[en] In the 'Institut fuer Nuklare Entsorgungstechnik' the borosilicate glass VG 98/12 has been developed for the solidification of the high level radioactive waste (HLW). This borosilicate glass can be used in a direct heated ceramic melter and forms together with the HLW the borosilicate glass product GP 98/12. This borosilicate glass product has been examined in detail both in liquid and solid state. The elements contained in the HLW can be incorporated without problems. Only in a few exceptions the concentration must be kept below certain limits to exclude the formation of a second phase ('yellow phase') by separation. No spontaneous crystallization and no crystallization over a long time could be observed as long as the temperature of the borosilicate glass product is kept below its transformation area. Simulating accidental conditions in the final storage, samples had been leached at temperatures up to 200⁰C and pressures up to 130 bar with saturated rock salt brine and saturated quinary salt brine. The leaching process seems to be stopped by the formed 'leached layer' on the surface of the borosilicate glass product after a limited leaching time. Detailed investigations have been started to explain this phenomenon. (orig.)

[en] The aim of the study is to measure the characteristic magnitudes taken into account in the safety analysis of fire risk in laboratories and factories and in the prediction calculation code. It is particularly concerned with the spread of fire, the evolution of thermal flux, the temperature and the heat and pollution flow. The trials comprise thermal decomposition and combustion of semi-finished organic products, for example, constituents of the confinement building, as well as electric cable bundles of varying shapes and sizes. The trial set-up is simple and rapid, and benefits from a systematic approach. The reproducibility of the results gives rise to a differentiation in materials as a function of their behaviour. The experimental procedure consists of placing the sample under conditions simulating an outbreak of fire in an unconfined atmosphere. The test material is submitted to a known, controlled incident thermal flux which, depending on the tests, is delivered by a radiant gas or electric panel. Two types of trial are carried out, depending on whether the minimum thermal flux giving rise to auto-inflammation or the discharge of noxious gases is to be determined. A propane pilot light is used to ignite the combustible gases. The temperature, thermal discharge, mass loss and concentration and flow of gas are recorded continuously. Data entry and treatment are carried out by an acquisition unit connected to a microcomputer. The results obtained lead to a comparison of the fire behaviour of different types of polymer panel (for minimum heat flow of auto-inflammation), and estimate the discharge of chemical and thermal pollution and the mass loss rate for various types and volumes of cable. (author). 3 refs, 8 figs, 2 tabs

[en] Electrical, structural and compositional properties of n-ZnO/c-Si heterojunctions prepared by chemical spray pyrolysis on single-crystal n-type and p-type monocrystalline silicon(1 0 0) substrates are examined with the C-V method and admittance spectroscopy at temperature ranges between 223 and 373 K. The n-ZnO/c-Si heterojunctions show a height barrier consistent with the difference in energy of the work functions of Si and ZnO; however, the n-ZnO:Al/c-Si heterojunctions present a more complex behavior due to the defects at or near the n-ZnO:Al/c-Si interface, causing a Fermi energy pinning

[en] Eight power plants are operating in Spain, 5 of them are PWR, 2 are BWR and one GCR type. All light water spent fuels are stored at pools in each NPP, being built of concrete, designed as seismic class I and stainless steel lined, and the saturation of their capacities is estimated to occur, on average, between 1993 and 2005. The GCR spent fuels are also stored in the NPP pool until its periodic sending to reprocessing. Racks are designed to maintain the spent fuel with a K_eff < 0.95. The pool water is cooled, filtered and demineralized. Controls are carried out on water temperature, level in the pool, flow rate in the cooling circuit, radiation level and radioactive concentration in the air, water chemistry, etc. Irradiated fuel assemblies are visually inspected by means of TV cameras and the cooling and purification systems are also visually inspected. A strategy is being elaborated for intermediate storage of spent fuels, considering both wet and dry storage. (author). 2 tabs

