of Open Access Journals (Sweden)
Prokopovich D. A.
2012-10-01
Full Text Available Growth, fabrication and characterization of indium-doped cadmium manganese telluride (CdMnTe radiation detectors have been described. Alpha-particle spectroscopy measurements and time resolved current transient measurements have yielded an average charge collection efficiency approaching 100 %. Spatially resolved charge collection efficiency maps have been produced for a range of detector bias voltages. Inhomogeneities in the charge transport of the CdMnTe crystals have been associated with chains of tellurium inclusions within the detector bulk. Further, it has been shown that the role of tellurium inclusions in degrading charge collection is reduced with increasing values of bias voltage. The electron drift velocity was calculated from the rise time distribution of the preamplifier output pulses at each measured bias. From the dependence of drift velocity on applied electric field the electron mobility was found to be μn = (718 ± 55 cm2/Vs at room temperature.
Stationary neutrino radiation transport by maximum entropy closure
International Nuclear Information System (INIS)
Bludman, S.A.
1994-11-01
The authors obtain the angular distributions that maximize the entropy functional for Maxwell-Boltzmann (classical), Bose-Einstein, and Fermi-Dirac radiation. In the low and high occupancy limits, the maximum entropy closure is bounded by previously known variable Eddington factors that depend only on the flux. For intermediate occupancy, the maximum entropy closure depends on both the occupation density and the flux. The Fermi-Dirac maximum entropy variable Eddington factor shows a scale invariance, which leads to a simple, exact analytic closure for fermions. This two-dimensional variable Eddington factor gives results that agree well with exact (Monte Carlo) neutrino transport calculations out of a collapse residue during early phases of hydrostatic neutron star formation
Problems and the present status of radiation educational curriculum
International Nuclear Information System (INIS)
Hiroi, Tadashi; Muraishi, Yukimasa; Mikado, Shogo; Watanabe, Tomohiro
1999-01-01
To examine teaching curriculum for radiation education requires a collective and extensive consideration on various subjects from many fields. The present study has been made from 4 points of view, namely 'physics', physics experiment', 'chemistry', and 'general science'. In 'physics', a curriculum in which learning about radiation followed by learning Newtonian mechanics was examined. Some group experiments taking radiation as the subject, a curriculum including radiation and radioactivity in high school chemistry course and general science are proposed and discussed briefly. (S. Ohno)
Political problems in the system of radiation protection laws of Japan
International Nuclear Information System (INIS)
Nakagawa, Haruo
2008-01-01
The lack of hierarchy and multiple restrictions by the radiation protection laws in Japan, causes multiple dose records of individual and scattering dose records. To solve the problem, the National Radiation Dose Registration Systems was proposed already by Atomic Energy Commission about 40 years ago. But only one radiation dose registration system is partly effective, which was applied for workers in nuclear plants. This paper reports political problems in the system of radiation protection laws of Japan, and proposes the new national radiation dose registration systems which will be able to have a function of supplementation of quality assurance of radiation protection laws. (author)
HZETRN radiation transport validation using balloon-based experimental data
Warner, James E.; Norman, Ryan B.; Blattnig, Steve R.
2018-05-01
The deterministic radiation transport code HZETRN (High charge (Z) and Energy TRaNsport) was developed by NASA to study the effects of cosmic radiation on astronauts and instrumentation shielded by various materials. This work presents an analysis of computed differential flux from HZETRN compared with measurement data from three balloon-based experiments over a range of atmospheric depths, particle types, and energies. Model uncertainties were quantified using an interval-based validation metric that takes into account measurement uncertainty both in the flux and the energy at which it was measured. Average uncertainty metrics were computed for the entire dataset as well as subsets of the measurements (by experiment, particle type, energy, etc.) to reveal any specific trends of systematic over- or under-prediction by HZETRN. The distribution of individual model uncertainties was also investigated to study the range and dispersion of errors beyond just single scalar and interval metrics. The differential fluxes from HZETRN were generally well-correlated with balloon-based measurements; the median relative model difference across the entire dataset was determined to be 30%. The distribution of model uncertainties, however, revealed that the range of errors was relatively broad, with approximately 30% of the uncertainties exceeding ± 40%. The distribution also indicated that HZETRN systematically under-predicts the measurement dataset as a whole, with approximately 80% of the relative uncertainties having negative values. Instances of systematic bias for subsets of the data were also observed, including a significant underestimation of alpha particles and protons for energies below 2.5 GeV/u. Muons were found to be systematically over-predicted at atmospheric depths deeper than 50 g/cm2 but under-predicted for shallower depths. Furthermore, a systematic under-prediction of alpha particles and protons was observed below the geomagnetic cutoff, suggesting that
Status and problem of radiation education in Thailand
International Nuclear Information System (INIS)
Aramrattana, Manoon
1999-01-01
Knowledge of radiation and its application and protection have been routinely taught, discussed and transferred to end users and the public. Limited resource and a strategic plan are identified to be the major obstacle to fully implementation of radiation education in Thailand. Current strategic planning on radiation education in Thailand will be discussed. (author)
Status and problem of radiation education in Thailand
Energy Technology Data Exchange (ETDEWEB)
Aramrattana, Manoon [Office of Atomic Energy for Peace, Vibhavadee Rangsit Road, Chatuchak, Bangkok (Thailand)
1999-09-01
Knowledge of radiation and its application and protection have been routinely taught, discussed and transferred to end users and the public. Limited resource and a strategic plan are identified to be the major obstacle to fully implementation of radiation education in Thailand. Current strategic planning on radiation education in Thailand will be discussed. (author)
Discussion on several problems in evolution of radiation protection system
International Nuclear Information System (INIS)
Ziqiang, P.
2004-01-01
As viewed from the standpoint of radiation protection practice, it is necessary that the current system of radiological protection should be made more simple and coherent. The human-based protective measures alone are far from having met the requirements of environmental protection in many circumstances. Protecting the environment from ionising radiation would be implicated in radiation protection. Collective dose is an useful indicator, of which applicable extent should be defined. Using such an quantity could help improve radiation protection level, but applicable conditions should be indicated, temporal or spatial. Natural radiation is the largest contributor to the radiation exposure of human. Occupational exposure from natural radiation should be controlled, for occupations such as underground miners and air crew. Controlling both man-made and natural radiation exposure of pregnant women and children needs to be enhanced, especially radiological diagnosis and treatment. China radiation protection community, as a whole, is paying considerable attention to the ICRP's new Recommendations. Prof. Clarke's article 'A Report on Progress towards New Recommendations', a communication from the International Commission on Radiological Protection, has been translated into Chinese and published on Radiation Protection, the Official Journal of China Radiation Protection Society with a view of intensifying awareness of the new Recommendations within more radiation protection workers and people concerned. In addition, a special meeting was convened in early 2002 to address the comments on the new Recommendations. (author)
International Nuclear Information System (INIS)
Lange, F.; Fett, H.J.; Gruendler, D.; Schwarz, G.
1993-01-01
Radiation exposures of members of critical groups of the general population and of transport personnel resulting from normal transport of radioactive wastes to the planned final waste repository Konrad have been evaluated in detail. By applying probabilistic safety assessment techniques radiological risks from transport accidents have been analysed by quantifying potential radiation exposures and contaminations of the biosphere in connection with their expected frequencies of occurrence. The Konrad transport study concentrates on the local region of the waste repository, where all transports converge. (orig.) [de
A symmetrized quasi-diffusion method for solving multidimensional transport problems
International Nuclear Information System (INIS)
Miften, M.M.; Larsen, E.W.
1992-01-01
In this paper, the authors propose a 'symmetrized' QD (SQD) method in which the non-self-adjoint QD diffusion problem is replaced by two self-adjoint diffusion problems. These problems are more easily discretized and more efficiently solved than in the standard QD method. They also give SQD calculational results for transport problems in x-y geometry
Overview and applications of the Monte Carlo radiation transport kit at LLNL
International Nuclear Information System (INIS)
Sale, K. E.
1999-01-01
Modern Monte Carlo radiation transport codes can be applied to model most applications of radiation, from optical to TeV photons, from thermal neutrons to heavy ions. Simulations can include any desired level of detail in three-dimensional geometries using the right level of detail in the reaction physics. The technology areas to which we have applied these codes include medical applications, defense, safety and security programs, nuclear safeguards and industrial and research system design and control. The main reason such applications are interesting is that by using these tools substantial savings of time and effort (i.e. money) can be realized. In addition it is possible to separate out and investigate computationally effects which can not be isolated and studied in experiments. In model calculations, just as in real life, one must take care in order to get the correct answer to the right question. Advancing computing technology allows extensions of Monte Carlo applications in two directions. First, as computers become more powerful more problems can be accurately modeled. Second, as computing power becomes cheaper Monte Carlo methods become accessible more widely. An overview of the set of Monte Carlo radiation transport tools in use a LLNL will be presented along with a few examples of applications and future directions
Analytical Radiation Transport Benchmarks for The Next Century
International Nuclear Information System (INIS)
Ganapol, B.D.
2005-01-01
Verification of large-scale computational algorithms used in nuclear engineering and radiological applications is an essential element of reliable code performance. For this reason, the development of a suite of multidimensional semi-analytical benchmarks has been undertaken to provide independent verification of proper operation of codes dealing with the transport of neutral particles. The benchmarks considered cover several one-dimensional, multidimensional, monoenergetic and multigroup, fixed source and critical transport scenarios. The first approach, called the Green's Function. In slab geometry, the Green's function is incorporated into a set of integral equations for the boundary fluxes. Through a numerical Fourier transform inversion and subsequent matrix inversion for the boundary fluxes, a semi-analytical benchmark emerges. Multidimensional solutions in a variety of infinite media are also based on the slab Green's function. In a second approach, a new converged SN method is developed. In this method, the SN solution is ''minded'' to bring out hidden high quality solutions. For this case multigroup fixed source and criticality transport problems are considered. Remarkably accurate solutions can be obtained with this new method called the Multigroup Converged SN (MGCSN) method as will be demonstrated
Hybrid subgroup decomposition method for solving fine-group eigenvalue transport problems
International Nuclear Information System (INIS)
Yasseri, Saam; Rahnema, Farzad
2014-01-01
Highlights: • An acceleration technique for solving fine-group eigenvalue transport problems. • Coarse-group quasi transport theory to solve coarse-group eigenvalue transport problems. • Consistent and inconsistent formulations for coarse-group quasi transport theory. • Computational efficiency amplified by a factor of 2 using hybrid SGD for 1D BWR problem. - Abstract: In this paper, a new hybrid method for solving fine-group eigenvalue transport problems is developed. This method extends the subgroup decomposition method to efficiently couple a new coarse-group quasi transport theory with a set of fixed-source transport decomposition sweeps to obtain the fine-group transport solution. The advantages of the quasi transport theory are its high accuracy, straight-forward implementation and numerical stability. The hybrid method is analyzed for a 1D benchmark problem characteristic of boiling water reactors (BWR). It is shown that the method reproduces the fine-group transport solution with high accuracy while increasing the computational efficiency up to 12 times compared to direct fine-group transport calculations
The mass transportation problem in Illinois : a final report
1959-06-01
Prepared by the State Mass Transportation Commission for the Honorable William G. Stratton, Governor of Illinois and the Honorable Members of the 71st General Assembly. The study contains the findings and recommendations of the Illinois State Mass Tr...
A reduced-cost iterated local search heuristic for the fixed-charge transportation problem
Buson, Erika; Roberti, Roberto; Toth, Paolo
2014-01-01
The fixed-charge transportation problem (FCTP) is a generalization of the transportation problem where an additional fixed cost is paid for sending a flow from an origin to a destination. We propose an iterated local search heuristic based on the utilization of reduced costs for guiding the restart
Ngastiti, P. T. B.; Surarso, Bayu; Sutimin
2018-05-01
Transportation issue of the distribution problem such as the commodity or goods from the supply tothe demmand is to minimize the transportation costs. Fuzzy transportation problem is an issue in which the transport costs, supply and demand are in the form of fuzzy quantities. Inthe case study at CV. Bintang Anugerah Elektrik, a company engages in the manufacture of gensets that has more than one distributors. We use the methods of zero point and zero suffix to investigate the transportation minimum cost. In implementing both methods, we use robust ranking techniques for the defuzzification process. The studyresult show that the iteration of zero suffix method is less than that of zero point method.
Computation of optimal transport and related hedging problems via penalization and neural networks
Eckstein, Stephan; Kupper, Michael
2018-01-01
This paper presents a widely applicable approach to solving (multi-marginal, martingale) optimal transport and related problems via neural networks. The core idea is to penalize the optimization problem in its dual formulation and reduce it to a finite dimensional one which corresponds to optimizing a neural network with smooth objective function. We present numerical examples from optimal transport, martingale optimal transport, portfolio optimization under uncertainty and generative adversa...
Rusakov, V N; Cherkashin, A V; Shishkanov, A P; Ian'shin, L A; Gracheva, T N
2010-12-01
Radiative and hygienic passportization is one of the most actual pattern of socio and hygienic monitoring in Armed Forces. Radiative and hygienic passport is the main document which characterizes the safety control in military unit and uses the sources of ionizing radiation. Sanitary and epidemiologic institutions were imputed to control the formation of radiative and hygienic passports, analysis and generalization of its data, formation of conclusions about the condition of radiation security in the military units. According to radiative and hygienic passportization, which took place in 2009, the radiation security in the Armed Forces and organizations is satisfactory, but there are some problems of providing of radiation security of personnel under the professional and medical radiation. The salvation of its problems requires the effective work of official functionary of radiac object and institutions of state sanitary and epidemiological supervision in Armed Forces of Russian Federation.
A new computational method for simulation of charge transport in semiconductor radiation detectors
International Nuclear Information System (INIS)
Holban, I.
1993-01-01
An effective computational method for simulation of charge transport in semiconductor radiation detectors is the purpose of the present work. Basic equations for analysis include (1) Poisson's equations, (2) continuity equation for electrons and holes, (3) rate equations for deep levels, (4) current equation for electrons and holes and (5) boundary conditions. The system of equations is discretized and equidistant space and time grids is brought. The nonlinearity of the problem is overcome by using Newton-Raphson iteration scheme. Instead of solving a nonlinear boundary problem we resolve a linear matrix equation. Our computation procedure becomes very efficient using a sparse matrix. The computed program allows to calculate the charge collection efficiency and transient response for arbitrary electric fields when trapping and detrapping effects are present. The earlier literature results are reproduced. (Author)
Study and application of the ANISN and DOT 3.5 codes to problems in nuclear radiation shielding
International Nuclear Information System (INIS)
Otto, A.C.
1983-01-01
The application of the Sn transport codes ANISN and DOT 3.5 to problems in radiation shielding is reviewed. In addition, a large array of codes involved in radiation shielding calculations is described and applied in this work. The ANISN and DOT 3.5 codes solve the multigroup transport equation in plane, cylindrical and spherical geometries, the first in one dimension and the second in two dimensions, by using the Sn approximation and were designed to solve coupled neutron-photon transport problems commonly found in reactor shielding calculations. In this work the numerical methods used in these codes are reviewed and their basic application to deep-penetration and void problems is discussed. Benchmark problems are solved by employing the array of codes previously mentioned. In particular, the ability of the ISOFLUXO program coupled to the DOT 3.5 code of mapping contours of regions with approximately the same scalar fluxes is illustrated, showing that they can be efficiently used in shielding analysis. (Author) [pt
The single-sink fixed-charge transportation problem: Applications and solution methods
DEFF Research Database (Denmark)
Goertz, Simon; Klose, Andreas
2007-01-01
The single-sink fixed-charge transportation problem (SSFCTP) consists in finding a minimum cost flow from a number of supplier nodes to a single demand node. Shipping costs comprise costs proportional to the amount shipped as well as a fixed-charge. Although the SSFCTP is an important special case...... of the well-known fixed-charge transportation problem, just a few methods for solving this problem have been proposed in the literature. After summarising some applications of this problem arising in manufacturing and transportation, we give an overview on approximation algorithms and worst-case results...
International Nuclear Information System (INIS)
Leimdoerfer, M.
1964-02-01
A description is given of a method for calculating the penetration and energy deposition of gamma radiation, based on Monte Carlo techniques. The essential feature is the application of the exponential transformation to promote the transport of penetrating quanta and to balance the steep spatial variations of the source distributions which appear in secondary gamma emission problems. The estimated statistical errors in a number of sample problems, involving concrete shields with thicknesses up to 500 cm, are shown to be quite favorable, even at relatively short computing times. A practical reactor shielding problem is also shown and the predictions compared with measurements
Energy Technology Data Exchange (ETDEWEB)
Leimdoerfer, M
1964-02-15
A description is given of a method for calculating the penetration and energy deposition of gamma radiation, based on Monte Carlo techniques. The essential feature is the application of the exponential transformation to promote the transport of penetrating quanta and to balance the steep spatial variations of the source distributions which appear in secondary gamma emission problems. The estimated statistical errors in a number of sample problems, involving concrete shields with thicknesses up to 500 cm, are shown to be quite favorable, even at relatively short computing times. A practical reactor shielding problem is also shown and the predictions compared with measurements.
Radiation protection problems by diagnostic procedures of pediatric nuclear medicine
International Nuclear Information System (INIS)
Kletter, K.
1994-01-01
Special dosimetry considerations are necessary in the application of radiopharmaceuticals in pediatric nuclear medicine. The influence of differences in irradiation geometry and biokinetic parameters on the radiation dose in children and adults is discussed. Assuming an equal activity concentration, both factors lead rather to a reduced radiation dose than an increased radiation burden in children compared to adults. However, the same radiation dose in children and adults may lead to a different detriment. This is explained by differences in life expectancy and radiation sensitivity for both groups. From special formulas an age dependent reduction factor can be calculated for the application of radiopharmaceuticals in pediatric nuclear medicine. Radiation exposure to hospital staff and parents from children, undergoing nuclear medicine diagnostic or therapeutic procedures, is low. (author)
Mines vs reactors: comparison of radiation problems and solutions
International Nuclear Information System (INIS)
Bush, W.R.
