Transient Analysis of Crossduct Break Scenarios Using the CATHARE2 Code for the 75MW ALLEGRO Demonstrator

2014 ◽  
Author(s):  
Gusztáv Mayer ◽  
Fabrice Bentivoglio
Keyword(s):  
Fast Reactor ◽  
Transient Analysis ◽  
Early Stage ◽  
Thermal Power ◽  
The Road ◽  
The Core ◽  
Nitrogen Injection ◽  
Stage Of Development ◽  
Wide Range ◽  
On The Road

The helium cooled Gas Fast Reactor (GFR) is one of the six reactor concepts selected in the frame of the Generation IV International Forum. Since no gas cooled fast reactor has ever been built, a medium power demonstrator reactor — named ALLEGRO — is necessary on the road towards the 2400MWth GFR power reactor. The French CEA completed a wide range of studies on the early stage of development of ALLEGRO, and later the ALLEGRO reactor have been developed in several European Union projects in parallel with the GFR2400. The 75 MW thermal power ALLEGRO is recently being developed in the frame of European ALLIANCE project. As a result of the collaboration between CEA and MTA EK new improvements were done in the CATHARE modeling of ALLEGRO. In particular, the capability of simulation of breaks located in the crossduct (concentrically arranged pipes with the hotduct located inside the colduct) has been developed. A first scenario of hotduct break has been simulated, that does not lead to the depressurization of the system because of the crossduct technology. Nevertheless this transient leads to a high bypass of the core. Then a scenario of full rupture of the hotduct and the colduct has been tested, leading to beyond design state with depressurized situation combined with a large bypass of the core. However this study shows that the peak cladding temperature can be kept below the cladding melting point using nitrogen injection. In this paper the CATHARE model implemented for the crossduct rupture scenario and the results of the simulation are presented and discussed.

scholarly journals Cycling Pathways

2021 ◽  
Author(s):  
Henk-Jan Dekker
Keyword(s):  
Climate Change ◽  
The Netherlands ◽  
Political Struggle ◽  
The Road ◽  
Wide Range ◽  
The World ◽  
Road Space ◽  
History Of ◽  
On The Road

In an effort to fight climate change, many cities try to boost their cycling levels. They often look towards the Dutch for guidance. However, historians have only begun to uncover how and why the Netherlands became the premier cycling country of the world. Why were Dutch cyclists so successful in their fight for a place on the road? Cycling Pathways: The Politics and Governance of Dutch Cycling Infrastructure, 1920-2020 explores the long political struggle that culminated in today’s high cycling levels. Delving into the archives, it uncovers the important role of social movements and shows in detail how these interacted with national, provincial, and urban engineers and policymakers to govern the distribution of road space and construction of cycling infrastructure. It discusses a wide range of topics, ranging from activists to engineering committees, from urban commuters to recreational cyclists and from the early 1900s to today in order to uncover the long and all-but-forgotten history of Dutch cycling governance.

How We Do Race

On Inhumanity ◽  
2020 ◽  
pp. 34-42
Author(s):  
David Livingstone Smith
Keyword(s):  
Human Beings ◽  
The Road ◽  
The Core ◽  
The Everyday ◽  
Core Elements ◽  
On The Road ◽  
Definition Of

This chapter teases out the core elements of the ordinary conception of “race.” This does not include a scientific or philosophical definition of race. Rather, the chapter talks about the view of race that most people just slip into when going about the everyday business of life. It is a conception that has been taken so thoroughly for granted that many do not even question it. The chapter argues that understanding the conception of race is key to understanding dehumanization, because beliefs about race lie at the heart of the dehumanizing process. It shows that dividing human beings into races—into “our kind” and “their kind”—is the first step on the road to dehumanizing them.

A Laboratory Method to Comprehensively Evaluate Abrasion, Traction and Rolling Resistance of Tire Tread Compounds

2007 ◽  
Vol 80 (4) ◽  
pp. 580-607 ◽  
Author(s):  
M. Heinz ◽  
K. A. Grosch
Keyword(s):  
Friction Coefficient ◽  
Laboratory Test ◽  
Rolling Resistance ◽  
Limited Range ◽  
Slip Angle ◽  
Testing Conditions ◽  
Side Force ◽  
The Road ◽  
Wide Range ◽  
On The Road

