Micromechanical modelling of irradiation creep in novel steels for nuclear fusion

Project ID: 2228cd1305 (You will need this ID for your application)

UCL Lead department: Mechanical Engineering

Project Summary:

The realisation of nuclear fusion is seen as ultimate solution for sustainable energy production. UK’s Tokamak (STEP) is the leading contender to deliver a prototype power plant by 2040 but key material-related challenges must be addressed for economically viable and safe deployment. For structural steels used in tritium breeding blankets, stress-induced dimensional changes intensified by mobile radiation-induced defects also called irradiation creep- are the main factors defining their maximum allowable operating conditions. Therefore, having quantitative understanding of irradiation creep, via predictive computational models, is needed to design and optimise new alloys and define accurate material lifing models for enhanced component design.

This project will combine novel computational and experimental activities to define a new multi-scale model for irradiation creep in advanced nuclear steels for fusion. The project will be in collaboration with the UK Atomic Energy Authority (UKAEA). They run the national fusion energy research programme with the aim of positioning the UK as a leader in sustainable nuclear energy. The PI has produced several original results that form the basis of a unified model for creep and further work is required to expand the models to in-service conditions relevant to fusion. Main activities to be conducted by the student include: 1) development of constitutive models describing nano-structural mechanisms during creep with and without-irradiation; 2) combine the constitutive models with Finite-element-based micromechanical simulations to address key micro-structural features necessary to predict creep in complex steels; 3) creep testing -in conjunction with the UKAEA- of irradiation and radiation-free test pieces to validate the models; 4) use advanced material characterisation methods based on Electron Microscopy to study material changes occurring during creep and feed back into the models. The results will help the UKAEA and other fusion companies define guidelines for steel optimisation against irradiation creep for improved in-service performance.