The Experts below are selected from a list of 129 Experts worldwide ranked by ideXlab platform
Rajamani Natarajan - One of the best experts on this subject based on the ideXlab platform.
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reprocessing of spent nuclear fuel in india present challenges and future programme
Progress in Nuclear Energy, 2017Co-Authors: Rajamani NatarajanAbstract:Abstract Adoption of the closed nuclear fuel cycle is an imperative option for the Indian nuclear power programme in view of the limited resources of natural uranium and abundance of thorium. The issues associated with the long-term radiotoxicity of spent fuel can also be addressed in the closed fuel cycle with this option. The present paper focusses on the scientific and technological challenges associated with reprocessing of spent fuel from both the thermal and fast reactors. The experience gained in the operation of reprocessing plants in the separation of spent fuel of thermal reactors into uranium, plutonium and high level waste is described in this paper. Challenges resolved during the reprocessing of spent Mixed Carbide fuel from Fast Breeder Test Reactor (FBTR) in CORAL plant are described in detail. This experience enabled the design of a commercial scale reprocessing plant which is under construction to handle the spent fuel from 500 MWe Prototype Fast Breeder Reactor (PFBR). Recent developments in the separation of minor actinides from high level waste is also briefly discussed. The experience gained in the thorium fuel cycle with the reprocessing of spent thorium fuel is also covered.
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fast reactor fuel reprocessing technology in india
Journal of Nuclear Science and Technology, 2007Co-Authors: Rajamani Natarajan, Baldev RajAbstract:The limited indigenous uranium resource coupled with the need of energy independence necessitated the Department of Atomic Energy (DAE) in India to opt for a three-stage nuclear power program comprising of PHWRs in Stage 1, FBRs in Stage 2 and Th-U233 based reactors in Stage 3, respectively to meet the energy needs of the growing Indian economy. Presently the country has stepped into the 2nd Stage. The transition from the Stage 1 to 2 was fruitful thanks to the 2-decade long R&D experience gained in Fast Reactor Fuel Reprocessing (FRFR). Closing the fast reactor fuel cycle through FRFR was inevitable for the success of the Indian Nuclear Power Program (INPP). The latest achievement by the center was the successful reprocessing of 100 GWd/t burnup Mixed Carbide fuel with 70% Pu, discharged from the Fast Breeder Test Reactor (FBTR) which is also located in the same center. The designs of the various equipments and process flow sheet had stemmed from the above experiences thereby increasing the confidence le...
Carsten Streb - One of the best experts on this subject based on the ideXlab platform.
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bottom up design of bimetallic cobalt molybdenum Carbides oxides for overall water splitting
Chemistry: A European Journal, 2020Co-Authors: Montaha H Anjass, Simon Greiner, Guangjin Zhang, Johannes Biskupek, Ute Kaiser, Carsten StrebAbstract:Earth-abundant transition-metal-based catalysts for electrochemical water splitting are critical for sustainable energy schemes. In this work, we use a rational design method for the synthesis of ultrasmall and highly dispersed bimetallic CoMo Carbide/oxide particles deposited on graphene oxide. Thermal conversion of the molecular precursors [H3 PMo12 O40 ], Co(OAc)2 4 H2 O and melamine in the presence of graphene oxide gives the Mixed Carbide/oxide (Co6 Mo6 C2 /Co2 Mo3 O8 ) nanoparticle composite deposited on highly dispersed, N,P-doped carbon. The resulting composite shows outstanding electrocatalytic water-splitting activity for both the oxygen evolution and hydrogen evolution reaction, and superior performance to reference samples including commercial 20 % Pt/C & IrO2 . Electrochemical and other materials analyses indicate that Co6 Mo6 C2 is the main active phase in the composite, and the N,P-doping of the carbon matrix increases the catalytic activity. The facile design could in principle be extended to multiple bimetallic catalyst classes by tuning of the molecular metal oxide precursor.
Narendra B Dahotre - One of the best experts on this subject based on the ideXlab platform.
