scholarly journals A Combined Method for Predicting the Boron Deposited Mass and the CIPS Risk

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Shengzhe Li ◽  
Dongmei Yang ◽  
Tengfei Zhang ◽  
Xiaojing Liu
Keyword(s):  
Power Distribution ◽  
Neutron Cross Section ◽  
Local Power ◽  
Combined Method ◽  
Boron Compounds ◽  
The Core ◽  
Simulation Results ◽  
Deposit Model ◽  
Power Distribution Control ◽  
The Impact

CIPS is a shift in the axial power towards the bottom half of the core, also known as axial offset anomaly (AOA), which results from the deposited of corrosion products during an operation. The main reason of CIPS is the solute particles especially boron compounds concentrated inside the porous deposit. The impact of CIPS is that the axial power distribution control may be more difficult and the shutdown margin can be decreased simultaneously. Besides, it also requires estimated critical condition (ECC) calculations to account for the effects of AOA. In this article, thermal-hydraulic subchannel code and boron deposit model have been combined to analyze the CIPS risk. The neutronics codes deal with the generation of homogenized neutron cross section as well as the calculation of local power factor. A simple rod assembly is analyzed with this combined method and simulation results are presented. Simulation results provide the boron hideout amount inside crud deposits and power shapes. The obtained results clearly show the power shape suppression in regions where crud deposits exist, which is a clear indication of CIPS phenomenon. And the CIPS effects on CHF have also been investigated. Result shows a margin of DNBR decrease in the crud case.

Detection of Insulation Defects in Automated In-Process Testing of Electric Wire during its Extrusion

2019 ◽  
Vol 942 ◽  
pp. 141-150
Author(s):  
Alexander Goldshtein ◽  
Galina Vavilova ◽  
Alexander Rumkin ◽  
Oldrich Starý
Keyword(s):  
Numerical Simulation ◽  
Mathematical Simulation ◽  
Physical Model ◽  
The Core ◽  
Process Testing ◽  
Capacitive Method ◽  
Simulation Results ◽  
Local Defects ◽  
Air Cavities ◽  
The Impact

The paper describes the electro-capacitive method for monitoring wire capacitance, which is implemented using the CAP-10 device, employed for in-process testing of the single core electric wire capacitance. Focus is made on the operating principle of the CAP-10 device. The possibility of using the CAP-10 device for detecting local defects in wire insulation is proved. Insulation defects such as foreign inclusions in the form of copper shavings, air cavities inside insulation and those at the core–insulation boundary are modeled. The impact of the defect geometric parameters on the wire capacitance measured during in-process testing is investigated through numerical simulation. Mathematical simulation results are validated through the physical model using the CAP-10 device.

scholarly journals Designing Stainless Steel Reflector at VR-1 Training Reactor

2020 ◽  
Vol 239 ◽  
pp. 17009
Author(s):  
Jan Frybort ◽  
Pavel Suk ◽  
Filip Fejt
Keyword(s):  
Stainless Steel ◽  
Power Distribution ◽  
Nuclear Data ◽  
Calculation Model ◽  
The Core ◽  
Standard Procedures ◽  
Engineering Department ◽  
Neutron Leakage ◽  
Special Approach ◽  
The Impact

Light-water reactor cores are commonly surrounded by a stainless steel and water reflector. The reflectors are improving power distribution in the core, reducing the leakage of neutrons and thus also protecting the pressurized vessel from the neutron irradiation and the following embrittlement. Contrary to the standard procedures utilized for generation of the fuel assembly data, the reflector elements require a special approach. The major difficulty with the reflectors is represented by an absence of neutron sources in the reflector elements. Some artificial neutron source simulating the realistic source of neutrons from neutron leakage from the surrounding fuel assemblies must be added in the calculation model. The reflector data in the full-core calculations have a great impact on the power distribution in the core. The research in this field is usually focused on the square geometry, and therefore the accurate data for the hexagonal geometry are lacking. Improvements in this area are needed. Training Reactor VR-1 is used for measurements related to nuclear engineering. Department of Nuclear Reactors operating this reactor at the Czech Technical University in Prague is currently designing reflector elements containing stainless steel in order to provide measurable characteristics that can be compared to calculations realized by either Monte-Carlo codes or macroscopic core simulators. This article summarizes the methodology of development of the reflector assemblies to improve their similarity with the VVER-1000 reflector. The impact of the evaluated nuclear data is assessed. Further improvements of the proposed design is necessary to reach better agreement with the neutron spectrum in VVER-1000 reactor reflectors. The influence of evaluated data on the global characteristics was found negligible.

