bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimal Dynamic Taxation with Distinctive Forms of Social Status Attainment
Authors: Chang Juin‐Jen , Tsai Hsueh‐Fang , Tsai Tsung‐Sheng 
Published: October 2017

AbstractWe examine the role of both consumption‐ and wealth‐induced social comparisons in setting dynamic optimal income taxation. Under complete information, state‐invariant labor income taxes are used to remedy the externality caused by consumption‐induced social comparisons, while state‐contingent capital income taxes are used to remedy the externalities caused by both consumption‐ and wealth‐induced social comparisons. Under incomplete information, distinct types of agents are subject to an identical marginal capital income tax, which removes social comparisons. To solve the information problem, low‐productivity agents could be subject to a lower marginal labor tax than high‐productivity agents, which contradicts the traditional result in the Mirrlees–Stiglitz models.
Who runs away from home and why? How families, schools, and bullying influence youth runaways
Authors: Radu Monica Bixby 
Published: October 2017

AbstractWhile prior research establishes that youth who experience family problems are more likely to leave home before reaching adulthood, we know less regarding how peer victimization in the form of bullying may influence youths' likelihood of becoming runaways. Youth often run away from home to escape family conflict or abusive home environments. Mental illness, behavioral problems, and delinquent peers are also powerful forces predicting the likelihood of running away from home. Additionally, recent literature suggests that negative experiences at school may increase youths' decisions to leave home prematurely. In this article, I review literature that addresseswhoruns away from home, including variations by age, race/ethnicity, sexual orientation, gender, family structure, mental health, problem behaviors, and peer networks. I also suggest directions for future research, including an approach that considers how families and schools individually and collectively affect youths' likelihood of running away from home. Finally, I recommend a focus on bully victimization to better understand how victimization outside of the family affects the likelihood that youth will become runaways.
Urban politics and the study of urban poverty: Promising developments and future directions
Authors: Levine Jeremy R. 
Published: October 2017

AbstractThe study of urban poverty is alive and well in sociology. The study of urban politics, by contrast, has stagnated. Though scholars agree that politics shapes the creation and durability of urban poverty, analytical connections between the two subfields are rarely made explicit. In this article, I make the case for a more integrated body of research. I first illustrate how urban poverty scholars implicitly discuss politics, and conversely, how urban politics scholars implicitly discuss poverty. I then highlight recent developments in the literature and propose two paths forward—by no means the only paths forward, but two ways to jumpstart greater conversation across both subfields. For the urban poverty literature, a focus on organizations can help scholars analyze political dynamics more directly. And for the urban politics literature, an emphasis on political mechanisms rather than overarching perspectives can disrupt the current theoretical malaise. These two moves can advance both literatures while drawing them closer together.
Experimental and Numerical Investigation of Temperature and Flow Distribution Inside a Glove Box Enclosure for a High-Accuracy Coordinate Measurement Machine
Authors: Spernjak Dusan , Morgan Robert , Mejia Alvarez Ricardo , Bernardin John , Ney Stephen A. 
Published: October 2017

Experiments and simulations were performed to assess the performance of an HVAC system for the cooling of a Leitz Infinity coordinate measurement machine (CMM) enclosed within a glove box (GB). Manufacturer specifications require maintaining very uniform temperatures with spatial and temporal variations not to exceed 0.3 °C/hr, 0.4 °C/day, and 0.1°C/m. Data were collected at 0.17 Hz by 2 thermocouples located outside the glovebox, 10 static thermocouples located inside the glovebox, and up to 28 thermocouples attached to the moving granite table of the CMM. The latter thermocouples are arrayed in a grid in the volume of interest (VOI) which envelopes the motion of the CMM measuring head above the granite table. Data were collected for periods ranging from 1 to 5 days to observe the effects of temperature variations within the enclosing facility.
Simulations were then performed on the enclosed volume of the GB using ANSYS-CFX to better understand the heat loads, and test temperature variation mitigation strategies. These simulations consisted of 18 runs which varied heat input from the CMM motors, inflow gas temperature from the HVAC system into the GB, and non-uniform GB wall temperature boundary conditions. Heat loads from the motors were found to be insignificant influences on the temperature distribution, while fluid entrainment inside the diffuser was discovered to lead to an adverse temperature distribution, and insufficient cooling in the VOI. Velocity distributions were examined by using a TSI VelociCalc 8345 to verify the presence of stagnant regions in the GB. Finally, modifications to the diffuser design were proposed to eliminate entrainment, improve the flow distribution, and enhance temperature uniformity.
Implementation of Liquid Metal Properties in RELAP5 MOD3.2 for Safety Analysis of Sodium-Cooled Fast Reactors
Authors: Song Jian , Liu Limin , Tang Simiao , Wu Yingwei , Tian Wenxi , Qiu Suizheng , Su Guanghui 
Published: October 2017

