Molten salt reactor

                In my last couple blogs, I have wrote about three different nuclear reactor designs. In this blog post, I will be writing about another. This next reactor design is the liquid fluoride thorium molten salt reactor. This means that the fuel or coolant (or both) is in the form of a molten salt, allowing it to run at higher operating temperatures for better thermodynamic efficiency. I will compare this design to current reactors in the three ways that I have compared the others in my previous blogs.

                The first concern for most people when they hear about a new nuclear reactor design is how safe it is. This reactor would have some easy safety features, one of which is a freeze plug. A freeze plug is a plug in a pipe that is cooled to freezing of the salt by an electric fan or pump that would stop functioning in the event of a power failure. The plug would also melt if the reactor got too hot from loss of coolant or control malfunction. When the plug melts, it would allow the entire contents of the fuel salt into emergency tanks that would stop the reaction and cool the fuel, stopping the meltdown. In this reactor, thorium-232 absorbs a neutron and turns into uranium-233 which is hit by another neutron, causing it to split and give off large amounts of heat and two or three neutrons that continue the process. One concern risen in regard to this cycle is the possibility of using such a reactor to produce uranium-233 for use in nuclear weapons. This is a real concern, as it would be easier to make a nuclear weapon out of this reactor than conventional reactors.

                The second main concern is the production of nuclear wastes. This is not as much of a problem with this type of reactor, but would still be a problem, as it still produces nuclear waste, just not as much. This type of reactor can be configured to be a “waste-burner”. This would be run with a combination of thorium and nuclear waste as the fuel. Thorium produces much less of the long-lived and problematic wastes than conventional reactors. This results in the reactor consuming more nuclear waste than it produces.

                The last major concern is the fuel for the reactor. As I have wrote in a previous blog post, Thorium, the main fuel for this reactor, is hundreds of times as abundant as useable uranium. This reactor can have other things added to the fuel to replace some of the thorium. Some of the thorium can be replaced with nuclear waste as stated above, and if we run out of nuclear waste, it can also use depleted uranium to replace some of the thorium. One fuel related problem is that it would need a considerable amount high grade fuel to start it every time it is shut down for maintenance. Overall, in my opinion, this choice is superior to the accelerator driven subcritical reactor, but only for a couple more years, as accelerator technology is improving rapidly to make more energy efficient accelerators.