[en] This thesis is dedicated to the development of a Monte Carlo neutron transport solver based on the subgroup (or multiband) method. In this formalism, cross sections for resonant isotopes are represented in the form of probability tables on the whole energy spectrum. This study is intended in order to test and validate this approach in lattice physics and criticality-safety applications. The probability table method seems promising since it introduces an alternative computational way between the legacy continuous-energy representation and the multigroup method. In the first case, the amount of data invoked in continuous-energy Monte Carlo calculations can be very important and tend to slow down the overall computational time. In addition, this model preserves the quality of the physical laws present in the ENDF format. Due to its cheap computational cost, the multigroup Monte Carlo way is usually at the basis of production codes in criticality-safety studies. However, the use of a multigroup representation of the cross sections implies a preliminary calculation to take into account self-shielding effects for resonant isotopes. This is generally performed by deterministic lattice codes relying on the collision probability method. Using cross-section probability tables on the whole energy range permits to directly take into account self-shielding effects and can be employed in both lattice physics and criticality-safety calculations. Several aspects have been thoroughly studied: • The consistent computation of probability tables with a energy grid comprising only 295 or 361 groups. The CALENDF moment approach conducted to probability tables suitable for a Monte Carlo code. • The combination of the probability table sampling for the energy variable with the delta-tracking rejection technique for the space variable, and its impact on the overall efficiency of the proposed Monte Carlo algorithm. • The derivation of a model for taking into account anisotropic effects of the scattering reaction consistent with the subgroup method. In this study, we generalize the Discrete Angle Technique, already proposed for homogeneous, multigroup cross sections, to isotopic cross sections on the form of probability tables. In this technique, the angular density is discretized into probability tables. Similarly to the cross-section case, a moment approach is used to compute the probability tables for the scattering cosine. • The introduction of a leakage model based on the B1 fundamental mode approximation. Unlike deterministic lattice packages, most Monte Carlo-based lattice physics codes do not include leakage models. However the generation of homogenized and condensed group constants (cross sections, diffusion coefficients) require the critical flux. This project has involved the development of a program into the DRAGON framework, written in Fortran 2003 and wrapped with a driver in C, the GANLIB 5. Choosing Fortran 2003 has permitted the use of some modern features, such as the definition of objects and methods, data encapsulation and polymorphism. The validation of the proposed code has been performed by comparison with other numerical methods: • The continuous-energy Monte Carlo method of the SERPENT code. • The Collision Probability (CP) method and the discrete ordinates (S_N) method of the DRAGON lattice code. • The multigroup Monte Carlo code MORET, coupled with the DRAGON code. Benchmarks used in this work are representative of some industrial configurations encountered in reactor and criticality-safety calculations: • Pressurized Water Reactors (PWR) cells and assemblies. • Canada-Deuterium Uranium Reactors (CANDU-6) clusters. • Critical experiments from the ICSBEP handbook (International Criticality Safety Benchmark Evaluation Program). (author)

