[en] The elastic pion-nucleus scattering in the (3/2-3/2) resonance region is analyzed. The aim of the work is threefold. Working with the Watson's multiple scattering theory, one strives for: -a better understanding of the pion-nucleus interaction in terms of elementary interaction; -a justification of the theoretical framework by using the Lee model; -a study of the sensitivity of the optical potential to the macroscopic parameters of the nucleus

[en] Peculiarities of the reprocessing plant, where French technology of high level liquid waste solidification in borosilicate glass will be used, are described. The plant productivity, its starting being planned for 1990, is sufficient for the satisfaction of Great Britain nuclear industry needs to the end of the century

[en] Since the spent-fuel pools at nuclear reactors were generally not designed for life-of-plant storage capacity, they are rapidly filling up. The U.S. Department of Energy, in accordance with the Nuclear Waste Policy Act of 1982, plans to alleviate this problem in 1998. Meanwhile, solutions to the storage problem are actively being sought. One of these, fuel consolidation, has already been demonstrated to be practical for pressurized water reactor fuel. The current cost of fuel consolidation appears to be very competitive with alternative technologies, such as on-site dry storage, and should decrease in time. However, to be an attractive solution, consolidation must also be clean, reliable, and effective. Based on previous experience working in spent-fuel pools, a system was chosen that would consist of simple, proven mechanisms, arranged to provide sufficient speed to achieve the cost goals. The challenge to the designers was to devise a simple machine that could get >500 spent-fuel rods into a close-packed array, compact the leftover hardware, and leave behind clean water and at least 40% more space. The resulting system is simple by design. Thus, its reliability should be high and its maintenance needs will be minima. The process rate is enhanced by providing duplicated devices where practical. Direct canister loading, reusing end fittings for canister handling, and on-line NFBC shearing are the salient features of the machine that differentiate it from others that have been demonstrated to date

[en] The inhibiting effects of soil build-up of copper differed among the five species of plants examined. - The repeated use of copper (Cu) fungicides to control vine downy mildew, caused by Plasmopara viticola, has been responsible for the heavy increase of Cu concentration in the upper layers of vineyard soils. To determine the effects of elevated soil Cu on plant development, we created an artificial soil gradient with Cu enrichments ranging from 0 to 400 mg kg^-1. On this gradient, and for five ruderal plant species commonly found in vineyards in southern France (Poa annua L., Dactylis glomerata L., Senecio vulgaris L., Hypochoeris radicata L., and Andryala integriflolia L.), we quantified survival, growth, and reproduction throughout one flowering season. High concentrations of Cu in the soil resulted in low survival, low total plant biomass, delay in flowering and fruiting, and low seed set. However, the effects differed among species. Furthermore, high soil Cu concentrations had contrasting effects on patterns of resource allocation depending on the plant species

[en] A research and development program on the vitrification of radioactive high-level waste (HLW) solutions has been under way in France for approximately thirty years and the first radioactive glass was produced in 1958. Glass blocks weighing 5 to 15 kg with a specific activity of about 1,000 Ci/dm³ were then made in 1963 by a process using gelification in a graphite crucible to permit laboratory examinations

[en] The purpose of the Prototypical Consolidation Demonstration Project (PCDP) is to develop and demonstrate the equipment system that will be used to consolidate the bulk of the spent nuclear fuel generated in the United States prior to its placement in a geological repository. The equipment must thus be capable of operating on a routine production basis over a long period of time with stringent requirements for safety, reliability, productivity and cost-effectiveness. Four phases are planned for the PCDP. Phase 1 is the Preliminary Design of generic consolidation equipment that could be installed at a Monitored Retrievable Storage (MRS) facility or in the Receiving ampersand Handling Facility at a geologic repository site. Phase 2 will be the Final Design and preparation of procurement packages for the equipment in a configuration capable of being installed and tested in a special enclosure within the TAN Hot Shop at DOE's Idaho National Engineering Laboratory. In Phase 3 the equipment will be fabricated and then tested with mock fuel elements in a contractor's facility. Finally, in Phase 4 the equipment will be moved to the TAN facility for demonstration operation with irradiated spent fuel elements. 55 figs., 15 tabs

[en] In France, at the present time, most of the nuclear spent fuel is stored under water, first in the reactor pools, then in the interim storage pools at La Hague, prior to reprocessing. However, some fuel elements are presently stored in dry conditions: gas cooled/heavy water reactors; fuel elements at the CASCAD facility at Cadarache; breeder reactor fuel elements at Marcoule. Among the various technologies available to increase the storage capacity of the water pools, fuel consolidation appears to be one of the most promising. Different consolidation equipment have been developed in various countries. This paper presents two systems developed in France by SGN: the first one relates to a fixed facility with a large capacity dedicated to an interim storage, the second one a mobile compact unit which can be used in reactor pools. This system was developed with BABCOCK and WILCOX (Lynchburg, Virginia). (author). 2 figs

[en] An new equilibrium molecular-dynamics method (the uniaxial Hugoniostat) is proposed to study the energetics and deformation structures in shocked crystals. This method agrees well with nonequilibrium molecular-dynamics simulations used to study shock-wave propagation in solids and liquids

[en] Research in France on the solidification of high-level wastes, i.e., concentrated fission product solutions is overviewed. It began in the late 1950s in two broad areas: the containment material itself and the solidification process. After preliminary investigation of various products, notably synthetic minerals, borosilicate glass was adopted for a number of technical reasons. Glass compositions have been developed for each type of solution stored in France. These solutions are produced by reprocessing spent fuel from commercial or defense gas- cooled reactors (GCRs) and especially from light water power reactors (LWRs). LWR solutions now constitute the principal high-level waste product with the commissioning of the UP2 and UP3 reprocessing plants at La Hague. The selected vitrification process involves an initial calcining step followed by glass melting. This process was implemented at the Marcoule vitrification facility (AVM)

[en] A model for phase transitions initiated on grain boundaries is proposed and tested against numerical simulations: this approach, based on a grain explicit model, allows us to consider the granular structure, resulting in accurate predictions for a wide span of nucleation processes. Comparisons are made with classical models of homogeneous (JMAK: Johnson and Mehl 1939 Trans. Am. Inst. Min. Eng. 135 416; Avrami 1939 J. Chem. Phys. 7 1103; Kolmogorov 1937 Bull. Acad. Sci. USSR, Mat. Ser. 1 335) as well as heterogeneous (Cahn 1996 Thermodynamics and Kinetics of Phase Transformations Im et al (Pittsburgh: Materials Research Society)) nucleation. A transition scale based on material properties is proposed, allowing us to discriminate between random and site-saturated regimes. Finally, we discuss the relationship between an Avrami-type exponent and the transition regime, establishing conditions for its extraction from experiments. (paper)