Thermal-Structural and Shock Event Evaluations of the Fueling Pellet Injection System for ITER

Abstract The United States is among seven partner nations in a collaborative effort to design, build, and demonstrate fusion’s ability to become a large-scale carbon-free energy source. Each country has its own domestic agencies that contribute directly to the ITER project. US ITER, which is a US Department of Energy Office of Science project managed by Oak Ridge National Laboratory, is developing world-class engineering solutions to the design, construction, and assembly of the burning plasma experiment that can demonstrate the scientific and technological feasibility of fusion. US ITER’s scope includes completing the preliminary and final design, qualifying materials and processes for manufacture and testing, executing manufacturing, and delivering the fueling pellet injection system (FPIS) to the ITER site for assembly. The US-ITER FPIS system is designed to inject cryogenically frozen pellets of deuterium-tritium into the plasma. The FPIS has two main functions: (1) providing a steady supply of deuterium and tritium fuel and (2) mitigating the impact of edge localized modes on the plasma-facing components. The FPIS will have the capability to reside in three port cells within a tritium second barrier containment cask. Each pellet cask contains three flight tubes linking with penetrations on the torus cryopump housing and vacuum vessel: two for the magnetic high-field side pellet injection and one for the magnetic low-field side pellet injection. This paper presents the results of the thermal-structural analyses of the FPIS flight tube structural components when subjected to various loads such as electromagnetic loads; nuclear heating; and seismic, operational, and dynamic shock events. The resulting temperatures and stresses under combined conditions satisfied the design criteria to ensure the safe and reliable operation of the FPIS flight tubes within the vacuum vessel.