Abstract A laboratory test method has been developed which allows the evaluation of diverse properties of tire tread compounds on the same sample. The laboratory test instrument consists of a rotating abrasive disk against which a rubber sample wheel runs under a given load, slip angle and speed. All three force components acting on the wheel during the tests are recorded. By changing the variable values over a wide range practically all severities encountered in tire wear are covered. The well-known fact that compound ratings depend on the road testing conditions is verified. Most compounds are only significantly distinguishable against a control over a limited range of testing conditions. Using a road test simulation computer program based on the laboratory data shows that not only ratings correspond to practical experience but also calculated absolute tire life times do. Tests on surfaces of different coarseness and sharpness indicate that sharp coarse surfaces give the best results with road tests, which of necessity are mostly carried out on public roads of differing constitution. The abrasive surface can be wetted with water at different temperatures and hence either the friction force at a locked wheel or the side force at a slipping wheel can be measured over a wide range of temperatures and speeds. At small slip angles the side force is dominated by dynamic cornering stiffness of the compound, at large slip angles by the friction coefficient. In this case, too, good correlations to road experience exist over a limited range of testing conditions. Low water temperatures and low slip speed settings in the laboratory produce side force ratings, which correlate closely with ABS braking on the road High and higher slip speeds give ratings in close agreement with locked wheel braking on the road. A heatable/coolable disk enables traction measurements on ice and newly abrasion measurements on surfaces at elevated surface temperature. Ice surface temperatures between −5 °C and −25 °C are possible. Friction measurements show that the difference in compound rating between summer and winter compounds is maintained over the whole temperature range. New investigations show not only a differentiation between different winter tire treads qualities but also an excellent correlation between tire and laboratory results. As a new topic side force measurements on dry surfaces highlight the correlation to dry handling of tires. The tire tread compound contributes to this performance through its shear stiffness and its friction coefficient. The shear stiffness contributes to the response of the tire in directional changes. The friction coefficient determines the maximum force, which can be transmitted. A simple operation possibility for evaluation of determined side forces is demonstrated. In addition to antecedent investigations the rolling resistance of the rubber wheel can be measured over a range of loads and speeds with the slip angle set at zero. Again for these new results good correlations are achieved with practical experience. In particular, the dependence of the rolling resistance on the velocity and loads are pointed out. Ultimately a good correlation between tire test and laboratory test results was demonstrated.

A Study and Development of Primary Circuit Simulation Code for China Experimental Fast Reactor

2013 ◽  
Author(s):  
Jin Wang ◽  
Donghui Zhang ◽  
Wenjun Hu ◽  
Lixia Ren
Keyword(s):  
Fast Reactor ◽  
Nuclear Energy ◽  
Circuit Simulation ◽  
Thermal Power ◽  
Physical Models ◽  
Primary Circuit ◽  
Cooling Channel ◽  
Simulation Code ◽  
Wide Range ◽  
China Experimental Fast Reactor

A fast reactor is one of recommended candidates of Generation IV nuclear energy systems, which would meet wide requirements such as sustainability, safety and economics for nuclear energy development. To be the China’s first fast reactor, China Experimental Fast Reactor (CEFR) typical technical options are following: 65 MW thermal power and 20 MW electric power, three circuits of sodium-sodium-water, integrated pool type structure for the primary circuit. To establish modular simulation system for sodium fast reactor, the code which simulated the thermal-hydraulic behavior of primary circuit was developed. The physical models include reactor core, reactor vessel cooling channel, pumps, protection vessel, intermediate heat exchangers, ionization chamber cooling channel, cold sodium pool, hot sodium pool, inlet plenum, and pipes, etc. The code could compute coolant pressures, flow rates, and temperatures in the primary circuit. This module was designed for analysis of a wide range of transients. Although based on CEFR, it can treat an arbitrary arrangement of components.

Analysis of Dynamic Load Level of High-Speed Heavy Vehicle Imposed on Uneven Pavement

2011 ◽  
Vol 138-139 ◽  
pp. 146-152
Author(s):  
Guo He Guo ◽  
Yu Feng Bai ◽  
Tao Wang
Keyword(s):  
Dynamic Load ◽  
High Speed ◽  
Load Level ◽  
Heavy Vehicle ◽  
Vehicle Speed ◽  
Destructive Effect ◽  
The Road ◽  
Wide Range ◽  
On The Road ◽  
Factor Interaction

Based on the significant destructive effect of heavy vehicle on uneven roads, two simplified models of pavement unevenness and vehicle dynamic load were established in accordance with D'A lembert principle, and Matlab software was used to analyze the changing law of dynamic load under the conditions of different road unevenness, vehicle speed and load. The results show that vehicles running on uneven road may produce more cumulative damages than static load, and DLC (dynamic load coefficient) changes in wide range, maximum up to 2.0 or more; the effect of speed and load on dynamic load is complex, and due to multi-factor interaction, DLC doesn’t consistently increase or decrease with speed and load increasing. Although the dynamic load level caused by high-speed heavy vehicle is not necessarily too high, its impact on the road can not be ignored.