[en] For solidification of high-level radioactive fission product solutions (HAW), the borosilicate glass VG 98/12 was developed. In the present article, physical properties (density, thermal expansion, viscosity, electric and thermal conductivity), thermal behaviour, and hydrolytic stability (leaching) of the glass material are reported, the chemical composition with 15 wt.% inactive simulated HAW oxides is presented. (GSCH)

[en] One of the main roles of ventilation in a nuclear plant is to maintain dynamic containment during normal or accidental operating conditions. Among the incidents likely to affect a nuclear installation, fire is one of those which, coming from the safety standpoint, requires the greatest attention because it is one of the most probable risks. The consequences of a fire have to be analyzed not only in the room where it breaks out, but also for the entire ventilation network. To evaluate these consequences and develop strategies against fire, the Commissariat a l'Energie Atomique uses several test rigs and calculation codes by which the impact of a fire upon the sensitive points of a network can be determined. Research and development studies currently under way give priority to the clogging of High Efficiency Particulate Air filters. Beginning with polymer fires in a 85 m³ ventilated room, the influence of filter clogging on the characteristic parameters of the associated ventilated network is highlighted. The resultant modeling study following these experiments reveals that coupling of a ventilation code with a fire code cannot be disassociated from the development of a filter clogging model. This paper also gives the first experimental results relative to the determination of the variation, according to time and mass of deposited aerosols, of the air flow resistance of a filter clogged by aerosols derived from combustion of standard polymers used in the nuclear industry (methyl acrylate polymer, polyvinyl chloride). A methodology to extend the results obtained on the clogging test rig to any ventilation network is then described

[en] We describe differences by sex in genotoxic damage found in a population of medical students exposed to a highly oxidative atmosphere, compared with a control group, measured by the single-cell gel electrophoresis assay and histological changes in nasal epithelium smears. Cells were obtained from the nasal epithelium and blood leukocytes. Higher DNA damage in nasal cells and leukocytes was found in males compared to females and control subjects. The percentage of squamous metaplastic changes in the nasal epithelium was also higher in males compared with females and controls. The commutation of normal nasal epithelium by squamous cells might modify its protective function in the nose, increasing the risk of damage to the lower respiratory tract. Although, as medical students, males and females were exposed to the same environment and activity patterns, male genotoxicity damage was higher in control and exposed subjects. More research should be done in order to identify direct or indirect sexual hormone intervention

[en] The environmental external gamma dose rate has been determined at the Mexican Nuclear Research Centre and surrounding communities, located in a forest area. Outdoor direct measurements of external gamma exposure and absorbed dose rates in air were performed using passive integrating thermoluminescent dosimeters. Radiological measurements were also carried out with a portable high pressure ionization chamber. The gamma dose rate was evaluated from data obtained along 10 years measurements. The activity concentrations of ⁴⁰K, ²²⁶Ra, ²³²Th, ¹³⁷Cs, and ²³⁵U in surface soil samples at sampling sites are also presented. The radionuclide activity concentrations were determined by low background gamma spectrometry with hyper-pure germanium detectors. A site specific lineal model to describe the relationship between the external gamma dose rate and the ²²⁶Ra concentration values in the soil is proposed. (author)

[en] In 1997-98, the Mediterranean Energy Observatory (l'Observatoire Mediterraneen de l'Energie, OME), within the framework of a working group composed of a number of specialists from Member companies, carried out a study on the prospects of the refining industry in the Mediterranean, looking forward to the year 2010. The declared objective of this work was to enlighten the various parties involved as to the consequences of decisions in the matter of refinery plant investment policy for the Mediterranean region, especially given the prospects of the progressive liberation of this sector. Based on analysis of the current situations and potential future situations developing from this, the study consisted of the projection of a range of scenarios, the characteristics and main results of which are presented below. (author)

[en] The neutron activation analysis (NAA) is a highly accurate and sensitive non-destructive analytic technique. For this reason it is widely used for the multielemental determination of geological samples. In this work, 28 elements from 7 samples of source rocks are determined