05 specimens at high compressive stress level and by acetone impregnation were compared with ASTM and Hg porosity with promising results. Good porosity/strength correlations were found and a previous strength/time mathematical model always verified for cement without fly-ash was adjusted with success, to establish limit strengths or strength reserves for infinite ages, related with potential compaction and durability.
Subbituminous cement compositions
gal021 33
05
98lo2134 Synthesis of zeolite ZSM-35 from coal gangue Feng, F. et al. Shiyou Xuebao, Shiyou Jiagong, 1997, 13, (4), 104-107. (In Chinese) Coal gangue was used for the synthesis of zeolite ZSM-35 with high crystallinity as a raw material in a hydrothermal system. The as-prepared ZSM-35 samples were identified by X-ray diffraction, SEM, and IR. The results showed that the samples had as excellent physical properties as those of ZSM-35 prepared with chemical reagents. The catalytic properties were characterized in the reaction of CO hydrogenation for making light olefins, with a CO conversion rate of 61.6% and a selectivity for Cz-C4 olefins of 10.3%.
FUELS
Scientific, Technical
fly ash-based blended hydraulic
Styron, R. W. U.S. US 5,714,003 (Cl. 106-705; C04B7/28), 3 Feb 1998, Appl. 798,711, 12 Feb 1997, 9 pp. The cement compositions comprise (based on total composition) retardant 0.1-7, KzCOs 0.1-4, citric acid 0.1-4 and sub-bituminous fly ash 85-99.7 wt%. Alternatively, the cement compositions comprise (based on total composition) retardant 0.1-7, alkali source selected from ~1 of KzCO3 and KOH 0.1-6 citric acid 0.1-4, lime-containing 1st sub-bituminous fly ash 2591.7 and second fly ash selected from lignite fly ash, bituminous fly ash, and scrubber material 8-60 wt%. The compositions are suitable for the manufacture of concrete and for patching. A composition containing subbituminous fly ash 96.65, cement 2.00, gypsum 0.19, borax 0.10, boric acid 0.03, K2C03 0.57 and citric acid 0.48 wt% had initial and final setting time 3 h and 15 min and 3 h 30 min, respectively.
NUCLEAR
Nuclear fuels (scientific, technical)
96/02139 Conceptual design of a high temperature power reactor cooled and moderated by supercritical light water Dobashi, K. et al. Ann. Nucf. Energy, 1998, 25, (8), 487-505. The technical feasibility and potential economic improvement of a high temperature reactor cooled and moderated by supercritical light water (SCLWR-H) has been assessed. The plant system is the once-through direct cycle and whole core coolant flows to the turbine. The cold coolant flowing up in the water rods is mixed with that of the fuel channel coolant above the core, when conventional ascending flow type water rods are used. The average core outlet temperature is low, 45°C. but it reaches 508°C in the core with the descending flow type water rods, because no mixing of the coolant occurs above the core. The fuel enrichment is also decreased. An orifice controls the flow rate of each fuel assembly in order to maximize the outlet coolant temperature. With thermal efficiency of 44.0% and electric power of 1610 MW, the reactor achieves a coolant flow rate per generated electricity which is 24% lower than that of an Advanced Boiling Water Reactor (ABWR). This will reduce the size of the balance of plant (BOP) system. The burn-up reactivity can be compensated by changing coolant flow rate ratio in the descending flow type water rods to the whole core through the fuel cycle. Furthermore, it is not necessary to change the inlet and outlet coolant temperature and total flow rate to maintain constant power.
Evaluations of radiation properties of gas media used in nuclear-pumped lasers
gal021 40
System of utilization of coal ash for cement admixtures and concrete aggregate raw materials
98102135
Takekawa, T. er al. Jpn. Kokai Tokkyo Koho JP 10 01,339 [98 01,339] (Cl. CO4BlS/OS), 6 Jan 1998, Appl. 961155,298, 17 Jun 1996,4 pp. (In Japanese) Coal-burning boiler fly ash is classified into (a) spherical powders containing a small amount of unburned components and (b) fly ashes containing a large amount of unburned components. Then, (b) is sintered by combusting the unburned components and the coal ash is dried, pulverized and melted to generate molten ash and vaporized low-boiling point substances. These substances are quenched to give (c) amorphous micropowders and the molten ash is pulverized with water to give (d) minute slag powders. The four substances produced are used as cement admixtures and concrete aggregate raw materials. It is possible to recycle the coal ash at high rate via this system.
