Tài liệu miễn phí Năng lượng
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Retrospective dosimetry using fingernail electron paramagnetic resonance response
The results demonstrate that the mechanically induced and radiation-induced signals have apparently different microwave power saturation behaviors. In addition, the mechanically induced signal shows a fading evolution over time and reaches a constant value. Chemical treatment using the different reagents showed that the minimum mechanically induced signal was obtained using the dithiothreitol reagent.
7/4/2019 3:35:22 AM +00:00
Seismic response characteristics of base-isolated AP1000 nuclear shield building subjected to beyond-design basis earthquake shaking
This study proposes a base-isolation design for the AP1000 nuclear shield building on considering the performance requirements of the seismic isolation systems and devices of shield building. The seismic responses of isolated and nonisolated shield buildings subjected to design basis earthquake (DBE) shaking and beyond-design basis earthquake (BDBE) shaking are analyzed, and three different strategies for controlling the displacements subjected to BDBE shaking are performed.
7/4/2019 3:34:59 AM +00:00
Wavelet operator for multiscale modeling of a nuclear reactor
This article introduces a methodology of designing a wavelet operator suitable for multiscale modeling. The operator matrix transforms states of a multivariable system onto projection space. In addition, it imposes a specific structure on the system matrix in a multiscale environment. To be specific, the article deals with a diagonalizing transform that is useful for decoupled control of a system.
7/4/2019 3:34:40 AM +00:00
Microscopic characterization of pretransition oxide formed on ZreNbeSn alloy under various Zn and dissolved hydrogen concentrations
Microstructural analysis indicated that there was no noticeable change in the microstructure of the oxide corresponding to water chemistry changes within the test duration of 100 days (pretransition stage) and no significant difference in the overall thickness of the oxide layer. Equiaxed grains with nano-size pores along the grain boundaries and microcracks were dominant near the water/oxide interface, regardless of water chemistry conditions. As the metal/oxide interface was approached, the number of pores tended to decrease.
7/4/2019 3:34:16 AM +00:00
Neutronics analysis of TRIGA Mark II research reactor
This article presents clean core criticality calculations and control rod worth calculations for TRIGA (Training, Research, Isotope production-General Atomics) Mark II research reactor benchmark cores using Winfrith Improved Multi-group Scheme-D/4 (WIMS-D/4) and Program for Reactor In-core Analysis using Diffusion Equation (PRIDE) codes. Cores 133 and 134 were analyzed in 2-D (r, q) and 3-D (r, q, z), using WIMS-D/4 and PRIDE codes.
7/4/2019 3:33:59 AM +00:00
Prognostics for integrity of steam generator tubes using the general path model
Concerns over reliability assessments of the main components in nuclear power plants (NPPs) related to aging and continuous operation have increased. The conventional reliability assessment for main components uses experimental correlations under general conditions. Most NPPs have been operating in Korea for a long time, and it is predictable that NPPs operating for the same number of years would show varying extent of aging and degradation.
7/4/2019 3:33:42 AM +00:00
Accurate determination of minor isotope ratios in individual plutoniumeuranium mixed particles by thermal ionization mass spectrometry
Isotopic analyses of plutonium and low-enriched uranium mixtures with particle sizes of 0.6e3.3 mm were performed using thermal ionization mass spectrometry with a continuous heating method to verify its effectiveness for the accurate analysis of minor isotopes without sample pretreatment. The mixed particles used in this study were prepared from a mixed solution of plutonium (SRM 947) and uranium (U010, 235U 1% enriched) reference materials.
7/4/2019 3:33:25 AM +00:00
Investigation of dust particle removal efficiency of self-priming venturi scrubber using computational fluid dynamics
The present work involves computational fluid dynamics (CFD) study of dust particle removal efficiency of a venturi scrubber operating in self-priming mode using ANSYS CFX. Titanium oxide (TiO2) particles having sizes of 1 micron have been taken as dust particles. CFD methodology to simulate the venturi scrubber has been first developed. The cascade atomization and breakup (CAB) model has been used to predict deformation of water droplets, whereas the Eulerian eLagrangian approach has been used to handle multiphase flow involving air, dust, and water.
7/4/2019 3:33:05 AM +00:00
An innovative idea for developing a new gamma-ray dosimetry system based on optical colorimetry techniques
In this article, an innovative idea for the development of a new gamma-ray dosimetry system is proposed. The method described in this article is based on optical colorimetry techniques. A color standard is fixed to the back of a BK-7 glass plate and then placed in a point in space where the absorbed dose needs to be determined. Gamma-rayeinduced defects (color centers) in the glass plate start occurring, leading to a degree of saturation of the standard color, which is proportional, on a certain interval, to the absorbed dose. After the exposure, a high-quality digital image of the sample is taken, which is then processed (MATLAB), and its equivalent IRGB intensity value is determined.