1981-01-01
Radiation protection in uranium mines and nuclear reactors is compared, with the objective of determining if any radiation protection practices which have worked well in one area can be adapted to the other area, especially from reactors to mines since radiation protection is more highly developed in reactors. Several areas are identified where improvements can be made in radiation protection in mines, the most important being improvement in ventilation at the workplace, greater attention to special monitoring during upset conditions, and a need for a substantial increase in radiation protection staff. It is concluded that, although considerable room exists for improvement, the general approach to radiation protection presently being followed seems appropriate for the circumstances encountered in mining
Some problems of antibiotic therapy in radiation sickness
International Nuclear Information System (INIS)
Shalnova, G.A.
1975-01-01
Data on the application of antibiotics and the mechanism of their action in radiation sickness are reviewed. Questions are discussed, such as the effect of antibiotics on the course and outcome of radiation sickness, the development of dysbacteriosis following irradiation, the effect of antibiotics on endogenic infection, the development of resistance of autoflora microbes to antibiotics in an irradiated organism and various aspects of the mechanism of action of antibiotics in radiation sickness. (author)
Application of Walsh functions to neutron transport problems. I. Theory
International Nuclear Information System (INIS)
Seed, T.J.; Albrecht, R.W.
1976-01-01
An approximation to the neutron transport equation is made by representing the angular flux with an expansion of the angular dependence in the orthogonal, complete, and binary valued sets of Walsh function. The Walsh approximation is applied to the one-speed, isotropic-scattering, rectangular-geometry form of the neutron transport equation. Sets of partial differential equations for the expansion coefficients are derived along with appropriate boundary conditions for their solution. The sets of the Walsh expansion to one- and two-dimensional forms of the transport equation are also obtained. The two-dimensional expansion coefficient equations are shown to be not only hyperbolic but also transformable to a set of S/sub N/-like equations that are coupled only through the scattering term. Such transformal sets of equations are termed Walsh-derived quadrature sets
International Nuclear Information System (INIS)
Surya Mohan, P.; Tarvainen, Tanja; Schweiger, Martin; Pulkkinen, Aki; Arridge, Simon R.
2011-01-01
Highlights: → We developed a variable order global basis scheme to solve light transport in 3D. → Based on finite elements, the method can be applied to a wide class of geometries. → It is computationally cheap when compared to the fixed order scheme. → Comparisons with local basis method and other models demonstrate its accuracy. → Addresses problems encountered n modeling of light transport in human brain. - Abstract: We propose the P N approximation based on a finite element framework for solving the radiative transport equation with optical tomography as the primary application area. The key idea is to employ a variable order spherical harmonic expansion for angular discretization based on the proximity to the source and the local scattering coefficient. The proposed scheme is shown to be computationally efficient compared to employing homogeneously high orders of expansion everywhere in the domain. In addition the numerical method is shown to accurately describe the void regions encountered in the forward modeling of real-life specimens such as infant brains. The accuracy of the method is demonstrated over three model problems where the P N approximation is compared against Monte Carlo simulations and other state-of-the-art methods.
New computational methodology for large 3D neutron transport problems
International Nuclear Information System (INIS)
Dahmani, M.; Roy, R.; Koclas, J.
2004-01-01
We present a new computational methodology, based on 3D characteristics method, dedicated to solve very large 3D problems without spatial homogenization. In order to eliminate the input/output problems occurring when solving these large problems, we set up a new computing scheme that requires more CPU resources than the usual one, based on sweeps over large tracking files. The huge capacity of storage needed in some problems and the related I/O queries needed by the characteristics solver are replaced by on-the-fly recalculation of tracks at each iteration step. Using this technique, large 3D problems are no longer I/O-bound, and distributed CPU resources can be efficiently used. (authors)
My Experience. My Perspective. Transportation to Work Presents Problems
Stegers, Markus
2008-01-01
Transportation challenges can often be one of the biggest stumbling blocks to having a successful vocational experience. The author presents a personal account of the difficulties people with disabilities encounter in trying to get themselves to their workplaces due to the limitations of various mobility services.
General problems associated with the control and safe use of radiation sources (199)
International Nuclear Information System (INIS)
Ahmed, J.U.
1993-01-01
There are problems at various levels in ensuring safety in the use of radiation sources. A relatively new problem that warrants international action is the smuggling of radioactive material across international borders. An international convention on the control and safe use of radiation sources is essential to provide a universally harmonized mechanism for ensuring safety
The radiation protection problems of high altitude and space flight
International Nuclear Information System (INIS)
Fry, R.J.M.
1993-01-01
This paper considers the radiation environment in aircraft at high altitudes and spacecraft in low earth orbit and in deep space and the factors that influence the dose equivalents. Altitude, latitude and solar cycle are the major influences for flights below the radiation belts. In deep space, solar cycle and the occurrence of solar particle events are the factors of influence. The major radiation effects of concern are cancer and infertility in males. In high altitude aircraft the radiation consists mainly of protons and neutrons, with neutrons contributing about half the equivalent dose. The average dose rate at altitudes of transcontinental flights that approach the polar regions are greater by a factor of about 2.5 than on routes at low latitudes. Current estimates of does to air crews suggest they are well within the ICRP (1990) recommended dose limits for radiation workers
Radiation protection, safety and associated problems in industrial radiography
International Nuclear Information System (INIS)
Le Roux, P.R.
1990-01-01
Industrial radiography is an indispensable tool for non-destructive testing. Its use entails potential radiation exposure to the operator as well as to the public. Since such radiation has the potential to be harmful, there is a need to limit radiation exposure to a level at which the risk is believed to be acceptable to the individual and to society. The Radiation Protection Society and the Department of National Health believe that the level of protection provided for radiation workers should be comparable with that in other 'safe' industries. The total risk for radiation workers includes the risk of non-radiation related accidents in the various occupations, as well as the special risks of radiation exposure. Industrial radiographers have one of the poorest safety records of all non-medical radiation workers. Operator errors and management errors seem to be the primary contributors to most accidental high exposures. It is necessary to remember that industrial radiography has to be carried out in a wide variety of work places under many different working conditions, both by day and by night. High energy end emissivity (X-ray output or source activity) is required for the radiation to be transmitted through specimens, because these are normally constructed of thick and dense materials such as steel. Additionally, most radiographic sources must be portable to permit use in field locations. On the negative side it must be mentioned that studies undertaken abroad conclude that the most important factors contributing to unsafe operations are human related. Careful planning of the method of work is essential if unnecessary risks are to be avoided. The most effective way of reducing accidents would seem to be to train employees to adhere to established and well documented procedures, to exercise common sense and sound judgement, and to use the protective equipment and devices provided in the manner specified. 2 tabs., 3 refs
Sternberg, Ernest; Lee, George C
2009-01-01
During a disaster, victims with varied morbidities are located at incident sites, while healthcare facilities with varied healthcare resources are distributed elsewhere. Transportation serves an essential equilibrating role: it helps balance the patients' need for care with the supply of care. Studying the special case of New York City, this article sets out the healthcare transportation components as: (1) incident morbidity; (2) transportation assets; and (3) healthcare capacity. The relationship between these three components raises an assignment problem: the management of healthcare transportation within a dynamic and partly unpredictable incident-transportation-healthcare nexus, under urban disruption. While the routine dispatch problem can be tackled through better geographic allocation software and technical algorithms, the disaster assignment problem must be confronted through real-time, mutual adjustment between institutions. This article outlines institutional alternatives for managing the assignment problem and calls for further research on the merits of alternative institutional models.
Study on Multi-Depot Collaborative Transportation Problem of Milk-Run Pattern
Directory of Open Access Journals (Sweden)
Lou Zhenkai
2016-01-01
Full Text Available Analyze the relevance between Milk Run mode and collaborative transportation problem, put forward collaborative transportation problem of multiple-depot on Milk Run mode under the supply and demand separate nodes, consider the value of transport and transport costs, introduce the concept of node - arc flow, by comparing the size of traffic flow determine nodes collection, and then constructed multi-transport model of the problem. Considering one-way pickup and delivery closed, construct two-stage algorithm model, use dynamic programming recursive solution to determine the best route to pick up, and then solving delivery routing problem with different start and return point based on geometric method of Cosine. Finally use a numerical example illustrates the effectiveness of the algorithm and reasonable model.
Contemporary state of the problem of radiation lesions of the lungs: scientometric analysis
International Nuclear Information System (INIS)
Artamonova, N.O.; Kulyinyich, G.V.; Gajsenyuk, L.O.; Masyich, O.V.; Pavlyichenko, Yu.V.
2011-01-01
Scientometric analysis of the contemporary state and prospects of development of the problem of lung radiation lesion allowed to prove its urgency. But among separate questions, the most important is solving the problem of lung radiation toxicity. The majority of publications about clinical trials suggest about a constant search for new means of prevention and treatment. It was established that the information search efficacy about lung radiation lesions depended on the adequate use of term corpus of PubMed database.
International Nuclear Information System (INIS)
Zazula, J.M.
1983-01-01
The general purpose code BALTORO was written for coupling the three-dimensional Monte-Carlo /MC/ with the one-dimensional Discrete Ordinates /DO/ radiation transport calculations. The quantity of a radiation-induced /neutrons or gamma-rays/ nuclear effect or the score from a radiation-yielding nuclear effect can be analysed in this way. (author)
Algorithms for solving the single-sink fixed-charge transportation problem
DEFF Research Database (Denmark)
Klose, Andreas
2006-01-01
The single-sink fixed-charge transportation problem is an important subproblem of the fixed-charge transportation problem. Just a few methods have been proposed in the literature to solve this problem. In this paper, solution approaches based on dynamic programming and implicit enumeration...... are revisited. It is shown how the problem size as well as the search space of a recently published dynamic programming method can be reduced by exploiting reduced cost information. Additionally, a further implicit enumeration approach relying on solution concepts for the binary knapsack problem is introduced...
A Survey on Transport Management Practices Associated with Injuries and Health Problems in Horses.
Padalino, Barbara; Raidal, Sharanne L; Hall, Evelyn; Knight, Peter; Celi, Pietro; Jeffcott, Leo; Muscatello, Gary
2016-01-01
An online survey was conducted to determine associations between transport management and transport-related injuries and diseases in horses in Australia. The survey was composed of three sections: respondents' demographic information, transport management strategies or procedures (before, during and after transportation) and transport diseases experienced in the previous two year period. Univariate and multivariate modelling was performed exploring associations between variables (respondents' details and transport management strategies) and the following transport-related diseases as outcomes: traumatic injuries, diarrhoea, heat stroke, muscular problems, laminitis, transport pneumonia and colic. The survey generated 797 responses. Traumatic injuries were the most common transport-related problem, with a reported incidence of 45.0%. Younger respondents (30 in a week) were more likely to report transport-related injuries. Injury risk was also linked to the use of protections and tranquilizers prior to transport, and checking horses after the journey. Diarrhoea (20.0%) and heat stroke (10.5%) were reported more by amateur than professional horse carers. Increased risk of heat stroke was linked to the restriction of hay and water prior to transportation. Muscular problems (13.0%) appeared to be exacerbated when horse health was not assessed before journey; whilst the risk of laminitis (2.9%) was around three fold greater when post transport recovery strategies were not applied. Associations were made between transport pneumonia (9.2%) and duration of journey, and with activity (horses involved in racing at greater risk). No associations were seen between the incidence of colic (10.3%) and the variables examined. Study findings should be interpreted with caution as they represent participant perceptions and recall. Nevertheless, results support many current recommendations for safe transportation of horses. They also highlight the need to further investigate many of
Annema, J.A.; Mouter, N.
2013-01-01
Key actors (consultants, scientists and policy makers) in the Netherlands transport policy cost-benefit analysis (CBA) practice consider ‘problem analysis’ to be one of the important CBA substantive problems. Their idea is that a good-quality problem analysis can help to identify proper solutions,
Energy Technology Data Exchange (ETDEWEB)
Cartier, J
2006-04-15
This thesis focuses on mathematical analysis, numerical resolution and modelling of the transport equations. First of all, we deal with numerical approximation of the solution of the transport equations by using a mixed-hybrid scheme. We derive and study a mixed formulation of the transport equation, then we analyse the related variational problem and present the discretization and the main properties of the scheme. We particularly pay attention to the behavior of the scheme and we show its efficiency in the diffusion limit (when the mean free path is small in comparison with the characteristic length of the physical domain). We present academical benchmarks in order to compare our scheme with other methods in many physical configurations and validate our method on analytical test cases. Unstructured and very distorted meshes are used to validate our scheme. The second part of this thesis deals with two transport problems. The first one is devoted to the study of diffusion due to boundary conditions in a transport problem between two plane plates. The second one consists in modelling and simulating radiative transfer phenomenon in case of the industrial context of inertial confinement fusion. (author)
Energy Technology Data Exchange (ETDEWEB)
Cartier, J
2006-04-15
This thesis focuses on mathematical analysis, numerical resolution and modelling of the transport equations. First of all, we deal with numerical approximation of the solution of the transport equations by using a mixed-hybrid scheme. We derive and study a mixed formulation of the transport equation, then we analyse the related variational problem and present the discretization and the main properties of the scheme. We particularly pay attention to the behavior of the scheme and we show its efficiency in the diffusion limit (when the mean free path is small in comparison with the characteristic length of the physical domain). We present academical benchmarks in order to compare our scheme with other methods in many physical configurations and validate our method on analytical test cases. Unstructured and very distorted meshes are used to validate our scheme. The second part of this thesis deals with two transport problems. The first one is devoted to the study of diffusion due to boundary conditions in a transport problem between two plane plates. The second one consists in modelling and simulating radiative transfer phenomenon in case of the industrial context of inertial confinement fusion. (author)
Fixing or Transferring Environmental Problems in the Transport Sector?
DEFF Research Database (Denmark)
Walnum, Hans Jakob
Transport accounts for 25 percent of global energy related greenhouse gas emissions and over half of the world’s oil consumption. The energy consumption is growing at a rate higher than any other sector. The thesis addresses some of the shortcomings with current policy strategies for reducing...... give an improved foundation for policy makers to find strategies and actions to limit such effects and their consequences....
Usefulness of the risk assessment technique in solving transportation problems
International Nuclear Information System (INIS)
Johnson, J.F.; Hall, R.J.
1976-08-01
The purpose was to develop and use a model to assess the risk associated with the shipment of nuclear and non-nuclear hazardous energy-related materials. The analysis method comprises the steps of describing the system, identifying the release sequence, evaluating the sequence, and calculating and assessing the risk. Plutonium shipment is used as an example. Uses of this method to improve transportation safety are discussed. 12 fig
Basic topical problems on health hazards from ionizing radiation
International Nuclear Information System (INIS)
Jacobi, W.; Paretzke, H.G.; Merkle, W.; Lechle, M.; Matthies, M.; Messerer, P.; Schindel, F.; Wirth, E.; Eisfeld, K.
In the framework of this research contract, a number of important questions have been considered which have been of basic interest in radiological protection against low doses of ionizing radiation. In particular, research concentrated on the various statistical concepts for the evaluation of epidemiological data for the purpose of radiation risk analysis, derivation of dose-time-effect-relationships for certain somatic effects, time dependence of selected dose-conversion factors, radiation hazards of carbon-14, tritium, and of radon daughter products. The essential results have been reported in separate publications, and therefore will only be shortly summarized here. (orig./HP) [de
Some problems concerning the radiation protection in nuclear power stations
International Nuclear Information System (INIS)
Bozoky, L.
1977-01-01
The appearance and fast spreading of the nuclear power stations raised new and difficult questions in connection with the theoretical bases of radiation protection. The new standpoint of the International Commission on Radiological Protection is that both the workers at a pile and the inhabitants take less risk because of ionizing radiation than they usually take in everyday life. The maximum dose which can be permitted remained 5 rem/year for those who professionally deal with ionizing radiation and 0.5 rem/year for the groups in special situation. (V.N.)
Advanced Monte Carlo methods for thermal radiation transport
Wollaber, Allan B.
During the past 35 years, the Implicit Monte Carlo (IMC) method proposed by Fleck and Cummings has been the standard Monte Carlo approach to solving the thermal radiative transfer (TRT) equations. However, the IMC equations are known to have accuracy limitations that can produce unphysical solutions. In this thesis, we explicitly provide the IMC equations with a Monte Carlo interpretation by including particle weight as one of its arguments. We also develop and test a stability theory for the 1-D, gray IMC equations applied to a nonlinear problem. We demonstrate that the worst case occurs for 0-D problems, and we extend the results to a stability algorithm that may be used for general linearizations of the TRT equations. We derive gray, Quasidiffusion equations that may be deterministically solved in conjunction with IMC to obtain an inexpensive, accurate estimate of the temperature at the end of the time step. We then define an average temperature T* to evaluate the temperature-dependent problem data in IMC, and we demonstrate that using T* is more accurate than using the (traditional) beginning-of-time-step temperature. We also propose an accuracy enhancement to the IMC equations: the use of a time-dependent "Fleck factor". This Fleck factor can be considered an automatic tuning of the traditionally defined user parameter alpha, which generally provides more accurate solutions at an increased cost relative to traditional IMC. We also introduce a global weight window that is proportional to the forward scalar intensity calculated by the Quasidiffusion method. This weight window improves the efficiency of the IMC calculation while conserving energy. All of the proposed enhancements are tested in 1-D gray and frequency-dependent problems. These enhancements do not unconditionally eliminate the unphysical behavior that can be seen in the IMC calculations. However, for fixed spatial and temporal grids, they suppress them and clearly work to make the solution more
International Nuclear Information System (INIS)
Roussin, R.W.
1993-01-01
From the very early days in its history Radiation Shielding Information Center (RSIC) has been involved with high energy radiation transport. The National Aeronautics and Space Administration was an early sponsor of RSIC until the completion of the Apollo Moon Exploration Program. In addition, the intranuclear cascade work of Bertini at Oak Ridge National Laboratory provided valuable resources which were made available through RSIC. Over the years, RSIC has had interactions with many of the developers of high energy radiation transport computing technology and data libraries and has been able to collect and disseminate this technology. The current status of this technology will be reviewed and prospects for new advancements will be examined
Monte Carlo radiation transport: A revolution in science
International Nuclear Information System (INIS)
Hendricks, J.
