Safety analysis and CFD dispersion simulation of cryogenic release in a deep underground large scale cryogenic installation

2014 ◽  
pp. 1737-1744 ◽  
Keyword(s):  
Large Scale ◽  
Safety Analysis ◽  
Deep Underground

Experiments on Gas Mixing and Stratification Driven by Jets and Plumes in Large-Scale, Multi-Compartment Geometries

2006 ◽  
Author(s):  
Robert Zboray ◽  
Domenico Paladino ◽  
Olivier Auban
Keyword(s):  
High Resolution ◽  
Time Evolution ◽  
Large Scale ◽  
Nuclear Reactor ◽  
Safety Analysis ◽  
Mixing Process ◽  
Gas Mixing ◽  
Computational Tools ◽  
Different Gases

The present paper discusses experiments carried out to examine mixing of different gases (steam, air) and the evolution their distributions in large-scale, multi compartment geometry imitating nuclear reactor containment compartments. The flow and the mixing process in the experiments are driven by plumes and jets representing source structures with different momentum-to-buoyancy strength. The time evolution of the relevant parameters like gas concentrations, velocities and temperatures are followed using dedicated instrumentation. The data obtained is meant to be used for the validation and development of high-resolution, mainly CFD based, 3D computational tools for nuclear reactor containment safety analysis.

Brittle Fracture Safety Analysis of German RPVs Based on Advanced Thermal Hydraulic Analysis

2008 ◽  
Author(s):  
Elisabeth Keim ◽  
Roland Hertlein ◽  
Ulf Ilg ◽  
Gu¨nter Ko¨nig ◽  
Norbert Schlu¨ter ◽  
...  
Keyword(s):  
Brittle Fracture ◽  
Large Scale ◽  
Thermal Stresses ◽  
Safety Margin ◽  
Safety Analysis ◽  
Local Analysis ◽  
Design Stage ◽  
Joint Analysis ◽  
Rpv Steel ◽  
Loss Of Coolant

During the design stage of the today operating German PWRs, one major design target was to manage the materials ageing behavior of the ferritic reactor pressure vessel (RPV) steel in oder to prevent a brittle fracture of the RPV under all possible loads. Very conservative thermal hydraulic input data were used in this context for the assessment of loss of coolant accidents. Today more realistic thermal hydraulic analyses based on large scale experimental results are available as well as more sophisticated fracture mechanics methods to assess postulated flaws. Using these tools an additional joint analysis of six German PWR RPVs is performed. A fully representative spectrum of all possible large and small break loss of coolant accidents is investigated. Locations of interest are the irradiated RPV core beltline region as well as those regions with negligible irradiation but higher loading, like the RPV MCL nozzles and the flange to cylinder transition area. The thermal hydraulic work comprises global system analyses with subsequent local analysis considering mixing phenomena like plume forming below the injecting nozzles. Dependent on the location of the postulated flaw (core or nozzle region), the postulated leak size is differing. In the core weld region medium leak sizes (100 to 200 cm2) with subsequent injection into the cold leg lead to dominating loading, whereas in the nozzle the small leak sizes (3 to 20 cm2) with injection into the hot leg are more important. This is due to the higher pressure at smaller leak sizes and the larger thermal stresses caused by the high temperature of the nozzle flange and the low temperature of the injected ECCS-water. But independent of the number of transients it turned out that all load paths of the postulated flaws and the investigated leak sizes show a similar behavior. As the result of this additional joint safety analysis of six German PWR RPVs with different injection modes, a brittle fracture of all RPV regions can be excluded with sufficient safety margin.

EARLY YEARS OF HIGH-ENERGY NEUTRINO PHYSICS IN COSMIC RAYS AND NEUTRINO ASTRONOMY (1957-1962)

2006 ◽  
Vol 21 (supp01) ◽  
pp. 1-11 ◽  
Author(s):  
IGOR ZHELEZNYKH
Keyword(s):  
Neutrino Physics ◽  
Large Scale ◽  
High Energy ◽  
Early Years ◽  
Atmospheric Neutrinos ◽  
High Energy Neutrino ◽  
Neutrino Telescopes ◽  
Energy Neutrino ◽  
Deep Underground ◽  
Neutrino Astronomy

Ideas of deep underground and deep underwater detection of high-energy cosmic neutrinos were firstly suggested by Moisey Markov in the end of 50th. Frederic Reines was one of those who first detected high-energy atmospheric neutrinos in underground experiments in the middle of 60th (as well as low energy reactor neutrinos 10 years earlier!). Markov and Reines closely collaborated in 70th – 80th in discussion of alternative techniques for large-scale neutrino telescopes. Some events of 50 – 80 years relating to the development of a new branch of Astronomy – the High-Energy Neutrino Astronomy, in which Markov and Reines took part, were described in my talk at ARENA Workshop. Below the first part of my talk at the Workshop is presented describing discussions and meetings the neutrino physics and astrophysics relating to the period 1957-1962 when I was Markov's student and later post-graduated student.

Evaluation of Solubility and Speciation of Actinides in Natural Groundwaters

1981 ◽  
Vol 11 ◽  
Author(s):  
Marc R. Schweingruber
Keyword(s):  
Safety Analysis ◽  
Theoretical Studies ◽  
Comprehensive Description ◽  
Groundwater Circulation ◽  
Deep Underground ◽  
Experimental And Theoretical Studies

Groundwater circulation is in the long term probably the most important mechanism for the transport of radionuclides from deep underground repositories to the biosphere. The fate of leached long-lived nuclides, such as the actinides, is of particular interest to repository safety analysis. Both experimental and theoretical studies should lead to a comprehensive description of their behaviour in the geosphere.

Large-scale automated proactive road safety analysis using video data

2015 ◽  
Vol 58 ◽  
pp. 363-379 ◽  
Author(s):  
Paul St-Aubin ◽  
Nicolas Saunier ◽  
Luis Miranda-Moreno
Keyword(s):  
Road Safety ◽  
Large Scale ◽  
Safety Analysis ◽  
Video Data

scholarly journals Evaluation of Highway-pilot Function Based on FMEA Safety Analysis

2019 ◽  
Vol 48 (3) ◽  
pp. 253-259
Author(s):  
Ádám Bényei ◽  
Gabor Vida ◽  
Krisztián Pintér ◽  
Zsolt Szalay ◽  
György Ágoston
Keyword(s):  
Autonomous Vehicles ◽  
Large Scale ◽  
Personal Data ◽  
Safety Analysis ◽  
Terrorist Attacks ◽  
Security Risk ◽  
Unauthorized Access ◽  
Vehicle Operation ◽  
Access To Data ◽  
At Home

Cybersecurity is becoming more and more relevant. Autonomous vehicles handle large amounts of data and can connect to more and more existing devices, smartphones, tablets, or even other cars and systems. This poses the risk of unauthorized access to data. Theoretically cars have separate computer units, operate in isolation, and are not connected, so there is less possibility to be attacked. However if the vehicles are interconnected, hackers can have easier access to personal data. They can get information about the location of the car owner, their typical trips, and, for example, allow an intruder to know when the tracked person is not at home. Furthermore it can also be happened that the vehicle operation is maliciously disturbed, which can result in a security risk for the passengers. In extreme cases, computer terrorist attacks can also be prepared - large-scale interventions on roads can lead to chaos across a region or country. In accordance with the introduced threats, it is a crucial objective of this research to indicate specific methods, which can help the industry to evaluate and prepare for these kinds of attacks in a proper way.

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