[en] The tropospheric ozone, secondary pollutant affecting the health of the human beings, concerns particularly the department of the Alpes-Maritimes during the photochemical season. Mountainous littoral space, this territory is widely dominated during summer notably by anticyclonic conditions allowing the thermal breezes to express themselves. This regime of wind is in the center of the problem of the ozone pollution because it pulls frequently an accumulation of primary and secondary pollutants in the course of days within the same air mass. Although being a weakly industrialized department, the Alpes-Maritimes are victims of a strong period of sunshine which allows primary pollutants emitted mainly by the road traffic to produce some ozone. Through the data of pollution stemming from the network of surveillance of the air quality AtmoPACA as well as from very numerous measures of ground, the objective is to understand better the relations between the spatial and temporal variability of the ozone and that of the weather conditions to various scales. Having detailed the history of the available ozone and nitrogen dioxide measures in the department, the first approach in macro-scale is led between the NCEP reanalysis and the ozone pollution levels in nine measures stations of the Alpes-Maritimes. This first level of analysis allows defining the general meteorological configurations characterizing an episode of pollution by the ozone. The presence of an anticyclonic ridge on the Western Europe associated with weak speeds of wind, weak rates of relative humidity and a weak relative vorticity, provoke a degradation of the air quality in the department. A second analysis level is then approached: it is a question of clarifying in meso-scale and in micro-scale the weather conditions convenient to strong ozone concentrations. For it, itinerant ozone measures campaigns are made in the whole of the department; an important data base is established on Nice and in its surroundings. The appeal to the meteorological model RAMS allows then to understand better the spatial and temporal ozone variability led by the local climatic conditions. The meteorological variables the most correlated to the ozone concentrations are the wind speed, the turbulent kinetic energy, the planetary boundary layer height and the relative humidity. Everything indicates that less the volume of air in which primary pollutants are emitted is important, and less the air admixture intensity is strong, then more the ozone concentrations are raised. It would also seem that this local weather conditions have more influence on the ozone pollution levels than the macro-scale weather configurations. Although being necessary, presence of the anticyclone on the Western Europe is not sufficient to explain local ozone behaviour in the Alpes-Maritimes. At the same time as these various approaches, the spatial previous history of the photochemical pollution affecting this mountainous littoral space are looked for. The advection of important ozone quantities by the sea breeze during day, indicates that this pollutant accumulates above the sea; except the phenomenon of round trip of the air mass guided by the alternation between the sea breeze and the land breeze, the origin of the strong ozone concentrations above the sea is not clearly included. It would seem that a plan of recirculation of the air masses in three dimensions allows the creation of a pile of layers stratified on the sea. (author)

[en] In the framework of the present thesis quasi-elastic processes in the reactions ²⁰⁶ Pb+²⁰⁸ Pb and ²⁰⁸ Pb+²⁰⁸ Pb were studied at an incident energy slightly above the Coulomb barrier (6.2 MeV/u) were studed. By means of the measured Particle-gamma correlations the quasi-elastic collisions were separated from the deep inelastic ones. Determined were the absolute cross sections and angular distributions of the exitation by inelastic collisions as well as by one- and two-neutron transfer. For the states excited by inelatic scattering the multiplicities of the γ quanta emitted in their decay were experimentally determined. The measured angular distributions of the inelastic reactions were compared with CCBA calculations. As most important result of this thesis the experimental detection of a member of the 2-phonon-octupole multiplet is to be considered. A hitherto unknown γ transition in the spectrum of ^-2^-0^-8 Pb with an energy of 2.485 MeV was detected. Because of the measured γγ coincidence ratios in ²⁰⁸ Pb this transition was assigned to the level scheme of ²⁰⁸Pb. Its decay to the 1-phonon state 3^- pursues via an E1-transition to the 5^- -state and a following E2-transition. The angular distribution of the 2-phonon-octupole state was calculated in the framework of the CCBA and compared with the experiment. The comparison with the CCBA calculation indicates a spin of I^π=6⁺ or 4⁺ . The experimental angular distributions of the one-neutron transfer reactions to ²⁰⁷ Pb and ²⁰⁹ Pb were compared with DWBA calculations. (orig./HSI)

[en] Enresa has designed a three-dimensional computer model of the Jose Cabrera nuclear power station that will provide the technicians with a powerful tool for optimising the planning, monitoring and control of the various sequences in the plant dismantling project. The model, which will be associated with a large database, will facilitate the dismantling of the systems components and buildings as well as making it easier to visualise. The model will also allow improved analysis of possible interferences, movements of loads and alternatives in the operating phases. Its contribution to safety and to the control of the radiological inventory of the process will also be highlighted. (Author)

[en] Enresa has designed a three-dimensional computer of the Jose Cabrera nuclear power plant that will provide the technicians with a powerful tool for optimising the planning, monitoring and control of the different sequences of the proposed dismantling of the plant. The model, which will be associated with a large database, will facilitate the dismantling of the systems components and buildings as well as making it a easier to visualise. The model will also allow improved analysis of possible interferences,movements of loads and alternatives in the operation phases. Its contribution to safety and to the control of the radiological inventory of the process will also be highlighted. (Author)