1993-01-01
When Enrico Fermi, Stan Ulam, Nicholas Metropolis, John von Neuman, and Robert Richtmyer invented the Monte Carlo method fifty years ago, little could they imagine the far-flung consequences, the international applications, and the revolution in science epitomized by their abstract mathematical method. The Monte Carlo method is used in a wide variety of fields to solve exact computational models approximately by statistical sampling. It is an alternative to traditional physics modeling methods which solve approximate computational models exactly by deterministic methods. Modern computers and improved methods, such as variance reduction, have enhanced the method to the point of enabling a true predictive capability in areas such as radiation or particle transport. This predictive capability has contributed to a radical change in the way science is done: design and understanding come from computations built upon experiments rather than being limited to experiments, and the computer codes doing the computations have become the repository for physics knowledge. The MCNP Monte Carlo computer code effort at Los Alamos is an example of this revolution. Physicians unfamiliar with physics details can design cancer treatments using physics buried in the MCNP computer code. Hazardous environments and hypothetical accidents can be explored. Many other fields, from underground oil well exploration to aerospace, from physics research to energy production, from safety to bulk materials processing, benefit from MCNP, the Monte Carlo method, and the revolution in science
Multi-level nonlinear diffusion acceleration method for multigroup transport k-Eigenvalue problems
International Nuclear Information System (INIS)
Anistratov, Dmitriy Y.
2011-01-01
The nonlinear diffusion acceleration (NDA) method is an efficient and flexible transport iterative scheme for solving reactor-physics problems. This paper presents a fast iterative algorithm for solving multigroup neutron transport eigenvalue problems in 1D slab geometry. The proposed method is defined by a multi-level system of equations that includes multigroup and effective one-group low-order NDA equations. The Eigenvalue is evaluated in the exact projected solution space of smallest dimensionality, namely, by solving the effective one- group eigenvalue transport problem. Numerical results that illustrate performance of the new algorithm are demonstrated. (author)
Radiation streaming: the continuing problem of shield design
International Nuclear Information System (INIS)
Avery, A.F.
1977-01-01
The practical problems of shield design are reviewed and the major difficulties are shown to be those associated with streaming problems. The situations in which streaming occurs in various types of reactor are described including LMFBR's and fusion devices, and examples are given of ways in which the problems have been solved
Goal based mesh adaptivity for fixed source radiation transport calculations
International Nuclear Information System (INIS)
Baker, C.M.J.; Buchan, A.G.; Pain, C.C.; Tollit, B.S.; Goffin, M.A.; Merton, S.R.; Warner, P.
2013-01-01
Highlights: ► Derives an anisotropic goal based error measure for shielding problems. ► Reduces the error in the detector response by optimizing the finite element mesh. ► Anisotropic adaptivity captures material interfaces using fewer elements than AMR. ► A new residual based on the numerical scheme chosen forms the error measure. ► The error measure also combines the forward and adjoint metrics in a novel way. - Abstract: In this paper, the application of goal based error measures for anisotropic adaptivity applied to shielding problems in which a detector is present is explored. Goal based adaptivity is important when the response of a detector is required to ensure that dose limits are adhered to. To achieve this, a dual (adjoint) problem is solved which solves the neutron transport equation in terms of the response variables, in this case the detector response. The methods presented can be applied to general finite element solvers, however, the derivation of the residuals are dependent on the underlying finite element scheme which is also discussed in this paper. Once error metrics for the forward and adjoint solutions have been formed they are combined using a novel approach. The two metrics are combined by forming the minimum ellipsoid that covers both the error metrics rather than taking the maximum ellipsoid that is contained within the metrics. Another novel approach used within this paper is the construction of the residual. The residual, used to form the goal based error metrics, is calculated from the subgrid scale correction which is inherent in the underlying spatial discretisation employed
The problem of criticality and initial-value problem in neutron transport theory
International Nuclear Information System (INIS)
Kyncl, J.
1984-10-01
The problem of criticality and the initial value problem are studied in the case of a linear Boltzmann equation and of both finite and infinite media. The space of functions where the problems are solved is chosen in such a way as to cover a wide range of physical situations. The asymptotic time behavior of the solution to the initial-value problem is also discussed, and main results are summarized in three basic theorems. (author)
The problem of radiation reaction in classical electrodynamics
International Nuclear Information System (INIS)
Sorg, M.
1976-01-01
A new covariant theory of the classical radiating electron is compared with other radiation reaction theories: On the one hand, the new theory can be deduced from Caldirola's finite-differences theory by suitable approximations; on the other hand, the Lorentz-Dirac theory and the theory of Mo and Papas are shown to be approximative forms of the new theory (orig./BJ) [de
Chapoutier, Nicolas; Mollier, François; Nolin, Guillaume; Culioli, Matthieu; Mace, Jean-Reynald
2017-09-01
In the context of the rising of Monte Carlo transport calculations for any kind of application, AREVA recently improved its suite of engineering tools in order to produce efficient Monte Carlo workflow. Monte Carlo codes, such as MCNP or TRIPOLI, are recognized as reference codes to deal with a large range of radiation transport problems. However the inherent drawbacks of theses codes - laboring input file creation and long computation time - contrast with the maturity of the treatment of the physical phenomena. The goals of the recent AREVA developments were to reach similar efficiency as other mature engineering sciences such as finite elements analyses (e.g. structural or fluid dynamics). Among the main objectives, the creation of a graphical user interface offering CAD tools for geometry creation and other graphical features dedicated to the radiation field (source definition, tally definition) has been reached. The computations times are drastically reduced compared to few years ago thanks to the use of massive parallel runs, and above all, the implementation of hybrid variance reduction technics. From now engineering teams are capable to deliver much more prompt support to any nuclear projects dealing with reactors or fuel cycle facilities from conceptual phase to decommissioning.
Directory of Open Access Journals (Sweden)
Chapoutier Nicolas
2017-01-01
Full Text Available In the context of the rising of Monte Carlo transport calculations for any kind of application, AREVA recently improved its suite of engineering tools in order to produce efficient Monte Carlo workflow. Monte Carlo codes, such as MCNP or TRIPOLI, are recognized as reference codes to deal with a large range of radiation transport problems. However the inherent drawbacks of theses codes - laboring input file creation and long computation time - contrast with the maturity of the treatment of the physical phenomena. The goals of the recent AREVA developments were to reach similar efficiency as other mature engineering sciences such as finite elements analyses (e.g. structural or fluid dynamics. Among the main objectives, the creation of a graphical user interface offering CAD tools for geometry creation and other graphical features dedicated to the radiation field (source definition, tally definition has been reached. The computations times are drastically reduced compared to few years ago thanks to the use of massive parallel runs, and above all, the implementation of hybrid variance reduction technics. From now engineering teams are capable to deliver much more prompt support to any nuclear projects dealing with reactors or fuel cycle facilities from conceptual phase to decommissioning.
Problems and issues for short-haul air transportation.
Vittek, J. F., Jr.
1972-01-01
The problems of developing an efficient short-haul air system are not primarily technical, but economic and political. The key issues are whether the community will accept new and expanded air facilities, what standards of service the passengers will demand and how the system will evolve. The solutions recommended are national in scope and require the federal government to take a leading role.
Uncertain multi-objective multi-product solid transportation problems
Indian Academy of Sciences (India)
Deepika Rani
... made more effective by incorporating some other factors, which make it useful in real life .... For the above problem to be balanced it should satisfy: ..... Now, first step is to balance the ...... In this work, the fuzzy optimal compromise solution is.
International Nuclear Information System (INIS)
1982-01-01
1 - Description of problem or function: Format: SAIL format; Number of groups: 23 neutron / 17 gamma-ray; Nuclides: Type 04 Concrete and Low Carbon Steel (A533B). Origin: Science Applications, Inc (SAI); Weighting spectrum: yes. SAIL is a library of albedo scattering data to be used in three-dimensional Monte Carlo codes to solve radiation transport problems specific to the reactor pressure vessel cavity region of a LWR. The library contains data for Type 04 Concrete and Low Carbon Steel (A533B). 2 - Method of solution: The calculation of the albedo data was perform- ed with a version of the discrete ordinates transport code DOT which treats the transport of neutrons, secondary gamma-rays and gamma- rays in one dimension, while maintaining the complete two-dimension- al treatment of the angular dependence
A hybrid transport-diffusion method for Monte Carlo radiative-transfer simulations
International Nuclear Information System (INIS)
Densmore, Jeffery D.; Urbatsch, Todd J.; Evans, Thomas M.; Buksas, Michael W.
2007-01-01
Discrete Diffusion Monte Carlo (DDMC) is a technique for increasing the efficiency of Monte Carlo particle-transport simulations in diffusive media. If standard Monte Carlo is used in such media, particle histories will consist of many small steps, resulting in a computationally expensive calculation. In DDMC, particles take discrete steps between spatial cells according to a discretized diffusion equation. Each discrete step replaces many small Monte Carlo steps, thus increasing the efficiency of the simulation. In addition, given that DDMC is based on a diffusion equation, it should produce accurate solutions if used judiciously. In practice, DDMC is combined with standard Monte Carlo to form a hybrid transport-diffusion method that can accurately simulate problems with both diffusive and non-diffusive regions. In this paper, we extend previously developed DDMC techniques in several ways that improve the accuracy and utility of DDMC for nonlinear, time-dependent, radiative-transfer calculations. The use of DDMC in these types of problems is advantageous since, due to the underlying linearizations, optically thick regions appear to be diffusive. First, we employ a diffusion equation that is discretized in space but is continuous in time. Not only is this methodology theoretically more accurate than temporally discretized DDMC techniques, but it also has the benefit that a particle's time is always known. Thus, there is no ambiguity regarding what time to assign a particle that leaves an optically thick region (where DDMC is used) and begins transporting by standard Monte Carlo in an optically thin region. Also, we treat the interface between optically thick and optically thin regions with an improved method, based on the asymptotic diffusion-limit boundary condition, that can produce accurate results regardless of the angular distribution of the incident Monte Carlo particles. Finally, we develop a technique for estimating radiation momentum deposition during the
Monte Carlo methods in electron transport problems. Pt. 1
International Nuclear Information System (INIS)
Cleri, F.
1989-01-01
The condensed-history Monte Carlo method for charged particles transport is reviewed and discussed starting from a general form of the Boltzmann equation (Part I). The physics of the electronic interactions, together with some pedagogic example will be introduced in the part II. The lecture is directed to potential users of the method, for which it can be a useful introduction to the subject matter, and wants to establish the basis of the work on the computer code RECORD, which is at present in a developing stage
Solving the Single-Sink, Fixed-Charge, Multiple-Choice Transportation Problem by Dynamic Programming
DEFF Research Database (Denmark)
Rauff Lind Christensen, Tue; Klose, Andreas; Andersen, Kim Allan
important aspects of supplier selection, an important application of the SSFCTP, this does not reflect the real life situation. First, transportation costs faced by many companies are in fact piecewise linear. Secondly, when suppliers offer discounts, either incremental or all-unit discounts, such savings......The Single-Sink, Fixed-Charge, Multiple-Choice Transportation Problem (SSFCMCTP) is a problem with versatile applications. This problem is a generalization of the Single-Sink, Fixed-Charge Transportation Problem (SSFCTP), which has a fixed-charge, linear cost structure. However, in at least two...... are neglected in the SSFCTP. The SSFCMCTP overcome this problem by incorporating a staircase cost structure in the cost function instead of the usual one used in SSFCTP. We present a dynamic programming algorithm for the resulting problem. To enhance the performance of the generic algorithm a number...
Energy Technology Data Exchange (ETDEWEB)
Colliander, J
1985-12-01
The following problems have been indentified: - A rational structure of transporting requires an established and relatively open market. - The necessary rolling stock for fuel conveyance by rail is not available. - Roads have to be improved and new roads have to be built. Railways with low load now might get a motivation for reinforcement. - Because of the irregular spread of consumption storing and terminals problems will arise and increase the cost of transport. - Terminals and stores are situated at a convenient place for one single enterprice. On a far-away aim this will not be rational.
Optimal solution of full fuzzy transportation problems using total integral ranking
Sam’an, M.; Farikhin; Hariyanto, S.; Surarso, B.
2018-03-01
Full fuzzy transportation problem (FFTP) is a transportation problem where transport costs, demand, supply and decision variables are expressed in form of fuzzy numbers. To solve fuzzy transportation problem, fuzzy number parameter must be converted to a crisp number called defuzzyfication method. In this new total integral ranking method with fuzzy numbers from conversion of trapezoidal fuzzy numbers to hexagonal fuzzy numbers obtained result of consistency defuzzyfication on symmetrical fuzzy hexagonal and non symmetrical type 2 numbers with fuzzy triangular numbers. To calculate of optimum solution FTP used fuzzy transportation algorithm with least cost method. From this optimum solution, it is found that use of fuzzy number form total integral ranking with index of optimism gives different optimum value. In addition, total integral ranking value using hexagonal fuzzy numbers has an optimal value better than the total integral ranking value using trapezoidal fuzzy numbers.
International conference. The problems of radiation genetics at the turn of the century. Abstracts
International Nuclear Information System (INIS)
2000-01-01
Information concerning International conference: The problems of radiation genetics at the turn of the century - held in Moscow, November, 2000, is presented. The conference is dedicated to the memory of Timofeev-Resovsky (centenary of birth). Analysis of the development of concepts of the radiation genetics founder concerning study of genetic radiation effects on plants, animals and man is given. Molecular-genetic mechanisms of radiation mutagenesis are considered. Problems related to the analysis of delayed genetic radiation effects on the different types. Populations and regularities in radiation-induced mutagenesis at cellular, tissue and body levels are discussed. Great attention is paid to the genetic consequences for population, flora and fauna of Chernobyl and Kyshtym accidents, nuclear explosions at Semipalatinsk test site and other emergency radiation situations [ru
Dynamic Scheduling for Cloud Reliability using Transportation Problem
P. Balasubramanie; S. K. Senthil Kumar
2012-01-01
Problem statement: Cloud is purely a dynamic environment and the existing task scheduling algorithms are mostly static and considered various parameters like time, cost, make span, speed, scalability, throughput, resource utilization, scheduling success rate and so on. Available scheduling algorithms are mostly heuristic in nature and more complex, time consuming and does not consider reliability and availability of the cloud computing environment. Therefore there is a need to implement a sch...
International Nuclear Information System (INIS)
Schwarz, G.; Fett, H.J.; Lange, F.
2004-01-01
Most radioactive material packages transported emit penetrating ionising radiation and radiation exposures of transport workers and the public may occur during their transport. The radiation exposures incurred by transport workers and members of the public can vary significantly depending on a number of factors: most important is the type of radiation emitted (primarily gamma and neutron radiation), the radiation field intensity in the surrounding of a package and conveyance and the duration of exposure to ionising radiation. The information and guidance material on occupational exposures has primarily been derived from a survey and analysis of personal monitoring data provided by a number of commercial transport operators in Germany known as major carrier and handler organisations of fuel cycle and non-fuel cycle material (in terms of the number of pack-ages and the activity carriaged). To some extent advantage was taken of compilations of statistical transport and exposure data collated within other transport safety analysis studies including research projects funded by the European Commission. The exposure data collected cover the time period of the last 4 - 8 years and are most representative for routine transport operations closely related to the movement phase of packaged radioactive material, i.e. receipt, vehicle loading, carriage, in-transit storage, intra-/intermodal transfer, vehicle unloading and delivery at the final destination of loads of radioactive material and packages and the related supervisory and health physics functions. Radiation dose monitoring of members of the public, however, is generally impracticable and, consequently, the information available relies on employing dose assessment models and reflects radiation exposures incurred by hypothetical or critical group individuals of members of the public under normal conditions of transport
Inverse radiative transfer problems in two-dimensional heterogeneous media
International Nuclear Information System (INIS)
Tito, Mariella Janette Berrocal
2001-01-01
The analysis of inverse problems in participating media where emission, absorption and scattering take place has several relevant applications in engineering and medicine. Some of the techniques developed for the solution of inverse problems have as a first step the solution of the direct problem. In this work the discrete ordinates method has been used for the solution of the linearized Boltzmann equation in two dimensional cartesian geometry. The Levenberg - Marquardt method has been used for the solution of the inverse problem of internal source and absorption and scattering coefficient estimation. (author)
The Techa river: 50 years of radiation problems
International Nuclear Information System (INIS)
Evlanov, D.
2000-01-01
A short history of radioecological problems on the Techa river is reviewed. Creating Techa's cascade ponds posed several problems such as rehabilitation (cleaning water, reduction and utilization of radioisotopes) and stabilization of closed ponds. The Mayak plant solves the complex problems of the industrial ponds on the Techa River using the following: Hydrological and hydro-geological studies of the Techa cascade ponds, and development of methods and technologies for cleaning the bottom of the ponds. The final solution to Techa's problems is possible .only with the collaboration of the South Ural Nuclear Power Plant. (authors)
Cosmic gamma-ray background radiation. Current understandings and problems
International Nuclear Information System (INIS)
Inoue, Yoshiyuki
2015-01-01
The cosmic gamma-ray background radiation is one of the most fundamental observables in the gamma-ray band. Although the origin of the cosmic gamma-ray background radiation has been a mystery for a long time, the Fermi gamma-ray space telescope has recently measured it at 0.1-820 GeV and revealed that the cosmic GeV gamma-ray background is composed of blazars, radio galaxies, and star-forming galaxies. However, Fermi still leaves the following questions. Those are dark matter contribution, origins of the cosmic MeV gamma-ray background, and the connection to the IceCube TeV-PeV neutrino events. In this proceeding, I will review the current understandings of the cosmic gamma-ray background and discuss future prospects of cosmic gamma-ray background radiation studies. (author)
Microbiological problems of radiation sterilization control of disposable medical products
International Nuclear Information System (INIS)
Horakova, V.
1975-01-01
Dose-response curves were determined for three strains of cocci and seven strains of aerobic spore-forming rods after irradiation by two different 60 Co sources and Van de Graaff electron accelerator. Besides the test strains Streptococcus faecium A 2 1, Bacillus sphericus Csub(I)A and Bacillus pumilus E601, some strains isolated from irradiated vaccines and animal diets, or found among common air-contaminating bacteria and pathogenic cocci were examined. The efficiency of the used radiation sources was compared. The control of the microbiological efficiency of radiation sterilization is discussed regarding routine practice. (author)
An application of reactor noise techniques to neutron transport problems in a random medium
International Nuclear Information System (INIS)
Sahni, D.C.
