963 resultados para Nuclear reactor accidents.


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A kinetic model has been developed for the prediction of the concentration gelds in an rf plasma reactor. A sample calculation for a SiCl4/H2 system is then performed. The model considers the mixing processes along with the kinetics of seven reactions involving the decomposition of these reactants. The results obtained are compared to those assuming chemical equilibrium. The predictions indicate that an equilibrium assumption will result in lower predicted temperature fields in the reactor. Furthermore, for the chemical system considered here, while differences exist between the concentration fields obtained by the two models, the differences are not substantial.

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In this paper, an AC plasma arc reactorwithworkinggasofhydrogen is applied to destruct chemicalagents. The temperature attains 6000℃ in the arc area and over 2000℃ in the other space of the crucible. The Arsenic (As) contained chemical agent -Adams (DM) used in the experiment, was added into the plasmareactorwith the additives: Fe, CaO, and SiO_2, etc. Pyrolysis and destructionofchemicalagents occurs very quickly in the high-temperature reactor. Gaseous hydrogen was injected into the reactor to form a reductive environment, to reduce the formation of As_2O_3 etc. In the bottom of the crucible, the solid residues of toxicant and additives were melted and formed as vitrified slag. The off-gas was treated by a wet scrubber. The amounts of arsenic distributed in the off-gas, vitrified slag, waste water and solids (soot) were measured. The result shows DM is completely destructed in the plasmareactor. The Arsenic content in the off-gas, vitrified slag, waste water and soot are 0.052 mg/l, 3.0%, 10.44 mg/l, and 5.1% respectively, which will be disposed as the pollutant matters. The results show that the plasma technology is an environmentally friendly technology to destruct chemicals.

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Nuclear fusion has arisen as an alternative energy to avoid carbon dioxide emissions, being the tokamak a promising nuclear fusion reactor that uses a magnetic field to confine plasma in the shape of a torus. However, different kinds of magnetohydrodynamic instabilities may affect tokamak plasma equilibrium, causing severe reduction of particle confinement and leading to plasma disruptions. In this sense, numerous efforts and resources have been devoted to seeking solutions for the different plasma control problems so as to avoid energy confinement time decrements in these devices. In particular, since the growth rate of the vertical instability increases with the internal inductance, lowering the internal inductance is a fundamental issue to address for the elongated plasmas employed within the advanced tokamaks currently under development. In this sense, this paper introduces a lumped parameter numerical model of the tokamak in order to design a novel robust sliding mode controller for the internal inductance using the transformer primary coil as actuator.

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This study examined the efficiency of fish diversion and survivorship of diverted fishes in the San Onofre Nuclear Generating Station Fish Return System in 1984 and 1985. Generally, fishes were diverted back to the ocean with high frequency, particularly in 1984. Most species were diverted at rates of 80% or more. Over 90% of the most abundant species, Engraulis mordax, were diverted. The system worked particularly well for strong-swimming forms such as Paralobrax clothratus, Atherinopsis californiensis, and Xenistius californiensis, and did not appreciably divert weaker-swimming species such as Porichthys notatus, Heterostichus rostratus, and Syngnathus sp. Return rates of some species were not as high in 1985 as in 1984. Individuals of most tested species survived both transit through the fish return system and 96 hours in a holding net. Some species, such as E. mordox, X. californiensis, and Umbrina roncador, experienced tittle or no mortality. Survivorship of Seriphus politus was highly variable and no Anchoa delicatissima survived. (PDF file contains 22 pages.)