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laser in situ synthesis of Mixed Carbide coating on steel
Journal of Materials Science, 2004Co-Authors: A Singh, Narendra B DahotreAbstract:A 2.5 KW Nd:YAG laser was employed to modify the surface of a AISI 1010 steel deposited with a precursor powder mixture of Fe, Ti, Cr and C. In-situ formation of TiC and chromium Carbides [M7C3 (M = Fe, Cr) and Cr7C3] was observed as function of laser processing power at constant scan speed. Although TiC was present in all the samples, the chromium Carbides were absent in samples processed at certain laser powers. Corresponding to this behavior, variation in mechanical properties of the coating was observed. The hardness and wear properties of the samples without chromium Carbides was inferior in comparison to samples with both TiC and chromium Carbides.
Carlos Alberto Alves Cairo - One of the best experts on this subject based on the ideXlab platform.
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reinforcing al2o3 with w ti Mixed Carbide
Materials Letters, 2000Co-Authors: Wilson Acchar, Antonio Eduardo Martinelli, Carlos Alberto Alves CairoAbstract:Abstract Recent advances in high-speed cutting materials have focused on reinforcing alumina with different Carbides and nitrides in order to improve hardness and fracture toughness. However, data on Mixed Carbides is still scarce. The potential use of this type of material for cutting tool applications has yet to be determined. The present study reports some preliminary results obtained reinforcing Al 2 O 3 with WTiC in the range of 5–30 wt.%. The material was hot-pressed at 1650°C for 30 min and then characterized. Vicker's microhardness ( H V ) and fracture toughness ( K IC ) were evaluated by the indentation method. The addition of WTiC did not result in any significant change in the fracture toughness of alumina, however hardness values in excess of 22 GPa were obtained.
Samim Anghaie - One of the best experts on this subject based on the ideXlab platform.
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processing and fabrication of Mixed uranium refractory metal Carbide fuels with liquid phase sintering
Journal of Nuclear Materials, 2002Co-Authors: Travis W Knight, Samim AnghaieAbstract:Abstract Optimization of powder processing techniques were sought for the fabrication of single-phase, solid-solution Mixed uranium/refractory metal Carbide nuclear fuels – namely (U, Zr, Nb)C. These advanced, ultra-high temperature nuclear fuels have great potential for improved performance over graphite matrix, dispersed fuels tested in the Rover/NERVA program of the 1960s and early 1970s. Hypostoichiometric fuel samples with carbon-to-metal ratios of 0.98, uranium metal mole fractions of 5% and 10%, and porosities less than 5% were fabricated. These qualities should provide for the longest life and highest performance capability for these fuels. Study and optimization of processing methods were necessary to provide the quality assurance of samples for meaningful testing and assessment of performance for nuclear thermal propulsion applications. The processing parameters and benefits of enhanced sintering by uranium Carbide liquid-phase sintering were established for the rapid and effective consolidation and formation of a solid-solution Mixed Carbide nuclear fuel.
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processing of Mixed uranium refractory metal Carbide fuels for high temperature space nuclear reactors
SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 2000, 2001Co-Authors: Travis W Knight, Samim AnghaieAbstract:Single phase, solid-solution Mixed uranium/refractory metal Carbides have been proposed as an advanced nuclear fuel for high performance, next generation space power and propulsion systems. These Mixed Carbides such as the pseudo-ternary, (U, Zr, Nb)C, hold significant promise because of their high melting points (typically greater than 3200 K), thermochemical stability in a hot hydrogen environment, and high thermal conductivity. However, insufficient test data exist under nuclear thermal propulsion conditions of temperature and hot hydrogen environment to fully evaluate their performance. Various compositions of (U, Zr, Nb)C were processed with 5% and 10% metal mole fraction of uranium. Stoichiometric samples were processed from the constituent Carbide powders while hypostoichiometric samples with carbon-to-metal (C/M) ratios of 0.95 were processed from uranium hydride, graphite, and constituent refractory Carbide powders. Processing techniques of cold pressing, sintering, and hot pressing were investigated to optimize the processing parameters necessary to produce dense (low porosity), homogeneous, single phase, solid-solution Mixed Carbide nuclear fuels for testing. This investigation was undertaken to evaluate and characterize the performance of these Mixed uranium/refractory metal Carbides for space power and propulsion applications.