Here is a nice presentation on an advanced fission reactor concept that is 1) Accelerator driven (for makeup neutrons) 2) Subcritical 3) Uses natural uranium (un-enriched) as a molten salt 4) Can remediate its own waste
http://www.ornl.gov/sci/nuclear_science_technology/nstip/presentation/Pierso n_seminar.pdf Biggest problem is the cost - especially the cost of accelerator beam line - which adds at least one billion $ to the overhead. Query: is there a place for LENR here ? How can that be? you ask . after all, LENR provides few neutrons . . well here is one way. Use LENR techniques only to make the "clusters" - then turn everything back over to the mainstream. That would be assuming the reality of "deuterium clusters", of course, and the known fact that the Arata powder is ferromagnetic. Combine it all with known science, and a new kind of low cost beam line can be imagined. This would be one where "loaded" nanoparticles are suspended in a permanent magnet field, and then accelerated by a travelling magnetic wave. Target can be depleted uranium. The threshold for neutrons here is only a few MeV compared to the GeV needed for efficient proton spallation. This "powder pusher" kind of accelerator is not all that different from the concept of the Bae Institute (Dr. Young K. Bae) and Winterberg for "micro-fusion". That concept was envisioned to employ acceleration of nanoparticles by an undisclosed hypervelocity method (v > 100 km/s) for fusion. How they push "powder" to that velocity is not clear but apparently it has been done by a magnetic traveling wave or some kind ... It is actually low velocity compared to gigavolt proton beams, which are near lightspeed. The tradeoff is much higher density "particles" being accelerated to a lower velocity, but the net energy deposited in the target can be similar - and the cost of neutrons should be far less. That remains to be demonstrated. This powder-pusher beam actually makes more sense for fission than fusion, since all you need for makeup neutrons is a few grams per year. Even a subcritical reactor has a high neutron multiplication factor, but the safety feature is the big selling point. Turn off the accelerator and the reactions quickly stops. That feature is priceless. What nextgen fission needs first is a 90% reduction in the makeup neutron source. Jones
