AVS 63rd International Symposium & Exhibition
    Applied Surface Science Tuesday Sessions
       Session AS-TuP

Paper AS-TuP5
Exploring the Surface and Sub-Surface Nature of Nuclear Graphite

Tuesday, November 8, 2016, 6:30 pm, Room Hall D

Session: Applied Surface Science Division Poster Session
Presenter: Chris Moffitt, Kratos Analytical Limited
Authors: J.D.P. Counsell, Kratos Analytical Limited, UK
S.J. Coultas, Kratos Analytical Limited, UK
C.J. Blomfield, Kratos Analytical Limited, UK
C. Moffitt, Kratos Analytical Limited
A. Theodosiou, University of Manchester
Correspondent: Click to Email
Graphite is a key material used in the current generation of UK nuclear reactors. Graphite has been recognised as an excellent neutron moderator and reflector in reactors, allowing sustainable, controlled fission. Contaminants in moderator rods are a major problem as they can act as neutron absorbers. This causes decreased fission and production of unwanted isotopes – a common cause of radioactive waste. The goal of this study is to understand the surface chemistry of graphites used in the UK nuclear industry today.

The surface compositions of Pile grade A (PGA) and Gliso coke graphites are determined using X-ray photoelectron spectroscopy (XPS). The results are compared to commercially available highly-ordered pyrolytic graphite (HOPG). The degree of sp2/sp3 character is determined for each graphite using Auger parameter analysis. Significant variation in sp2 character was observed between graphites. Depth profiling of the surface was performed utilising both monatomic Ar+ ions and cluster Arn+ ions. The mechanics of cluster/monatomic ion bombardment are discussed with respect to surface damage and a suitable method for graphite bulk analysis is proposed.