Fusion Technologies for Tritium - Suppressed D - D Fusion

The proposal for tritium-suppressed D-D fusion and the understanding of the turbulent pinch in magnetically confined plasma are new developments in fusion science that create an alternate and potentially advantageous technology pathway. Tritiumsuppressed D-D fusion eliminates the need to breed fuel from lithium, reduces the damage from 14 MeV neutrons, and allows structural materials now qualified for fission systems to be used for fusion. The turbulent pinch gives scientists the ability to design magnetic confinement systems that control the direction of the turbulent particle and heat flux. In a levitated dipole, plasma profiles become highly peaked, and plasma energy confinement can significantly exceed particle confinement. Additionally, because a levitated dipole confines plasma at near unity beta, in steady-state, and without toroidal magnetic field coils, large plasma confinement volume does not incur high system cost. Experiments and simulations indicate that the levitated dipole can meet the physics requirements for tritium-suppressed D-D fusion, and the reduced neutron heating from advanced fuels makes plausible the technology of self-powered cryogenic cooling of an internal superconducting coil. However, tritium-suppressed fusion in general and the levitated dipole fusion concept in particular require the development of high-field, highstrength, and high-temperature superconductors that exceed the performance of today’s Nb3Sn superconductors. Because the technology pathway for tritium-suppressed D-D fusion is different from the pathway for steady-state D-T/Li fusion power and because the pursuit of multiple technology pathways enhances the likelihood of successful fusion energy development, our nation’s strategy for fusion technology development should include research that advances high-field, high-strength superconducting magnet technology and continues the exploration of fusion based on the tritium-suppressed D-D fuel cycle.