[en] Among the most important works from the point of view of PR implementation, safety and the Draft Dismantling and Decommissioning of Nuclear Power Plant Jose Cabrera is conducting ENRESA, they are those related to the segmentation of the reactor vessel and the primary circuit. These works are a challenge in the project, which is now a national and international reference in the field of decommissioning and nuclear power plants. (Author)

[en] This article summarizes the legal framework defining the strategies, the main activities and the basic responsibilities and roles of the various agents involved in the decommissioning of nuclear facilities in Spain. It also describes briefly the most relevant projects and activities already developed and/or ongoing nowadays, which have positioned Spain within the small group of countries having an integrated and proved experience and know how in this particular field. (Author)

[en] Based on information drawn primarily from official planning documents issued by national governments and/or utilities, the authors examined the outlook for the power sector in the year 2000 in nine countries: China, India, Indonesia, Thailand, the Philippines, South Korea, Taiwan, Argentina and Mexico. They found that the implicit rates of average annual growth of installed electric power capacity between 1991 and 2001 range from a low of 3.3% per year in Argentina to a high of 13.2% per year in Indonesia. In absolute terms, China and India account for the vast majority of the growth. The plans call for a shift in the generating mix towards coal in six of the countries, and continued strong reliance on coal in China and India. The use of natural gas is expected to increase substantially in a number of the countries. The historic movement away from oil continues, although some countries are maintaining dual-fuel capabilities. Plans call for considerable growth of nuclear power in South Korea and China and modest increases in India and Taiwan. The feasibility of the official plans varies among the countries. Lack of public capital is leading towards greater reliance on private sector participation in power projects in many of the countries. Environmental issues are becoming a more significant constraint than in the past, particularly in the case of large-scale hydropower projects. The financial and environmental constraints are leading to a rising interest in methods of improving the efficiency of electricity supply and end use. The scale of such activities is growing in most of the study countries

[en] Lattice calculation by Monte Carlo methods is expected to compete against deterministic tools such as collision probability or the method of characteristics, provided that its calculation time can be shortened. In this paper, we investigate the possibility of using cross-section probability tables conjointly with optimized energy meshes in a multigroup Monte Carlo algorithm. Regarding the Monte Carlo method, probability tables cross-sections are frequently used in the unresolved range. In deterministic lattice codes, this formalism can serve during the self-shielding stage, typically in a subgroup method. We propose using probability tables cross-sections on the entire energy range in a Monte Carlo algorithm, together with an adequate energy structure. Numerical results are proposed using legacy benchmarks and comparison with multigroup, deterministic and pointwise, Monte Carlo solutions is discussed. We demonstrate that using probability tables in Monte Carlo multigroup calculations with only 295 or 361 groups can lead to accurate results, as far as the probability tables are consistently evaluated. (authors)

[en] The chemical and the pulp/paper industries combined provide 55% of CHP generation in the US industry. Yet, significant potential for new CHP capacities exists in both industries. From the present steam consumption data, the authors estimate about 50 GW of additional technical potential for CHP in both industries. The reduced carbon emissions will be equivalent to 44% of the present carbon emissions in these industries. They find that most of the carbon emissions reductions can be achieved at negative costs. Depending on the assumptions used in calculations, the economic potential of CHP in these industries can be significantly lower, and carbon emissions mitigation costs can be much higher. Using sensitivity analyses, they determine that the largest effect on the CHP estimate have the assumptions in the costs of CHP technology, in the assumed discount rates, in improvements in efficiency of CHP technologies, and in the CHP equipment depreciation periods. Changes in fuel and electricity prices and the growth in the industries' steam demand have less of an effect. They conclude that the lowest carbon mitigation costs are achieved with the CHP facility is operated by the utility and when industrial company that owns the CHP unit can sell extra electricity and steam to the open wholesale market. Based on the results of the analyses they discuss policy implications