scholarly journals Investigation of the impact of steady-state VVER-1000 (1200) core characteristics on the reactor stability with respect to xenon oscillations

2020 ◽  
Vol 6 (4) ◽  
pp. 289-294
Author(s):  
Rashdan Talal Al Malkawi ◽  
Sergey B. Vygovsky ◽  
Osama Wasef Batayneh
Keyword(s):  
Numerical Experiments ◽  
Neutron Field ◽  
Scale Model ◽  
Local Power ◽  
Explicit Dependence ◽  
The Core ◽  
Reactor Stability ◽  
Core Characteristics ◽  
The Impact ◽  
Kalinin Npp

The article presents a method for obtaining an analytical expression for the criterion of stability of a VVER-1000 (1200) reactor with respect to xenon oscillations of the local power in the core, containing an explicit dependence of the criterion ratio coefficients on the arbitrary axial neutron field distribution in steady states of the core. Based on the data of numerical experiments using a full-scale model of the Kalinin NPP power units, the authors present the results of checking the validity of this expression for the reactor stability criterion with respect to xenon oscillations for different NPPs with VVER-1000 (1200) reactors.

Identifying influential spreaders based on diffusion K-truss decomposition

2018 ◽  
Vol 32 (22) ◽  
pp. 1850238 ◽  
Author(s):  
Li Yang ◽  
Yu-Rong Song ◽  
Guo-Ping Jiang ◽  
Ling-Ling Xia
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Network Structure ◽  
Decomposition Method ◽  
Spreading Behavior ◽  
The Core ◽  
Influential Nodes ◽  
Simulation Results ◽  
The Impact ◽  
Real Complex

Identifying the most influential spreaders is important in optimizing the network structure or disseminating information through networks. Recent study showed that the K-truss decomposition could filter out the nodes that performed a worse spreading behavior in the maximal K-shell subgraph. The spreaders belonging to the maximal K-truss subgraph show better performance compared to previously used importance criteria. However, the accuracy of the K-truss or the K-shell in determining node coreness is largely susceptible to core-like group. In this paper, we propose an improved diffusion K-truss decomposition method by considering both the diffusion and clustering of edges to eliminate the impact of core-like group on identifying influential nodes. To validate the effectiveness of the proposed method, we compare it with five typical methods by carrying out Monte–Carlo simulations over six real complex networks. Simulation results demonstrate that the proposed method can effectively disintegrate the core-like group and accurately identify the influential nodes.

Boron Transient Analysis by the GRS Coupled Code Systems QUABOX-CUBBOX/ATHLET and TORT-TD/ATHLET

2009 ◽  
Author(s):  
K. Velkov ◽  
A. Seubert ◽  
I. Pasichnyk ◽  
A. Pautz
Keyword(s):  
Transient Analysis ◽  
Transport Theory ◽  
State Of The Art ◽  
Diffusion Theory ◽  
Coarse Mesh ◽  
Code System ◽  
The Core ◽  
Simulation Results ◽  
The Impact ◽  
Transport Approach

The application of modern coupled thermal-hydraulic neutron-kinetic code systems is state of the art for performing safety analyses. In this paper, a radially asymmetric boron dilution transient in a PWR MOX/UO2 core is defined. The transient is analysed using the coupled code system QUABOX-CUBBOX/ATHLET which is based on fuel-assembly coarse mesh diffusion theory, and the results are compared to the solution obtained with the transport theory-based coupled code system TORT-TD/ATHLET with a pin-wise representation of the core. The aim of this study is to investigate the impact of the transport approach and the diffusion approximation on the simulation results.

scholarly journals Modeling of Downlink Interference in Massive MIMO 5G Macro-Cell

