scholarly journals Investigation of the capacity of train stations in case of a large-scale emergency evacuation

10.29007/j32s ◽  
2019 ◽  
Author(s):  
Anna Braun ◽  
Mohcine Chraibi ◽  
Lukas Arnold
Keyword(s):  
Urban Areas ◽  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
Emergency Evacuation ◽  
Railway Transportation ◽  
Pedestrian Dynamics ◽  
Train Station ◽  
Dynamics Simulations ◽  
Hurricanes Katrina And Rita

Nature and human-made hazards, like hurricanes, inundations, terroristic attacks or in- cidents in nuclear power plants, make it necessary to evacuate large urban areas in a short time. So far, the consideration of railway transportation is rarely part of the evacuation strategies. One of the reasons is the unknown capacity of this infrastructure.In the case of hurricanes Katrina and Rita (USA) the evacuation was accomplished with pri- vate vehicles and buses. In Germany, especially in the conurbation of Nordrhein-Westfalen, where many roads are overloaded during the daily rush hours, it will not be possible to use only road dependent vehicles like private cars or busses to evacuate a large number of people into save areas.After the nuclear power plant disaster of Fukushima, the working group ‘AG Fukushima’ was founded, which recommends the use of trains for large-scale emergency evacuations. However, it is not clear if the capacity of train stations is enough to handle these large evacuations in time. Hence, this work deals with the question of how the capacity of train stations can be quantified and optimised for this application. In order to estimate the capacity of train stations we use and further develop the Ju ̈lich Pedestrian Simula- tor (JuPedSim), a software for pedestrian dynamics simulations. Therefore, a model of a train station is built in JuPedSim and several parameters like the inflow and outflow of the pedestrians are examined, to find the best routing strategy and organisational ac- tions inside the station. The focus of this contribution lies in the identification of critical bottlenecks. An estimation of which parameters are influencing congestion at these bottle- necks is presented. Additionally, organisational strategies are outlined, which can prevent congestion and increase the capacity of a train station.

scholarly journals On the Root Causes of the Fukushima Daiichi Disaster from the Perspective of High Complexity and Tight Coupling in Large-Scale Systems

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 414
Author(s):  
Atsuo Murata ◽  
Waldemar Karwowski
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
High Complexity ◽  
Tight Coupling ◽  
Large Scale Systems ◽  
Safety Issues ◽  
Loss Of Coolant ◽  
Station Blackout ◽  
Fukushima Daiichi

This study explores the root causes of the Fukushima Daiichi disaster and discusses how the complexity and tight coupling in large-scale systems should be reduced under emergencies such as station blackout (SBO) to prevent future disasters. First, on the basis of a summary of the published literature on the Fukushima Daiichi disaster, we found that the direct causes (i.e., malfunctions and problems) included overlooking the loss of coolant and the nuclear reactor’s failure to cool down. Second, we verified that two characteristics proposed in “normal accident” theory—high complexity and tight coupling—underlay each of the direct causes. These two characteristics were found to have made emergency management more challenging. We discuss how such disasters in large-scale systems with high complexity and tight coupling could be prevented through an organizational and managerial approach that can remove asymmetry of authority and information and foster a climate of openly discussing critical safety issues in nuclear power plants.

Development of 1500-r/min 75-Inch Ultra-Long Last Stage Blades for Nuclear Steam Turbine

2017 ◽  
Author(s):  
Deqi Yu ◽  
Jiandao Yang ◽  
Wei Lu ◽  
Daiwei Zhou ◽  
Kai Cheng ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
Vibration Monitoring ◽  
Steam Turbines ◽  
Element Analysis ◽  
Rotating Blade ◽  
Lifetime Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Last Stage

The 1500-r/min 1905mm (75inch) ultra-long last three stage blades for half-speed large-scale nuclear steam turbines of 3rd generation nuclear power plants have been developed with the application of new design features and Computer-Aided-Engineering (CAE) technologies. The last stage rotating blade was designed with an integral shroud, snubber and fir-tree root. During operation, the adjacent blades are continuously coupled by the centrifugal force. It is designed that the adjacent shrouds and snubbers of each blade can provide additional structural damping to minimize the dynamic stress of the blade. In order to meet the blade development requirements, the quasi-3D aerodynamic method was used to obtain the preliminary flow path design for the last three stages in LP (Low-pressure) casing and the airfoil of last stage rotating blade was optimized as well to minimize its centrifugal stress. The latest CAE technologies and approaches of Computational Fluid Dynamics (CFD), Finite Element Analysis (FEA) and Fatigue Lifetime Analysis (FLA) were applied to analyze and optimize the aerodynamic performance and reliability behavior of the blade structure. The blade was well tuned to avoid any possible excitation and resonant vibration. The blades and test rotor have been manufactured and the rotating vibration test with the vibration monitoring had been carried out in the verification tests.

