Spin Polarized LiD and 3He injector development at ORNL for a SPF test on the DIII-D National Fusion Facility*

The goal of the spin polarized fusion (SPF) program is to measure the lifetime of spin polarized nuclei (D, 3He)  in the DIII-D tokamak.  Polarized D-T fuel for a fusion reactor is attractive because it could approximately double the fusion power (compared to ordinary, unpolarized nuclei in D-T power plants), while significantly reducing the required tritium inventory.  This project is a collaboration between Thomas Jefferson Laboratory (JLab), University of Virginia (UVa), ORNL, and the University of California Irvine (UCI). Producing polarized deuterium pellets is JLab’s responsibility, polarized 3He shell pellets are UVa’s responsibility, and injecting the polarized pellets is ORNL’s responsibility. UCI’s role is project coordination, plasma scenario development, and polarization detection.  Gas gun injectors for both LiD pellets, where the D is polarized, and polarized 3He in an inertial confinement fusion shell are being developed for this project.  The LiD injector and injection line must be maintained as close to 4 K temperature as possible and  in a 20 mT magnetic field.  The 3He injector must be maintained at 77K and similar magnetic field.  Here we describe the  injector development and the prototype injector designs thus far achieved and requirements for installation of the two injectors on DIII-D.