As the French leader for research on materials for nuclear applications, CEA launched the MINOS project (Materials Innovation for Nuclear Optimized Systems) in 2011.
This centre of excellence for nuclear materials was created by the Nuclear Energy Division (DEN) to promote, strengthen, and optimize research programs on materials used for nuclear power reactors and activities for the back end of the fuel cycle. It brings together all of the skills and means of DEN division dedicated to nuclear materials.
The objective is to find solutions for current and future nuclear challenges, such as: increasing the safety level, lifespan and availability of current reactors, optimizing the fuel cycle for current reactors, developing new materials for 4th generation reactors, and consolidating waste management policies.
MINOS consists of 720 staff members contributing to fundamental and applied research on nuclear materials in areas such as chemistry, physics, mechanics and behavior under irradiation. The research programs are guided by industrial needs, and MINOS sustains strategic research partnerships and innovative research programs for elaboration, characterization, design, physical understanding and modeling/simulation of nuclear materials (metals, alloys, ceramics, composites, glasses, concrete, bitumen, and geo-lolymers) and structures in extreme conditions.
In the frame-work of the GENESIS French National Investment program, the LECI hot laboratory of the CEA Nuclear Materials Department, which is dedicated to the microstructural and mechanical characterization of irradiated materials, purchased a FIB to be nuclearized and, equipped with EBSD capabilities. This device, which is scheduled to be operational by the end of 2018, will allow the manufacture of nano samples for APT (Atom Probe Tomography) analysis of irradiated materials for microstructural and chemical studies at very small scales (10-9 - 10-10 m). The APT will be used to construct three-dimensional digital representations of samples with magnification up to 800,000x.
Comprehensive knowledge of the ageing of in-core and structural materials is critical to many of the challenges that we are currently facing, including the extension of the lifespan of current reactors, the development of new generation fast neutron reactors, and the continuous improvement of the safety of those systems. These endeavors require a multi-physics and multi-scale approach. An area of particular interest is the modeling of the population of radiation-induced defects and their impact on the mechanical plastic behavior of materials (stainless steels, zirconium alloys). As part of a recent project performed at the CEA Department of Nuclear Materials, the Cluster Dynamics code CRESCENDO (co-developed along with EDF) and the Dislocation Dynamics code NUMODIS (co-developed along with INRIA and CNRS) were chained within the MATIX_P numerical simulation platform. Based on the evolution of the radiation-induced defects computed with CRESCENDO, it is now possible to simulate the behavior of dislocations and their interactions with the defects using NUMODIS, and thus, to describe the micromechanical behavior of a metallic iron grain as a function of irradiation dose. The successful chaining of these codes will soon allow researchers to describe the multi-scale behavior of irradiated model and industrial materials.
The first in situ raman spectroscopy analysis was recently achieved in the triple beam chamber of the JANNuS irradiation platform at CEA Saclay. the experiment was performed using a silicon carbide (SiC) sample irradiated with 4 MeV gold ions (2.5 dpa after 150 minutes), until the material was completely amorphous. This new device offers a large range of new non-destructive characterization possibilities for materials under irradiation with reduced experimentation time.
The PLEIADES multi-scale simulation platform, which was co-developed by the Fuel Research Department of CEA and EDF R&D, with support from AREVA, allows the simulation of the behavior of fuel and cladding in a reactor invironments, both in normal operating conditions and accident scenarios. In the field of micro-mechanics, recent REV (Representative Elementary Volume) application developments resulted in the identification of the links between deformation mechanisms at the dislocation scale and mechanical interactions at the scale of the grains of the polycrystalline structure of the fuel. Using specialized homogeneization methods, the PLEIADES software can simulate the loss of the mechanical integrity of the fuel at the microstructural scale.
First experiments with the MARS beamline of the SOLEIL synchrotron in saclay with samples irradiated in reactors over the exemption threshold
A series of analyses (transmission XRD and x-ray absorption spectroscopy) was achieved in September 2013 with an ODS steel specimen, which was irradiated in the 1990s in different reactors (Osiris, Phénix and BOR 60). The objective of the study was to evaluate the stability of nano-size oxide particles under irradiation. At the request of SOLEIL, a video (Copyright SOLEIL) was made of the experiments.
Prospect of a new MINOS Workshop in 2019
Nuclearized FIB (Zeiss Auriga 40) and future lay-out in shielded cell at the LECI hot laboratory.
Image of an iron grain microstructure (0.4 µm in size) irradiated with neutrons in a reactor (27 days, 0.3 dpa), obtained with the NUMODIS Dislocation Dynamics code based on data generated by the Cluster Dynamics code CRESCENDO.
Raman probe located in the triple beam chamber of JANNuS-Saclay irradiation platform.
PLEIADES multi-scale simulation platform: pellet-cladding interaction (pellet cracking), microstructure (crystal plasticity mapping of fuel grains).
Last update : 08/22 2017 (109)
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