2017 | AFC ACCOMPLISHMENTS 172 Figure 1. Depth profile of carbon concentration in unirradiated HT-9, HT-9 irradiated to 100, and to 280 dpa at 400°C. Accelerator-based ion beam irradiation techniques have been used to study radiation effects in materials for decades.The popularity of this technique was initially quite high due to the ease and speed of performing irradiations. However, popularity eventually waned as many people cast doubt on its effectiveness for assessing neutron irradiation effects. However, in recent years as access to neutron irradiation facilities capable of providing high dose has greatly diminished, and recent advanced reactor concepts have called for very high burnup fuels, a need for ion irradiations has grown. To make best use of this technique, the Advanced Fuels Campaign (AFC) is carefully examining and altering ion irradiation techniques to improve their ability to provide useful irradiation effects information. Presented here are two recent insights into the ion irradia- tion method and consequent changes to the method. Advances in the Effective Use of Ion Irradiations for Core Materials Research Principal Investigator: Mychailo Toloczko, PNNL Collaborators: Jing Wang, PNNL