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Vibrational effect on unidirectional timedependent angular momentum in low-symmetry aromatic ring molecule induced by two linearly polarized UV laser

In this study, we present the results of a theoretical study of the time-dependent angular momentum equation for low-symmetry aromatic ring molecule combine with vibrational effect using two linearly polarized UV laser.

Nghiên cứu và phân tích nguồn gốc ô nhiễm không khí ở thành phố Huế thông qua rêu Barbular bằng phần mềm Statistica 8.0

Bài viết này tiến hành nghiên cứu đo nồng độ nguyên tố trong mười sáu mẫu rêu Barbular thu thập tại thành phố Huế, được phân tích bằng phương pháp phân tích kích hoạt neutron (Neutron Activation Analysis) tại Viện Nghiên cứu Hạt nhân Dubna – Nga.

Bài dự thi Hội thi sáng tạo kỹ thuật Trần Đại Nghĩa: Giải pháp tái sử dụng nguồn năng lượng dư thừa làm đèn tiết kiệm năng lượng góp phần bảo vệ môi trường

Nội dung bài dự thi trình bày nhằm góp phần trong việc bảo vệ môi trường, sử dụng năng lượng một cách tiết kiệm, tác giả đã có ý tưởng tái sử dụng các nguồn năng lượng dư thừa và rác thải để chế tạo các sản phẩm phục vụ đời sống con người mà chủ yếu là chế tạo các loại đèn Led. Sự kết hợp này vừa mang lại lợi ích về kinh tế, vừa phát huy được khả năng sáng tạo trong việc thiết kế đèn, vừa góp phần bảo vệ môi trường đồng thời có thể triển khai mở rộng cho học sinh bậc trung học.

A review of renewable energy sources, sustainability issues and climate change mitigation.

The need for energy and its related services to satisfy human social and economic development, welfare and health is increasing. Returning to renewables to help mitigate climate change is an excellent approach which needs to be sustainable in order to meet energy demand of future generations. The study reviewed the opportunities associated with renewable energy sources which includes: Energy Security, Energy Access, Social and Economic development, Climate change mitigation, and reduction of environmental and health impacts. Despite these opportunities, there are challenges that hinder the sustainability of renewable energy sources towards climate change mitigation. These challenges include market failures, lack of information, access to raw materials for future renewable resource deployment, and our daily carbon footprint.

Ảnh hưởng của kết cấu và vật liệu tạo tấm hấp phụ đến thông số nhiệt của bộ thu năng lượng mặt trời

Nghiên cứu khả năng nâng nhiệt của bộ thu nhiệt năng lượng mặt trời với kết cấu và vật liệu khác nhau là hết sức quan trọng để có cơ sở khoa học tính toán lựa chọn vật liệu và kết cấu bộ thu hợp lý cho các thiết bị ứng dụng nhiệt năng lượng mặt trời.

Structural assessment of reactor pressure vessel under multi layered corium formation conditions

In the present study, several key factors related to molten corium behaviors and thermal characteristics were examined under multi-layered corium formation conditions. Thereafter, systematic finite element analyses and subsequent damage evaluation with varying parameters were performed on a representative reactor pressure vessel (RPV) to figure out the possibility of high temperature induced failures.

Status of the astrid core at the end of the preconceptual design phase 1

Within the framework of the ASTRID project, core design studies are being conducted by the CEA with support from AREVA and EDF. The pre-conceptual design studies are being conducted in accordance with the GEN IV reactor objectives, particularly in terms of improving safety. This involves limiting the consequences of 1) a hypothetical control rod withdrawal accident (by minimizing the core reactivity loss during the irradiation cycle), and 2) an hypothetical loss-of-flow accident (by reducing the sodium void worth).

Severe accident issues raised by the fukushima accident and improvements suggested

This paper revisits the Fukushima accident to draw lessons in the aspect of nuclear safety considering the fact that the Fukushima accident resulted in core damage for three nuclear power plants simultaneously and that there is a high possibility of a failure of the integrity of reactor vessel and primary containment vessel.

Thermal shock fracture of silicon carbide and its application to lwr fuel cladding performance during reflood

In this study, an experimental assessment of thermal shock performance of a monolithic alpha phase SiC tube was conducted by quenching the material from high temperature (up to 1200ºC) into room temperature water. Post-quenching assessment was carried out by a Scanning Electron Microscopy (SEM) image analysis to characterize fractures in the material. This paper assesses the effects of pre-existing pores on SiC cladding brittle fracture and crack development/propagation during the reflood phase. Proper extension of these guidelines to an SiC/SiC ceramic matrix composite (CMC) cladding design is discussed.

