Atomistic Scale Study of Radiation Effects in ABO3 Perovskites

Lead Research Organisation: University of Oxford
Department Name: Materials

Abstract

Summary
The development of nuclear power is at an important juncture, with two competing but in many ways complementary technologies: fusion and fission. However, while the nuclear methodology is different the engineering challenge is the same, that is, the need to remove the generated heat while structures are subject to high levels of radiation damage and residual nuclear products. In particular, radiation damage effects and gas bubble formation are problematic issues for the development of both fusion and GenIV fission reactors. For example in a GenIV fission core, the Xe and Kr gas comes from fission of the fissile nuclei, that is, Pu and U, while in a fusion core He is formed within the D-T plasma. This proposal aims to address these issues using tunable perovskites, as model materials, and focusing on the following issues:

1. Crystalline to amorphous transformation mechanisms in tunable ceramics instigated using non-radioactive ion beams.
2. Bubble nucleation at micro-structural traps in predominantly fission reactor materials, e.g. oxide based fuels, and ODS materials, but which can be formed by He implantation from fusion plasma He nucleation, and damage in materials for use in fusion cores, such as YBCO superconductors suggested as magnetic containment in for example, ITER and DEMO.

The research will be undertaken using the approach of experimental and simulation techniques combined holistically. The experimental study will utilise in-situ and bulk irradiation, primarily in combination with advanced electron microscopy and atom probe tomography. The complementary simulation programme will be based on irradiated materials, but focusing on recovery mechanisms, bubble evolution, and validation of current models.

The outcomes of the research will be used in the development of new materials for use as both fuels, for example Inert Matrix, or as magnetic containment devices in ITER/DEMO. The information from this research can also be utilised in other non-standard reactor technologies such as the travelling wave designs.

The information derived will also help the design of future waste forms for Pu/U, specifically into new phases capable of tolerating the effects of radiation damage, and He bubble formation.

Publications

10 25 50
 
Description The project has advanced techniques for the multi-scale characterisation of perovskite materials.
Methods for atomic-scale visualisation based on high resolution electron microscopy and atom probe tomography have been developed.
In the case of atom probe tomography, the yield of successful experiments was very low, and so new specimen preparation methodologies were developed.
Furthermore, the experimental parameters were found to have significant effect on the final measurements. The work undertaken in this project sheds new light on how the way the experiment is applied is affecting the results, and enables optimisation of the analysis and ultimately shows that these materials can be characterised at the nanoscale with a high degree of confidence.
Exploitation Route The project has made significant inroads into the characterisation of these materials.
Rigorous experimental methodologies have been developed and presented, along with further understanding to interpret the results.
The project has put these methodolgies in place such that other researchers can now implement these approaches directly.
Further, development will enable analysis of peroskite materials for a broad range of applications.
In particular it will underpin atomic scale investigation of radiation damage in these materials and their applicability as a waste-form for active nuclear materials.
This is of interest to those working in the Energy and Defence sectors in the UK, where there is an increasing emphasis on nuclear energy and the safe and responsible management of waste.
Sectors Aerospace, Defence and Marine,Energy

 
Description ORNL Center for Nanophase Materials Sciences User Program
Amount £79,224 (GBP)
Funding ID CNMS2015-093 
Organisation U.S. Department of Energy 
Sector Public
Country United States
Start 01/2015 
End 12/2015
 
Title Access to Advanced Analytical TEM facility for CLTO 
Description Dr. Danaie has led efforts to successfully apply for access time to a new JEOL 200-ARM instrument based at Oxford, which is part of a multi-institution facility. With this, he had been able to identify microstructural segegation and details of ordering within perovskite structures, which would be difficult to obtain using any other TEM facilities. 
Type Of Material Improvements to research infrastructure 
Provided To Others? No  
Impact This work is currently being drafted for publication. 
 
Title Coating of Atom Probe Tomography samples for increasing yield during analysis 
Description Dr. Pedrazzini spent a research visit at Cameca, Madison, where she worked on using novel metal/oxide coatings around her perovskite samples to explore ways of improving the yield during analysis of her brittle samples. This work confirmed that there is a very strong depedence of success on perovskite type, which was previously unknown. 
Type Of Material Improvements to research infrastructure 
Provided To Others? No  
Impact Cameca now advise at global meetings on which perovskite materials are not suitable for APT analysis at present (SrTiO3), and this work has provided new insights into how best to apply protective coatings on all APT samples 
 
Title Optimisation of APT running conditions for YBCO 
Description The accurate measurement of chemistries by Atom Probe Tomography is vital to ensure data can be relied upon to interpret irradiation damage. We have explored a full range of operation parameters for the analysis of (un-irradiated) Yttrium Barium Copper Oxide, and hae found what we believe is the most accurate measurement of this composition to date. 
Type Of Material Improvements to research infrastructure 
Provided To Others? No  
Impact This work is currently being drafted for publication. 
 
Description Dr. Edmondson relocation 
Organisation Oak Ridge National Laboratory
Country United States 
Sector Public 
PI Contribution Dr Philip Edmondson has taken up a staff position at Oak Ridge National Laboratory. This will boost the project by offering access to the LEAP 4000 instrument based there, which offers an alternative facility to examine perovksite materials by Atom Probe Tomography
Collaborator Contribution n/a
Impact n/a
Start Year 2014
 
Description UNIQ Summer School 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact This UNIQ Materials Science course is an opportunity for students to experience a subject that is not offered at A-Level but uses concepts across a broad spectrum of subjects from maths to chemistry to engineering to even biology. The aim of the course is to give brief insight into this unique subject, and to break down those conventional physics, chemistry, maths subject separations.

Lectures include topics such as molecular modelling, photovoltaic cells and materials for nuclear fusion, then move onto a more practical element in the afternoons, where students get to experience making your own solar cells and running mechanical property tests - sometimes with open ended investigation. There is also a tutorial session in groups of 3 to give students the full "Oxford experience", giving you them the chance to converse with experts in their field. A few tips on interviews can be picked up during the mock interview session later in the week.

UNIQ is a free summer school. Most of the students that were selected to attend the school meet one or both conditions of being from a disadvantaged socio-economic background and/or from a neighbourhood with low participation in higher education. A number of the students who attended the school ultimately applied to study Materials Sceince at Oxford
Year(s) Of Engagement Activity 2015
URL http://www.uniq.ox.ac.uk/content/materials-science-0
 
Description Women in Science Workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact SP delivered presentations at two "Women in Science Workshops".
The workshops were aimed at female final year school students, interested in studying science at university.
The day included advice on the Oxford admissions process, a Q&A session with current female science undergraduates, and seminars and talks from
lecturers.
Year(s) Of Engagement Activity 2015,2016