1989-01-01
Neutron transport problems in a random medium are considered by defining a joint Markov process describing the fluctuations of one neutron population and the random changes in the medium. Backward Chapman-Kolmogorov equations are derived which yield an adjoint transport equation for the average neutron density. It is shown that this average density also satisfied the direct transport equation as given by the phenomenological model. (author)
Simulation of neutron transport equation using parallel Monte Carlo for deep penetration problems
International Nuclear Information System (INIS)
Bekar, K. K.; Tombakoglu, M.; Soekmen, C. N.
2001-01-01
Neutron transport equation is simulated using parallel Monte Carlo method for deep penetration neutron transport problem. Monte Carlo simulation is parallelized by using three different techniques; direct parallelization, domain decomposition and domain decomposition with load balancing, which are used with PVM (Parallel Virtual Machine) software on LAN (Local Area Network). The results of parallel simulation are given for various model problems. The performances of the parallelization techniques are compared with each other. Moreover, the effects of variance reduction techniques on parallelization are discussed
Volume-based geometric modeling for radiation transport calculations
International Nuclear Information System (INIS)
Li, Z.; Williamson, J.F.
1992-01-01
Accurate theoretical characterization of radiation fields is a valuable tool in the design of complex systems, such as linac heads and intracavitary applicators, and for generation of basic dose calculation data that is inaccessible to experimental measurement. Both Monte Carlo and deterministic solutions to such problems require a system for accurately modeling complex 3-D geometries that supports ray tracing, point and segment classification, and 2-D graphical representation. Previous combinatorial approaches to solid modeling, which involve describing complex structures as set-theoretic combinations of simple objects, are limited in their ease of use and place unrealistic constraints on the geometric relations between objects such as excluding common boundaries. A new approach to volume-based solid modeling has been developed which is based upon topologically consistent definitions of boundary, interior, and exterior of a region. From these definitions, FORTRAN union, intersection, and difference routines have been developed that allow involuted and deeply nested structures to be described as set-theoretic combinations of ellipsoids, elliptic cylinders, prisms, cones, and planes that accommodate shared boundaries. Line segments between adjacent intersections on a trajectory are assigned to the appropriate region by a novel sorting algorithm that generalizes upon Siddon's approach. Two 2-D graphic display tools are developed to help the debugging of a given geometric model. In this paper, the mathematical basis of our system is described, it is contrasted to other approaches, and examples are discussed
INTERMODAL TRANSPORTATION: CONSIDERATIONS IN PREFERENCE AND THE PROBLEMS BETWEEN EUROPE AND TURKEY
Balca Berfin UYGUÇ; Bengü SEVİL OFLAÇ
2017-01-01
Intermodal transportation has become increasingly important, as global supply chains tend to spread their activities in diversified countries. Intermodal transportation has its own issues that should be investigated in a deeper sense. Therefore, through conducting semi-structured interviews with logistics companies, this study aims to analyze the considerations in intermodal preference and problems faced during intermodal operations between Europe and Turkey.
Opportunity Structure for Gambling and Problem Gambling among Employees in the Transport Industry
Revheim, Tevje; Buvik, Kristin
2009-01-01
Working conditions for employees in the transport sector might present an opportunity structure for gambling by providing access to gambling during the workday. This study investigates connections between opportunity structure, gambling during the workday, and gambling problems among employees in the transport sector. Data has been collected from…
1973-01-01
Conclusions and recommendations are presented for an analysis of the total energy situation; the effect of the energy problem on air transportation; and hydrogen fuel for aircraft. Properties and production costs of fuels, future prediction for energy and transportation, and economic aspects of hydrogen production are appended.
Some problems and prospects for marine transportation of oil in the 1970s
Zannetos, Z. S.
1973-01-01
The problems associated with, and the financial resources required for ocean transportation of petroleum in the 1970s are discussed in terms of the energy crisis. Spot rate fluctuations for tankers are examined along with the financial requirements for ocean transportation.
The problems and suggestions on supervision of the radioactive material transport
International Nuclear Information System (INIS)
Cao Fangfang; Que Ji; Zhang Min; Pan Yuting
2012-01-01
The developing background and importance of the rules on supervision of the radioactive material transport are discussed in the paper. Based on the existing problems found in the process of implementing the rule 'Regulations for the safe transport of Radioactive Material', some countermeasures are proposed. (authors)
Parallel unstructured mesh optimisation for 3D radiation transport and fluids modelling
International Nuclear Information System (INIS)
Gorman, G.J.; Pain, Ch. C.; Oliveira, C.R.E. de; Umpleby, A.P.; Goddard, A.J.H.
2003-01-01
In this paper we describe the theory and application of a parallel mesh optimisation procedure to obtain self-adapting finite element solutions on unstructured tetrahedral grids. The optimisation procedure adapts the tetrahedral mesh to the solution of a radiation transport or fluid flow problem without sacrificing the integrity of the boundary (geometry), or internal boundaries (regions) of the domain. The objective is to obtain a mesh which has both a uniform interpolation error in any direction and the element shapes are of good quality. This is accomplished with use of a non-Euclidean (anisotropic) metric which is related to the Hessian of the solution field. Appropriate scaling of the metric enables the resolution of multi-scale phenomena as encountered in transient incompressible fluids and multigroup transport calculations. The resulting metric is used to calculate element size and shape quality. The mesh optimisation method is based on a series of mesh connectivity and node position searches of the landscape defining mesh quality which is gauged by a functional. The mesh modification thus fits the solution field(s) in an optimal manner. The parallel mesh optimisation/adaptivity procedure presented in this paper is of general applicability. We illustrate this by applying it to a transient CFD (computational fluid dynamics) problem. Incompressible flow past a cylinder at moderate Reynolds numbers is modelled to demonstrate that the mesh can follow transient flow features. (authors)
The problem of radiative depolarization in the 'Siberian Snake'
International Nuclear Information System (INIS)
Schwitters, R.
1979-01-01
As pointed out by Derbenev and Kondratenko and by the LEP Study Group, a 'Siberian Snake' may be a convenient method for providing longitudinally polarized beams at LEP. The author shows that at the highest LEP energies (approximately>60 GeV) synchrotron radiation with spin-flip may depolarize the beams. (Auth.)
RAMs: the problem of transient errors due to alpha radiation
International Nuclear Information System (INIS)
Goujon, Pierre.
1980-01-01
Errors that remained unexplained for a long time have occurred with dynamic random access memories. It has been known since 1978 that they are due to stray alpha radiation. A good understanding of this phenomenon enables its effects to be neutralized and the reliability of the products to be guarantied [fr
Radiation inactivation studies of renal brush border water and urea transport
International Nuclear Information System (INIS)
Verkman, A.S.; Dix, J.A.; Seifter, J.L.; Skorecki, K.L.; Jung, C.Y.; Ausiello, D.A.
1985-01-01
Radiation inactivation was used to determine the nature and molecular weight of water and urea transport pathways in brush border membrane vesicles (BBMV) isolated from rabbit renal cortex. BBMV were frozen to -50 degrees C, irradiated with 1.5 MeV electrons, thawed, and assayed for transport or enzyme activity. The freezing process had no effect on enzyme or transport kinetics. BBMV alkaline phosphatase activity gave linear ln(activity) vs. radiation dose plots with a target size of 68 +/- 3 kDa, similar to previously reported values. Water and solute transport were measured using the stopped-flow light-scattering technique. The rates of acetamide and osmotic water transport did not depend on radiation dose (0-7 Mrad), suggesting that transport of these substances does not require a protein carrier. In contrast, urea and thiourea transport gave linear ln(activity) vs. dose curves with a target size of 125-150 kDa; 400 mM urea inhibited thiourea flux by -50% at 0 and 4.7 Mrad, showing that radiation does not affect inhibitor binding to surviving transporters. These studies suggest that BBMV urea transport requires a membrane protein, whereas osmotic water transport does not
Problems with radiation protection concerning volunteers accompanying radiological patients
International Nuclear Information System (INIS)
Adrian Daoud
2008-01-01
Full text: The purpose of this work is to point out, within the framework of the Radiation Protection guidelines, the irregular situation of the 'volunteer' or 'accompanying person' who accompanies anyone requiring medical treatment with ionising radiation, as well as to suggest a possible justification for such role. It should be noted that most of these persons are subject to ionising radiation without knowing anything about the effects that it could cause on them, so that their condition could be hardly considered as 'voluntary'. There are several circumstances under which the presence of accompanying persons is required, being different among them. Several examples could be mentioned such as: those who are accompanying a direct relative (family bonds), those who are acting in service during their normal work (social workers, policemen) and even those who are forced by unusual under an accidental situation. The qualitative classification that radiological protection established in society concerning radiation risks for people in general enables to set mechanisms of justification, optimisation and dose limitation for each category, being perfectly identified which of them each person belongs to. But the figure of 'accompanying person' has been excluded from such characterisation. They are subject to radiation exposure without knowing it, or without having any information concerning the potential risks. For them, no balance between the net benefit of an adequate medical treatment versus potential health detriment may be applied as for the case of a patient. Thus, their exposure could be not justified. It is not the purpose of this work to question radiological medicine or its practices, but to clarify certain aspects involving members of the public in general, patients and members of the radiological community, as well as to propose lines of action concerning this subject. We conclude that it is not the volunteer who should decide about medical actions, a role
Energy Technology Data Exchange (ETDEWEB)
DeSteese, J.G.
1979-03-01
This report contains a summary characterization of the petroleum transportation system and an assessment of some potential problems that may impact petroleum transportation in the United States during the balance of the century. A primary purpose of this task is to provide information and perspective that contribute to the evaluation of research and development needs and priorities in future programs. The system characterization in Section 3 includes a review of petroleum product movements, modal operations and comparisons, and transportation regulations and safety. This system overview summarizes domestic production and consumption scenarios to the year 2000. A median scenario based on published projections shows that the US will probably rely on foreign oil to supply between 40 and 50 percent of domestic petroleum needs throughout the balance of the century. Potential problems in petroleum transportation were identified by the analysis and prioritization of current issues. The relative priorities of problem concerns were judged on the basis of their overall impact on the system and the immediacy of this potential impact. Two classes of concern are distinguished: 1. Potential problems that appear to require new programmatic action, in addition to effort already committed, to minimize the possible future impact of these concerns. 2. Latent concerns that may increase or decrease in priority or entirely change in nature as they develop. While the trend of these concerns should be monitored, new program action does not appear necessary at this time.
TRU waste transportation -- The flammable gas generation problem
International Nuclear Information System (INIS)
Connolly, M.J.; Kosiewicz, S.T.
1997-01-01
The Nuclear Regulatory Commission (NRC) has imposed a flammable gas (i.e., hydrogen) concentration limit of 5% by volume on transuranic (TRU) waste containers to be shipped using the TRUPACT-II transporter. This concentration is the lower explosive limit (LEL) in air. This was done to minimize the potential for loss of containment during a hypothetical 60 day period. The amount of transuranic radionuclide that is permissible for shipment in TRU waste containers has been tabulated in the TRUPACT-II Safety Analysis Report for Packaging (SARP, 1) to conservatively prevent accumulation of hydrogen above this 5% limit. Based on the SARP limitations, approximately 35% of the TRU waste stored at the Idaho National Engineering and Environmental Lab (INEEL), Los Alamos National Lab (LANL), and Rocky Flats Environmental Technology Site (RFETS) cannot be shipped in the TRUPACT-II. An even larger percentage of the TRU waste drums at the Savannah River Site (SRS) cannot be shipped because of the much higher wattage loadings of TRU waste drums in that site's inventory. This paper presents an overview of an integrated, experimental program that has been initiated to increase the shippable portion of the Department of Energy (DOE) TRU waste inventory. In addition, the authors will estimate the anticipated expansion of the shippable portion of the inventory and associated cost savings. Such projection should provide the TRU waste generating sites a basis for developing their TRU waste workoff strategies within their Ten Year Plan budget horizons
International Nuclear Information System (INIS)
Marignac, Y.; Coeytaux, X.; Large, J.H.
2004-09-01
This report concerns the safety and the protection of plutonium dioxide transported from Cogema La Hague to the mixed oxide fuel plant of Marcoule and Cadarache. The French approach of the transport safety is based on the combining of two essential principles: the first one affirms that the performances of the FS47 container in regard of containment (norms TS-R-1 from IAEA for the accidental conditions) is conceived to resist in any situation even terrorism or sabotage. In fact, the IAEA norm follows a probabilistic study without a voluntary attack such a terrorist one. The second principle rests on the ability to prevent the treat of terrorism acts, because of a secrecy policy on the plutonium transport. It appeared that the Green peace association has succeeded several times to know exactly the hours, the trips of the plutonium transport and this simple thing raises more questions than it solves. (N.C.)
Iterated local search and record-to-record travel applied to the fixed charge transportation problem
DEFF Research Database (Denmark)
Andersen, Jeanne; Klose, Andreas
The fixed charge transportation problem (FCTP) is a well-known and difficult optimization problem with lots of applications in logistics. It consists in finding a minimum cost network flow from a set of suppliers to a set of customers. Beside costs proportional to quantities transported......, transportation costs do, however, include a fixed charge. Iterated local search and record-to-record travel are both simple local search based meta-heuristics that, to our knowledge, not yet have been applied to the FCTP. In this paper, we apply both types of search strategies and combine them into a single...
International Nuclear Information System (INIS)
Wykes, J.S.; Surzyn, P.M.; Croke, G.M.; Adsley, Ian.
1980-01-01
The invention relates to a process for determining the nature of a substance transported, comprising the collimation of the radiation of not less than two energies so that they form beams; the irradiation of the matter transported by the beams, the detection of the non-scattered radiations for the two energies at least, after passing in the transported matter, and the deduction of the nature of the transported matter according to the radiations detected. The radiations are collimated by placing a shield around the gamma source (americium 241 or cesium 137). The detector is protected by a shield so that it prevents any significant interference due to the reactions near the surface provoked by those radiations not of the lowest energy, with detection of those radiations of lesser energy. In a variation, a source of relatively higher energy radiations is placed at a distance from the source of relatively lesser energy radiations. The latter have a component taken from natural ionizing radiation and this component is withdrawn to a predetermined calibration [fr
The problem with detriment. [Radiation detriment/health detriment
Energy Technology Data Exchange (ETDEWEB)
Dunster, H.J. (National Radiological Protection Board, Chilton (UK))
1991-05-01
The International Commission on Radiological Protection introduced the term detriment as a quantitative expression of 'all the deleterious effects of exposure to radiation'. Detriment due only to effects on health was called 'health detriment'. It is implicit in the definition of radiation detriment, even if limited to health detriment, that it is derived from many components of different characteristics. These components include: attributable death due to cancer, illness and anxiety before that death; illness, therapy and anxiety associated with non-fatal cancer; hereditary disorders in the observable offspring and in later generations; and, at high doses, deterministic effects. The contribution that each of these components makes to the detriment is influenced by both the probability of its occurrence and its severity if it does occur. (author).
Radiation problems of Fukushima. Little exposure of residents
International Nuclear Information System (INIS)
Togasawa, Hidetoshi
2012-01-01
More than one and half year passed after Fukushima nuclear accident, radiation hazards, especially due to internal irradiation, were still public concern of people living within Fukushima prefecture and Tokyo metropolitan area. However according to several investigations, internal exposure was greatly lower than the level of health hazards due to internal radiation. In August 2012, Fukushima prefecture published internal dose rate of 26 persons was greater than 1 mSv (max 3 mSv) and others than 1 mSv based on whole body counters test results for 63366 residents after June 2011. Appropriate disclosure of exposure dose and related risks was required for risk communication. Target of internal exposure dose rate less than 1 mSv/year was almost attained and people with rather higher dose should be individually checked to reduce exposure. (T. Tanaka)
Superconducting magnets in high radiation environments: Design problems and solutions
International Nuclear Information System (INIS)
St Lorant, S.J.; Tillmann, E.
1989-11-01
As part of the Stanford Linear Collider Project, three high-field superconducting solenoid magnets are used to rotate the spin direction of a polarized electron beam. The magnets are installed in a high-radiation environment, where they will receive a dose of approximately 10 3 rad per hour, or 10 8 rad over their lifetimes. This level of radiation and the location in which the magnets are installed, some 10 meters below ground in contiguous tunnels, required careful selection of materials for the construction of the solenoids and their ancillary cryogenic equipment, as well as the development of compatible component designs. This paper describes the materials used and the design of the equipment appropriate for the application. Included are summaries of the physical and mechanical properties of the materials and how they behave when irradiated. 16 refs., 7 figs., 1 tab
Bone marrow transplantation for treatment of radiation disease. Problems involved
International Nuclear Information System (INIS)
Fliedner, T.M.
1992-01-01
Transplantation of bone marrow cells still is one of the major means available for treatment of radiation injuries. The decisive indication is the diagnostic of irreversible damage to the hemopoietic stem cells, which becomes manifest about 5 or 6 days after exposure, by severe granulocytopenia and simultaneous, progressive thrombopenia. The radiation dose provoking such severe injury is estimated to be at least 9-10 Gy of homogeneous whole-body irradiation. Preparatory measures for transplantation include proof of tissue compatibility of donor and patient, sufficient immunosuppression prior to and/or after irradiation and bone marrow transplantation. The donor's marrow should be free of T-cells. In spite of preparatory treatment, complications such as immunological reactions or disturbance of organ functions are to be very probable. These are treated according to therapy protocols. (orig./MG) [de
Problems in radiation absorbed dose estimation from positron emitters
International Nuclear Information System (INIS)
Powell, G.F.; Harper, P.V.; Reft, C.S.; Chen, C.T.; Lathrop, K.A.