Three dimensional flow phenomena in a wire wrapped 37-pin fuel bundle for sfr

The main purpose of the current study is to understand the three-dimensional complex flow phenomena in a wire-wrapped fuel assembly to support the license issue for the core design. Computational fluid dynamics results show good agreement with friction factor correlation models. The secondary flow in the corner and edge subchannels is much stronger than that in an interior subchannel. The axial velocity averaged in the corner and edge subchannels is higher than that averaged in the interior subchannels.

Validation of numerical methods to calculate bypass flow in a prismatic gas cooled reactor core

One of the important requirements for GAMMA+ and AGREE is an accurate modeling capability of a bypass flow in a prismatic core. Recently, a series of air experiments were performed at Seoul National University (SNU) in order to understand bypass flow behavior and generate an experimental database for the validation of computer codes. The main objective of the present work is to validate the GAMMA+ and AGREE codes using the experimental data published by SNU.

Vibration displacement measurement technology for cylindrical structures using camera images

In this paper, a method is proposed to measure vibration displacements remotely using a camera without having to approach the structure. Furthermore, an estimation method for the measurement resolution and measurement error is proposed for the vibration displacement of a cylindrical structure measured using the proposed measurement method. The proposed methods are described, along with experimental results that verify their accuracy.

Study on the recycling of nuclear graphite after micro-oxidation

In this paper, a feasible strategy for the recycling of nuclear graphite is reported, based on the formation mechanism and the removal of carbon-14 by micro-oxidation. We investigated whether ground micro-oxidation graphite could be used as a filler to make new recycled graphite and which graphite/pitch coke ratio will give the recycled graphite outstanding properties (e.g., apparent density, flexural strength, compressive strength, and tensile strength).

The impact of power coefficient of reactivity on candu 6 reactors

In particular, CANDU reactors have always taken advantage of the small value of the PCR associated with their design characteristics, such that the overall design and safety characteristics of the reactor are not sensitive to the value of the PCR. For other reactor design concepts a PCR which is both large and negative is an important aspect in the design of their engineered systems for controlling reactivity.

Validation of a new design of tellurium dioxide irradiated target

The results show that the tightness of the targets is ensured up to 600C with the appearance of deformations on lids beyond 450C. The study of heat transfer through the target was conducted by adopting a one-dimensional approximation, under consideration of the three transfer modesdconvection, conduction, and radiation.

Validation of computational fluid dynamics calculation using rossendorf coolant mixing model flow measurements in primary loop of coolant in a pressurized water reactor model

The aim of this work is to simulate the thermohydraulic consequences of a main steam line break and to compare the obtained results with Rossendorf Coolant Mixing Model (ROCOM) 1.1 experimental results. The objective is to utilize data from steady-state mixing experiments and computational fluid dynamics (CFD) calculations to determine the flow distribution and the effect of thermal mixing phenomena in the primary loops for the improvement of normal operation conditions and structural integrity assessment of pressurized water reactors. The numerical model of ROCOM was developed using the FLUENT code.

Verification of electromagnetic effects from wireless devices in operating nuclear power plants

This design change can improve the ability of the operators and personnel to respond to an emergency situation by using important equipment for a safe shutdown. IEEE 802.11 smartphones (Wi-Fi standard), Internet Protocol (IP) phones, personal digital assistant (PDA) for field work, notebooks used with web cameras, and remote site monitoring tablet PCs for on-site testing may be considered as wireless devices that can be used in domestic operating NPPs.

Sensitivity analyses of the use of different neutron absorbers on the main safety core parameters in mtr type research reactor

In this paper, three types of operational and industrial absorbers used at research reactors, including Ag-In-Cd alloy, B4C, and Hf are selected for sensitivity analyses. Their integral effects on the main neutronic core parameters important to safety issues are investigated. These parameters are core excess reactivity, shutdown margin, total reactivity worth of control rods, thermal neutron flux, power density distribution, and Power Peaking Factor (PPF). The IAEA 10 MW benchmark core is selected as the case study to verify calculations. A two-dimensional, three-group diffusion model is selected for core calculations.

Sensitivity analysis of core neutronic parameters in electron accelerator driven subcritical advanced liquid metal reactor

In addition, sensitivity of the core neutronic parameters in accelerator-driven subcritical advanced liquid metal reactors, such as electron beam energy (Ee) and source multiplication coefficient (ks), has been investigated. A Monte Carlo code (MCNPX_2.6) has been used to calculate neutronic parameters such as effective multiplication coefficient (keff), net neutron multiplication (M), neutron yield (Yn/ e), energy constant gain (G0), energy gain (G), importance of neutron source (4* ), axial and radial distributions of neutron flux.

Terrapower, LLC traveling wave reactor development program overview

The fast neutron spectrum allows up to a ~30-fold gain in fuel utilization efficiency when compared to conventional light water reactors utilizing enriched fuel. When compared to other fast reactors, TWRs represent the lowest cost alternative to enjoy the energy security benefits of an advanced nuclear fuel cycle without the associated proliferation concerns of chemical reprocessing. On a country level, this represents a significant savings in the energy generation infrastructure for several reasons 1) no reprocessing plants need to be built, 2) a reduced number of enrichment plants need to be built, 3) reduced waste production results in a lower repository capacity requirement and reduced waste transportation costs and 4) less uranium ore needs to be mined or purchased since natural or depleted uranium can be used directly as fuel.

