b'An I-Loop will be installed so that test train extraction and instrument leads route through the top closure plug while permanent coolant plumbing will penetrate through the side of the reactor pressure vessel in existing L-flanges in a manner typical for many successful lead-out type experiments performed at ATR. The loop will be designed so that it can a variety of tests including PWR/BWR base irradiations, ramp testing, and creep testing. Ramp testing is performed by flux manipulation via a helium-3 screen or movement within the reactors flux gradient. The slight offset (~20cm offset over ~6m length) of these in-pile tubes will require thatvia overhead casks. Facility modifica- Figure 5. Investigation of I-Loops for test trains are designed with sometion to include these new I-Loops,ramp testing: project team photo.compliance to facilitate insertionhowever, is a retrofit operation with and extraction. See Figure 3 for ATRsome key mechanical constraints. The in-vessel facility layout. Test trainreactor pressure vessels existing top extraction in this fashion also permitsclosure plate will be replaced with a the transport of irradiation tests tonew plate so that eight new periph-ATRs sizeable spent fuel storage pool,eral penetrations exist in addition the adjacent dry transfer cubicle hotto the current nine for the flux traps cell, or to a variety of off-site hot-cell(see Figure 4). This closure plate is a for several options in between-cyclerelatively small part of the pressure and postirradiation examinations. vessel head (1.2m diameter) and can ATRs native facility design is heavilybe removed during the upcoming core based around the nine flux trap loopsinternal change-out (CIC), planned as manifest in existing penetrationsin 2021. This would create a rare through the pressure vessel andopportunity for this modification with shielding structures for high-pressureslight impact planned operations. plumbing and test train extraction 2019|AFC ACCOMPLISHMENTS 129'