1986-01-01
The positron emitters commonly used in clinical imaging studies for the most part are short-lived, so that when they are distributed in the body the radiation absorbed dose is low even though most of the energy absorbed is from the positrons themselves rather than the annihilation radiation. These considerations do not apply to the administration pathway for a radiopharmaceutical where the activity may be highly concentrated for a brief period rather than distributed in the body. Thus, high local radiation absorbed doses to the vein for an intravenous administration and to the upper airways during administration by inhalation can be expected. For these geometries, beta point source functions (FPS's) have been employed to estimate the radiation absorbed dose in the present study. Physiologic measurements were done to determine other exposure parameters for intravenous administration of O-15 and Rb-82 and for administration of O-15-CO 2 by continuous breathing. Using FPS's to calculate dose rates to the vein wall from O-15 and Rb-82 injected into a vein having an internal radius of 1.5 mm yielded dose rates of 0.51 and 0.46 (rad x g/μCi x h), respectively. The dose gradient in the vein wall and surrounding tissues was also determined using FPS's. Administration of O-15-CO 2 by continuous breathing was also investigated. Using ultra-thin thermoluninescent dosimeters (TLD's) having the effective thickness of normal tracheal mucosa, experiments were performed in which 6 dosimeters were exposed to known concentrations of O-15 positrons in a hemicylindrical tracheal phantom having an internal radius of 0.96 cm and an effective length of 14 cm. The dose rate for these conditions was 3.4 (rads/h)/(μCi/cm 3 ). 15 references, 7 figures, 6 tables
Experimental validation of GADRAS's coupled neutron-photon inverse radiation transport solver
International Nuclear Information System (INIS)
Mattingly, John K.; Mitchell, Dean James; Harding, Lee T.
2010-01-01
Sandia National Laboratories has developed an inverse radiation transport solver that applies nonlinear regression to coupled neutron-photon deterministic transport models. The inverse solver uses nonlinear regression to fit a radiation transport model to gamma spectrometry and neutron multiplicity counting measurements. The subject of this paper is the experimental validation of that solver. This paper describes a series of experiments conducted with a 4.5 kg sphere of α-phase, weapons-grade plutonium. The source was measured bare and reflected by high-density polyethylene (HDPE) spherical shells with total thicknesses between 1.27 and 15.24 cm. Neutron and photon emissions from the source were measured using three instruments: a gross neutron counter, a portable neutron multiplicity counter, and a high-resolution gamma spectrometer. These measurements were used as input to the inverse radiation transport solver to evaluate the solver's ability to correctly infer the configuration of the source from its measured radiation signatures.
Sakamoto, Y
2002-01-01
In the prevention of nuclear disaster, there needs the information on the dose equivalent rate distribution inside and outside the site, and energy spectra. The three dimensional radiation transport calculation code is a useful tool for the site specific detailed analysis with the consideration of facility structures. It is important in the prediction of individual doses in the future countermeasure that the reliability of the evaluation methods of dose equivalent rate distribution and energy spectra by using of Monte Carlo radiation transport calculation code, and the factors which influence the dose equivalent rate distribution outside the site are confirmed. The reliability of radiation transport calculation code and the influence factors of dose equivalent rate distribution were examined through the analyses of critical accident at JCO's uranium processing plant occurred on September 30, 1999. The radiation transport calculations including the burn-up calculations were done by using of the structural info...
Epistemological problems in assessing cancer risks at low radiation doses
International Nuclear Information System (INIS)
Walinder, G.
1987-01-01
Historically, biology has not been subjected to any epistemological analysis as has been the case with mathematics and physics. Our knowledge of the effects in biological systems of various stimuli proves to be dualistic in a complementary (although not mutually exclusive) way, which bears resemblance to the knowledge of phenomena in quantum physics. The dualistic limbs of biological knowledge are the action of stimuli and the response of the exposed, biological system. With regard to radiogenic cancer, this corresponds to the action of the ionizations and the response of the exposed mammal to that action, respectively. The following conclusions can be drawn from the present analysis: Predictions as to radiogenic cancer seem often if not always to have neglected the response variability (variations in radiosensitivity) in individuals or among individuals in populations, i.e. the predictions have been based exclusively on radiation doses and exposure conditions. The exposed individual or population, however, must be considered an open statistical system, i.e. a system in which predictions as to the effect of an agent are only conditionally possible. The knowledge is inverse to the size of the dose or concentration of the active agent. On epistemological grounds, we can not gain knowledge about the carcinogenic capacity of very low (non-dominant) radiation doses. Based on the same principle, we can not predict cancer risks at very low (non-dominant) radiation doses merely on the basis of models, or otherwise interpolated or extrapolated high-dose effects, observed under special exposure conditions
Problems linked to effects of ionizing radiations low doses
International Nuclear Information System (INIS)
Anon.
1995-10-01
The question of exposure to ionizing radiations low doses and risks existing for professional and populations has been asked again, with the recommendations of the International Commission of Radiation Protection (ICRP) to lower the previous standards and agreed as guides to organize radiation protection, by concerned countries and big international organisms. The sciences academy presents an analysis which concerned on epidemiological and dosimetric aspects in risk estimation, on cellular and molecular aspects of response mechanism to irradiation. The observation of absence of carcinogen effects for doses inferior to 200 milli-sieverts and a re-evaluation of data coming from Nagasaki and Hiroshima, lead to revise the methodology of studies to pursue, to appreciate more exactly the effects of low doses, in taking in part, particularly, the dose rate. The progress of molecular and cellular biology showed that the extrapolation from high doses to low doses is not in accordance with actual data. The acknowledge of DNA repair and carcinogenesis should make clearer the debate. (N.C.). 61 refs., 9 annexes
Marco A. Contreras; Woodam Chung; Greg Jones
2008-01-01
Forest transportation planning problems (FTPP) have evolved from considering only the financial aspects of timber management to more holistic problems that also consider the environmental impacts of roads. These additional requirements have introduced side constraints, making FTPP larger and more complex. Mixed-integer programming (MIP) has been used to solve FTPP, but...
The analysis by several neutron transport methods of a small PWR model problem
International Nuclear Information System (INIS)
Halsall, M.J.
1980-09-01
A small model problem in x-y co-ordinate geometry is specified in detail to permit readers to make their own calculations. The problem is analysed using diffusion theory, differential and integral transport methods and a Monte Carlo code, and a best estimate eigenvalue is deduced. (author)
Alamsyah, Andry; Rachmadiansyah, Imam
2018-03-01
Online transportation service is known for its accessibility, transparency, and tariff affordability. These points make online transportation have advantages over the existing conventional transportation service. Online transportation service is an example of disruptive technology that change the relationship between customers and companies. In Indonesia, there are high competition among online transportation provider, hence the companies must maintain and monitor their service level. To understand their position, we apply both sentiment analysis and multiclass classification to understand customer opinions. From negative sentiments, we can identify problems and establish problem-solving priorities. As a case study, we use the most popular online transportation provider in Indonesia: Gojek and Grab. Since many customers are actively give compliment and complain about company’s service level on Twitter, therefore we collect 61,721 tweets in Bahasa during one month observations. We apply Naive Bayes and Support Vector Machine methods to see which model perform best for our data. The result reveal Gojek has better service quality with 19.76% positive and 80.23% negative sentiments than Grab with 9.2% positive and 90.8% negative. The Gojek highest problem-solving priority is regarding application problems, while Grab is about unusable promos. The overall result shows general problems of both case study are related to accessibility dimension which indicate lack of capability to provide good digital access to the end users.
International Nuclear Information System (INIS)
Frankel, J.I.
1995-01-01
This investigation uses symbolic computation in developing analytical methods and general computational strategies for solving both linear and nonlinear, regular and singular, integral and integro-differential equations which appear in radiative and combined mode energy transport. This technical report summarizes the research conducted during the first nine months of the present investigation. The use of Chebyshev polynomials augmented with symbolic computation has clearly been demonstrated in problems involving radiative (or neutron) transport, and mixed-mode energy transport. Theoretical issues related to convergence, errors, and accuracy have also been pursued. Three manuscripts have resulted from the funded research. These manuscripts have been submitted to archival journals. At the present time, an investigation involving a conductive and radiative medium is underway. The mathematical formulation leads to a system of nonlinear, weakly-singular integral equations involving the unknown temperature and various Legendre moments of the radiative intensity in a participating medium. Some preliminary results are presented illustrating the direction of the proposed research
Solving the Single-Sink, Fixed-Charge, Multiple-Choice Transportation Problem by Dynamic Programming
DEFF Research Database (Denmark)
Christensen, Tue; Andersen, Kim Allan; Klose, Andreas
2013-01-01
This paper considers a minimum-cost network flow problem in a bipartite graph with a single sink. The transportation costs exhibit a staircase cost structure because such types of transportation cost functions are often found in practice. We present a dynamic programming algorithm for solving...... this so-called single-sink, fixed-charge, multiple-choice transportation problem exactly. The method exploits heuristics and lower bounds to peg binary variables, improve bounds on flow variables, and reduce the state-space variable. In this way, the dynamic programming method is able to solve large...... instances with up to 10,000 nodes and 10 different transportation modes in a few seconds, much less time than required by a widely used mixed-integer programming solver and other methods proposed in the literature for this problem....
2D numerical comparison between S{sub n} and M{sub 1} radiation transport methods
Energy Technology Data Exchange (ETDEWEB)
Gonzalez, Matthias [Instituto de Fusion Nuclear, Universidad Politecnica de Madrid, calle Jose Gutierrez Abascal 2, 28006 Madrid (Spain)], E-mail: matthias@din.upm.es; Garcia-Fernandez, Carlos [Instituto de Fusion Nuclear, Universidad Politecnica de Madrid, calle Jose Gutierrez Abascal 2, 28006 Madrid (Spain)], E-mail: carlos@din.upm.es; Velarde, Pedro [Instituto de Fusion Nuclear, Universidad Politecnica de Madrid, calle Jose Gutierrez Abascal 2, 28006 Madrid (Spain)], E-mail: velarde@din.upm.es
2009-07-15
In this article we study the accuracy of the M{sub 1} method to solve some relevant radiation transport problems in 2D. We compare two radiation models (S{sub n} and M{sub 1}) with analytical and numerical tests to highlight the strengths and limitations of each method. These methods give comparable results except when sharp geometry effects are present. We have used these methods in a test that mimics, without fluid motion or electron heat conduction, the cone-target interaction relevant to inertial confinement fusion physics. In this case, we show that S{sub n} and M{sub 1} models agree with a quite good accuracy but shows differences in the temperature profiles and heating times inside the target. These results point out that M{sub 1} is a possible alternative candidate for 3D simulations, where full energy transport methods are extremely computer time consuming.
Survey of projected growth and problems facing air transportation, 1975 - 1985
Williams, L. J.; Wilson, A.
1975-01-01
Results are presented of a survey conducted to determine the current opinion of people working in air transportation demand forecasting on the future of air transportation over the next ten years. In particular, the survey included questions on future demand growth, load factor, fuel prices, introduction date for the next new aircraft, the priorities of problems facing air transportation, and the probability of a substantial change in air transportation regulation. The survey participants included: airlines, manufacturers, universities, government agencies, and other organizations (financial institutions, private research companies, etc.). The results are shown for the average responses within the organization represented as well as the overall averages.
Problems of economic security in Russian transportation and intermediate carrier infrastructure
Directory of Open Access Journals (Sweden)
Valeriy Anatol'evich Tsvetkov
2012-03-01
Full Text Available This paper reviews the basic problems of economic security in infrastructural ensuring of the implementation of transportation and intermediate carrier potential of Russia: development and reconstruction of communication lines, usage of innovative transportation methods, building a network of transportation and logistics centers, development of regional airport hubs and others. Particular attention is paid to the problems of transportation and transit potential implementation of Siberia and the Far East. It is shown that the increase of transit facilities in the territory of Russia takes place in a competitive market of infrastructure projects. At the same time it is emphasized that along with exhausting the possibilities of commodity economy development, a natural competitive advantage of Russia as a transport bridge between Europe, Asia and America will be implemented in full force.
Problems of economic security in Russian transportation and intermediate carrier infrastructure
Directory of Open Access Journals (Sweden)
Valeriy Anatol'evich Tsvetkov
2012-06-01
Full Text Available This paper reviews the basic problems of economic security in infrastructural ensuring of the implementation of transportation and intermediate carrier potential of Russia: development and reconstruction of communication lines, usage of innovative transportation methods, building a network of transportation and logistics centers, development of regional airport hubs and others. Particular attention is paid to the problems of transportation and transit potential implementation of Siberia and the Far East. It is shown that the increase of transit facilities in the territory of Russia takes place in a competitive market of infrastructure projects. At the same time it is emphasized that along with exhausting the possibilities of commodity economy development, a natural competitive advantage of Russia as a transport bridge between Europe, Asia and America will be implemented in full force.
International Nuclear Information System (INIS)
Hall, M.L.; Davis, A.B.
2005-01-01
Accurate modeling of radiative energy transport through cloudy atmospheres is necessary for both climate modeling with GCMs (Global Climate Models) and remote sensing. Previous modeling efforts have taken advantage of extreme aspect ratios (cells that are very wide horizontally) by assuming a 1-D treatment vertically - the Independent Column Approximation (ICA). Recent attempts to resolve radiation transport through the clouds have drastically changed the aspect ratios of the cells, moving them closer to unity, such that the ICA model is no longer valid. We aim to provide a higher-fidelity atmospheric radiation transport model which increases accuracy while maintaining efficiency. To that end, this paper describes the development of an efficient 3-D-capable radiation code that can be easily integrated into cloud resolving models as an alternative to the resident 1-D model. Applications to test cases from the Intercomparison of 3-D Radiation Codes (I3RC) protocol are shown
A Photon Free Method to Solve Radiation Transport Equations
International Nuclear Information System (INIS)
Chang, B
2006-01-01
The multi-group discrete-ordinate equations of radiation transfer is solved for the first time by Newton's method. It is a photon free method because the photon variables are eliminated from the radiation equations to yield a N group XN direction smaller but equivalent system of equations. The smaller set of equations can be solved more efficiently than the original set of equations. Newton's method is more stable than the Semi-implicit Linear method currently used by conventional radiation codes
International Nuclear Information System (INIS)
Yamano, Naoki; Minami, Kazuyoshi; Koyama, Kinji; Naito, Yoshitaka.
1989-03-01
A modular code system RADHEAT-V4 has been developed for performing precisely neutron and photon transport analyses, and shielding safety evaluations. The system consists of the functional modules for producing coupled multi-group neutron and photon cross section sets, for analyzing the neutron and photon transport, and for calculating the atom displacement and the energy deposition due to radiations in nuclear reactor or shielding material. A precise method named Direct Angular Representation (DAR) has been developed for eliminating an error associated with the method of the finite Legendre expansion in evaluating angular distributions of cross sections and radiation fluxes. The DAR method implemented in the code system has been described in detail. To evaluate the accuracy and applicability of the code system, some test calculations on strong anisotropy problems have been performed. From the results, it has been concluded that RADHEAT-V4 is successfully applicable to evaluating shielding problems accurately for fission and fusion reactors and radiation sources. The method employed in the code system is very effective in eliminating negative values and oscillations of angular fluxes in a medium having an anisotropic source or strong streaming. Definitions of the input data required in various options of the code system and the sample problems are also presented. (author)
Anthology of the development of radiation transport tools as applied to single event effects
International Nuclear Information System (INIS)
Akkerman, A.; Barak, J.; Murat, M.; Duzellier, S.; Hubert, G.; Gaillardin, M.; Raine, M.; Jordan, T.; Jun, I.; Koontz, S.; Reddell, B.; O'Neill, P.; Foster, C.; Culpepper, W.; Lei, F.; McNulty, P.; Nieminen, P.; Saigne, F.; Wrobel, F.; Santin, G.; Sihver, L.; Tang, H.H.K.; Truscott, P.R.
2013-01-01
This anthology contains contributions from eleven different groups, each developing and/or applying Monte Carlo-based radiation transport tools to simulate a variety of effects that result from energy transferred to a semiconductor material by a single particle event. The topics span from basic mechanisms for single-particle induced failures to applied tasks like developing web sites to predict on-orbit single event failure rates using Monte Carlo radiation transport tools. (authors)
Anthology of the Development of Radiation Transport Tools as Applied to Single Event Effects
Reed, R. A.; Weller, R. A.; Akkerman, A.; Barak, J.; Culpepper, W.; Duzellier, S.; Foster, C.; Gaillardin, M.; Hubert, G.; Jordan, T.; Jun, I.; Koontz, S.; Lei, F.; McNulty, P.; Mendenhall, M. H.; Murat, M.; Nieminen, P.; O'Neill, P.; Raine, M.; Reddell, B.; Saigné, F.; Santin, G.; Sihver, L.; Tang, H. H. K.; Truscott, P. R.; Wrobel, F.
2013-06-01
This anthology contains contributions from eleven different groups, each developing and/or applying Monte Carlo-based radiation transport tools to simulate a variety of effects that result from energy transferred to a semiconductor material by a single particle event. The topics span from basic mechanisms for single-particle induced failures to applied tasks like developing websites to predict on-orbit single event failure rates using Monte Carlo radiation transport tools.
The status quo, problems and improvements pertaining to radiation source management in China
International Nuclear Information System (INIS)
Jin Jiaqi
1998-01-01
Early in 1930s, radiation sources were used in medicine in China, and since then their application has been widely extended in a variety of fields. This paper presents a brief outline of the status quo, problems on management for radiation sources, and some relevant improvements as recommended by author are also included in it. (author)
A numerical method for two-dimensional anisotropic transport problem in cylindrical geometry
International Nuclear Information System (INIS)
Du Mingsheng; Feng Tiekai; Fu Lianxiang; Cao Changshu; Liu Yulan
1988-01-01
The authors deal with the triangular mesh-discontinuous finite element method for solving the time-dependent anisotropic neutron transport problem in two-dimensional cylindrical geometry. A prior estimate of the numerical solution is given. Stability is proved. The authors have computed a two dimensional anisotropic neutron transport problem and a Tungsten-Carbide critical assembly problem by using the numerical method. In comparision with DSN method and the experimental results obtained by others both at home and abroad, the method is satisfactory
Synthetic acceleration methods for linear transport problems with highly anisotropic scattering
International Nuclear Information System (INIS)
Khattab, K.M.; Larsen, E.W.
1992-01-01
The diffusion synthetic acceleration (DSA) algorithm effectively accelerates the iterative solution of transport problems with isotropic or mildly anisotropic scattering. However, DSA loses its effectiveness for transport problems that have strongly anisotropic scattering. Two generalizations of DSA are proposed, which, for highly anisotropic scattering problems, converge at least an order of magnitude (clock time) faster than the DSA method. These two methods are developed, the results of Fourier analysis that theoretically predict their efficiency are described, and numerical results that verify the theoretical predictions are presented. (author). 10 refs., 7 figs., 5 tabs
Synthetic acceleration methods for linear transport problems with highly anisotropic scattering
International Nuclear Information System (INIS)
Khattab, K.M.; Larsen, E.W.
