Modeling metal interfaces in extreme environments
Title: Modeling metal interfaces in extreme environments
SNIC Project: SNIC 2014/1-171
Project Type: SNAC Medium
Principal Investigator: Mattias Klintenberg <mattias@physics.uu.se>
Affiliation: Uppsala universitet
Duration: 2014-05-30 – 2015-06-01
Classification: 21001
Keywords:

Abstract

Different nuclear technologies is one option for future low CO2 emission energy production. This project focus on the materials challenges that structural- and cladding materials experience in the harsh environments of the future nuclear reactors such as the lead cooled (LFR) or sodium coold fast reactor (SFR) systems. Typical challenges here are radiation induced creep, void swelling, radiation-induced hardening and embrittlement and in addition there are corrosion and erosion related challenges in the LFR environment. Creep and swelling can be traced back to point defect clusters and gas bubbles (He) and this together with the fact that the energetics of defect recombination at mismatched metallic interfaces are most favorable, make out the basis for this project. To understand erosion, corrosion and liquid metal embrittlement related properties electronic structure and molecular dynamics techniques are used to study metal-metal interfaces. MD potentials need to be developed for a variety of systems including, Fe-Al-Pb, Fe-Cr-Pb, Fe-Al-Cr-Pb, CuNb and CuW. For the latter two systems we have already successfully developed MEAM and EAM pots. The potentials development is performed using standard electronic structure methods, mainly the VASP implementation within the DFT framework, together with routines for calculating phase diagrams. VASP is a well established pseudo potential code. It should be noted that the VASP calculations are rather core time consuming because of the relatively large cells needed. MD testing and preliminary production runs will be done using LAMMPS. If time allows three additional sub-project will be carried out: 1) Activation energies and diffusion barriers for common defects in the Cu/Nb and Cu/W interface systems. 2) He will be introduced in the systems (MD potentials and MD runs). He bubble formation is one of the big concerns in future cladding materials mainly because it is the main cause of radiation induced creep and void swelling. 3) Cascade simulations to simulate radiation damage on the cladding materials. The holy grail is to understand creep and swelling. Part of the present project is part of the RADINTERFACES FP7 project.