7/4/2019 3:32:45 AM +00:00
Theoretical models of threshold stress intensity factor and critical hydride length for delayed hydride cracking considering thermal stresses
The research results for radial cracking cases indicate that a better agreement for KIH can be achieved; the negative axial thermal stresses can lessen KIH and enlarge the critical hydride length, so its effect should be considered in the safety evaluation and constraint design for fuel rods; the critical hydride length lC changes slightly in a certain range of stress intensity factors, which interprets the phenomenon that the DHC velocity varies slowly in the steady crack growth stage.
7/4/2019 3:32:27 AM +00:00
Research on flow characteristics in supercritical water natural circulation: Influence of heating power distribution
The distribution types of uniform, power increasing, power decreasing and sine function are investigated. Through the analysis, it can be concluded that different power distribution has a great influence on the flow of natural circulation if the total power of heating is constant. It was found that the peak flow of supercritical water natural circulation is maximal when the distribution of heating power is monotonically decreasing, minimal when it is monotonically increasing, and moderate at uniform or the sine type of heating.
7/4/2019 3:32:05 AM +00:00
Numerical prediction of a flashing flow of saturated water at high pressure
The present simulation results obtained using the two different outflow boundary conditions were discussed through a comparison with the predictions using a simple nonflashing model neglecting the effects of phase change. In addition, the applicability of each of the non-flashing water discharge and saturated water flashing models for the confirmatory assessments of new SG designs was examined.
7/4/2019 3:31:47 AM +00:00
Correlation between rare earth elements in the chemical interactions of HT9 cladding
Metallic fuel has been considered for sodium-cooled fast reactors because it can maximize the uranium resources. It generates rare earth elements as fission products, where it is reported by aggravating the fuelecladding chemical interaction at the operating temperature. Rare earth elements form a multicomponent alloy (CeeNdePreLaeSmeetc.) during reactor operation, where it shows a higher reaction thickness than a single element.
7/4/2019 3:31:27 AM +00:00
Highly efficient adsorptive removal of uranyl ions from aqueous solutions using dicalcium phosphate nanoparticles as a superabsorbent
The investigation of adsorption isotherms indicated that the maximum adsorption capacities (qm) for C-DCP and S-DCP were 714.3 and 666.7 mg g1 (at 293 K), respectively. The experimental kinetics were well-described by the pseudo-second-order kinetic and the equilibrium data were fitted with both Langmuir and Freundlich adsorption models. Thermodynamic studies indicated that the adsorption of uranyl ions on the monetite surface was a spontaneous exothermic process.
7/4/2019 3:31:05 AM +00:00
Development status of microcell UO2 pellet for accident-tolerant fue
In this study, the material concepts of metallic and ceramic microcell UO2 pellets were designed, and the fabrication process of microcell UO2 pellets embodying the designed concept was developed. We successfully implemented the microcell UO2 pellets and produced microcell UO2 pellets.
7/4/2019 3:30:40 AM +00:00
Development of field programmable gate arrayebased encryption module to mitigate man-in-the-middle attack for nuclear power plant data communication network
This article presents a security module based on a field programmable gate array (FPGA) to mitigate man-in-the-middle cyber attacks. Nowadays, the FPGA is considered to be the state of the art in nuclear power plants I&C systems due to its flexibility, reconfigurability, and maintainability of the FPGA technology; it also provides acceptable solutions for embedded computing applications that require cybersecurity.
7/4/2019 3:30:22 AM +00:00
Calibration of digital wide-range neutron power measurement channel for open-pool type research reactor
This work provides a comprehensive overview of the calibration of DWRNPM channels by describing the configuration of the DWRNPM system and by summarizing the theories of operation and the reference power estimation methods with their associated calibration procedure. The calibration procedure was actually performed during the commissioning of an open-pool type research reactor, and the results and experience are documented herein.
7/4/2019 3:30:04 AM +00:00
Nghiên cứu cảm biến ánh sáng dùng trong hệ thống tự động bám theo mặt trời
Cảm biến ánh sáng đóng vai trò quan trọng trong hệ thống tự động bám theo năng lượng mặt trời. Khi cảm biến hoạt động chính xác, dễ lắp đặt sẽ giúp cho thiết kế cũng như lập trình cho hệ thống đơn giản đi rất nhiều.
7/3/2019 6:30:21 PM +00:00
Tính toán năng lượng sóng cho công nghệ phát điện
Năng lượng sóng biển có thể được tính toán bằng thu thập số liệu về chu kỳ của sóng và dựa vào từng dạng sóng, mực nước biển áp dụng vào các biểu thức, tính toán ra các thông số đặc trưng của sóng.
7/3/2019 6:20:57 PM +00:00
Solving point burnup equations by Magnus method
The burnup equation of nuclides is one of the most equations in nuclear reactor physics, which is generally coupled with transport calculations. The burnup equation describes the variation of the nuclides with time. Because of its very stiffness and the need for large time step, this equation is solved by special methods, for example transmutation trajectory analysis (TTA) or the matrix exponential methods where the matrix exponential is approximated by CRAM.
