Uncertainties and assumptions associated with APT and SANS characterisation of irradiation damage in RPV steels

Atom probe tomography (APT) and small angle neutron scattering (SANS) have been extensively used to characterise irradiation damage in reactor pressure vessel steels. There have been some notable successes, but also some difficulties reconciling the data from these techniques. Indeed, as techniques improve, we learn more about their intrinsic limitations and the inherent assumptions used in the data analyses. In this research, some of the key uncertainties associated with the two techniques are identified and it is shown how apparently reasonable assumptions can lead to radically different conclusions. It is also demonstrated that the use of multiple techniques helps compensate for the shortcomings of individual techniques. However, uncertainties still remain, particularly in our ability to characterise matrix damage. (C) 2013 Elsevier B.V. All rights reserved.