DWELLING ON THE ROAD: ROUTINES, RITUALS AND ROADBLOCKS IN SOUTHERN GHANA

Africa ◽  
2013 ◽  
Vol 83 (3) ◽  
pp. 446-469 ◽  
Author(s):  
Gabriel Klaeger
Keyword(s):  
Spatial Practices ◽  
Self Reflection ◽  
The Road ◽  
The Core ◽  
Everyday Practices ◽  
On The Road ◽  
Southern Ghana

ABSTRACTThe Accra–Kumasi road, one of Ghana's most important trunk roads, traverses numerous towns and settlements whose residents at times engage intimately with the road on their doorstep. In this article, I provide ethnographic insights into the ways in which roadside dwellers conceptualize – and spatialize – the road and its roadside through distinct repertoires of movement (performed and encountered), through localized storytelling and narratives, through self-reflection, and also through disruptive and vigilante actions. I describe the spatial practices that are at the core of the dwellers' ‘anthropological’ experience of the road and its roadside, a space that is continuously domesticated, appropriated and, thus, implicated in the mundane and everyday. The dwellers' everyday practices, as well as the exceptional performances oriented to the road, appear as closely intertwined both with the liveliness, socialities and opportunities the road affords, as well as with its dangers and potential for destruction and death. Thus the ‘ambivalent nature of road experiences’, in Masquelier's phrase – namely the experience of the road as a space of both perils and possibilities – is crucial to how roadside dwellers socially produce the Accra–Kumasi road.

Analyses of Severe Accidents in GFR Demonstrator ALLEGRO With MELCOR 2.1

2016 ◽  
Author(s):  
Petr Vácha ◽  
Ladislav Bělovský
Keyword(s):  
Fast Reactor ◽  
Heat Removal ◽  
Computer Code ◽  
Full Scale ◽  
Severe Accident ◽  
The Road ◽  
Passive Safety Systems ◽  
Station Blackout ◽  
On The Road ◽  
Further Development

The helium-cooled Gas Fast Reactor (GFR) is one of the six reactor concepts selected for further development in the frame of the Generation IV International Forum (GIF). Since no gas cooled fast reactor has ever been built, a small demonstration reactor is necessary on the road towards the full-scale GFR reactor. A concept of this demonstrator is called ALLEGRO. The French Commissariat à l’énergie atomique et aux énergies alternatives (CEA) developed between 2001–2009 a pre-conceptual design of both the full-scale GFR called GFR2400 and the small demonstration unit called ALLEGRO (75 MWt). Since 2013 ALLEGRO has been under development by several partners from Czech Republic, France, Hungary, Poland and Slovakia. No severe accident study of ALLEGRO using a dedicated computer code has been published so far. This paper is the first attempt to perform computer simulations of the ALLEGRO CEA 2009 concept, using MELCOR version 2.1. A model of the ALLEGRO CEA 2009 concept has been developed with the aim to perform safety analyses; to confirm that MELCOR can be used for such a study, to investigate what scenarios lead to a severe accident and to study in detail the progression of the severe accident during the in-vessel phase. Several pressurized and depressurized protected scenarios were investigated; four of them are presented in this paper. It was observed that even long-lasting station blackout (SBO) without further failures of the passive safety systems does not lead to a severe accident as long as there is enough water in the decay heat removal (DHR) system. Loss of coolant (LOCA) transients with DHR system in the forced-convection mode can lead to peak cladding temperatures causing limited core damage in the early phase of the accidents, but without further development into core meltdown. On the other hand, LOCA combined with SBO leads to excessive core melting in orders of minutes, which represents a weak point of ALLEGRO 2009 concept. Recommendations were formulated for the further development of the ALLEGRO concept.