The effect of hydrogen and oxygen contents on hydride reorientations of zirconium alloy cladding tubes

The lower hydrogen contents and the slower cooling rate generated a larger fraction of radial hydrides, a longer radial hydride length, and a lower ultimate tensile strength and plastic elongation. In addition, the oxidized specimens generated a smaller fraction of radial hydrides and a lower ultimate tensile strength and plastic elongation than the nonoxidized specimens.

Uncertainty propagation analysis for yonggwang nuclear unit 4 by mccard master core analysis system

This paper concerns estimating uncertainties of the core neutronics design parameters of power reactors by direct sampling method (DSM) calculations based on the two-step McCARD/MASTER design system in which McCARD is used to generate the fuel assembly (FA) homogenized few group constants (FGCs) while MASTER is used to conduct the core neutronics design computation. It presents an extended application of the uncertainty propagation analysis method originally designed for uncertainty quantification of the FA FGCs as a way to produce the covariances between the FGCs of any pair of FAs comprising the core, or the covariance matrix of the FA FGCs required for random sampling of the FA FGCs input sets into direct sampling core calculations by MASTER.

Uranium Enrichment determination using a New Analysis code for the U XKa Region: HyperGam-U

To describe the X-ray peaks, a Lorentzian broadened shape function was used, and methods were developed to reduce the number of fitting parameters for decomposing the strongly overlapping peaks using channel-energy, energy-width, and energy-efficiency calibration functions

Study of a betavoltaic battery using electroplated nickel 63 on nickel foil as a power source

A betavoltaic battery was prepared using radioactive 63Ni attached to a three-dimensional single trenched PeN absorber. The optimum thickness of a 63Ni layer was determined to be approximately 2 mm, considering the minimum self-shielding effect of beta particles. Electroplating of radioactive 63Ni on a nickel (Ni) foil was carried out at a current density of 20 mA/cm2 .

Study of core support barrel vibration monitoring using ex core neutron noise analysis and fuzzy logic algorithm

A distinct pattern of phase differences was observed for each of the vibration models. The developed fuzzy logic module demonstrated successful recognition of the vibration frequencies, modes, orders, directions, and phase differences within 0.4 ms for the beam and shell mode vibrations

Study of the effect of (U0.8Pu0.2)O2 uraniume plutonium mixed fuel fission products on a living organism

The article describes the results of experiments conducted on pigs to determine the effect of plutonium, which is the most radiotoxic and highly active element in the range of mixed fuel (U0.8Pu0.2)O2 fission products, on living organisms. The results will allow empirical prediction of the emergency plutonium radiation dose for various organs and tissues of humans in case of an accident in a reactor running on mixed fuel (U0.8Pu0.2)O2.

Transient diagnosis and prognosis for secondary system in nuclear power plants

This paper introduces the development of a transient monitoring system to detect the early stage of a transient, to identify the type of the transient scenario, and to inform an operator with the remaining time to turbine trip when there is no operator's relevant control. This study focused on the transients originating from a secondary system in nuclear power plants (NPPs), because the secondary system was recognized to be a more dominant factor to make unplanned turbine-generator trips which can ultimately result in reactor trips.

Spectrum weighted responses of several detectors in mixed fields of fast and thermal neutrons

The spectrum weighted responses of various detectors were calculated to provide guidance on the proper selection and use of survey instruments on the basis of their energy response characteristics on the neutron fields. To yield the spectrum weighted response, the detector response functions of 17 neutron-measuring devices were numerically folded with each of the produced calibration neutron spectra through the in-house developed software ‘K-SWR’.

Strain based plastic instability acceptance criteria for ferritic steel safety class 1 nuclear components under level d service loads

This paper proposes strain-based acceptance criteria for assessing plastic instability of the safety class 1 nuclear components made of ferritic steel during level D service loads. The strain-based criteria were proposed with two approaches: (1) a section average approach and (2) a critical location approach. Both approaches were based on the damage initiation point corresponding to the maximum load-carrying capability point instead of the fracture point via tensile tests and finite element analysis (FEA) for the notched specimen under uni-axial tensile loading.

Study of lower hybrid current drive for the demonstration reactor

Steady-state operation of a fusion power plant requires external current drive to minimize the power requirements, and a high fraction of bootstrap current is required. One of the external sources for current drive is lower hybrid current drive, which has been widely applied in many tokamaks. Here, using lower hybrid simulation code, we calculate electron distribution function, electron currents and phase velocity changes for two options of demonstration reactor at the launched lower hybrid wave frequency 5 GHz.

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