Planning of Large-Scale In-Situ Gas Generation Experiment in Korean Radioactive Waste Repository

2010 ◽  
Author(s):  
Juyoul Kim ◽  
Sukhoon Kim ◽  
Jin Beak Park ◽  
Sunjoung Lee
Keyword(s):  
Radioactive Waste ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Large Scale ◽  
Radioactive Waste Disposal ◽  
Gas Generation ◽  
Radioactive Waste Repository ◽  
Waste Repository

In the Korean LILW (Low- and Intermediate-Level radioactive Waste) repository at Gyeongju city, the degradation of organic wastes and the corrosion of metallic wastes and steel containers would be important processes that affect repository geochemistry, speciation and transport of radionuclides during the lifetime of a radioactive waste disposal facility. Gas is generated in association with these processes and has the potential threat to pressurize the repository, which can promote the transport of groundwater and gas, and consequently radionuclide transport. Microbial activity plays an important role in organic degradation, corrosion and gas generation through the mediation of reduction-oxidation reactions. The Korean research project on gas generation is being performed by Korea Radioactive Waste Management Corporation (hereafter referred to as “KRMC”). A full-scale in-situ experiment will form a central part of the project, where gas generation in real radioactive low-level maintenance waste from nuclear power plants will be done as an in-depth study during ten years at least. In order to examine gas generation issues from an LILW repository which is being constructed and will be completed by the end of December, 2012, two large-scale facilities for the gas generation experiment will be established, each equipped with a concrete container carrying on 16 drums of 200 L and 9 drums of 320 L of LILW from Korean nuclear power plants. Each container will be enclosed within a gas-tight and acid-proof steel tank. The experiment facility will be fully filled with ground water that provides representative geochemical conditions and microbial inoculation in the near field of repository. In the experiment, the design includes long-term monitoring and analyses for the rate and composition of gas generated, and aqueous geochemistry and microbe populations present at various locations through on-line analyzers and manual periodical sampling. A main schedule for establishing the experiment facility is as follows: Completion of the detailed design until the second quarter of the year 2010; Completion of the manufacture and on-site installation until the second quarter of the year 2011; Start of the operation and monitoring from the third quarter of the year 2011.

EMERGENCY EVACUATION SIMULATION FOR A RADIATION DISASTER: A CASE STUDY OF A RESIDENTIAL SCHOOL NEAR NUCLEAR POWER PLANTS IN KOREA

2020 ◽  
Vol 189 (3) ◽  
pp. 323-336
Author(s):  
Juyoul Kim ◽  
Faith Rukundo ◽  
Ashraf Musauddin ◽  
Batbuyan Tseren ◽  
Gazi Muhammad Borhan Uddin ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Residential Building ◽  
Emergency Evacuation ◽  
Night Time ◽  
Evacuation Simulation ◽  
Emergency Situations ◽  
Nuclear Disaster ◽  
Night And Day ◽  
The Times

Abstract Ensuring evacuation of people from a building in a fast and secure manner is of great significance in the event of emergency situations. This study aimed at evaluating the level of evacuation preparedness and movement of residents at the KEPCO International Nuclear Graduate School (KINGS) in the event of a nuclear emergency. Evacuation times from KINGS after a nuclear disaster at Shin Kori nuclear power plant (NPP) were estimated using Pathfinder. Four scenarios of night and day time by assuming the normal and worst scenarios were simulated. With regard to worst scenarios, the times estimated for residents to gather and leave the assembly point for the night time scenario were estimated to 22~23 min, whereas 38~39 min were calculated for the crowd to leave the assembly point. The results of this study can be used by emergency planners when planning for evacuation from a residential building nearby NPP.

A Study of Nanoparticle-Enhanced Heat Transfer

2010 ◽  
Author(s):  
Lawrence M. Jones ◽  
Timothy Sirk ◽  
Eugene Brown
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Molecular Dynamics ◽  
Heat Flux ◽  
Nuclear Power ◽  
Power Plants ◽  
Md Simulations ◽  
Theoretical Description ◽  
Different Temperatures ◽  
Dynamics Simulations

The study of the heat transfer characteristics of nanofluids, i.e. fluids that are suspensions of nanometer size particles, has gained significant attention in the search for new coolants that can effectively service a variety of needs ranging from the increasing heat transfer demands of ever smaller microelectronic devices to mitigating the effects of loss of coolant accidents in nuclear power plants. Experimental data has shown large increases in thermal conductivity and associated increases in the level of critical heat flux in nuclear reactors; however, in some cases the range of the applicability of the experimental results is uncertain and there is a lack of a theory by which this can be resolved. Complicating the theoretical description of heat transfer in nanofluids is the fact that fluids in the vicinity of the nanoparticles are a complex combination of phase transition, interfacial, and transport phenomena. This paper describes a study in which molecular dynamics simulations were used to enhance the understanding of the effect of nanoparticles on heat transfer. The molecular dynamics (MD) simulations presented here model a Lennard-Jones fluid in a channel where the walls are maintained at different temperatures. The heat flux is calculated for a variety of nanoparticle sizes and concentrations. The results are compared to experimental data in order to provide information that will more confidently bound the data and provide information that will guide the development of more comprehensive theories. We also anticipate that this work could contribute to the design of biosensors where suspended molecules are transported through micro- and nano-channels in the presence of heat transfer.