Due to great deal of operation experience and technology accumulation, sodium cooled fast reactor (SFR) is the most promising among the six Generation IV reactors, which has advantages of breeding nuclear fuel, transmuting long-lived actinides and good safety characteristics. Thermal-hydraulic computer codes will have to be developed, verified, and validated to support the conceptual and final designs of new SFRs. However, work on developing thermal hydraulic analysis code for SFR is very limited in China, while the common software RELAP5 MOD3 is unable to analyze liquid metal systems. So the modified RELAP5 MOD3.2 is being considered as the thermal-hydraulic system code to support the development of the SFRs.
The thermodynamic and transport properties of sodium liquid and vapor have been implemented into the RELAP5 MOD3.2 code, as well as the specific heat transfer correlations for liquid metal. The sodium liquid properties use polynomial equations based on data obtained from Argonne National Laboratory, and the vapor is assumed to be perfect gas. The property equations are acceptably accurate for analysis of SFR, especially for single-phase liquid. New files are added to the fluids directory to generate property tables for new working fluid, which are similar to the table interpolation subroutines for light and heavy water in the original file directory. The method of code modifications are universal for other working fluids and will not affect the code original performance. Some basic verification work for the modified code are carried out. The steam generator of CEFR is analyzed to verify the modified code. The calculated results show that all the water will boil off in the evaporator and the calculated results are in good agreement with the design values. By using modified RELAP5 to model the primary loop of EBR-II fast reactor, the SHRT-17 PLOF test was analyzed. The results show that the natural circulation can be established in the EBR-II primary system after main pumps off to remove the core decay residual heat effectively, and the peak temperature under the safety limits. Moreover, the results computed in this work compared well with the test experimental data for the steady state condition. During the transients, the changing trends of temperature and pressure are similar to experimental data. The discrepancies between calculation and experiment are considered acceptably which need to be improved in the future work. Our work could demonstrate the capability and reliability of the modified RELAP5 for the analysis of SFRs further.
CFD Simulation of Passive Containment Cooling System in Hot Leg SB-LOCA for 1000MW PWR
Authors: Li Jingya , Zhang Xiaoying 
Published: October 2017

The passive cooling system (PCCS) for reactor containment is a security system that can be used to cool the atmosphere and reduce pressure inside of containment in case of temperature and pressure increase caused by vapor injection, which requires no external power because it works only with natural forces. However, as the driving forces from natural physical phenomena are of low amplitude, uncertainties and instabilities in the physical process can cause failure of the system. This article aims to establish a CFD simulation model for the Passive Containment Cooling System of 1000MW PWR using Code_Saturne and FLUENT software. The comparison of 4 different models based respectively on mixture model, COPAIN test, Uchida correlation and Chilton-Colburn analogy which simulate the condensing effect and the improvement of source code are based on a 3D simulation of PCCS system. To simulate the thermal-hydraulic condition in the containment after LOCA accident caused by a double-ended main pipe rupture, a high temperature vapor with the given mass flow rate are supposed to be the source of energy and mass into containment. Meanwhile the surface of three condensing island applies the wall condensation model.
The simulation results show similar transient process obtained with the 4 models, while the difference between the transient simulation and the steady-state analysis of three models is less than 3%. The large mass flow rate of water loss status inside the containment cause a high flow rate of vapor which could be uniformly mixed with air in a short time. For the self-condensing efficiency of 3 groups of PCCS system, the non-centrosymmetric injection position resulting that the condensing efficiency is slightly higher for the two heat exchanger groups nearby. During the first 2400s of simulation time, more than 75.69% of the vapor is condensed, indicating that for the occurrence of condensation at the wall mainly driven by natural convection, the effect of thermodynamic siphon could improve the flow of gas mixture inside the tubes when the velocity of mixture is not large enough, so that the vapor could smoothly enter the tube and reach the internal cooling surface then to be condensed. Besides, PCCS ensure the containment internal pressure maintained below 2 bar and the temperature maintained below 380K during 3600s.
Constrained Least Squares Method Used in Nuclear Accident Source Term Inversion
Authors: Xuan Wang , Fenglei Du , Xiaodong Huang 
Published: October 2017

