Approaching the Development of a Universal Molten Salt Fast Reactor for Worldwide Destruction of High-Level Nuclear Waste

Abstract

Earlier work has demonstrated that the molten salt nuclear reactor in all its various forms appears to be the most suitable system for general worldwide use. To a large extent, this arises from its natural outstanding safety characteristics. Prominent among these is the high negative coefficient of reactivity which arises not only from thermal expansion of the effectively near incompressible nature of the fuel-coolant itself but from the exceedingly useful characteristic that gaseous fission products are voided immediately in the fuel-coolant to give an immediate strong negative feedback effect in reactor control. The future seems clear to embark on a massive expansion of nuclear fission using this improved technology. One purpose of this is to give us our main energy source, which is electrical power, generated from a basic source which can, if necessary, exclude the use of fossil fuels completely and thus avoid further adverse effects on our climate. The scientific evidence is more than just suggestive that the world is getting far too close to a dangerous runaway form of GHG emission which could send our civilisation back to the Stone Age. Yet major manufacturing nations such as Japan and Germany are seriously considering a return to using fossil fuels instead of nuclear fission. Japan has experienced the reality of Fukushima and Germany, equally conscious of the safety of its densely populated nation, is well aware of the risks of reactors which use water in the reactor core. Added to this is the need to have technology for reprocessing spent nuclear fuel safely. Pyroprocessing of spent fuel has shown much promise and is ideal for eliminating long-lived actinide nuclear waste in a fast neutron spectrum molten salt reactor. The problem is one of choice, namely that any fast reactor can destroy long-lived nuclear waste and the greater experience we have with lead-bismuth fast reactors suggests that in some ways this is the more attractive approach to use in fuel reprocessing. It is recommended that the lead cooled fast reactor may be preferable initially until more experience, particularly with pyroprocessing, is gained with molten salt reactors.