IRSN is looking for several Post-Docs in various nuclear fields.
All advertised positions are potentially eligible for a MSCA application (further information on this point is to be discussed with the contact person appointed in each description)
Postdoctoral position : CFD analysis of flow deviation induced by ballooned nuclear fuel rods
Workplace
Cadarache Center – Provence-Alpes-Côte d’Azur – France
Main scientific field
Fluid mechanics
Keywords
CFD, multiphase phase flow, heat transfer
The candidate will work for the Incident and Accident Management Service (SEMIA). The activities conducted in this department covers especially the assessment of design basis accidents in nuclear power plants. This includes LOss of Coolant Accidents (LOCA) that correspond to transients induced by a pipe break in the primary loop of the plant.
Study of the development of ISR concrete pathology, interpretation through the notions of durability indicators and scale effect applied to the international ODOBA project
Thematics: Civil engineering; Materials; Engineering Sciences
Keywords: Internal Sulfate Reaction (ISR), experimental data interpretation, sustainability indicators, scale effect, international ODOBA project
Place: Cadarache (13), France
Availability date: As soon as possible (May 2023)
Duration: 18 months
The proposed work is part of the research conducted at the Institute for Radiation Protection and Nuclear Safety (IRSN) concerning the ageing of concrete in nuclear power plant containments (extension of the operating life of nuclear reactors) in the framework of the international ODOBA project. This project focuses on internal swelling reactions (ISR) at the scale of massive blocks. They are of two types: the Internal Sulfate Reaction (ISR) and the Alkali-Aggregate Reaction (AAR). These reactions can lead to the degradation of the mechanical properties of the concrete but especially to cracking, potentially resulting in a loss of efficiency of the third containment barrier for radioactive materials.
Monte-Carlo propagation of nuclear data uncertainties in depletion calculations using Random sampling methods
Location:
IRSN Fontenay-aux-Roses, France
Unit:
Laboratoire de Neutronique (LN) – Service de Neutronique et des risques de Criticité (SNC)
Duration:
1 year
Starting date:
June 2023
The objective of this work is to carry out a comparative study, between VESTA and TRIPOLI 4®, of the nuclear data uncertainty obtained on quantities of interest in depletion calculations after a first comparative study between the two codes on these same quantities of interest k inf and isotopic compositions of criticality safety nuclides.
Domain Decomposition for Next-Generation Monte-Carlo Neutron Transport Code TRIPOLI-5
Start in: As soon as possible
Workplace: Fontenay-aux-roses,
France Duration: 18 months
Monte Carlo burnup calculations are actually memory-bound, and the solution to this limitation lies in some sort of Domain Decomposition in order to distribute the memory requirements of a single simulation over several compute nodes. The problem of domain decomposition does not present the same challenges nor does it use the same approaches for deterministic methods and for Monte-Carlo simulations. A number of domain-decomposition methods adapted to neutron transport criticality calculations have been suggested in the literature, and a few codes, both production and research type, have tested some implementations.
Simulation aux grandes échelles de la déflagration de mélanges H2/air/vapeur d’eau ; application aux expériences ENACCEF2
Lieu de travail : Cadarache – Bouche du Rhône – France
Champ scientifique principal : Applied Mathematics, Fluid Mechanics
Key words: Large Eddy Simulation, numerical scheme
Fonction: Education and research
The work proposed in the framework of this post-doctorate is divided into two stages.
Firstly, it consists in extending the space discretization for LES applications on unstructured meshes. This type of development is a difficult problem. In particular, it seems that it is necessary to choose the richest possible approximations of the pressure, while preserving stability (discrete inf-sup condition). Such work has been proposed in the literature for Crouzeix-Raviart finite elements, for the simulation of incompressible flows. The objective is to extend these ideas in two directions:
a) adaptation to compressible flows, within the framework of schemes developed over the last ten years by the Institut de Mathématique de Marseille (I2M) and the IRSN,
b) extension to discretization in space of the same type (i.e. with velocity degrees of freedom associated with faces) but based on cells of different shape: hexahedra (Rannacher-Turek elements), prisms and pyramids.
In a second step, the validation of these schemes will be done on hydrogen, air and water vapour deflagration tests in a flame acceleration tube (ENACCEF2 experiments, performed at the ICARE Laboratory of the CNRS in Orléans). The simulations should make it possible to characterise the turbulence in the flow and the structure of the flame front.
