[en] The exchange of thallium atoms in labelled Tl(I)₃ Tl(III)Cl₆ has been studied in the solid state. The process is hardly affected by ionising radiation but greatly accelerated by grinding. The kinetics of the exchange are complex, but compatible with three first order processes with different energies of activation. Introduction of dislocations and increase of surface by grinding does not change these energies but alters the proportions exchanging by the different processes

[en] This chapter deals with a series of technological developments in the manufacture of steels which have occurred during the last years, in particular reporting the results obtained in Reinosa with some of these methods in the fabrication of castings as well as forgings and rolled products. (author)

[en] A kinetic study has been performed with the aim of verifying the validity of the equilibrium assumption. The most important chemical reactions of iodine and cesium in a steam/hydrogen environment, including a surface reaction, have been chosen. The following step has been the estimation of the rate constants of the involved reactions through the Activated Complex Theory. The main problem encountered in this calculation has been the estimation of the activation energies, since these parameters are normally obtained by experimentation. In any case, experimental data were used when they exist. After this, the concept of the ideal tubular chemical reactor was introduced to establish dynamic balance equations leading to systems of differential equations from which the distribution of iodine and cesium species in a flowing pipe that simulates the primary circuit can be obtained. This kinetic model has been applied to analyze several cases corresponding to PHEBUS-FP and severe fuel damage experiments. It can be pointed out that equilibrium values have not been achieved at the end of the pipe in most of cases and the surface reactions can play an important role in the phenomenology of severe accidents. (author)

[en] A study on the corrosion resistance of lead in simulated natural media of an underground repository of high-level radioactive wastes was made. Potentiostatic polarization tests and weight-loss measurements were carried out between 293 K and 353 K. The media studied were: groundwater, bentonite suspensions (10 wt%) as well as sodium chloride, acetate and nitrate solutions, extending over a broad range of concentrations. The increase in temperature led to an increase in corrosion, being particularly noticeable in media yielding soluble lead salts. The lowest corrosion rate was found in natural groundwater (NG) at 348 K, even under the most aggressive conditions (348 K and saturation with oxygen). The increase of lead impurities content also increases the corrosion rate by a factor of six, compared with that a pure lead (99.999%). In the case of bentonite suspensions the corrosion rates at 348 K were very low. (orig.)

[en] There are two types of anisotropies, the horizontal and vertical, the latter being the most important calibration since it will normally be carried out with the power vertical, 0 90 degree centigrade, as recommended by the standard. Since in most systems is the source position can be rotated about its vertical axis during transport from your accommodation to the point of irradiation, the uncertainty associated with the vertical anisotropy of a neutron source should be into account in any equipment calibration procedure, incorporating an anisotropy factor.

[en] A theoretical method to obtain the propagation and coupling characteristics of channel optical waveguides is presented. The waveguides show graded-index profiles in both transverse directions. Commonly, they are fabricated by metal diffusion on LiNbO₃. The method models the waveguide, in the vertical direction, by means a multilayer structure. We combine the effective index method with the WKB method to solve the whole waveguide. Propagation constants for isolated waveguides and results of coupling parameters for directional couplers are presented. (Author) 12 refs

[en] In this report, a kinetic model has been developed with the aim to try to reproduce the chemical phenomena that take place in a flowing system containing steam, hydrogen and iodine and caesium vapours. The work is divided into two different parts. The first part consists in the estimation, through the Activited Complex Theory, of the reaction rate constants, for the chosen reactions, and the development of the kinetic model based on the concept of ideal tubular chemical reactor. The second part deals with the application of such model to several cases, which were taken from the Phase B 'Scoping Calculations' of the Phebus-FP Project (sequence AB) and the SFD-ST and SFD1.1 experiments. The main conclusion obtained from this work is that the assumption of instantaneous equilibrium could be inacurrate in order to estimate the iodine and caesium species distribution under severe accidents conditions

[en] What is intended with this document is to locate and organize the minimum regulatory requirements necessary to comply with the basic requirements of safety and health in the protection of fire risks in building works.

[en] Loss of organic matter is one of the main forms of soil degradation in Mediterranean agricultural soils, and external sources of organic matter are required to improve soil properties. the two-phase centrifugation system in the olive-oil extraction industry produces a large amount of olive mill waste sludge (TPOMW) which can be used to add organic C to degraded soils. (Author)

[en] The objective of this research is to get pills with distribution of porosity to simulate mechanical properties in the irradiated fuel resulting from own burnt of the material to produce the release of fission gases. (Author)