Publications related to Void coefficient

An experimental and analytical study of wind turbine wakes under pressure gradient

Fernando Porté Agel, Arslan Salim Dar, Abraham Starbuck Gertler

This work is dedicated to the systematic investigation of wind turbine wakes under the effect of pressure gradients. Wind tunnel experiments are carried out with a wind turbine positioned on straight ramps of increasing angle such that it experiences an ap ...

2023

LDP and CLT for SPDEs with transport noise

Lucio Galeati

In this work we consider solutions to stochastic partial differential equations with transport noise, which are known to converge, in a suitable scaling limit, to solution of the corresponding deterministic PDE with an additional viscosity term. Large devi ...

SPRINGER2023

Advanced methodologies for modeling and assessment of SFR safety functions

Janos Bodi

The present doctoral work was performed to contribute to the conceptual design development and safety assessment of a Generation IV Sodium Fast Reactor (SFR) in the frame of the European Sodium Fast Reactor Safety Measures Assessment and Research Tools (ES ...

EPFL2022

Design optimization of the Upper Steering Mirror Assembly (USMA) for ITER ECHUL in view of disruptive events

Timothy Goodman, René Chavan, Matteo Vagnoni, Anastasia Xydou

Four Electron Cyclotron Heating Upper Launchers (ECHUL) will be used at ITER to counteract magneto-hydrodynamic plasma instabilities by targeting them with up to 20 MW of mm-wave power at 170 GHz. The millimeter waves are guided through a set of fixed mirr ...

2021

The COLIBRI experimental program in the CROCUS reactor: characterization of the fuel rods oscillator

Andreas Pautz, Vincent Pierre Lamirand, Mathieu Hursin, Carlo Fiorina, Oskari Ville Pakari, Pavel Frajtag, Axel Guy Marie Laureau, Adolfo Rais, Daniel Godat

The present article presents the mechanical characterization of the fuel rods oscillator developed for the purposes of the COLIBRI experimental program in CROCUS. COLIBRI aims at investigating the radiation noise related to fuel vibrations. The main motiva ...

2020

Systematic Sensitivity and Uncertainty Analysis of Sodium-Cooled Fast Reactor Systems

Friederike Bostelmann

Sodium-cooled fast reactor (SFR) technologies have the potential to guarantee energy supply and to reduce the burden of nuclear waste for future generations. For an adequate simulation of these reactor systems, well-established tools that have so far been ...

EPFL2020

One-dimensional fluid–structure interaction models in pressurized fluid-filled pipes: a review

Anton Schleiss, Pedro Filipe De Almeida Manso

The present review paper aims at collecting and discussing the research work, numerical and experimental, carried out in the field of Fluid–Structure Interaction (FSI) in one-dimensional (1D) pressurized transient flow in the time-domain approach. Backgrou ...

2018

Modelling of fuel fragmentation, relocation and dispersal during Loss-of-Coolant Accident in Light Water Reactor

Vladimir Vladimirov Brankov

Recent LOCA tests with high burnup fuel at the OECD Halden Reactor Project and at Studsvik demonstrated the susceptibility of the fuel to fragment to small pieces, to relocate and possibly cause a hot-spot effect and to be dispersed in the event of claddin ...

EPFL2017

Analysis of reactivity worths of burnt PWR fuel samples measured in LWR-PROTEUS Phase II using a CASMO-5 reflected-assembly model

Mathieu Hursin, Hakim Ferroukhi, Daniel Jerôme Siefman

The reactivity loss of PWR fuel with burnup has been investigated experimentally by measuring the reactivity worths of highly-burnt fuel samples in a PWR test lattice in the framework of the LWR-PROTEUS Phase II program. Seven UO2 samples cut from fuel rod ...

2017

On the formation of stacking fault tetrahedra in irradiated austenitic stainless steels – A literature review

Robin Schäublin, Raluca Schibli

Irradiated austenitic stainless steels, because of their low stacking fault energy and high shear modulus, should exhibit a high ratio of stacking fault tetrahedra relative to the overall population of radiation induced nanometric defects. Experimental obs ...