9BtO2136
Use of coal-beneficiation wastes in firing of cement
clinker Babushkin, V. 1. et al. Koks. Khim., 1997, Coal beneficiation wastes utilisation during kilns was evaluated based on experimental the clinker at 700-800°C decreased natural clinker.
(8) 32-35. (In Russian) cement clinker firing in rotary data. Addition of 5% waste to gas consumption by >7 m3/ton
Use of fly ash or silica fume to Increase the resistance of concrete to feed acids
96102137
De Belie, N. et al. Msg. Concr. Res., 1997, 49, (181), 337-344. Feed and manure in animal houses subject the concrete to aggressive substances. Chemical attack by the most important feed acids, lactic and acetic acids and abrasion caused by animals and cleaning were simulated and studied using accelerated corrosion tests. The resistance of concrete prisms with different percentages of fly ash or silica fume to simulation liquids with different pH values was investigated. The volume decrease in terms of percentage and mass loss per unit area were measured, as well as the pH change and calcium content of the liquids. Fly ash addition and, even more so, the addition of silica fume seemed to help to increase the resistance of concrete to highly and very highly aggressive simulation liquids. Fly ash below 30% by weight of cement seemed to be best. The difference between using silica fume as an addition or as a cement replacement was small. A correlation was found between the mass of the dissolved material and the calcium content of the liquid. 96102136 Utilization of optionally classified ashes from coalfired power plant steam bollers Kirchen, G. and Lehrke, J. Ger. Offen. DE 19,538,710 (Cl. C04B7/28), 24 Apr 1997, Appl. 19,538,710, 18 Ott 1995, 3 pp. (In German) The ashes are withdrawn and added in dry form as fuel and raw material in the manufacture of cement, as bed sand in fluidized-bed firing or fuel carrier and sintering aid in the manufacture of light weight aggregate, or as mineral components, e.g. as fuel or active carbon, and as fine sand.
Lukashin, G. M. et al. IEEEINPSS Symp. Fusion Eng., 1995,16, (l), 70-73. The gas media activity of the cell due to fission products coming out from the uranium coat is about 10% of total activity of the coal one hour after reactor’s stopping and equal 5.3 x 10-s Bk/fis. The composition of the activity is the next: aerosol phase 88%, volatile phase 0.6%, gaseous phase 11.4%. More than 60% of FP (fission products) activity is given by particles with the size less than 0.5 Fm. Diffusion output at FP into gas after the end of reactor’s work is about 0.1% of the kinetic output at the same time instant. Radio nuclide composition of activity coming out from the coat has no serious differences from the referred data for uranium 235.
Nodal neutron kinetics model based on nonlinear iteration procedure for LWR analysis
90ltI2141
Zimin, V. G. and Ninokata, H. Ann. Nucl. Energy, 1998, 25, (8), 507-528. Based on the analytical nodal method and non-linear iteration procedure, a three-dimensional neuron kinetics model has been developed for Light Water Reactor (LWR) transient calculations. The solution procedure is decoupled on a local solution of the nodal equations for two-node problems and global iterations of the coarse-mesh finite-difference method. An efficient algorithm of the solution of the nodal equations for the two-node problem resulted from an orthogonality of the basic functions used for the neutron flux expansion. The initial system of 8G nodal equations is reduced to a set of G and 2G equations, where G is a number of neutron energy groups. A fully implicit scheme with an analytical treatment of the delayed neutron precursors equations is used for time integration. An adaptive time-step size control procedure based on the time-step doubling technique is applied. The computer code SKETCH-N employs all these numerical methods. The 3D LWR Langenbuch-Maures-Werner (LMW) operational transient and 2D and 3D Boiling Water Reactor (BWR) LRA superprompt-critical benchmark problems are calculated in order to verify the code. The validity and efficiency of the SKETCH-N code was confirmed by a comparison between the computed results with the solutions obtained by the other nodal computer codes.
Quick and reliable estimation of power distribution in a PHWR by ANN
98/02142
Dubey, B. P. et al. Ann. Nucl. Energy, 1998, 25, (8), 567-579. From the operation and maintenance viewpoint of the reactor, it is important to know the distribution of power in all the channels of a pressurized heavy water reactor (PHWR) as a result of a perturbation caused by one or more of the regulating devices. On modern PCs, theoretical design codes available for this purpose take several minutes to calculate the channel power distribution. Artificial neural networks (ANNs) have been employed in predicting channel power distribution of Indian PHWRs for any given configuration of regulating devices of the reactor and have proved both faster and accurate. The methodology of ANN, its reliability, the validation range, and scope for its possible on-line use in the actual reactor are discussed in this paper.
Fuel and Energy Abstracts
May 1996
193