1991-01-01
This paper reports on the diffusion synthetic acceleration (DSA) algorithm that effectively accelerates the iterative solution of transport problems with isotropic or mildly anisotropic scattering. However, DSA loses its effectiveness for transport problems that have strongly anisotropic scattering. Two generalizations of DSA are proposed, which, for highly anisotropic scattering problems, converge at least an order of magnitude (clock time) faster than the DSA method. These two methods are developed, the results of Fourier analyses that theoretically predict their efficiency are described, and numerical results that verify the theoretical predictions are presented
A difference quotient-numerical integration method for solving radiative transfer problems
International Nuclear Information System (INIS)
Ding Peizhu
1992-01-01
A difference quotient-numerical integration method is adopted to solve radiative transfer problems in an anisotropic scattering slab medium. By using the method, the radiative transfer problem is separated into a system of linear algebraic equations and the coefficient matrix of the system is a band matrix, so the method is very simple to evaluate on computer and to deduce formulae and easy to master for experimentalists. An example is evaluated and it is shown that the method is precise
Radiology and radiation protection. Present-day problems
International Nuclear Information System (INIS)
Andrieu, L.
1978-01-01
With the development of nuclear energy the present-day problems of radioprotection are studied in the light of new radiobiological knowledge. The following points are analysed in turn: radioprotection norms, the notion of acceptable risk; influence of dose rate and fractionation; the low-dose problem; relative biological effectiveness (RBE) and quality factor (Q.F.); the biological problem of long-term effects. The genetic risk due to accepted radioprotection norms is estimated. The part played by radioprotection organisations is underlined, with emphasis on the fact that radioactivity is the most strictly and effectively regulated of all industrial inconveniences. It is pointed out that medical irradiation is not subject to the legislations and regulations listed [fr
Padalino, B; Raidal, S L; Hall, E; Knight, P; Celi, P; Jeffcott, L; Muscatello, G
2017-07-01
Transportation can affect equine health and is a potential source of economic loss to the industry. To identify journey (duration, vehicle, commercial or noncommercial) and horse (sex, age, breed, use, amateur or professional status) characteristics associated with the development of transport-related health problems in horses. Cross-sectional online survey. An online survey was conducted targeting amateur and professional participants in the Australian equine industry; eligible respondents were required to organise horse movements at least monthly. Respondents provided details of the last case of a transport-related health problem that had affected their horse(s). Associations between type of health problem, journey and horse characteristics were examined with multivariable multinomial regression analysis. Based on 214 responses, health problems were classified as injuries, muscular problems, heat stroke, gastrointestinal and respiratory problems, and death or euthanasia. Respiratory problems were reported most frequently (33.7%), followed by gastrointestinal problems (23.8%) and traumatic injuries (16.3%). The type of health problem was associated with journey duration (Pproblems, and death or euthanasia) were more likely to occur on long journeys. Using Standardbreds as the reference group, Thoroughbreds, Arabians and Warmbloods were more likely to experience a severe illness than an injury. Self-selected participation in the study and the self-reported nature of transport-related problems. Horses undertaking journeys of longer than 24 h are at greater risk for the development of severe disease or death. Further studies on long-haul transportation effects are required to safeguard the welfare of horses moved over long distances. © 2016 EVJ Ltd.
Analysis of some greedy algorithms for the single-sink fixed-charge transportation problem
DEFF Research Database (Denmark)
Görtz, Simon; Klose, Andreas
2009-01-01
-charge transportation problem. Nevertheless, just a few methods for solving this problem have been proposed in the literature. In this paper, some greedy heuristic solutions methods for the SSFCTP are investigated. It is shown that two greedy approaches for the SSFCTP known from the literature can be arbitrarily bad......, whereas an approximation algorithm proposed in the literature for the binary min-knapsack problem has a guaranteed worst case bound if adapted accordingly to the case of the SSFCTP....
On the propagation problem in gravitational radiation theory
International Nuclear Information System (INIS)
Damour, T.
1986-01-01
The authors emphasize that a suitable combination of analytical and numerical methods might be useful to overcome the limitations of both methods. In particular, analytical methods are needed, on the one hand to provide boundary conditions to numerical codes, and on the other hand to relate the gravitational field at the outer edge of the grid with the asymptotic outgoing wave form. The authors present an explicit formula which solves approximately the latter ''propagation problem'' in a simplified situation which might be relevant to the problem of computing the gravitational wave form emitted during the three-dimensional collapse of a star
Uses of ionizing radiation and medical-care-related problems
International Nuclear Information System (INIS)
Smathers, J.B.
1988-01-01
The uses of ionizing radiation in medicine are currently undergoing changes due to at least four major influences: (1) the constantly changing public perception of the hazards of radiation, (2) continuing technical innovation and development in equipment, (3) the imposition of diagnosis-related group funding by government health-care funding agencies, and (4) an increase in the average age of the U.S. population. The combined effect of these influences will probably result in a major increase in biplanar fluoroscopic examinations to support nonsurgical approaches such as percutaneous transluminal coronary angioplasty, percutaneous transluminal neuroembolism, and lithotripsy (the fracturing of kidney stones). As some of these examinations can result in 1.5 h of fluoroscopy, major doses to the patient and to the clinical staff can be expected. In addition, improved diagnostic techniques, such as using positron emission tomography (a combination of biochemistry and positron-emitting isotopes), can be expected to increase the number of small cyclotrons installed in medical centers. Counteracting these increases in radiation exposure is the development of digital radiography, which generally results in a lowering of the dose per diagnostic procedure. In the realm of therapeutic uses, one can expect higher-energy treatment accelerators, more patients being released from the hospital on therapeutic doses of isotopes, and a potential acceptance of neutron therapy as a cancer treatment modality. The latter treatment may take the form of boron capture therapy, 252Cf implant therapy, or external beam therapy using high-energy cyclotrons and the p,Be or the d,Be reaction to create the neutrons
Problems of radiation protection linked to the computers omnipresence
International Nuclear Information System (INIS)
Rosenwald, J.C.
2009-01-01
The common point between the serious radiation accidents was in relation with an error of the time of treatment and the introduction of a new procedure. The introduction of filters to modify the beams constitutes an other factor of risk. It exists a risk that the increasing of the complexity leads to a lack of the human control on the process and then accidents can happen, essentially because an insufficient understanding of the user and/or to a lack of resources. (N.C.)
The great east Japan earthquake and radiation exposure problem in Fukushima
International Nuclear Information System (INIS)
Otani, Koji; Konno, Shinichi; Shishido, Hiroaki
2012-01-01
Described are actions taken by Fukushima Medical University (FMU) and its Department of Orthopedic Surgery (DOS) after the Quake Disaster (Mar. 11, 2011), and present state, at about 1 year later, of Fukushima Prefecture suffering from the Fukushima Daiichi Power Plant (FDPP) radiation problem. Firstly described are the roles played by FMU as a backup medical supporting facility and by DOS therein according to the following time frame. During several days after the Quake, 35 DMAT (Disaster Medical Assistant Team) consisting from 180 professionals gathered in FMU. The number of emergent outpatients within 3 days after the quake was 168, and 10 patients involving 4 with trauma underwent 11 operations by DOS. Within the next 1 week after, FMU tentatively received 175 patients transported from evacuation area localizing at 30 km distance from FDPP. At later than 2 weeks after, FMU re-started the routine medicare of outpatients in its all departments (Mar. 28), when high grade DMAT and local family medicare team started to visit refuges and isolated patients, respectively. Numbers of patients with the disaster-related trauma needed for hospitalization in 3 DOS related facilities having >1,000 beds in the Prefecture were 18-38, 10-25, 5-9 and 3-8, in the order of respective months from March to June. Second, FMU activities against radiation exposure started with visit of 4 possibly exposed residents on Mar. 12, with voluntary cooperation of many medical students. Medical training held in Sep. 2010 was quite useful for the rapid action of FMU to the Disaster, which made personnel recognize the importance of such education. Problems of external and internal exposure of low dose radiation are the future task, for which follow-up of health survey of 2,020 thousands Prefectural residents is to be continued for >30 years onward. At present, restoration of medicare seems difficult to recover to the level before the Disaster as exemplified by the decrease of hospital doctors
Department of Environmental and Radiation Transport Physics - Overview
International Nuclear Information System (INIS)
Woznicka, U.
2002-01-01
geological structures, in collaboration with the Institute of Geological Sciences of Polish Academy of Sciences. The geological fault system which surrounds the ''Las Wolski'' horst is covered with loess overburden. An evident increase in radon concentration in the upper loess layer is observed over the fault position. This may have important environmental implications. Several samples of soil taken from those areas were analysed for the concentration of natural isotopes (U, Th, and K). Natural radioactivity measurements in various samples (soils, rocks, raw, and building materials, etc.) have been carried out using low background spectrometers (with NaI(Tl) and HPGe detectors). We took part in the national inter-comparison concerning the methodology of ''radon-in-water'' measurements. The results are to be published. A joint project ''The Radon Centre - Non- Governmental International Scientific Network'' has been started in co-operation with the Central Mining Institute in Katowice. The main goals are to prepare and execute joint research projects and programmes, and to disseminate and put into practice the results of research activities of particular Network members. Neutron methods are an important part of nuclear geophysics and are also used in medical modalities. Investigations of the neutron transport parameters require usually the detection and/or calculation of spatial, time, and energy distributions of fast, epithermal and thermal neutrons, and of the accompanying γ radiation. The research has been directed into several aspects: - Basic theoretical and experimental investigation for the thermal neutron transport: a) the temperature behaviour of the pulsed parameters in a hydrogenous moderator, b) diffusion cooling in small two-region systems containing substances of different types of energy characteristics of thermal neutron scattering. - Calculations of the radiation field and energy deposition in the water beam dump for the TESLA electron-positron collider for
Intermodal safety research needs report of the sixth workshop on national transportation problems
Energy Technology Data Exchange (ETDEWEB)
Warshawer, A.J. (ed.)
1976-04-01
This conference brought together DOT policymakers, university principal investigators and other professionals to consider the intermodal safety research requirements of the Department of Transportation. The objectives of the conference were: (1) to highlight safety problems and needed transportation safety research identified by DOT modal safety managers and to stimulate university or university/industry teams to respond with research proposals which emphasize multi-modal applicability and a system view; and (2) to provide a forum for university research groups to inform DOT safety managers of promising new directions in transportation safety research and new tools with which to address safety related problems. The conference addressed the research requirements for safety as identified by the Statement of National Transportation Policy and by the modal safety managers in three principal contexts, each a workshop panel: I, Inter-Institutional Problems of Transportation Safety. Problems were described as: Federal-State, local; Federal-Industry; Federal-Public, Consumer groups. II, Goal Setting and Planning for Transportation Safety Programs. Issues were: modifying risk behavior, safety as a social value, and involving citizens in development of standards as a way of increasing probability of achieving program objectives. III, DOT Information, Management, and Evaluation Systems Requirements. Needs were: data requirements and analytic tools for management of safety programs.
Energy Technology Data Exchange (ETDEWEB)
Pomarola, J.; Savouyaud, J. [Service de Controle des Radiations et de Genie Radioactif, Commissariat a l' Energie Atomique, Saclay (France)
1960-07-01
I. The handling and transport of radioactive waste involves the risk of irradiation and contamination. It is necessary to draw up special regulations governing the removal and transport of waste within the centres or from one centre to another, and to entrust transport to a group in charge of specialized teams. The organization, equipment and efficiency of such teams is then considered. II. Certain types of transport operation are particularly dangerous and require special transport units and fixed installations. This applies, in particular, to the disposal of highly radioactive liquids. A description is given of a composite transport unit, consisting of a towing vehicle, semi-trailer and tank holding 500 l of liquid with an activity of up to 1,000 c/l. The drawing-off of the liquid waste, routing of the transport unit and precautions to be taken are discussed. (author) [French] I - La manipulation et le j transport des dechets radioactifs presentent des dangers d'irradiation et de contamination. Il est necessaire: - d'edicter des consignes speciales applicables a l'enlevement et au transport des dechets dans les centres ou de centre a centre. - de confier les transports a un groupe dont relevent des equipes specialisees. On examine l'organisation, les moyens, le rendement de ces equipes. II - Certains transports sont particulierement dangereux et necessitent des engins speciaux et des installations fixes. C'est le cas, notamment, de l'evacuation des liquides tres actifs. On decrit : Inverted-Exclamation-Mark - un engin de transport compose d'un ensemble: tracteur, semi- remorque et d'un recipient qui contient 500 litres de liquide dont l'activite peut atteindre 1.000 c/l. - les operations de transvasement, l'acheminement de l'engin, les precautions prises. (author) [Spanish] I - La manipulacion y el transporte de desechos radiactivos ofrecen riesgos de irradiacion y de contaminacion. Es necesario: - dictar consignas especiales para retirar los desechos y para su
International Nuclear Information System (INIS)
Uchino, Minako; Itazawa, Tomoko; Someya, Masanori; Nakamura, Satoaki
2007-01-01
The Japanese Association for Therapeutic Radiation Oncology (JASTRO) holds a seminar for medical students every summer, which has developed into a joint program with a session addressing radiation treatment planning. To clarify this topic for medical students, we have incorporated Problem Based Learning skills into the session. Not only has the students' comprehension improved but the instructors have also found this teaching experience valuable and productive in advancing their own clinical skills. Our experience suggests that the application of this Problem Based Learning session for radiation treatment planning in undergraduate medical school education has proven to be effective. (author)
Monte Carlo analysis of radiative transport in oceanographic lidar measurements
Energy Technology Data Exchange (ETDEWEB)
Cupini, E.; Ferro, G. [ENEA, Divisione Fisica Applicata, Centro Ricerche Ezio Clementel, Bologna (Italy); Ferrari, N. [Bologna Univ., Bologna (Italy). Dipt. Ingegneria Energetica, Nucleare e del Controllo Ambientale
2001-07-01
The analysis of oceanographic lidar systems measurements is often carried out with semi-empirical methods, since there is only a rough understanding of the effects of many environmental variables. The development of techniques for interpreting the accuracy of lidar measurements is needed to evaluate the effects of various environmental situations, as well as of different experimental geometric configurations and boundary conditions. A Monte Carlo simulation model represents a tool that is particularly well suited for answering these important questions. The PREMAR-2F Monte Carlo code has been developed taking into account the main molecular and non-molecular components of the marine environment. The laser radiation interaction processes of diffusion, re-emission, refraction and absorption are treated. In particular are considered: the Rayleigh elastic scattering, produced by atoms and molecules with small dimensions with respect to the laser emission wavelength (i.e. water molecules), the Mie elastic scattering, arising from atoms or molecules with dimensions comparable to the laser wavelength (hydrosols), the Raman inelastic scattering, typical of water, the absorption of water, inorganic (sediments) and organic (phytoplankton and CDOM) hydrosols, the fluorescence re-emission of chlorophyll and yellow substances. PREMAR-2F is an extension of a code for the simulation of the radiative transport in atmospheric environments (PREMAR-2). The approach followed in PREMAR-2 was to combine conventional Monte Carlo techniques with analytical estimates of the probability of the receiver to have a contribution from photons coming back after an interaction in the field of view of the lidar fluorosensor collecting apparatus. This offers an effective mean for modelling a lidar system with realistic geometric constraints. The retrieved semianalytic Monte Carlo radiative transfer model has been developed in the frame of the Italian Research Program for Antarctica (PNRA) and it is
Metaheuristics for the dynamic stochastic dial-a-ride problem with expected return transports.
Schilde, M; Doerner, K F; Hartl, R F
2011-12-01
The problem of transporting patients or elderly people has been widely studied in literature and is usually modeled as a dial-a-ride problem (DARP). In this paper we analyze the corresponding problem arising in the daily operation of the Austrian Red Cross. This nongovernmental organization is the largest organization performing patient transportation in Austria. The aim is to design vehicle routes to serve partially dynamic transportation requests using a fixed vehicle fleet. Each request requires transportation from a patient's home location to a hospital (outbound request) or back home from the hospital (inbound request). Some of these requests are known in advance. Some requests are dynamic in the sense that they appear during the day without any prior information. Finally, some inbound requests are stochastic. More precisely, with a certain probability each outbound request causes a corresponding inbound request on the same day. Some stochastic information about these return transports is available from historical data. The purpose of this study is to investigate, whether using this information in designing the routes has a significant positive effect on the solution quality. The problem is modeled as a dynamic stochastic dial-a-ride problem with expected return transports. We propose four different modifications of metaheuristic solution approaches for this problem. In detail, we test dynamic versions of variable neighborhood search (VNS) and stochastic VNS (S-VNS) as well as modified versions of the multiple plan approach (MPA) and the multiple scenario approach (MSA). Tests are performed using 12 sets of test instances based on a real road network. Various demand scenarios are generated based on the available real data. Results show that using the stochastic information on return transports leads to average improvements of around 15%. Moreover, improvements of up to 41% can be achieved for some test instances.
International Nuclear Information System (INIS)
Maskewitz, B.F.; Trubey, D.K.; Roussin, R.W.; McGill, B.L.
1976-04-01
The Radiation Shielding Information Center (RSIC) is engaged in a program to seek out, organize, and disseminate information in the area of radiation transport, shielding, and radiation protection. This information consists of published literature, nuclear data, and computer codes and advanced analytical techniques required by ERDA, its contractors, and the nuclear power industry to improve radiation analysis and computing capability. Information generated in this effort becomes a part of the RSIC collection and/or data base. The purpose of this report on project 219-1 is to document the results of the survey of information and computer code needs of the nuclear power industry in the area of radiation analysis and protection
Energy Technology Data Exchange (ETDEWEB)
Maskewitz, B.F.; Trubey, D.K.; Roussin, R.W.; McGill, B.L.
1976-04-01
The Radiation Shielding Information Center (RSIC) is engaged in a program to seek out, organize, and disseminate information in the area of radiation transport, shielding, and radiation protection. This information consists of published literature, nuclear data, and computer codes and advanced analytical techniques required by ERDA, its contractors, and the nuclear power industry to improve radiation analysis and computing capability. Information generated in this effort becomes a part of the RSIC collection and/or data base. The purpose of this report on project 219-1 is to document the results of the survey of information and computer code needs of the nuclear power industry in the area of radiation analysis and protection.
