2018 | AFC ACCOMPLISHMENTS 160 TheTransient ReactorTest (TREAT) Fuel SafetyTesting for Advanced Reactors has continued with efforts in developing fuel safety research plan for advanced metal fuel alloy experiments, design separate effects tests to study metal fuel behavior, and advanced reactor irradiation capability designs, specifically working onTemperature Heat-sink Overpower Response module (THOR) and a metals fuel loop design. Project Description: The objective of theTREAT Fuel Safety Testing for Advanced Reactors is to develop and qualify metal fuels with improved performance, reliability, and safety characteristics during normal operations, accident conditions and with reduced waste generation.The goal of fuel development for advanced fast reactors is to create a nuclear fuel system that performs at high burnup while supporting the use of recycled actinides. Nuclear Science and Technology (NS&T) transient testing program has worked on research and development of a metals fuel test plan that can be used in the following years as a guidance document for future metal fuels transient experiments to help improve and qualify metal fuels.The transient testing program developed metal fuels separate effects tests inTREAT.The separate effects tests Fuel Safety Testing – TREAT (AR) Principal Investigator: Dan Wachs Collaborator:Todd Pavey designs concentrated on irradiation impacted phase diagram and annular fuel stability under overpower conditions.The transient testing program is working on conceptual design ofTHOR for separate effects testing in the future.The MK III sodium test loop that was used in past transient experiments prior to 1994 is being redesigned for future metals fuels transient testing.The NS&T transient testing program is working on a conceptual design of a metal fuels test loop. Accomplishments: Metallic fuel is a mature technology with a sufficient performance database to support licensing technology within the bounds of the existing database.The primary objective of this program is to reconnect to historical knowledgebase, maintain, and develop the technical basis for metallic fuel performance in off-normal conditions.These objectives may also provide crosscutting Research and Development (R&D) capabilities and expertise to support R&D needs of oxide fuel of interest to many in the international community. A presentation titled, "New Generation ofTransientTesting for SFR Fuels at TREAT," was presented at the American Nuclear Society (ANS) meeting in June 2018 by Colby Jensen.