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Abstract : Preliminary Stress Corrosion Cracking Modeling Study of a Dissimilar Material Weld of Alloy (Inconel) 182 with Stainless Steel 316 in Pressurized Water Nuclear Reactor
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Abstract: Dissimilar welds (DW) are normally used in many components junctions in structural project of PWR (Pressurized Water Reactors) in Nuclear Plants. One had been departed of a DW of a nozzle located at a Reactor Pressure Vessel (RPV) of a PWR reactor, that joins the structural vessel material with an A316 stainless steel safe end. This weld is basically done with Inconel/Alloy 182 with a weld buttering of Inconel/Alloy 82. It had been prepared some axial cylindrical specimens retired from the Alloy 182/A316 weld end to be tested in the slow strain rate test machine located at CDTN laboratory. Based in these stress corrosion susceptibility results, it was done a preliminary semi-empiric modeling application to study the failure initiation time evolution of these specimens. The used model is composed by a deterministic part, and a probabilistic part according to the Weibull distribution. It had been constructed a specific Microsoft Excel worksheet to do the model application of input data. The obtained results had been discussed according with literature and also the model application limits. Keywords: Dissimilar Welds, Pressurized Water Stress Corrosion Cracking, Semi-Empiric-Probabilistic Modeling, Slow Strain Rate Tests, Weld Nickel Alloys (Inconel) 82/182.Download Full Article |
Abstract : Development of a Hydrous Ethanol Fuel Feeding Device for Spark-Ignition Engine
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Abstract: While the Philippine Biofuels Act of 2006 mandates the use of anhydrous bioethanol as blend for gasoline, the potential of hydrous ethanol as an alternative fuel for spark-ignition engines has not been fully realized. This study explored the possibility of using hydrous ethanol as fuel for spark-ignition engines with minimal modifications and without the need for gasoline blend. A fuel feeding device was developed to feed hydrous ethanol fuel into the intake manifold of the engine, bypassing the carburetor. By replacing the components that are not compatible with hydrous ethanol and installing a fuel feeding device developed at PhilRice, two spark-ignition engines were able to run solely on 80-95% hydrous ethanol fuel. The fuel economy was found to be a significant issue in the utilization of hydrous ethanol fuel as there is a 75% increase in fuel consumption when using hydrous ethanol. There is potential for hydrous ethanol to be used as fuel if it can be produced locally and sold at half the pump price of gasoline. Keywords: Hydrous ethanol, fuel feeding device, spark ignition engine.Download Full Article |
Abstract : Obstacles and Way Forward in Promoting Renewable Energy in Nigeria
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Abstract: Nigeria is one of the world’s leading producers of crude oil and yet it is a net importer of refined oil. Its average daily premium motor spirit (PMS) consumption is 30 million liters. At 100% capacity the nation’s refineries will produce 17.74 million liters of premium motor spirit daily. A shortfall of over 10 million liters per day exists. Recent estimates stipulate that Nigeria requires 20,000 MW of electricity per annum. The projected electricity supply from all sources (conventional and renewable) in Nigeria in the short (2007), medium (2015) and long term (2025) is estimated to be 7000 MW, 14000 MW and 29,000 MW respectively. Annual peak electricity demand in Nigeria will increase from 4,558 MW to 45,755 MW in 2050 at high growth rate and 4,558 to 19,599 MW for low growth. Nigeria’s electricity per capita of 27 W/person is not enough to light an electric incandescent bulb of 30 W. These provide enough justification for the use of renewable energy in Nigeria. The use of renewable energy in Nigeria is hindered by the lack of regulation, financial incentives, energy infrastructures, framework for sustainability and technical expertise. Overcoming these obstacles will require invigorating research and development in renewable energy technologies, training and education to build local technical capacity, diversification of energy mix and scaling up of renewable energy utilization, aggressive capacity building in all areas of energy development and creation of enabling environment that will attract investment in energy infrastructure. This paper discusses the obstacles and way forward in promoting renewable energy in Nigeria. Keywords: Obstacle, way forward, promotion, renewable energy, Nigeria.Download Full Article |
Abstract : Neutron Flux Variation at the Inner Irradiation Channel of the Nigeria Research Reactor-1 (NIRR-1)
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Abstract: In order to ascertain the level of flux variation in one of the inner irradiation channels of the Nigeria Research Reactor-1 (NIRR-1), the irradiation container used for routine activation analysis was employed with copper wires as flux monitors. Measurements were carried out with these wires arranged in axial direction to determine the thermal neutron flux at selected positions using absolute foil activation method. Our results show that there exists a slight flux variation from one position to another ranging from (4.57 ± 0.24) x 1011 to (5.20 ± 0.20) x 1011 cm-2s-1. Individual foil shows slight flux variation from one position to another in the same irradiation container but they all pointed toward a level of stability in spite of the recent installation of the cadmium lined irradiation channel. The values obtained in this work are in good agreement with the previously measured value of (5.14 ± 0.24) x 1011 cm-2s-1 after commissioning of NIRR-1. This shows that the cadmium lined installation does not affect the flux stability. In order to improve the accuracy of neutron activation analysis (NAA) using NIRR-1 facility, there is need for flux corrections to be made by miniature neutron source reactor (MNSR) users during NAA particularly long irradiation, where more than six samples are irradiated simultaneously in the same container. Keywords: Nuclear Flux, Irradiation Channel, NAA. NIRR-1.Download Full Article |
