Super X Diverters for Solving Heat Flux and Neutron Shielding Problems of Magnetic Fusion Plasma Devices

Physical Sciences : Physics

Available for licensing


  • Michael Kotschenreuther, Ph.D. , Institute for Fusion Studies
  • Swadesh Mahajan, Ph.D. , Institute for Fusion Studies
  • Prashant Valanju, Ph.D. , Institute for Fusion Studies

Background/unmet need

With the onset of global warming, economical de-carbonization of energy sources is becoming an urgent need. Given the known limitations of renewable sources, nuclear fission is the leading mature technology that can be ramped up fast enough to replace steady power from coal. However, so far there is no socially accepted solution to the nuclear waste problem. New methods to destroy the most biohazardous long-lived nuclear waste fully, economically, and rapidly can revitalize the large nuclear energy market.

Invention Description

Research at The University of Texas at Austin has yielded a series of inventions that can solve the nuclear waste problem. These have enabled designs of optimal nuclear fuel cycles combining existing light water reactors with new fusion-fission hybrid reactors. This allows a small number (six) of hybrids to burn the waste of many (100) fission reactors, reducing the total system cost to less than the cost of storage.

Such high support ratios (much smaller than fission-only systems using critical fast-spectrum reactors (FR)) are possible only because at the core of the hybrid sits the powerful Compact Fusion Neutron Source (CFNS) made possible by the Super-X Divertor (SXD). The SXD allows safe handling of the extreme heat and neutron fluxes in the small removable CFNS module. The large flux of neutrons from the CFNS will allow a sub-critical fast-spectrum fission assembly to safely and rapidly burn 99% of the most difficult-to-burn transuranic isotopes. The modularity of the CFNS allows designing it mostly with existing technology because it can be replaced every two years. This reduces projected development times and cost.


  • The large support ratio (about one hybrid per 15 nuclear reactors) reduces system cost below fission-only systems—either storing the waste or waste destruction with fast reactors.
  • The huge flux of neutrons from the hybrid allows reduces the time needed to destroy 99% of the most biohazardous transuranic nuclear waste from centuries (with FR) to decades.
  • Requirements of geological repositories to safely store nuclear waste are reduced by 100 times.
  • The SXD allows much higher fusion power density in the core plasma than any other method.
  • The SXD is also a major advance towards developing fusion-only power reactors.


    The small size and modularity of the CFNS enormously improves reliability while reducing more R&D time and cost than all its competing technologies (other fusion sources like ITER, other non-fission sources of neutrons such as accelerator-based spallation neutron source, and purely fission based techniques using both thermal and fast reactors).

Market potential/applications

The SXD may be necessary and sufficient for most economic applications of magnetic fusion devices. The CFNS can be used in a broad range of strong neutron source applications, including fusion-fission Hybrids for destroying nuclear waste, breeding nuclear reactor fuel, etc.

IP Status