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 597
Author(s):  
Kamil Bechta ◽  
Cezary Ziółkowski ◽  
Jan M. Kelner ◽  
Leszek Nowosielski
Keyword(s):  
Power Distribution ◽  
Communication Systems ◽  
Channel Model ◽  
Radio Channel ◽  
Angular Separation ◽  
Simulation Method ◽  
Antenna System ◽  
Propagation Model ◽  
Simulation Results ◽  
The Impact

Multi-beam antenna systems are the basic technology used in developing fifth-generation (5G) mobile communication systems. In practical implementations of 5G networks, different approaches are used to enable a massive multiple-input-multiple-output (mMIMO) technique, including a grid of beams, zero-forcing, or eigen-based beamforming. All of these methods aim to ensure sufficient angular separation between multiple beams that serve different users. Therefore, ensuring the accurate performance evaluation of a realistic 5G network is essential. It is particularly crucial from the perspective of mMIMO implementation feasibility in given radio channel conditions at the stage of network planning and optimization before commercial deployment begins. This paper presents a novel approach to assessing the impact of a multi-beam antenna system on an intra-cell interference level in a downlink, which is important for the accurate modeling and efficient usage of mMIMO in 5G cells. The presented analysis is based on geometric channel models that allow the trajectories of propagation paths to be mapped and, as a result, the angular power distribution of received signals. A multi-elliptical propagation model (MPM) is used and compared with simulation results obtained for a statistical channel model developed by the 3rd Generation Partnership Project (3GPP). Transmission characteristics of propagation environments such as power delay profile and antenna beam patterns define the geometric structure of the MPM. These characteristics were adopted based on the 3GPP standard. The obtained results show the possibility of using the presented novel MPM-based approach to model the required minimum separation angle between co-channel beams under line-of-sight (LOS) and non-LOS conditions, which allows mMIMO performance in 5G cells to be assessed. This statement is justified because for 80% of simulated samples of intra-cell signal-to-interference ratio (SIR), the difference between results obtained by the MPM and commonly used 3GPP channel model was within 2 dB or less for LOS conditions. Additionally, the MPM only needs a single instance of simulation, whereas the 3GPP channel model requires a time-consuming and computational power-consuming Monte Carlo simulation method. Simulation results of intra-cell SIR obtained this way by the MPM approach can be the basis for spectral efficiency maximization in mMIMO cells in 5G systems.

Soziale Disziplinierung im flexiblen Kapitalismus

2004 ◽  
Vol 34 (136) ◽  
pp. 339-356
Author(s):  
Tobias Wölfle ◽  
Oliver Schöller
Keyword(s):  
Social Welfare ◽  
Second Step ◽  
Social Rights ◽  
Federal Law ◽  
Capitalist Development ◽  
The Core ◽  
The Past ◽  
The Impact ◽  
Municipal Level

Under the term “Hilfe zur Arbeit” (aid for work) the federal law of social welfare subsumes all kinds of labour disciplining instruments. First, the paper shows the historical connection of welfare and labour disciplining mechanisms in the context of different periods within capitalist development. In a second step, against the background of historical experiences, we will analyse the trends of “Hilfe zur Arbeit” during the past two decades. It will be shown that by the rise of unemployment, the impact of labour disciplining aspects of “Hilfe zur Arbeit” has increased both on the federal and on the municipal level. For this reason the leverage of the liberal paradigm would take place even in the core of social rights.

Citizen Deliberation Online

2019 ◽  
pp. 689-712
Author(s):  
Patrícia Rossini ◽  
Jennifer Stromer-Galley
Keyword(s):  
Political Engagement ◽  
Future Research ◽  
The Internet ◽  
Digital Platforms ◽  
The Core ◽  
Political Conversation ◽  
Political Talk ◽  
Citizen Deliberation ◽  
The Impact

Political conversation is at the heart of democratic societies, and it is an important precursor of political engagement. As society has become intertwined with the communication infrastructure of the Internet, we need to understand its uses and the implications of those uses for democracy. This chapter provides an overview of the core topics of scholarly concern around online citizen deliberation, focusing on three key areas of research: the standards of quality of communication and the normative stance on citizen deliberation online; the impact and importance of digital platforms in structuring political talk; and the differences between formal and informal political talk spaces. After providing a critical review of these three major areas of research, we outline directions for future research on online citizen deliberation.

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