[en] This paper presents the analysis of Reactivity Induced Accident caused by ejection of a Control Element Assembly (CEA) from APR 1400 reactor vessel within 0.05 second. The initial condition were assumed as following: power level at 102%, delayed neutron fraction β = 412 pcm and CEA worth = 110 pcm. The analysis was simulated by RELAP5 code through two step: calculation of steady state and calculation of transient with initial condition mentioned as above. Some output results were presented with explanation: sequence of events corresponding to the time of the accident, the system behavior as power, reactivity feedback from fuel temperature changes (Doppler) as well as temperature, pressure, DNBR within 6 second of the accident. (author)

[en] RELAP5 - a thermal hydraulic system code - in recent years is used by many researchers in Vietnam for the reactor thermal-hydraulic analysis. In the other hand, VVER-1000 reactor is selected to be the nuclear reactor technology for the first nuclear power plant in Vietnam. So the studying on VVER-1000 reactor is very important. The project purpose is modeling the thermal-hydraulic systems of VVER-1000 reactor. The project also targets enhancement of experiences in using RELAP5/SCDAPSIM code and modeling for components of VVER-1000 reactor in steady state and transient, including: steady state at 100% power, transient with switch off 1 or 2 main coolant pumps. The thermal hydraulic parameters were analysed versus time. The thermal hydraulic parameters, such as: outlet pressure, coolant temperature, maximum fuel temperature, water level of pressurizer and steam generator, etc. were compared, analysed and assessed. In steady state, the errors are less 10 per cent. (author)

[en] In this project, these fuel and moderator temperature coefficients were calculated in APR1400 nuclear reactor by MVP code. APR1400 is an advanced water pressurized reactor, that was researched and developed by Korea Experts, its electric power is 1400 MW. The neutronics calculations of full core is very important to analysis and assess a reactor. Results of these calculation is input data for thermal-hydraulics calculations, such as fuel and moderator temperature coefficients. These factors describe the self-safety characteristics of nuclear reactor. After obtaining these reactivity parameters, they were used to re-run the thermal hydraulics calculations in LOCA and RIA accidents. These thermal-hydraulics results were used to analysis effects of reactor physics parameters to thermal hydraulics situation in nuclear reactors. (author)

[en] This project presents overview about the role of PSA and the levels of PSA, the process of selecting initial event and accident sequence modeling, and system analysis for PSA level 1. The project also study initially data-base development cho PSA. In this part, two method was shown classical method and Bayesian method. The project calculated the uncertainty of ECCS in case of large break LOCA (LB LOCA) of nuclear power EPR 1600 MWe. The results of core damage calculation in case of large break LOCA is 5.9E-8 a year shown that initial large break LOCA has small contribution to core damage. The result also shown that, the accumulator, electric system and low head injection pump have an important role. They are need to concern in the maintenance. Compare with the data, these results are not compatible well. (author)

[en] Nowadays, there are many thermal hydraulics code base on the best estimate method such as: CATHARE, TRACE, COBRA, RELAP, etc. RELAP/SCDAPSIM is one of the thermal hydraulics codes for using the safety analysis of the nuclear power plant (NPP). It is used to modeling for the thermal hydraulics systems in NPP. It can model the systems in many different case like steady state, transients and design basic accidents. The purposes of the study are enhancement of experiences to using RELAP/SCDAPSIM code and modeling for components in nuclear power plant. In this study, the pressurizer has model in the steady state and transients conditions by RELAP/SCDAPSIM code. The scenarios have been built by the pressure changes that leading operation of safety valves, spray valves and heaters. They have been opened by control trips. (author)

[en] SnO₂@CMK-3 composites with different SnO₂ contents have been successfully synthesized using incipient wetness technique. Because of a high specific area and porosity, CMK-3 enables facile penetration of SnCl₄ solution inside. Accordingly, SnCl₄ clusters confined in the CMK-3 mesopores easily transform to SnO₂ nanoparticles. The obtained SnO₂@CMK-3 composites show a high surface area in a range from 224.8 to 398.1 m2/g and good lithium storage properties. Among the resultant composites, the composite-70 with 70 % of SnO₂ shows the best electrochemical performance. At the rate of C/10, the composite-70 electrode delivers an average discharge capacity of 678 mAh/g. At high rates such as 5C, and 10C the electrode still achieves a discharge capacity of 270, and 201 mAh/g, respectively. Even after 1000 cycles at the rate of C/2, the electrode maintains 67.8 % of the initial capacity. (author)

