Large and Small Scale Materials Testing of HT-9 Irradiated in the STIP Irradiation Program

The Fuel Cycle R&D (FCRD) initiative is investigating methods of burning minor actinides in a transmutation fuel. To achieve this goal, the fast reactor core materials must withstand very high doses. Small scale materials testing methods in addition to large scale materials testing allows one to gain more insight by providing more data on the same sample while being able to probe areas of interest which are not accessible otherwise. Furthermore, the sample volumes were so small that the tests could be considered a non destructive test since the amount of material needed is so small that a macroscopic structure would not be affected. Tensile testing, micro hardness testing and micro compression testing on focused ion beam (FIB) microscope manufactured pillars were performed on remaining parts of tensile test specimens tested and irradiated in the Spallation Target Irradiation Program (STIP). It is shown that the increases of yield strength measured by tensile testing, micro compression testing and micro hardness testing all showed the same trend. In addition FIB based techniques also allowed fabrication of LEAP samples of such a small size that their residual activity was below detectable levels thus allowing them to be handled and analyzed in a manner comparable to inactive specimens.