Recent Progress in Heavy Ion Inertial Fusion

It proved challenging to achieve ignition and gain at the National Ignition Facility. Sufficient gain for commercial power production has not yet been demonstrated. Consequently many laser fusion researchers are placing increased emphasis on options such as direct drive and fast ignition. But those concepts have not been experimentally validated at the scale needed for commercial power production.

Heavy ion accelerators can have very high efficiency and their cost scales favorably with increasing driver energy. In this paper we report progress showing that, for heavy ion fusion, indirect drive remains an attractive option. Specifically we design heavy ion fusion power plants by varying a large number of parameters that describe the power plant to minimize the cost of electricity. These variables include total driver energy, ion kinetic energy, number of beams, etc. By readjusting the variables we find that the cost of electricity is quite insensitive to rather large uncertainties in target gain and target fabrication costs — particularly at plant capacities > 1 GWe. We emphasize that this research does not preclude the use of of untested options such as direct drive and fast ignition. But they do not appear to be necessary.

We have also explored a number of options to achieve good economics at smaller plant size and capacity. We will discuss these options.