Papers by Keyword: Nuclear

Abstract: Development of accident-tolerant fuel (ATF) cladding materials for LWR (Light Water Reactors) is being intensively carried out in many research centers in the world as the lesson-learned from the Fukushima Daiichi nuclear reactor power plant accident. One of the advanced high temperature materials which is intensively developed is Oxide Dispersion strengthened (ODS) steel. The strengthened mechanism is generated by homogeneous dispersion of nanometer sized ceramic oxide particles in the matrix of the steel which is done by mechanical alloying technique so called mechanosynthesis. Synthesis of an austenitic ODS steel powder of SS316L with additional element of 4% aluminum and dispersion of nanoparticles of 0.5% yttrium oxide (yttria: Y₂O₃) has been done. The aim of the research is to achieve a better performance of SS316L steel as the established material for power plant at elevated temperature. Mechanosynthesis was done using High Energy ball Milling (HEM) for 30 hours with BPR (Ball to Powder Ratio) of 10:1. Afterward, the sample was characterized using Scanning Electron Microscope-Energy Dispersive Spectroscope (SEM-EDS) and X-ray diffraction (XRD) to analyze the microstructure characteristics. The results showed that the alloying between SS316L and aluminum powders was formed. Furthermore, crystal grains and the particles of SS316L-4Al-0.5Y₂O₃ powder was smaller than as received SS316L and aluminum powders.

Abstract: 3C-SiC layers of different microstructures (monocrystalline (100) and (111) oriented and polycrystalline) were implanted with high energy (800 keV) ¹²⁹Xe⁺⁺ ions. Implantations were performed at room temperature (RT) and at 500 °C using two different fluences of Φ₁ = 1x10¹⁶ and Φ₂ = 1x10¹⁷ at/cm². Surface blistering was only observed for RT and Φ₂ implantations into poly-SiC material while mono-SiC kept rather smooth surface. This was due to more homogeneous Xe bubbles distribution (200 nm deep) in the mono-SiC than in the poly-SiC. Xe retention was found to be almost complete for all samples. Some Xe enhanced diffusion was detected in the poly-SiC material which was attributed to grain boundaries. Some irradiation-induced oxidation effect was evidenced, O element being located at the depth where Xe bubbles are accumulating. This was more pronounced for poly than for mono-SiC. These results demonstrate that SiC microstructure affects many aspects of its behavior upon Xe irradiation.

Abstract: Heat removal from nuclear reactor core has been one of the major Engineering considerations in the construction of nuclear power plant. At the center of this consideration is the nuclear fuel pellet whose burning efficiency determines the rate of heat transfer to the coolant. This research, focuses on the study of temperature distribution of solid fuel, temperature distribution of annular fuel with external cooling and the temperature distribution of annular fuel with internal and external cooling. We analyzed the different distribution and made a conclusion on the possibility of improving temperature management of Nuclear fuel rod, by designing fuel pellets based on this geometrical and thermal Analysis. To date, a lot of studies has been done on the thermal and geometrical properties of Nuclear fuel pellet, it is observed that annular fuel pellet with simulteneous internal and external cooling can achieve better temperature distribution which leads to high linear heat generation rate, thus generating more power in the design [1]. It has also been observed that annular fuel pellets has low fission gas release [10]. In large LOCA, the peak cladding temperature of annular fuel is about 600 which is significantly less than that of solid fuel (920 ), this is due to the fact that annular fuel cladding has lower initial temperature and the thinner annular fuel can be cooled more efficiently than the solid fuel. One of drawbacks of annular fuel technology is “the fuel gap conductance assymmetry” which is caused by outward thermal expansion, it has a potential effect on the MDNBR (Minimum Departure from Nucleate Boiling Ratio), which is the minimum ratio of the critical to actual heat flux found in the core [10]. In this model, we used the ceramic fuel pellet of UO₂ as our case study. All the parameters in this model are assumed parameters of UO₂. The Heat Transfer tool (ANSYS APDL) was used to validate the Analytical Model of this research.

Abstract: The electric valve, cutting off or connecting pipeline of nuclear equipment, is an essential component of nuclear facilities for safe operation. The structure of self-developed enclosed nuclear electric valve is introduced in the paper firstly, and dynamics analysis of steam fluid in valve is carried out to tackle typical problems including leakage in the rapid open-close process of valve for high-temperature and high-pressure steam fluid. It can be determined that dynamic characteristic of steam fluid will directly affect force suffered by valve in the rapid open-close process, greatly influencing movement and ultimate position accuracy of valve gate.

Abstract: Metal hydrides have high hydrogen atom density, which is equivalent to that of liquid water. An application of the hafnium hydride has been investigated as a neutron absorber in the Fast Breeder Reactors (FBRs). Fast neutrons are efficiently moderated by hydrogen in Hf hydrides and are absorbed by Hf. Since three isotopes of Hf have large cross sections, increase in the life of control rod is considered by Hf hydride. Results of design study of the core with Hf hydride control rods shows that the long lived hafnium hydride control rod is feasible in the large sodium-cooled FBR. Results of irradiation test conducted in BOR-60 has demonstrated the integrity of the capsules during irradiation. Na bonded capsule has an advantage in confinement effect of hydrogen compared with He bonded one. An application of hydride technique to transmutation target of MA was also discussed. MA hydride target is able to enhance the transmutation rate in FBR.

Abstract: The electric valve cutting off or connecting pipeline of nuclear equipment is an essential component of nuclear facilities for safe operation, whose reliability directly determines working performance of entire nuclear device. Based on function analysis, module partition and structure analysis of valve have been carried out in the paper, and the direct correspondence between common faults and structural modularization of valve has been established. Furthermore, the proper methods and procedures of fault diagnosis for nuclear valve are put forward, which can guarantee safe operation of nuclear facilities.

Abstract: Today, faced with the problem of international energy supply difficulties, due to the nuclear power’s fewer of its resources consumption, little environmental pollution and other advantages, it has become one of the essential pillars of the electricity supply. This paper analyzed from a comprehensive localization of nuclear power plants, then use the non-equidistant GM (1,1) model and the exponential regression model to predict the construction cost of nuclear power, and do the error analysis. The conclusion that by increasing the degree of localization of domestic nuclear power construction, which can effectively reduce the cost of building nuclear power plants conclusions.

Abstract: Elevated water temperatures are the major threats from thermal discharges of coastal power plants. The effects of thermal discharge from power plant on phytoplankton were reviewed. With increasing amount of nuclear power plants in China, The effects of thermal discharge from a nuclear power plant on phytoplankton were investigated. Several results and suggestions were proposed.

Abstract: This paper gives an over-view of the many areas in which polymer concrete technology can create opportunities for developing and manufacturing products of immediate and local interest. It is postulated that such opportunities, if grasped and sensibly addressed will create sustainable employment which in turn will lead to prosperity throughout the world and the creation of world peace. An extensive Bibliography is provided to enable the interested reader to access further and more detailed information on the various application areas and also to study the state-of-the-art R&D in these areas involving various types of polymer concrete.

Abstract: This paper discusses two important issues: one is the Malaysian government decision to go nuclear to meet the future energy demands and the other is Lynas Rare-earth project to boost up the economy of the country. It should be noted that Malaysia is not new to such experiences as the Asian rare-earth project in the 1980s proved very costly causing rash of birth defects, painful miscarriages, and leukemia cases because of radioactive waste. This paper highlights the needs that future energy needs and economic targets can be overcome through other sources probably investing in renewable energy such as solar, wind, and hydropower.