Conceptual Design Report for the Xe-6/7/8 Experiment in the NE Flux Trap

X energy, LLC has initiated conceptual design of a high-temperature, pebble-bed reactor and requested that Idaho National Laboratory evaluate the feasibility of irradiating several fuel pebbles in the Advanced Test Reactor. The proposed fuel for the X energy reactor utilizes the same tristructural-isotropic coated fuel particles as are used in the Department of Energy-sponsored Advanced Gas Reactor (AGR) fuel tests, which have been irradiated in the ATR since 2006. The X energy test has been denoted XE 6/7/8 based on nomenclature from the AGR fuel-test series. Three tests will be combined into one test train: XE 6 constitutes the fuel qualification test, whose aim is to demonstrate fuel performance at the upper end of prototypical reactor conditions; XE 7 is designated a "margin test," and its purpose is to demonstrate fuel integrity at conditions substantially beyond reactor operating conditions; and XE 8 incorporates designed-to-fail particles in order to release fission products and help validate fission product release codes. The XE series of experiments would consist of multiple separate capsules that would be irradiated simultaneously. Each capsule would have its own inert sweep-gas atmosphere with individual on line temperature monitoring. The sweep-gas effluent from each capsule would also have online fission product monitoring to track performance of the fuel in each individual capsule during irradiation.