La participation des forces démocratiques à l'expérience française de planification régionale

1972 ◽  
Vol 5 (1) ◽  
pp. 1-27
Author(s):  
Alain Baccigalupo
Keyword(s):  
Economic Development ◽  
Regional Planning ◽  
Trade Unions ◽  
Administrative Reform ◽  
The Road ◽  
The Core ◽  
On The Road ◽  
And Function ◽  
And Control ◽  
Vast Range

After briefly pointing out the weakness of participation at the core of the Regional Committees for Economic Expansion (CREE), the author analyses in depth the notion of participation as it has existed in France since the administrative reform of March 14, 1964, within the Commissions of Regional Economic Development (CODER).Having touched on the place occupied by and the role played by these organizations throughout the process of elaboration, execution, and control of the plan at the regional districts level, the author then turns to an examination of the composition and function of these consultative processes.As far as the composition of the CODER is concerned, the article deals with three main features: the tripartite nature of the commissions; the imbalance of forces particularly to the detriment of the trade unions; and the major reforms capable of improving the representativeness of the commission.Regarding the functioning of the CODERs, the author, having described the vast range of duties which are devolved on them by the texts, puts into perspective the extreme weakness of their “powers” in contrast to the unquestionable authority of the regional prefect. Thus, the CODERs are described as bodies directly under prefectorial control, veritable registry offices deeply divided at their centre, without real expertise and without great impact on public opinion.At the end of the study the author recalls the abortive attempt at regional reform on April 27, 1969, and concludes that it will be necessary to set to work on a far-reaching reform in order to get France on the road towards real democratization of the process of regional planning.

scholarly journals Behavior signal processing for vehicle applications

2013 ◽  
Vol 2 ◽  
Author(s):  
Chiyomi Miyajima ◽  
Pongtep Angkititrakul ◽  
Kazuya Takeda
Keyword(s):  
Signal Processing ◽  
Research Field ◽  
Driving Safety ◽  
Human Machine Interaction ◽  
Lane Changing ◽  
The Road ◽  
Wide Range ◽  
Active Research ◽  
On The Road ◽  
Driver Identification

Within the past decade, analyzing and modeling human behavior by processing large amounts of collected data has become an active research field in the area of human–machine interaction. The research community is striving to find principled ways to explain and represent important behavioral characteristics of humans, with the goal of developing more efficient and more effective cooperative interactions between humans, machines, and environment. This paper provides a summary of the progress we have achieved to date in our study, which has focused specifically on interactions between driver, vehicle, and driving environment. First, we describe the method of data collection used to develop our on-the-road driving data corpus. We then provide an overview of the data-driven, signal processing approaches we used to analyze and model driver behavior for a wide range of practical vehicle applications. Next, we perform experimental validation by observing the actual driving behavior of groups of real drivers. In particular, the vehicle applications of our research include driver identification, behavior prediction related to car following and lane changing, detection of emotional frustration, and improving driving safety through driver coaching. We hope this paper will provide some insight to researchers with an interest in this field, and help identify areas and applications where further research is needed.

scholarly journals SERAT ECENG GONDOK SEBAGAI BAHAN ALTERNATIF ADMIXTURE PADA LASTON TIPE XI SNI 03-1737-1989 DITINJAU TERHADAP NILAI-NILAI UJI MARSHALL

Jurnal CIVILA ◽  
2018 ◽  
Vol 3 (2) ◽  
pp. 154
Author(s):  
Errine Yulia Rizqi Intanti ◽  
Zulkifli Lubis
Keyword(s):  
Water Hyacinth ◽  
Asphalt Mixture ◽  
Road Construction ◽  
Flexible Pavement ◽  
The Road ◽  
Concrete Layer ◽  
Wide Range ◽  
On The Road ◽  
Marshall Stability

In Indonesia, the road construction has experienced a fairly good development. From a wide range of road constructions, flexible pavement is the most chosen one because its characteristics: easy, fast, and efficient. However, flexible pavement has many weaknesses, for example the premature damage on the road surface after some time passed by the traffic so that the road cannot reach the planned age. For that, it is done a research to add a hot asphalt mixture material that aims to improve the quality of the mixture results. The selected ingredient is natural water hyacinth. The method used is trial and error with reference of SNI 03-1737-1989. Variations used are 2%, 4%, 6%, 8% and 10% of the asphalt weight, asphalt level used is 5.72 %. Of the 5 variations of mixture used on Type XI Asphalt Concrete Layer, it is obtained the result that the water hyacinth fiber level which has the best score and meet the specifications of SNI 03-1737-1989 is on the percentage of 6% which obtained from calculation data using graphs and regression model where Marshall Stability is equal to 644,46 Kg, flow 3,39 mm, VMA (voids in the mineral aggregate) is equal to 13,83 %, VFWA (voids filled with asphalt) is equal to 65,35%, VIM (voids in the mix) is equal to 2,52 %, density of 2.31 gr/cc, and Marshall Quotient of 164.03 Kg / mm.

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