04984 A 3D coarse-mesh time dependent code for nuclear reactor kinetic calculations

04984 A 3D coarse-mesh time dependent code for nuclear reactor kinetic calculations

05 Nuclear fuels (scientific, technical) Utllizatlon of fly ash in the development of a cost96lO4970 effective cementltlous product Sarker, S. L. et...

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05

Nuclear fuels (scientific, technical)

Utllizatlon of fly ash in the development of a cost96lO4970 effective cementltlous product Sarker, S. L. et al., Am. Concr. Inst., SP, 1995,, 1, 439-457. The individual binding capacity of fly ash in ltme bearing systems and gypsum on its own is well established. The study is aimed at utilizing gypsum as phosphogypsum and industrial lime in conjunction with high volume fly ash to develop a cost-effective cementitious binder product by advantageously utilizing the individual binding capacity of the materials. Vapor grown carbon fibers from benzene pyroly96104971 s/s: Fllament length dlstrlbutlons Jayasankar, M. et al., Carbon, 1996, 34, (1) 127-134. The fibre length distributions of carbon fibres grown on alumina substrates by the vapour phase decomlxosition of benzene have been measured at different lenghthening times tn the temperature range of 1283-1353 K and at two concentrations of benzene. The proportion of longer fibres increased with lengthening time. A two-parameier model has be& used to compare the calculated and experimental fibre length distribution at various lengthening times. The evolution of the length distributions with time suggests the presence of an activation (of catalyst) step, leading to an induction phenomenon. Vapor pressure estimation for hydrocarbons In a 96/049?2 coal-derived liquld Harikae. S. Y. et al.. Coal Sci. Technol.. 1995. 24. (2). 1451-1454. Describes the examination of the vapour pressure’ of a coal-derived recycle solvent using a pseudocomponent approach in which the coal liquid was fractionated into-6 compound classes:.alkanes, monocyclic aromatic, naphthalene-type diaromatics, biphenyl-type diaromatics, tri- and tetracyclic aromatics, and polycyclic aromatics and polar compounds. Zeolite catalyst for hydrocracking coal-derived dis96104973 tillates -cleavage of naphthenic rings over zeolite catalystsKameoka, T. et al., Coal Sci. Technol., 1995, 24, (2), 1479-1482. Describes how catalysts were screened and evaluated for activity in hydrocracking of coal-derived middle distillates and in reaction of naphthenic and aromatic model compounds.

05 NUCLEAR FUELS Scientific,

Technical

Analytical numerical methods applied to linear dis96104974 continuous angular approximations of the transport equation In slab geometryDe Barros, R. C. et al., Kerntechnik, May 1996, 61, (2), 111-116. Describes two analvtical numerical methods aoolied to one-soeed slabgeometry deep penetration transport problems.‘The linear discontinuous (LDs) equations are used to approximate the monoenergetic Boltzmann equation in slab geometry; they are obtained by considering a linear expansion of the angular flux inside each of the N elements of a uniform angular arid. The two analvtical numerical methods are referred to as the soectral green’s function (SGF) nodal method and the Laplace transform (LTLD?) method. The SGF nodal method and the LTLD, method generate numertcal solutions to the LD.,. equations that are completely free of spatial approximations, apart from finite arithmetic considerations. A’umkrical results to tvoical model oroblems and suueestions for future work are also __ presented. ” 96104975 Avoid the unexpected. Use a 3D CAD model before building or maintenance Lockau, J. Nuclear Engineering Int., Aug. 1996, 41, (505) 30-32. The author discusses the advantages of 3D CAD models over 2D and how they are used to save time and money. 96104976 Buildinn seven simulators simultaneously Nuclear Engineering I%, Aug. 1996, 41, (505), 28-29. _ At Cergy, near Paris, France, 250 Thomson-CSF staff are building seven full-scope simulators for French, Germany and Dutch nuclear power plants at the same time. Short report on the progress of the work. Calculation of forces due to transverse impact of 96/049?? damped polycrystalline graphite beams McMillan, A. J. et al., Carbon, 1996, 34, (l), 121-125. Exoeriments were made bv Birch and Brocklehurst to determine the imoact properties of four types of nuclear reactor graphite using beam and plate specimens, In the beam experiments, the impactor consisted of a steel anvil, with a spherical surface, located at the end of a pivoted arm. The present study has investigated how damping of the vibrational response of a beam modifies orevious elastic analvses. A semi-empirical approach is adopted, in which’ a damping term is I’ncluded in the vibrational’equation for a beam. The predicted contact force functions are compared with typical experimental data and with results from elastic theory.