Energy Technology Data Exchange (ETDEWEB)
Philip, Bobby, E-mail: philipb@ornl.gov [Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN 37831 (United States); Berrill, Mark A.; Allu, Srikanth; Hamilton, Steven P.; Sampath, Rahul S.; Clarno, Kevin T. [Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN 37831 (United States); Dilts, Gary A. [Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM 87545 (United States)
2015-04-01
This paper describes an efficient and nonlinearly consistent parallel solution methodology for solving coupled nonlinear thermal transport problems that occur in nuclear reactor applications over hundreds of individual 3D physical subdomains. Efficiency is obtained by leveraging knowledge of the physical domains, the physics on individual domains, and the couplings between them for preconditioning within a Jacobian Free Newton Krylov method. Details of the computational infrastructure that enabled this work, namely the open source Advanced Multi-Physics (AMP) package developed by the authors is described. Details of verification and validation experiments, and parallel performance analysis in weak and strong scaling studies demonstrating the achieved efficiency of the algorithm are presented. Furthermore, numerical experiments demonstrate that the preconditioner developed is independent of the number of fuel subdomains in a fuel rod, which is particularly important when simulating different types of fuel rods. Finally, we demonstrate the power of the coupling methodology by considering problems with couplings between surface and volume physics and coupling of nonlinear thermal transport in fuel rods to an external radiation transport code.
Directory of Open Access Journals (Sweden)
Yan Sun
2015-09-01
Full Text Available Purpose: The purpose of study is to solve the multi-modal transportation routing planning problem that aims to select an optimal route to move a consignment of goods from its origin to its destination through the multi-modal transportation network. And the optimization is from two viewpoints including cost and time. Design/methodology/approach: In this study, a bi-objective mixed integer linear programming model is proposed to optimize the multi-modal transportation routing planning problem. Minimizing the total transportation cost and the total transportation time are set as the optimization objectives of the model. In order to balance the benefit between the two objectives, Pareto optimality is utilized to solve the model by gaining its Pareto frontier. The Pareto frontier of the model can provide the multi-modal transportation operator (MTO and customers with better decision support and it is gained by the normalized normal constraint method. Then, an experimental case study is designed to verify the feasibility of the model and Pareto optimality by using the mathematical programming software Lingo. Finally, the sensitivity analysis of the demand and supply in the multi-modal transportation organization is performed based on the designed case. Findings: The calculation results indicate that the proposed model and Pareto optimality have good performance in dealing with the bi-objective optimization. The sensitivity analysis also shows the influence of the variation of the demand and supply on the multi-modal transportation organization clearly. Therefore, this method can be further promoted to the practice. Originality/value: A bi-objective mixed integer linear programming model is proposed to optimize the multi-modal transportation routing planning problem. The Pareto frontier based sensitivity analysis of the demand and supply in the multi-modal transportation organization is performed based on the designed case.
Solution of stochastic media transport problems using a numerical quadrature-based method
International Nuclear Information System (INIS)
Pautz, S. D.; Franke, B. C.; Prinja, A. K.; Olson, A. J.
2013-01-01
We present a new conceptual framework for analyzing transport problems in random media. We decompose such problems into stratified subproblems according to the number of material pseudo-interfaces within realizations. For a given subproblem we assign pseudo-interface locations in each realization according to product quadrature rules, which allows us to deterministically generate a fixed number of realizations. Quadrature integration of the solutions of these realizations thus approximately solves each subproblem; the weighted superposition of solutions of the subproblems approximately solves the general stochastic media transport problem. We revisit some benchmark problems to determine the accuracy and efficiency of this approach in comparison to randomly generated realizations. We find that this method is very accurate and fast when the number of pseudo-interfaces in a problem is generally low, but that these advantages quickly degrade as the number of pseudo-interfaces increases. (authors)
Compendium to radiation physics for medical physicists 300 problems and solutions
Podgorsak, Ervin B
2014-01-01
This exercise book contains 300 typical problems and exercises in modern physics and radiation physics with complete solutions, detailed equations and graphs. This textbook is linked directly with the textbook "Radiation Physics for Medical Physicists", Springer (2010) but can also be used in combination with other related textbooks. For ease of use, this textbook has exactly the same organizational layout (14 chapters, 128 sections) as the "Radiation Physics for Medical Physicists" textbook and each section is covered by at least one problem with solution given. Equations, figures and tables are cross-referenced between the two books. It is the only large compilation of textbook material and associated solved problems in medical physics, radiation physics, and biophysics.
International Nuclear Information System (INIS)
Roberds, R.M.
1975-01-01
A space-angle synthesis (SAS) method has been developed for treating the steady-state, two-dimensional transport of neutrons and gamma rays from a point source of simulated nuclear weapon radiation in air. The method was validated by applying it to the problem of neutron transport from a point source in air over a ground interface, and then comparing the results to those obtained by DOT, a state-of-the-art, discrete-ordinates code. In the SAS method, the energy dependence of the Boltzmann transport equation was treated in the standard multigroup manner. The angular dependence was treated by expanding the flux in specially tailored trial functions and applying the method of weighted residuals which analytically integrated the transport equation over all angles. The weighted-residual approach was analogous to the conventional spherical-harmonics (P/sub N/) method with the exception that the tailored expansion allowed for more rapid convergence than a spherical-harmonics P 1 expansion and resulted in a greater degree of accuracy. The trial functions used in the expansion were odd and even combinations of selected trial solutions, the trial solutions being shaped ellipsoids which approximated the angular distribution of the neutron flux in one-dimensional space. The parameters which described the shape of the ellipsoid varied with energy group and the spatial medium, only, and were obtained from a one-dimensional discrete-ordinates calculation. Thus, approximate transport solutions were made available for all two-dimensional problems of a certain class by using tabulated parameters obtained from a single, one-dimensional calculation
Education and Training in Radiation, Transport and Waste Safety Newsletter, No. 2b, May 2013
International Nuclear Information System (INIS)
2013-05-01
The IAEA Strategic Approach to Education and Training in Radiation, Transport and Waste Safety (2011-2020) provides a framework for establishing a sustainable education and training infrastructure in Member States that addresses national needs for building and maintaining competence in radiation, transport and waste safety that is consistent with IAEA Safety Standards. For this purpose, IAEA's General Conference has encouraged Member States to develop a national strategy for education and training, underlining the fundamental importance of sustainable programmes for building competence in radiation, transport and waste safety, as a key component of safety infrastructure. Furthermore Member States that receive assistance from IAEA are obliged to apply IAEA Safety Standards which require, inter alia, governments to establish a national policy and strategy for safety, including provisions for acquiring and maintaining the necessary competence nationally for ensuring safety. IAEA's Division of Radiation, Transport and Waste Safety is assisting Member States to develop their own national strategies in Asia and the Pacific via the Regional project RAS/9/066 on ''Strengthening Education and training Infrastructure, and Building Competence in Radiation Safety'', which includes, inter alia, Regional Workshops on National Strategies for education and training in radiation transport and waste safety. IAEA's Regional Training Centres (RTCs) in Malaysia and Syrian Arabic Republic are key partners in the Asian and the Pacific region.
Education and Training in Radiation, Transport and Waste Safety Newsletter, No. 2c, May 2013
International Nuclear Information System (INIS)
2013-05-01
The IAEA Strategic Approach to Education and Training in Radiation, Transport and Waste Safety (2011-2020) provides a framework for establishing a sustainable education and training infrastructure in Member States that addresses national needs for building and maintaining competence in radiation, transport and waste safety that is consistent with IAEA Safety Standards. For this purpose, IAEA's General Conference has encouraged Member States to develop a national strategy for education and training, underlining the fundamental importance of sustainable programmes for building competence in radiation, transport and waste safety, as a key component of safety infrastructure. Furthermore Member States that receive assistance from IAEA are obliged to apply IAEA Safety Standards which require, inter alia, governments to establish a national policy and strategy for safety, including provisions for acquiring and maintaining the necessary competence nationally for ensuring safety. IAEA's Division of Radiation, Transport and Waste Safety is assisting Member States to develop their own national strategies in Europe via the Regional Project RER/9/109 on ''Strengthening Education and training Infrastructure, and Building Competence in Radiation Safety'', which includes, inter alia, Regional Workshops on National Strategies for education and training in radiation transport and waste safety. IAEA's Regional Training Centres (RTCs) in Greece and Belarus are key partners in the European region.
Education and Training in Radiation, Transport and Waste Safety Newsletter, No. 2d, June 2013
International Nuclear Information System (INIS)
2013-06-01
The IAEA Strategic Approach to Education and Training in Radiation, Transport and Waste Safety (2011-2020) provides a framework for establishing a sustainable education and training infrastructure in Member States that addresses national needs for building and maintaining competence in radiation, transport and waste safety that is consistent with IAEA Safety Standards. For this purpose, IAEA's General Conference has encouraged Member States to develop a national strategy for education and training, underlining the fundamental importance of sustainable programmes for building competence in radiation, transport and waste safety, as a key component of safety infrastructure. Furthermore Member States that receive assistance from IAEA are obliged to apply IAEA Safety Standards which require, inter alia, governments to establish a national policy and strategy for safety, including provisions for acquiring and maintaining the necessary competence nationally for ensuring safety. IAEA's Division of Radiation, Transport and Waste Safety is assisting Member States to develop their own national strategies in Latin America via the Regional Project RLA/9/070 on ''Strengthening Education and training Infrastructure, and Building Competence in Radiation Safety'', which includes, inter alia, Regional Workshops on National Strategies for education and training in radiation transport and waste safety. IAEA's Regional Training Centres (RTCs) in Argentina and Brazil are key partners in the Latin-American region.
Education and Training in Radiation, Transport and Waste Safety Newsletter, No. 2a, May 2013
International Nuclear Information System (INIS)
2013-05-01
The IAEA Strategic Approach to Education and Training in Radiation, Transport and Waste Safety (2011-2020) provides a framework for establishing a sustainable education and training infrastructure in Member States that addresses national needs for building and maintaining competence in radiation, transport and waste safety that is consistent with IAEA Safety Standards. For this purpose, IAEA's General Conference has encouraged Member States to develop a national strategy for education and training, underlining the fundamental importance of sustainable programmes for building competence in radiation, transport and waste safety, as a key component of safety infrastructure. Furthermore Member States that receive assistance from IAEA are obliged to apply IAEA Safety Standards which require, inter alia, governments to establish a national policy and strategy for safety, including provisions for acquiring and maintaining the necessary competence nationally for ensuring safety. IAEA's Division of Radiation, Transport and Waste Safety is assisting Member States to develop their own national strategies in Africa via the Regional project RAF/9/04 on ''Strengthening Education and training Infrastructure, and Building Competence in Radiation Safety'', which includes, inter alia, Regional Workshops on National Strategies for education and training in radiation transport and waste safety. AFRA Regional Designated Centres, in Algeria, Ghana and Morocco, equivalent to the IAEA's Regional Training Centres (RTCs) present in all the other regions, are key partners in the African region.
Transport analysis of high radiation and high density plasmas in the ASDEX Upgrade tokamak
Directory of Open Access Journals (Sweden)
Casali L.
2014-01-01
Full Text Available Future fusion reactors, foreseen in the “European road map” such as DEMO, will operate under more demanding conditions compared to present devices. They will require high divertor and core radiation by impurity seeding to reduce heat loads on divertor target plates. In addition, DEMO will have to work at high core densities to reach adequate fusion performance. The performance of fusion reactors depends on three essential parameters: temperature, density and energy confinement time. The latter characterizes the loss rate due to both radiation and transport processes. The DEMO foreseen scenarios described above were not investigated so far, but are now addressed at the ASDEX Upgrade tokamak. In this work we present the transport analysis of such scenarios. Plasma with high radiation by impurity seeding: transport analysis taking into account the radiation distribution shows no change in transport during impurity seeding. The observed confinement improvement is an effect of higher pedestal temperatures which extend to the core via stiffness. A non coronal radiation model was developed and compared to the bolometric measurements in order to provide a reliable radiation profile for transport calculations. High density plasmas with pellets: the analysis of kinetic profiles reveals a transient phase at the start of the pellet fuelling due to a slower density build up compared to the temperature decrease. The low particle diffusion can explain the confinement behaviour.
Application of the finite element method to problems with heat radiation exchange
International Nuclear Information System (INIS)
Breitbach, G.; Altes, J.
1985-07-01
The calculation of temperature distributions for systems exchanging heat radiation requires in a first step the determination of the heat fluxes caused by radiation at its surfaces. In this paper the radiation transport equation is developed and it is shown, that it can be derived from a variational principle. The functional of the variational principle is the starting point of a numerical solution method. By using Finite Element Procedures a system of linear equations is derived, which supplies an approximation of the radiosity. Having the radiosity the heat flux at the surfaces, which governs as the boundary condition the temperature distribution in the structure, can be calculated. (orig.) [de
Radiation transport effects in divertor plasmas generated during a tokamak reactor disruption
International Nuclear Information System (INIS)
Peterson, R.R.; MacFarlane, J.J.; Wang, P.
1994-01-01
Vaporization of material from tokamak divertors during disruptions is a critical issue for tokamak reactors from ITER to commercial power plants. Radiation transport from the vaporized material onto the remaining divertor surface plays an important role in the total mass loss to the divertor. Radiation transport in such a vapor is very difficult to calculate in full detail, and this paper quantifies the sensitivity of the divertor mass loss to uncertainties in the radiation transport. Specifically, the paper presents the results of computer simulations of the vaporization of a graphite coated divertor during a tokamak disruption with ITER CDA parameters. The results show that a factor of 100 change in the radiation conductivity changes the mass loss by more than a factor of two
Problems of radiation safety of petroleum and gas production
International Nuclear Information System (INIS)
Garibov, A.A.
2002-01-01
Oil and gas production is the basis of economy of the Azerbaijan Republic and its cause in ecological and radioecology problems. One form this problem is the pollution by radionuclides of environment at the time of gas and petroleum production. At the time of petroleum and gas production the three-phase radionuclides are emitted in atmosphere: Emissions consisted from solid U-238, Ra-226, Th-232, K-40 discharged to atmosphere at the time of production, exploring and exploitation of petroleum and gas. They are presented in compounds of sand, clay, and petroleum residues; During the drilling and production the gross quantities of water flows out and collects. These water areas consist of radium, uranium, Th and K-40 dissolved in water salts; There are the radionuclides being in 902 condition emitted in atmosphere at the places of petroleum and gas production. The radon and its isotopes are emitted at this time; At the places of petroleum and gas production it is observed at local pollution areas polluted by solid emissions that at this territories the doze of exposition power variable 100 - 1000 micro/hour. The radioactivity at this system according to 2-1000 year/k consists from Ra, K-40, and U. At this areas the value of total background changes 5 - 1000 micro R/hour. The total radioactivity of water polls formed at the places of petroleum and gas production consisted 50 -150 Bq/L. In the case of gas the separated radionuclides are mainly consisted from Radon and its isotopes. In the compound of produced gas the concentration of radon varied 20 - 1700 Bq/m 3 . Thus, at the places of petroleum and gas production radioactive pollutants emitted to atmosphere, forms the polluted environment for working and living people at the same territory. This problem's status haven't been investigated thoroughly, the sources of pollution hasn't been uncovered concretely, the cleaning technology for polluted areas is unknown
International Nuclear Information System (INIS)
Sacco, D.; Ruggeri, F.; Bindi, G.; Bonanni, A.; Casciardi, S.; Delia, R.; Loppa, A.; Rossi, P.; Venturini, L.
1996-01-01
The steel scrap recycling by steel mill is increasing moved by profits and by purpose of protection of environmental resources. Besides the use of radioactive sources in several fields (medical, industrial and in scientific researches) on one hand, and the disposal of made radioactive materials from nuclear reactors on the other one, makes the likelihood no more negligible that some radionuclides could be found, accidental y or fraudulently, in steel recycling scrap. Radiation protection problems for surveillance both employees in the production cycle and of people and environment in general arose. First of all, we characterize different type of radioactive materials that can found in scraps, pointing out the potential hazards from exposure of workers and people and from environmental contamination, related to physical and chemical specifications of the involved radionuclides. Some suitable monitoring equipment for scrap recycling facilities are discussed, related to the different step of production cycle (transport, storage, manipulation and melting). At last experimental data, taken in some periods of the monitoring campaign made at the Italian border on imported scraps, are presented. (author)
Using ionising radiation against terrorism and contrabandism - dosimetric problems
International Nuclear Information System (INIS)
Ankerhold, U.; Hupe, O.; Buchholz, G.
2006-01-01
As will be explained in more detail in a talk at this conference, the personnel X-ray scanners can be divided into two groups, one using the transmitted X rays for image creation, the other one using the Compton back scatters X-rays. In the case of a backscatter scanner, a narrow, pencil -like X-ray beam is produced by a rotating chopper-wheel. The person/object is scanned in a raster scan pattern. The backscattered X-rays of all points are measured and recorded. The transmission X-ray scanner can use both fan-like and pencil like X-ray beams. The transmission detectors are installed behind the object and detect the absorption of the scanned person. Due to the very low dose values of the X-ray scanner systems in combination with a high dose rate in the direct beam for a short irradiation time, special dosemeters have to be used. In the literature and in manufacturers' specifications, the dose values given for some systems are in the range from 0.05 μSv to 5 μSv per scan with a typical irradiation time of a few milliseconds. Due to this pulse-like character of the radiation fields, the dose rate is several sieverts per hour. For the measurements of the investigated scanner, dosemeters were therefore needed having the capability to measure low doses at high dose rates and to measure in pulsed radiation fields. For the optimization of the measurements, the use of measuring devices with a direct indication is necessary. Ionisation chambers are the most suitable measuring instruments to fulfill these requirements. The difficulty for the measurements with an ionisation chamber is that the leakage charge integrated over time can reach values at the level of the expected radiation-produced charge. Additionally unpredictable variations of the leakage charge can be in the same order of magnitude as the expected signal. This challenge led to the development of a special electronics which allow the execution of time-resolved measurements. With this time resolution, it is
International Nuclear Information System (INIS)
Jammet, H.P.