Through experience feedback of the Chernobyl and Fukushima nuclear accidents, source term determination including release rates and release curves, becomes a key issue in nuclear accident impact assessment. When faced with monitoring device failure, use of off-site monitoring data and atmospheric dispersion model simulation results to inverse the source term has been proven an effective means in many case studies.
In this paper, we have developed a powerful source term inverse system based on constrained least squares algorithm approach and Gaussian atmospheric diffusion model, and we carried out 15 SF6 field trace experiments at a coastal nuclear power plant site in China from August 22, 2007 to August 31,2007, to validate the source term inversion model. From the 15 simulation results, the 5th,8th and 9th inverse results are the best, and the relative error of inverse source term and true source term is between 10.12% and 16.42%, this is mainly because these three experiments are the most successful, and effective sample points of three experiments are above 25, its distribution is also uniform. It is shown that accuracy, number and distribution of the on-site monitoring will directly affect the inversion source term results.
In general, results of source term inversion model are close to the field experiment, within the same magnitude, which shows that constrained least squares algorithm method and Gaussian atmospheric diffusion model can be applied in nuclear accident source term determination. Results of this study show that constrained least squares method is simple and highly efficient and has a high application value.
Performances Analyses of Crud of EPR Fuel Assembly
Authors: Wang Xuming , Yuan Cenxi , Ye Chen 
Published: October 2017

Taishan European Pressurized Water Reactor (EPR) is a third generation advanced pressurized water reactor (PWR), which adopts the third generation advanced fuel assembly (AFA-3G-LE) from AREVA for the first time. As suggested by American Electric Power Research Institute (EPRI), an EPRI level III crud risk assessment is necessary for new type of plants. Because crud induced power offset (CIPS) and crud induced local corrosion (CILC) can lead to axial offset anomaly (AOA) and fuel cladding failure, respectively.
A EPRI level III CIPS/CILC risk assessment for Taishan EPR is performed with a new framework of simulation by using sub-channel code FLICA, crud code BOA, and Monte Carlo transport code Tripoli-4. Such framework enables a self-consistent calculation, including a detailed description on neutronics contributed by boron. The validation of present work is confirmed because of the good agreement with the experienced data of EPRI. The results show that AFA-3G-LE has a good performance on crud risk assessment. Even in the worst case, the boron-10 deposition (2.6 g) and the maximum thickness of crud (59 μm) are lower than the low risk threshold, 31.33 g and 75 μm, respectively. Hence, It is expected that Taishan EPR has a very low risk on CIPS and CILC.
Control Scheme Research of 10MW Fluoride Salt Cooled High Temperature Experiment Reactor
Authors: Ruan Jian , Zou Yang , Li Minghai , Xu Hongjie 
Published: October 2017

Fluoride salt cooled High temperature Reactor (FHR) is a kind of Gen-IV reactor which possesses many attractive features, such as high temperature, low pressure etc. Thermal-hydraulic features of molten salt are different from coolants of traditional reactors, which dominate operation transient behavior of FHR. However, as a new type reactor with sphere fuel element and fluoride salt coolant, FHR has inadequate operating experience and data used for reactor control and the design of power regulating system. Therefore, research of power regulation strategy is very important for FHR in automatic control operation and commercial application.
A code programmed in Fortran platform is used for investigating the system transient behavior, control logic and strategy. Based on the transient analysis code OCFHR for FHR, power control logic strategy is studied on a model of 10 MW Fluoride salt cooled High Temperature Experiment Reactor. OCFHR is a specialized code in FHR transient analysis, which contains point reactor model, simplified core thermal-hydraulic model, molten salt-salt exchanger and molten salt-air exchanger with a tube-shell type, control rod system and power regulation and control model. The control module of OCFHR uses the incremental PID controller to regulate control parameters and adopts the compound mode of control rod adjustment, load adjustment and molten salt flow adjustment, so that it can adjust the control rod position, primary and secondary molten salt flow rate and air flow rate of load at different operating power levels.
Two kinds of steady operation strategies are studied in this paper, which are a) constant outlet coolant temperature and b) constant average coolant temperature. The power level is regulated by control rod while the working temperatures are adjusted by shifting the load with weight coefficients of power and temperature deviations.
The results show that the incremental PID controller with optimized parameters can achieve the control requirement. Both of temperature control strategies gain great performances under 10%FPand 50%FP power regulation. The target power is reached quickly and accurately by using the incremental PID controller while the temperature control is very time-consuming. Compared with b), strategy a) has less temperature overshoot but larger power overshoot and longer adjusting time. The step wise power regulation for FHER is doable when a wide power adjustment range is needed and the simulation 10%FP treated as a step works well. Besides, the preliminary study of varying secondary coolant flow rate also indicates that the secondary loop plays an important part in restraining the deviation of secondary coolant temperatures during the process of balancing the power and load, so it is better to adjust the secondary coolant flow in terms of the power regulation range.
Nuclear Safety Information and Education Strategy for the Public Developed by IRSN: How to Share Technical and Scientific Knowledge With the Public
Authors: Matahri Naoëlle , Choffel de Witte Ilma , Bigot Marie-Pierre 
Published: October 2017

