b'an unexpected halt to preparation ofdirected research and development the AFC-4F and -G tests, but the testwas undertaken in 2020 to investigate matrix itself remains an intellectuallymethods for large scale boosted fast sound product expected to be usefulflux irradiations in ATR. This concept, in future developments. referred to as the Advanced Reactor The phase 1 AFC-IRT1 project isConcepts In Thermal-spectrum Capa-planned to end in December of 2020bility (ARCTIC), uses commercially with the prospect of a phase 2 projectavailable plate type fuel assemblies in still uncertain. Design enrichmenta flux trap, in concert with cadmium calculations and fabrication effortsneutron filtering, to achieve an were initiated to construct a handfulpredicted fast-to-thermal neutron of rodlets to be used in a potentialratio of 100:1. Multiple rods up to phase 2 irradiation (-IRT2). Thesefull length with representative linear rodlets will be notable in using sourceheating rates can be accommodated material from recycled light waterin a novel high conductivity capsule reactor fuel rather than the simulateddesign while providing opportunities compositions used in -IRT1. The -IRT2for in-reactor instrumentation. As the rodlets are expected to be fabricatedprogram looks forward to a revitaliza-prior to the end of calendar year 2020tion of resources in order to support and placed in storage with readyadvanced reactor metallic fuel devel-to irradiate status while awaitingopment, it is expected that the legacy potential commencement of a poten- of the AFC series irradiations will live tial phase 2 project. on in a new generation of test series within FAST, ARCTIC, and beyond.The successful fabrication and immi-nent irradiation of the first FAST experiments marks the beginning of a new era for small specimen capsule irradiations in ATR. As such, it is expected that the AFC series will be largely retired (with perhaps the exception of continued irradiation of the -IRT2 specimens). The diminu-tive size of FAST rodlets (~2 cm fuel), however, will be inadequate to address future data needs such as full-scale effects of fabrication process and safety performance testing in the Transient Reactor Test facility. A small project funded by laboratory 2020|AFC ACCOMPLISHMENTS 141'