Grid-Connected Nuclear Power Plant Key Issues Summary

2014 ◽  
Vol 521 ◽  
pp. 530-535
Author(s):  
Meng Wang ◽  
Jian Ding ◽  
Tian Tang ◽  
Zhang Sui Lin ◽  
Zhen Da Hu ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
Power Modeling ◽  
Modeling Simulation ◽  
Load Following ◽  
Key Issues ◽  
The Impact

The current situation of nuclear power plants at home and abroad is described, and the impact of large-scale nuclear power accessing to the grid is analyzed, specifically in the aspects of nuclear power modeling, simulation, load following, reliability, fault diagnosis, etc. Nuclear power accessing to the grid will bring a series of problems, the causes of each problem, the main solutions and future development directions are summarized.

Lessons Learned From the Operation of Large-Scale Reprocessing-Recycling Facilities in France: What Is in It for China?

2017 ◽  
Author(s):  
Jean-Pierre Gros
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
Central Government ◽  
Fuel Cycle ◽  
Public Information ◽  
Lessons Learned ◽  
Mitigation Measures ◽  
Spent Fuel ◽  
The Impact

AREVA has been running since decades nuclear reprocessing and recycling installations in France. Several industrial facilities have been built and used to this aim across the time. Following those decades and with the more and more precise monitoring of the impact of those installations, precise data and lessons-learned have been collected that can be used for the stakeholders of potential new facilities. China has expressed strong interest in building such facilities. As a matter of fact, the issue of accumulation of spent fuel is becoming serious in China and jeopardizes the operation of several nuclear power plants, through the running out of space of storage pools. Tomorrow, with the extremely high pace of nuclear development of China, accumulation of spent fuel will be unbearable. Building reprocessing and recycling installations takes time. A decision has to be taken so as to enable the responsible development of nuclear in China. Without a solution for the back end of its nuclear fuel cycle, the development of nuclear energy will face a wall. This is what the Chinese central government, through the action of its industrial CNNC, has well understood. Several years of negotiations have been held with AREVA. Everybody in the sector seems now convinced. However, now that the negotiation is coming to an end, an effort should be done towards all the stakeholders, sharing actual information from France’s reference facilities on: safety, security, mitigation measures for health protection (of the workers, of the public), mitigation measures for the protection of the environment. Most of this information is public, as France has since years promulgated a law on Nuclear transparency. China is also in need for more transparency, yet lacks means to access this public information, often in French language, so let’s open our books!

Validation of Analysis Models on Relocation Behavior of Molten Core Materials in Sodium-Cooled Fast Reactors Based on the Melt Discharge Experiment

2020 ◽  
Author(s):  
Kai Igarashi ◽  
Ryoji Onuki ◽  
Takaaki Sakai ◽  
Shinya Kato ◽  
Ken-ichi Matsuba ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
Heat Removal ◽  
Early Discharge ◽  
Core Material ◽  
Bottom Plate ◽  
Guide Tube ◽  
Control Rod ◽  
Analysis Models

Abstract In order to improve the safety of nuclear power plants, it is necessary to make sure measures against their severe accidents. Especially, in the case of a sodium-cooled fast reactor (SFR), there is a possibility of significant energy release due to formation of a large-scale molten fuel pool accompanied by re-criticality in the event of a core disruptive accident (CDA). It is important to ensure in-vessel retention that keeps and confines damaged core material in the reactor vessel even if the CDA occurs. CDA scenario initiated by Unprotected Loss Of Flow (ULOF), which is a typical cause of core damage, is generally categorized into four phases according to the progression of core-disruptive status, which are the initiating, early-discharge, material-relocation and heat-removal phases for the latest design in Japan. During the material-relocation phase, the molten core material flows down mainly through the control rod guide tube and is discharged into the inlet coolant plenum below the bottom of the core. The discharged molten core material collides with the bottom plate of the inlet plenum. Clarification of the accumulation behavior of molten core material with such a collision on the bottom plate is important to reduce uncertainties in the safety assessment of CDA. In present study, in order to make clear behavior of core melt materials during the CDAs of SFRs, analysis was conducted using the SIMMER-III code for a melt discharge simulation experiment [1] in which low-melting-point alloy was discharged into a shallow water pool. This report shows the validation results for the melt behavior by comparing with the experimental data.

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