Elsevier Science Bv2013

Analysis of selected Phenix EOL tests with the FAST code system - Part II: Unprotected phase of the Natural Convection Test

Rakesh Chawla, Aurélia Chenu, Konstantin Mikityuk

Experimental results from the unprotected phase of the Natural Convection (NC) Test performed in the Phenix reactor in the frame of end-of-life (EOL) experiments have been used to qualify the FAST code system for Sodium-cooled Fast Reactor (SFR) transient ...

Elsevier2012

Analysis of Advanced Sodium-cooled Fast Reactor Core Designs with Improved Safety Characteristics

Kaichao Sun

In order to meet the steadily increasing worldwide energy demand, nuclear power is expected to continue playing a key role in electricity production. Currently, the large majority of nuclear power plants are operated with thermal-neutron spectra and need r ...

EPFL2012

Void reactivity decomposition for the Sodium-cooled Fast Reactor in equilibrium fuel cycle

Rakesh Chawla, Konstantin Mikityuk, Jiri Krepel, Kaichao Sun

The Sodium-cooled Fast Reactor (SFR) is one of the most promising Generation IV systems with many advantages, but has one dominating neutronic drawback - a positive sodium void reactivity. The aim of this study is to develop and apply a methodology, which ...

Elsevier2011

Interaction between BaCO3 and OPC/BFS composite cements at 20 degrees C and 60 degrees C

Emmanuel Gallucci

A BaCO3 slurry, containing radioactive C-14, is produced during the reprocessing of spent nuclear fuel. This slurry is encapsulated in a Portland-blastfurnace slag composite cement. The effect of BaCO3 on the hydration of OPC and Portland-blastfurnace slag ...

Pergamon-Elsevier Science Ltd2011

5f-Element complexes with a p-tert-butylcalix[4]arene bearing phosphinoyl pendant arms: Separation from rare earths and structural studies

Rosario Scopelliti, Jean-Claude Bünzli

Phosphinoylated calixarenes feature high coordination ability toward f elements and a great potentiality toward actinide/rare earth separation. Here, we report three characteristic properties of a tetra-phosphinoylated p-tert-butylcalix[4]arene, B(4)bL(4) ...

Elsevier2011

Intrinsic defect complexes in CdTe and ZnTe

Alexandra Sarabando de Carvalho

Radiation defects in CdTe and ZnTe are modeled from first principles. The most important intrinsic defects resulting from cation evaporation or displacement are cation vacancies and tellurium anti-sites, electrically active defects characterized by a low f ...

2011

Improvement of the Decay Heat Removal Characteristics of the Generation IV Gas-cooled Fast Reactor

Aaron Simon Epiney

Gas cooling in nuclear power plants (NPPs) has a long history, the corresponding reactor types developed in France, the UK and the US having been thermal neutron-spectrum systems using graphite as the moderator. The majority of NPPs worldwide, however, are ...

EPFL2010

Energy-Efficient Variable-Flow Liquid Cooling in 3D Stacked Architectures

David Atienza Alonso, Ayse Kivilcim Coskun, Bruno Michel

Liquid cooling has emerged as a promising solution for addressing the elevated temperatures in 3D stacked architectures. In this work, we first propose a framework for detailed thermal modeling of the microchannels embedded between the tiers of the 3D syst ...

ACM/IEEE Press2010

Void reactivity coefficient benchmark results for a 10x10 BWR assembly in the full 0-100% void fraction range

Rakesh Chawla, Fabian Jatuff, Flavio Dante Giust

A boiling water reactor SVEA-96+ fresh fuel lattice has been used as the basis for a benchmark study of the void reactivity coefficient at assembly level in the full voidage range. Results have been obtained using the deterministic codes CASMO-4, HELIOS, P ...

Elsevier Science Ltd.2009

Management of actinide waste inventories in nuclear phase-out scenarios

Rakesh Chawla, Marco Cometto

The improvement of the "radiological cleanliness" of nuclear energy is a primary goal in the development of advanced reactors and fuel cycles. The multiple recycling of actinides in advanced nuclear systems with fast neutron spectra represents a key option ...

Elsevier Ltd2008