350

Fuel and Energy

Abstracts

September

1996

96104978 Characterization of the cable flre In Block 1 of the Greifswald nuclear power plant Albrecht, L. and Gelfort, E. Kerntechnik, May 1996, 61, (2), 77-85. In December 1975 a cable fire was initiated in a stand-by power distribution by a short circuit and an incorrectly fitted diode. Unpredictably and accidentally, some control and power cables were destroyed during the first. This caused the failure of safety-relevant components. Decay heat removal was achieved initially by natural convection in the primarv loop, and finally by an emergency feed pump in the secondary loop, for which-a provisional power cable had been successfully installed after approximately 8.5 hours. This serious accident was caused by human failure and lack of experience, by the insufficiency of the redundancies as provided in the plant design, by the lack of spatial separation of safety systems, and by insufficient quality control.

96104979 Chromium In aqueous nitrate plutonlum process streams: Corrosion of 316 stainless steel and chromium speclation Smith, W. H. and Purdy, G. M. Ware Management, 1995, 1.5, (7) 477-484. The study was undertaken to determine if chromium(+6) could exist in plutonium process solutions under normal operating conditions. Four individual reactions were studied.

96/04980 Clad effects In correction Cabral, J. S. and Martinez, A. S. 117-121.

calculations

of

the

Dancoff

Kerntechnik, May 1996, 61, (2)

The clad effects of Dancoff correction calculations are analyzed considering the general procedure of separating the clad region contribution in a correction factor. This factor relates the Dancoff correction C,,, calculated assuming the clad region as a void, and the Dancoff correction C,a, calculated treating the clad region explicitly. The clad correction factor ts physitally interpreted as a transmission probability, and this interpretation leads to an understanding of the limits of the approximations in the described procedures. An expression for the clad correction factor calculated without any simplification; as, e.g. variable separation, is also presented

96104981 Confluence of calculational and experimental lnformation for determination of power distribution and burnup Serov, I. V. and Hoogenboom, J.‘ E. Ann. Nucl. Energy, May 1996, 23, (8) 625-640. A technique for the statistical confluence of any number of possibily correlated informational sources employed in reactor analysis can be used to improve the estimates of physical quantities given by the sources taken seoaratelv. The formulas of the oresented technioue beine based on multi;ariate Bayesian conditioning aYe general and can be employed in different applications, Insight into the nature of the informational source allows different types of data associated with the source to be improved. Estimation of biases, variances and correlation coefficients for the systematic and statistical errors asociated with the informational sources is essential for reliable confluence, but pays off by providing optimal estimates.

Consortium’s SC replacement hat-trick 96104902 Gominski, J. Nuclear Engineering fnt., Aug. 1996, 41, (505), 20-21. Discusses how by joining forces to compete in the steam generator replacement market, Framatome and Siemens achieved an industry first in 1995, the two-company consortium completed three projects in three different European countries.

96104983 Correlated nuclear properties of heavy even 2 nuclei with 2 Z-N = 36 Ronen, Y. Kerntechrtik, May 1996, 61, (2), 101-102. In this paper some nuclear properties of 226Ra, 232Th, ‘%, zL’Pu, ““Cm and “‘Cf are shown to be correlated. These nuclides have even Z and 2 Z-N = 38. Based on the obtained correlations. it is oredicted that “6Ra should be a soontaneous-fission nuclide and that “‘Cf and 25’Es should be beta- emitt&s. It is also predicted that the first excited level of 2.‘6Cf should have a half-life of 9.7 X l@*ns.

A 3D coarse-mesh time dependent code for nuclear 96104904 reactor kinetic calculations Montagnini, B. et al., Ann. Nucl. Energy, Apr. 1996, 23, (6), 517-532. A coarse-mesh code for time-dependent multigroup neutron diffusion calculation based on a direct integration scheme for the time dependence and a low order nodal flux expansion approximation for the space variables has been implemented as a fast tool for transient analysis.