An advanced materials irradiation facility for materials and fuels irradiations at the high flux isotope reactor

The Materials Irradiation Facility (MIF) at the High-Flux Isotope Reactor (HFIR) of Oak Ridge National Laboratory (ORNL) is one of the two experimental platforms in the US that can host fully instrumented and monitored experiments in a high-neutron-flux environment. The unique advantage of instrumented capsules is that the researcher can monitor and acquire in situ data and change capsule operating conditions in real time during the irradiation. This also enables measurement of a variety of material properties, such as conductivity, fission product composition, etc., that otherwise would only be available upon post irradiation examination where nonequilibrium conditions brought upon by irradiation do not exist. Recently ORNL funded a Laboratory-Directed Research and Development (LDRD) project to strategically enhance the capabilities of this facility and provide researchers with a more flexible experimental platform. MIF improvements include an updated and more sophisticated experiment monitoring system, a modular design allowing easier addition of simultaneous experiments, and features that allow rapid incorporation of additional instrumentation. This paper introduces the MIF and discusses the features that make the MIF attractive for new material irradiation experiments. At the heart of the facility is the gas supply system that is used to control experiment temperature during irradiation. Historically, the gas supply and associated control logic were specific to each experiment, thus requiring a redesign for each experimental program and increasing time and experiment cost. The current system has a gas delivery system that is both modular and re-configurable. The need to redesign the instrumentation and control (I&C) system and build specific hardware for each experiment is avoided by incorporating software-reconfigurable control modules. The paper highlights MIF and HFIR irradiation capabilities and provides a synopsis of the facility, emphasizing new MIF scientific capabilities to make challenging irradiation measurements that support national and international fission and fusion energy programs.