A New Coupled CFD/Neutron Kinetics System for High Fidelity Simulations of LWR Core Phenomena: Proof of Concept

The Institute for Neutron Physics and Reactor Technology (INR) at the Karlsruhe Institute of Technology (KIT) is investigating the application of the meso- and microscale analysis for the prediction of local safety parameters for light water reactors (LWR). By applying codes like CFD (computational fluid dynamics) and SP3 (simplified transport) reactor dynamics it is possible to describe the underlying phenomena in a more accurate manner than by the nodal/coarse 1D thermal hydraulic coupled codes. By coupling the transport (SP3) based neutron kinetics (NK) code DYN3D with NEPTUNE-CFD, within a parallel MPI-environment, the NHESDYN platform is created. The newly developed system will allow high fidelity simulations of LWR fuel assemblies and cores. In NHESDYN, a heat conduction solver, SYRTHES, is coupled to NEPTUNE-CFD. The driver module of NHESDYN controls the sequence of execution of the solvers as well as the communication between the solvers based on MPI. In this paper, the main features of NHESDYN are discussed and the proof of the concept is done by solving a single pin problem. The prediction capability of NHESDYN is demonstrated by a code-to-code comparison with the DYNSUB code. Finally, the future developments and validation efforts are highlighted

Development and validation of a one-dimensional solver in a CFD platform for boiling flows in bubbly regimes

This paper presents a new one-dimensional solver for two-phase flow simulations where boiling is involved. The solver has been implemented within the OpenFOAM® platform. The basic formulation follows the Eulerian description of the Navier–Stokes equations. Different closure equations for one-dimensional simulations are also included, as well as a subcooled boiling model in order to perform accurate computations of the mass and heat transfer between phases. In addition to the fluid, a domain is included in order to represent the solid structure, so the solver is able to solve conjugate heat transfer problems. Two different test cases are presented in this work, first a single-phase test case in order to verify the conjugate heat transfer, and then a case based on the Bartolomej international benchmark, which consists of a vertical pipe where the fluid runs upwards while it is heated. Transient calculation were performed, and the results were compared to the TRACE system code, and to the experimental data in the corresponding case. With this calculations, the capability of this new solver to simulate one-dimensional single-phase and two-phase flows including boiling is demonstrated. This work is a first step of a final objective, which consists in allowing a 1D–3D coupling within the CFD platform, avoiding external links

Evaluation of hydraulic mixing performance in a full-scale anaerobic digester with an external liquid recirculation system using CFD and experimental validation

Anaerobic digestion (AD) has become an essential process for sludge treatment and its optimum performance is related to its mixing degree. In this study, a full-scale Anaerobic Digester (ADer) with an external recirculation mixing system was studied via single-phase 3D-CFD simulations to assess the influence of recirculation flow and a 3-blade propeller. The model was validated with inert tracer tests. The design and mixing parameters were studied to characterise the mixing efficiency in different scenarios. The design parameters were assessed first, but wide deviations from the recommended values were found. Local mixing parameters were found to be useful for defining the degree and type of mixing, and are highly recommended in the CFD studies of ADers. A second-order statistical moment was proposed as a global mixing parameter to describe geometrical and local mixing, and to state a reliable homogenisation time.Funding for open access charge: CRUE-Universitat Jaume

Effect of alkali doping on CIGS photovoltaic ceramic tiles

This report studies the influence of alkali elements (Na, K) to morphological, structural and optoelectronic properties of CIGS ceramic tile solar cell. Several ceramic enamels with altered chemical composition in terms of amount of alkali elements have been tested and compared. The influences of alkali type, its quantity and transfer mechanism have been investigated. The solar cell device has been assembled and characterized. The achieved results indicate that alkali elements (Na and K combination) modified the surface roughness and its diffusion from the enamel toward the absorber affect to the structural and final optoelectronic properties of the device. The alkali doping improve the Ga incorporation in the crystal lattice and an increasing in open circuit voltage (Voc) values, fill factor (FF) and the device efficiency. Optimal alkali quantities have been also determined. The best conversion efficiency is achieved for the cell with 4% wt Na2O and 3.2 % wt K2O (Eff. = 3,5 %), which presents an improvement of 30 % in efficiency relative to the standard (STD) solar cell sample chosen for comparative purposes

Study of idfferential protein expression in healthy human skeletal muscles using electrophoresis bidimentional

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MATH APPS UTILIZATION: ITS PERCEIVED EFFECTS TO THE ACADEMIC PERFORMANCE OF MATHEMATICS MAJOR STUDENTS

This study aimed to determine the perceived effects of apps utilization to study habits and academic performance. Further, it also sought to determine the views of the participants and respondents on their engagement in math apps and their relationship with study habits and academic performance. This study made use of explanatory-sequential design. The purposive sampling design was used to determine the respondents in quantitative data while the quota sampling design was also used to determine the participants in qualitative data. The study revealed that the mathematical application that is mostly used by the students is the calculator app as it garnered the highest percentage value of 80.85.%. The participants agreed that math applications serve as an aid for math problems, aid for lack of teaching by the teacher, promote learning of specific lessons and increase, and help in improving their academic performance. Respondents’ perception of their utilization of math apps is due to technical problems. The respondents also agreed that math application also affected their study habits in which they become dependent on it which led to laziness and tiredness. In addition, this study also found that there is a significant relationship between respondents’ utilization of math applications and their study habits. Lastly, there is also a significant relationship between the study habits and academic performance of selected math students of Notre Dame of Midsayap College.  Article visualizations

Femtosecond laser microstructuring of zirconia dental implants

This study evaluated the suitability of femtosecond laser for microtexturizing cylindrical zirconia dental implants surface. Sixty-six cylindrical zirconia implants were used and divided into three groups: Control group (with no laser modification), Group A (microgropored texture), and Group B (microgrooved texture). Scanning electron microscopy observation of microgeometries revealed minimal collateral damage of the original surface surrounding the treated areas. Optical interferometric profilometry showed that ultrafast laser ablation increased surface roughness (Ra, Rq, Rz, and Rt) significantly for both textured patterns from 1.2× to 6×-fold when compared with the control group (p Group B 8.4% ± 0.42% > Group A 1.6% ± 0.35%) and aluminum (Control 4.3% ± 0.9% > Group B 2.3% ± 0.3% > Group A 1.16% ± 0.2%) in the laser-treated surfaces (p Group A 1.94% > Group B 1.72%) as the surfaces were processed with ultrashort laser pulses. We concluded that femtosecond laser microstructuring offers an interesting alternative to conventional surface treatments of zirconia implants as a result of its precision and minimal damage of the surrounding areas

Perception of Nuclear Energy and Coal in France and the Netherlands

This study focuses on the perception of large scale application of nuclear energy and coal in the Netherlands and France. The application of these energy-sources and the risks and benefits are judged differently by various group in society. In Europe, France has the highest density of nuclear power plants and the Netherlands has one of the lowest. In both countries scientists and social scientists completed a questionnaire assessing the perception of the large scale application of both energy sources. Furthermore, a number of variables relating to the socio cultural and political circumstances were measured. The results indicate that the French had a higher risk perception and a more negative attitude toward nuclear power than the Dutch. But they also assess the benefits of the use of nuclear power to be higher. Explanations for these differences are discussed