In France, since 2006, the legal framework has been reinforced in order to have a better compliance with the safety features of nuclear installations but also a relevant communication with the public about the nuclear risks and the nuclear decisions. Starting with the Nuclear Safety Transparency law of 2007 defining transparency in the nuclear field as “the set of provisions adopted to ensure the public’s right to reliable and accessible information on nuclear safety”, afterwards reinforced by the Law on Energy Transition and Renewable Energy in 2015. This law reinforced the transparency provisions, requiring not only transparent one way information but also public participation.
Even before the first transparency law, in France, communication consisted in a classic one way information process based on reporting incidents or events which occurred on Nuclear Power Plants or installations. Next it was decided to publish all technical inspection notifications on nuclear installations on the regulatory website. The French Technical Support Organization IRSN, and the Nuclear safety Authority ASN, promote these reports and publications through press conferences and nowadays also through twitter.
IRSN, way before the transparency requirements, made it one of their priorities to develop different methods and tools for the improvement of communication between Experts and Public promoting visibility and trustworthiness. Thanks to the new legal framework, the development of new tools to inform and engage citizens is accelerated. The traditional tools available are annual reports, newsletters, websites, magazines, Press data center, press conferences, etc...today completed with new tools such as YouTube, twitter, Facebook.
In addition, IRSN developed ways and tools promoting direct contact with the public, such as “Open House Days” allowing the public to discover work on site and to dialogue with Experts. In line with the “face to face” formula, IRSN implemented an Information and Education Strategy for the Public to enhance their Radiation Protection and Nuclear Safety Culture.
The objective of this article is to explain further each method developed and the support used to enhance the Public’s Radiation Protection and Nuclear Safety Culture.
Research on Flow Characteristics of Top and Vertical Containment Surface With Different Structures
Authors: Xinxin Pan , Jie Liu 
Published: October 2017

Following an accident, the passive nuclear power plant CAP1400 mainly uses cooling water evaporation on the outer containment surface to remove the decay heat inside containment to outside environment to ensure the plant to a stable status. But the outside surface of the containment vessel is attached by a large number of different forms of the disorder structure including circumferential welds and longitudinal welds on the containment surface, and small local bulge, which may affect water film flow and coverage outside containment surface. Once a large amount of water splashes and can’t return to the containment surface, the heat removal capacity of the system during and after an accident will be significantly reduced, and the safety of power plants will be threatened.
This paper simulates the water flow characteristics on the containment surface. Firstly, a simplified analysis model of water film flow structure is established considering different forms of structures including the circumferential weld, small local bulge and etc. The circumferential weld is simplified with the horizontal protrusion. Local small uplift is simulated with point-like protrusion. Computational fluid dynamics (CFD) software STAR CCM+ is applied in this simulation with the volume of fluid method and surface tension model, and sets contact angle and other parameters according to the characteristics of the containment surface coating, so as to establish the CFD analysis method. The analysis results and water flow test results agree well. And then, the CFD analysis method is used to analyze the flow patterns of water film on the surface of the wall under different conditions.
The results show that the circumferential weld has a certain influence on the initial water film covering only. But the film coverage rate of the water film is stable after the water film is stable, and there is no loss of the water film. For the circumferential weld on the vertical wall, the effect on the water film coverage is little. Water film loss of low-flow is negligible, and water film loss of high-flow is no more than 1%. For the form of local small protrusions, little change of the flow characteristics of water film can be observed.
The structure form of the containment outside wall is various. According to the rules of the water film, including the water film covering width and the water film loss, it can be used as the design input of the accident analysis program WGOTHIC to guide the system design.