[en] In this project, some thermalhydraunics and neutronics parameters (multiplier factor k-eff, reactivity, critical heat flux CHF), were calculated in subchannel of Water-Water Energetic Reactor (VVER) with electric power is 1000 MW by SRAC, MVP, and RELAP codes. These parameters are used to carry out nuclear reactor safety analysis. Although these calculated results are not high correct level but they was the first step to young researchers can access to VVER1000 technology, and to use thermalhydraulics and neutronics codes. (author)

[en] The objective of this study is to identify the sources of the formation water in the Southwest Su-Tu-Den (STD SW) basement reservoir. To achieve the objective, isotopic techniques along with geochemical analysis for chloride, bromide, strontium dissolved in the water were applied. The isotopic techniques used in this study were the determination of water stable isotopes signatures (δ²H and (δ¹⁸O) and of the ⁸⁷Sr/⁸⁶Sr ratio of strontium in rock cutting sample and that dissolved in the formation water. The obtained results showed that the stable isotopes compositions of water in the Lower Miocene was -3‰ and -23‰ for (δ¹⁸O and (δ²H, respectively indicating the primeval nature of seawater in the reservoir. Meanwhile, the isotopic composition of water in the basement was clustered in a range of alternated freshwater with (δ¹⁸O and (δ²H being -(3-4)‰ and -(54-60)‰, respectively). The strontium isotopes ratio for water in the Lower Miocene reservoir was lower compared to that for water in the basement confirming the different natures of the water in the two reservoirs. The obtained results are assured for the techniques applicability, and it is recommended that studies on identification of the flow-path of the formation water in the STD SW basement reservoir should be continued. (author)

[en] The objective of this study is to identify the sources of the formation water in the Southwest Su Tu Den (STD SW) basement reservoir. To achieve the objective, isotopic techniques along with geochemical analysis for chloride, bromide, strontium dissolved in the water were applied. The isotopic techniques used in this study were the determination of water stable isotopes signatures (δ"2H and δ"1"8O) and of the "8"7Sr/"8"6Sr ratio of strontium in rock cutting sample and that dissolved in the formation water. The obtained results showed that the stable isotopes compositions of water in the Lower Miocene was -3‰ and -23‰ for δ"1"8O and δ"2H, respectively indicating the primeval nature of seawater in the reservoir. Meanwhile, the isotopic composition of water in the basement was clustered in a range of alternated freshwater with δ"1"8O and δ"2H being -(3-4)‰ and -(54-60)‰, respectively). The strontium isotopes ratio for water in the Lower Miocene reservoir was lower compared to that for water in the basement confirming the different natures of the water in the two reservoirs. The obtained results are assured for the techniques applicability, and it is recommended that studies on identification of the flow-path of the formation water in the STD SW basement reservoir should be continued. (author)

[en] Manganese oxides doped by Co and Fe were prepared by anodic deposition at density current of 50 mA/cm² using electrolyte containing manganese sulfate and either cobalt sulfate or ferro sulfate. Surface morphology and crystal structure of oxides were studied using scanning electron microscope (SEM) and X-ray diffraction (XRD). Chemical compositions of materials were analyzed by using X-ray energy Dispersive Spectroscope (EDS). Average valence of manganese was estimated using iodometric titration and complexometric titration methods. Result showed that the obtained doped manganese oxides were composed of nano-particles sizing of 5-20 nm and remained amorphous structure after heat treatment at 100^oC in 2 hours. After annealing at 400^oC the crystalline Mn₂O₃ and MnO² phase were recognized obviously. The average valent of Mn increased from +3.808 to +3.867 after doping Co and from +3.808 to + 3.846 after doping Fe. (author)