1977-01-01
Problems associated with the organization and planning of medical treatment for radiation accident casualties are considered for different types of radiation accident: whole-body or partial irradiation, external or internal contamination and small or large numbers of cases. The problems posed are ones of competence, urgency and capacity; on the diagnostic side there is the problem of evaluating the exposure or contamination and assessing the resultant damage, while on the treatment side the questions of first aid, conventional treatment and specialized treatment have to be considered. The solutions envisaged involve organization at the local and national levels and planning of medical treatment by skilled, multidisciplinary medical teams. (author)
Factors affecting radiation doses from dedicated rail transport of spent reactor fuel
International Nuclear Information System (INIS)
Martin, J.E.
1988-01-01
This paper reports there are two exposure control concerns associated with the shipment of spent reactor fuel in dedicated trains -- compliance with transportation regulations for maximum allowable radiation levels, and minimizing the dose received by the general public. This article examines the methods used to calculate the dose equivalent rates alongside stationary (transport regulations) and moving trains (public exposure) of various lengths. The factors examined include the source term, the effect of overlapping radiation fields, the speed of the train, and the location of the population relative to the train. Trains made up of series of cars that individually meet transport regulations can, as a whole, exceed transport vehicle dose equivalent rate limits by up to 23% due to overlapping radiation fields. For moving trains and the worst case analyzed -- a person located 20 feet from the tracks and a train speed of 5 mph --- 141 rail cars would have to pass by to deliver a dose equivalent of 1 mrem
INTERMODAL TRANSPORTATION: CONSIDERATIONS IN PREFERENCE AND THE PROBLEMS BETWEEN EUROPE AND TURKEY
Directory of Open Access Journals (Sweden)
Balca Berfin UYGUÇ
2017-12-01
Full Text Available Intermodal transportation has become increasingly important, as global supply chains tend to spread their activities in diversified countries. Intermodal transportation has its own issues that should be investigated in a deeper sense. Therefore, through conducting semi-structured interviews with logistics companies, this study aims to analyze the considerations in intermodal preference and problems faced during intermodal operations between Europe and Turkey.
SOLVING TRANSPORT LOGISTICS PROBLEMS IN A VIRTUAL ENTERPRISE THROUGH ARTIFICIAL INTELLIGENCE METHODS
PAVLENKO, Vitaliy; PAVLENKO, Tetiana; MOROZOVA, Olga; KUZNETSOVA, Anna; VOROPAI, Olena
2017-01-01
The paper offers a solution to the problem of material flow allocation within a virtual enterprise by using artificial intelligence methods. The research is based on the use of fuzzy relations when planning for optimal transportation modes to deliver components for manufactured products. The Fuzzy Logic Toolbox is used to determine the optimal route for transportation of components for manufactured products. The methods offered have been exemplified in the present research. The authors have b...
Application of direct discrete method (DDM) to multigroup neutron transport problems
International Nuclear Information System (INIS)
Vosoughi, Naser; Salehi, Ali Akbar; Shahriari, Majid
2003-01-01
The Direct Discrete Method (DDM), which produced excellent results for one-group neutron transport problems, has been developed for multigroup energy. A multigroup neutron transport discrete equation has been produced for a cylindrical shape fuel element with and without associated coolant regions with two boundary conditions. The calculations are illustrated for two-group energy by graphs showing the fast and thermal fluxes. The validity of the results are tested against the results obtained by the ANISN code. (author)
International Nuclear Information System (INIS)
Poplavskij, K.K.
1989-01-01
Problems of activity optimization of the sanitary and epidemiologic stations (SES) concerning state inspection of for radiation source application are considered to improve the effort efficiency of the radiological subdivisions. The necessity to specify the inspection objects is shown. Inspection of all the stages of creation, introduction and application of radioactive substances and other sources, as well as, of radioactive waste utilization remains urgent problem. Determination of internal and external radiation doses to population in different regions as well as, radiation protection of personnel and patients in nuclear medicine are vital problems as well. Justification of the necessity to enlist specialists in different fields, to determine rationally their functional duties presents sufficient component of the SES activity optimization. Usage optimization of dosimetric and radiometric devices, laboratory equipment and instruments is a vital problem
Security measures in transport of radiation source in Jordan
Energy Technology Data Exchange (ETDEWEB)
Mohammad, Alslman [Korea Advanced Institute of Science and Technology, Kaist Daejeon (Korea, Republic of); Choi, Kwang Sik [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)
2011-05-15
Radioactive materials are used in Jordan for peaceful applications in medicine, industry, agriculture, environmental science, education and research and military applications. Most of these radioactive sources used are imported, therefore trans-boundary movement is a significant factor in consideration of security measures during movement of these sources. After 11/9 2001 event, IAEA efforts began to focus and concentrate on security in transport of radioactive materials, after the emergence of risks of using these sources in terrorist activities. In 2002, Efforts were initiated by the IAEA to provide additional guidance for security in the transport of radioactive materials, based upon the new security requirements in the Recommendations on the Transport of Dangerous Goods. This paper reviews some of the measures relating to the transport of radioactive materials in Jordan
On the dark radiation problem in the axiverse
Energy Technology Data Exchange (ETDEWEB)
Gorbunov, Dmitry; Tokareva, Anna, E-mail: gorby@ms2.inr.ac.ru, E-mail: tokareva@ms2.inr.ac.ru [Institute for Nuclear Research of Russian Academy of Sciences, 117312 Moscow (Russian Federation)
2017-06-01
String scenarios generically predict that we live in a so called axiverse: the Universe with about a hundred of light axion species which are decoupled from the Standard Model particles. However, the axions can couple to the inflaton which leads to their production after inflation. Then, these axions remain in the expanding Universe contributing to the dark radiation component, which is severely bounded from present cosmological data. We place a general constraint on the axion production rate and apply it to several variants of reasonable inflaton-to-axion couplings. The limit merely constrains the number of ultralight axions and the relative strength of inflaton-to-axion coupling. It is valid in both large and small field inflationary models irrespectively of the axion energy scales and masses. Thus, the limit is complementary to those associated with the Universe overclosure and axion isocurvature fluctuations. In particular, a hundred of axions is forbidden if inflaton universally couples to all the fields at reheating. In the case of gravitational sector being responsible for the reheating of the Universe (which is a natural option in all inflationary models with modified gravity), the axion production can be efficient. We find that in the Starobinsky R {sup 2}-inflation even a single axion (e.g. the standard QCD-axion) is in tension with the Planck data, making the model inconsistent with the axiverse. The general conclusion is that an inflation with inefficient reheating mechanism and low reheating temperature may be in tension with the presence of light scalars.
Radiation induced dry eye: problem and potential remedies
International Nuclear Information System (INIS)
Vemuganti, Geeta K.; Tiwari, Shubha
2016-01-01
Advances in orbital radiotherapy have significantly increased therapeutic efficiency and reduced the side effects but a significant proportion of patients are still seen with ophthalmic complication like dry eye syndrome (DES). The treatment of DES involves temporary palliative therapies like ocular surface lubrication and rehydration. We aimed at establishing the human lacrimal gland cultures and evaluating for the presence of stem cells and secretory potential. Using human lacrimal gland tissues obtained from samples of therapeutic exenteration post-radiotherapy, we established a monolayer as well as 3D lacrispheres that show evidence of stem cells, secretory acinar cells, duct like formation and other cells like myoepithelial cells and duct like cells. The stem cells were identified as CD 117 positive that co-segregated with G0/G1 phase, ALDH high, label retaining cells and high clone forming ability. The most promising evidence of its secretory function was seen in the presence of tear substances like lysosymes, lactiferrin, and scIg A in the conditioned media of the lacrimal gland cultures. This novel development would pave way for development of a functionally competent 3D construct for potential clinical application in severe cases of radiation induced dry eye. (author)
Energy Technology Data Exchange (ETDEWEB)
Kostin, Mikhail [Michigan State Univ., East Lansing, MI (United States); Mokhov, Nikolai [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Niita, Koji [Research Organization for Information Science and Technology, Ibaraki-ken (Japan)
2013-09-25
A parallel computing framework has been developed to use with general-purpose radiation transport codes. The framework was implemented as a C++ module that uses MPI for message passing. It is intended to be used with older radiation transport codes implemented in Fortran77, Fortran 90 or C. The module is significantly independent of radiation transport codes it can be used with, and is connected to the codes by means of a number of interface functions. The framework was developed and tested in conjunction with the MARS15 code. It is possible to use it with other codes such as PHITS, FLUKA and MCNP after certain adjustments. Besides the parallel computing functionality, the framework offers a checkpoint facility that allows restarting calculations with a saved checkpoint file. The checkpoint facility can be used in single process calculations as well as in the parallel regime. The framework corrects some of the known problems with the scheduling and load balancing found in the original implementations of the parallel computing functionality in MARS15 and PHITS. The framework can be used efficiently on homogeneous systems and networks of workstations, where the interference from the other users is possible.
Directory of Open Access Journals (Sweden)
Rustamzade M.N.
2017-03-01
Full Text Available in the transition of the leading countries of the world on an innovative way of development, transport is considered as one of the most important factors of socio-economic growth in Russia. Transport contributes to strengthening the unity of the economic area of the country, improves the interregional and international transport and economic relations, increases the efficient using of natural resources, develops entrepreneurship and international cooperation. However, there is a number of obstacles before implementation of transport and transit potential of Russia. The paper deals with features of international and national transport corridors on the territory of Russia and the key problems of their functioning and possible ways to overcome them.
An LP-based heuristic for the fixed charge transportation problem
DEFF Research Database (Denmark)
Klose, Andreas
2007-01-01
The fixed charge transportation problem consists in finding a minimum cost network flow from a set of suppliers to a set of customers. Beside costs proportional to quantities transported, transportation costs also include a fixed charge. The paper describes a linear programming based heuristic...... approach for computing lower and upper bounds on the minimal cost. To this end, the LP relaxation is iteratively strengthened by means of adding cuts; in each iteration the current LP solution is then used to guide a local search heuristic. In addition to standard polyhedral cuts as lifted cover...
SOLVING TRANSPORT LOGISTICS PROBLEMS IN A VIRTUAL ENTERPRISE THROUGH ARTIFICIAL INTELLIGENCE METHODS
Directory of Open Access Journals (Sweden)
Vitaliy PAVLENKO
2017-06-01
Full Text Available The paper offers a solution to the problem of material flow allocation within a virtual enterprise by using artificial intelligence methods. The research is based on the use of fuzzy relations when planning for optimal transportation modes to deliver components for manufactured products. The Fuzzy Logic Toolbox is used to determine the optimal route for transportation of components for manufactured products. The methods offered have been exemplified in the present research. The authors have built a simulation model for component transportation and delivery for manufactured products using the Simulink graphical environment for building models.
PROBLEMS OF THE EFFICIENCY INCREASING OF TRANSPORTATION BY AIR OF UKRAINIAN SSR (1960-1980
Directory of Open Access Journals (Sweden)
Anatoliy Gorban
2015-11-01
Full Text Available The article is devoted to the problems of the efficiency increasing of the air transportation. The difficulties of increasing the efficiency of transportation by air in Ukrainian SSR in 1960-1980 were researched, factors that adversely affected the organization of the transport sector were determined and depicted. The article analyzes what caused such difficulties and it was found out that the causes of these difficulties are connected with the organizational problems of air transport of Ukrainian SSR, which negatively affected the operation of the industry. The central aim of the research is to focus on the main problems of air transport of Ukrainian SSR. So, we should say that the transport operation of those years was distributed too unevenly and was dependent on the population density of the territory of the republic. Purpose of the article is to determine, compile and analyze the factors that negatively affected the organization of air transportation of the Ukrainian republic and reduced the efficiency of its operation. Results of the research shows technical, organization and economical deficiency of air transport of Ukrainian SSR which caused the ineffectiveness of this type of transport and determines the nature of such difficulties. Statement of the problem. During the specified period (1960–1980 the air transport had undergone rapid development. Many new airlines were opened, airports were being built and reconstructed, the terms of exploiting of turbojet aircrafts were increased, the speed of planes was increasing. All these facts ensured safe and reliable air connection of all district centers, connected Ukraine with the other Soviet republics and foreign countries by air corridors. Ukrainian Department of Civil Aviation became the biggest regional Department of the Ministry of Civil Aviation of the USSR. But, at the same time the intensity of the increase of cargo and passenger transportation since 1970s led to accumulation of
THE PROBLEM OF PROPER CARGO SECURING IN ROAD TRANSPORT – CASE STUDY
Directory of Open Access Journals (Sweden)
Maria CIEŚLA
2013-12-01
Full Text Available This paper presents the problem of improper security of cargo in trucks as the cause of about 25% of the accidents that takes place in road transport. Attention was drawn to aspects of legal liability for errors resulting from incorrect load securing according to polish law. Article was enriched with practical examples illustrating the effects of improper cargo securing on transport unit and shows how it had to be prepared properly. When planning the proper transport protection of metal sheets rolled both calculation methods and computer applications were used.
The spectral element approach for the solution of neutron transport problems
International Nuclear Information System (INIS)
Barbarino, A.; Dulla, S.; Ravetto, P.; Mund, E.H.
2011-01-01
In this paper a possible application of the Spectral Element Method to neutron transport problems is presented. The basic features of the numerical scheme on the one-dimensional diffusion equation are illustrated. Then, the AN model for neutron transport is introduced, and the basic steps for the construction of a bi-dimensional solver are described. The AN equations are chosen for their structure, involving a system of coupled elliptic-type equations. Some calculations are carried out on typical benchmark problems and results are compared with the Finite Element Method, in order to evaluate their performances. (author)
Current problems of nuclear power radiation ecology and hygiene
Energy Technology Data Exchange (ETDEWEB)
Vorob' ev, E I; Il' in, L A; Knizhnikov, V A; Aleksakhin, R M
1979-10-01
Perspectiveness of different kinds of energetics is mainly defined by their effect on environment and human health. Hygiene and ecology at present time can not give an objective characteristic of detriment because of the effluents from the fuel-energy cycle facilities, especially from facilities of the traditional energetics. The role of the radiactive effluents into environment is defined by their possible effect on the human health, but not the ecological effects. Meanwhile, the development of the principles of ecological normalization is an actual problem. It is important to carry out a quantitative stady of the dose-effect dependencies of the effluents of cancerogens of the physical and chemical nature into environment. It is advisable to estimate the possible effect of cancerogens from the positions of thresholdlessness of their action.
Current problems of nuclear power radiation ecology and hygiene
International Nuclear Information System (INIS)
Vorob'ev, E.I.; Il'in, L.A.; Knizhnikov, V.A.; Aleksakhin, R.M.
1979-01-01
Perspectiveness of different kinds of energetics is mainly defined by their effect on environment and human health. Hygiene and ecology at present time can not give an objective characteristic of detriment because of the effluents from the fuel-energy cycle facilities, especially from facilities of the traditional energetics. The role of the radiactive effluents into environment is defined by their possible effect on the human health, but not the ecological effects. Meanwhile, the development of the principles of ecological normalization is an actual problem. It is important to carry out a quantitative stady of the dose-effect dependencies of the effluents of cancerogens of the physical and chemical nature into environment. It is advisable to estimate the possible effect of cancerogens from the positions of thresholdlessness of their action
Department of Environmental and Radiation Transport Physics - Overview
International Nuclear Information System (INIS)
Loskiewicz, J.
2000-01-01
absorbing centres has been pursued. The influence of the components of new drilling fluids on the interpretation of neutron logs has been tested. The problem of a proper description of the thermal neutron diffusion parameters dependent on the energy flux distribution in finite hydrogenous media has been studied. Granada's synthetic model for slow-neutron scattering has been used. As the valuable result of the research the thermal neutron diffusion cooling coefficient in polyethylene has been calculated, using individual characteristics of the scattering kernel for this substance. The experimental set-up at the pulsed neutron generator has been equipped with a new-built thermostatic chamber. Artificial neural network (ANN) applications in petrophysics have been studied: ANN analysis was applied with success to assess Σa values for the data from Miocene formations near Tarnogrod. And also the artificial intelligence methods have been used for appreciation of two different methods of measurement of thermal neutron absorption cross section Σ a . A part of the samples was measured by first method and the other one by the second method. Using ANN it was possible to detect a systematic difference of results from both methods on the level of the standard deviation. A later large experiment consisting of the measurement of all samples by both methods has validated the ANN results. The semi-empirical calibration method of neutron borehole tools was further developed. The three-layer case solution, based on diffusion approximation solution of neutron transport equation, does not give correct results when compared with experimental values. This discrepancy was due to the fact that in the case of highly absorbing media like iron or boron the diffusion approximation should not be applied for such media. The calculations of the migration length in the simple three cylindrical layer case with the use of Monte Carlo codes are studied. The work focused on the improvement of radon
International Nuclear Information System (INIS)
Sanchez, Richard.
1980-11-01
This work is divided into two parts: the first part deals with the solution of complex two-dimensional transport problems, the second one (note CEA-N-2166) treats the critically mixed methods of resolution. A set of approximate solutions for the isotropic two-dimensional neutron transport problem has been developed using the interface current formalism. The method has been applied to regular lattices of rectangular cells containing a fuel pin, cladding, and water, or homogenized structural material. The cells are divided into zones that are homogeneous. A zone-wise flux expansion is used to formulate a direct collision probability problem within a cell. The coupling of the cells is effected by making extra assumptions on the currents entering and leaving the interfaces. Two codes have been written: CALLIOPE uses a cylindrical cell model and one or three terms for the flux expansion, and NAUSICAA uses a two-dimensional flux representation and does a truly two-dimensional calculation inside each cell. In both codes, one or three terms can be used to make a space-independent expansion of the angular fluxes entering and leaving each side of the cell. The accuracies and computing times achieved with the different approximations are illustrated by numerical studies on two benchmark problems and by calculations performed in the APOLLO multigroup code [fr
Directory of Open Access Journals (Sweden)
Nurdan Cetin
2014-01-01
Full Text Available We consider a multiobjective linear fractional transportation problem (MLFTP with several fractional criteria, such as, the maximization of the transport profitability like profit/cost or profit/time, and its two properties are source and destination. Our aim is to introduce MLFTP which has not been studied in literature before and to provide a fuzzy approach which obtain a compromise Pareto-optimal solution for this problem. To do this, first, we present a theorem which shows that MLFTP is always solvable. And then, reducing MLFTP to the Zimmermann’s “min” operator model which is the max-min problem, we construct Generalized Dinkelbach’s Algorithm for solving the obtained problem. Furthermore, we provide an illustrative numerical example to explain this fuzzy approach.