7/3/2019 4:43:10 PM +00:00
Improvement of the MARS subcooled boiling model for a vertical upward flow
In the thermal-hydraulic system codes, such as MARS and RELAP5/MOD3, the Savannah River Laboratory (SRL) model has been adopted as a subcooled boiling model. It, however, has been shown that the SRL model cannot take into account appropriately the effects of inlet liquid velocity and hydraulic diameter on axial void fraction development.
7/3/2019 4:42:52 PM +00:00
Evaluation of gamma-ray and neutron attenuation properties of some polymers
In the present work, we determined the gamma-ray attenuation characteristics of eight different polymers(Polyamide (Nylon 6) (PA-6), polyacrylonitrile (PAN), polyvinylidenechloride (PVDC), polyaniline (PANI), polyethyleneterephthalate (PET), polyphenylenesulfide (PPS), polypyrrole (PPy) and polytetrafluoroethylene (PTFE)) using transmission geometry utilizing the high resolution HPGe detector and different radioactive sources in the energy range 81e1333 keV.
7/3/2019 4:42:33 PM +00:00
Development of multi-cell flows in the three-layered configuration of oxide layer and their influence on the reactor vessel heating
We investigated the influence of the aspect ratio (H/R) of the oxide layer on the reactor vessel heating in three-layer configuration. Based on the analogy between heat and mass transfers, we performed mass transfer experiments to achieve high Rayleigh numbers ranging from 6.70 1010 to 7.84 1012. Twodimensional (2-D) semi-circular apparatuses having the internal heat source were used whose surfaces of top, bottom and side simulate the interfaces of the oxide layer with the light metal layer, the heavy metal layer, and the reactor vessel, respectively.
7/3/2019 4:42:11 PM +00:00
Nuclear reactor vessel water level prediction during severe accidents using deep neural networks
Acquiring instrumentation signals generated from nuclear power plants (NPPs) is essential to maintain nuclear reactor integrity or to mitigate an abnormal state under normal operating conditions or severe accident circumstances. However, various safety-critical instrumentation signals from NPPs cannot be accurately measured on account of instrument degradation or failure under severe accident circumstances.
7/3/2019 4:41:55 PM +00:00
The exfoliation of irradiated nuclear graphite by treatment with organic solvent: A proposal for its recycling
In this new study, an affordable process to remove 14C has been proposed using samples taken from the Nuclear Power Plant in Latina (Italy) which have been used to investigate the capability of organic and inorganic solvents in removing 14C from exfoliated nuclear graphite, with the aim to design a practicable approach to obtain graphite for recycling or/and safety disposed as L& LLW.
7/3/2019 4:41:40 PM +00:00
Radiation damage to Ni-based alloys in Wolsong CANDU reactor environments
In addition, damage caused by Ni two-step reactions was considered. Estimations were made for the annulus spacers in a CANDU reactor that are located axially along a fuel channel and made of Inconel X-750. The calculation results indicate that the transmutation gas production from the Ni two-step reactions is predominant as the effective full power year increases.
7/3/2019 4:41:20 PM +00:00
Low-frequency modes in the fluid-structure interaction of a U-tube model for the steam generator in a PWR
In the SG (steam generator) of PWR (pressurized water reactor) for a nuclear plant, hundreds of Ushaped tubes are used for the heat exchanger system. They interact with primary pressurized cooling water flow, generating flow-induced vibration in the secondary flow region. A simplified U-tube model is proposed in this study to apply for experiment and its counterpart computation. Using the commercial code, ANSYS-CFX, we first verified the Moody chart, comparing the straight pipe theory with the results derived from CFD (computational fluid dynamics) analysis.
7/3/2019 4:40:58 PM +00:00
Performance analysis of the passive safety features of iPOWER under Fukushima-like accident conditions
This study evaluates (i) the performance and effectiveness of the passive safety features of iPOWER (innovative Power Reactor), and (ii) whether a severe accident condition could be reached if the passive safety systems are damaged, namely the case of heat exchanger tube rupture. Analysis results show that the reactor coolant system remains in the hot shutdown condition without operator actions or electricity for over 72 h when the passive auxiliary feedwater systems (PAFSs) are operable without damage.
7/3/2019 4:40:40 PM +00:00
Evaluation of effectiveness of fault-tolerant techniques in a digital instrumentation and control system with a fault injection experiment
Recently, instrumentation and control (I&C) systems in nuclear power plants have undergone digitalization. Owing to the unique characteristics of digital I&C systems, the reliability analysis of digital systems has become an important element of probabilistic safety assessment (PSA). In a reliability analysis of digital systems, fault-tolerant techniques and their effectiveness must be considered.
7/3/2019 4:40:21 PM +00:00
Fragility assessment for electric cabinet in nuclear power plant using response surface methodology
The fundamental frequency of the electric cabinet is sensitive because of many attached devices. To bypass this complex problem, the average spectral acceleration ðSaÞ in the range of period that cover the first mode period is chosen as an intensity measure on the fragility function. The nonlinear time history analyses for cabinet are conducted using a suite of 40 ground motions. The obtained curves with different approaches are compared, and the variability of risk assessment is evaluated for restrained and anchored models.
7/3/2019 4:39:58 PM +00:00