b'for longer and multiple fuel pins. This large experiment capability is an important progression in the transient testing experiment program that is necessary for the forthcoming NASA hydrogen loop and NatriumTM sodium loop testing. The capability is designed with backward compatibility for existing (small) BUSTER test devices such as SERTTA and Temperature Heat Sink Overpower Response.The TWIST capsule is also designed with hot cell integration in mind and design efforts are already underway to support testing previously irradiated fuels, with preliminary design for High-burnup Experiments in Reactivity Initiated Accidents (HERA)-High Burnup (HBu) and LOCA-HBu experiments. Pre-irradiated experiments are assembled in the Hot Fuel Examina-tion Facility (HFEF). Additionally, design efforts continue towards developing remote handling capability in HFEF for the TWIST capsule to allow for assembly of pre-irradiated experiments.Accomplishments: The TWIST capsule final design was completed in February 2023. North Holmes Laboratory completed fabri-cation of the first TWIST capsule components meeting a level three milestone in May 2023. The TWIST capsule assembly completed allFigure 1. First assembly of the TWIST test device for LOC-C-1 tested in Sept. 2023non-radioactive material assembly 2023|AFC ACCOMPLISHMENTS 201'