Change of Thinking, Molten Salt Reactor (MSR)

A loss of coolant in a nuclear power plant using solid nuclear fuel can cause a severe nuclear accident, surpassing a design-basis accident, and may include a meltdown and subsequent steam and hydrogen explosion leading to a major release of radioactive material to the environment. A molten salt reactor (MSR), one of the six concepts for a Generation-IV non-pressurized water reactor, utilizes liquid fuel in which the coolant and nuclear fuel are integrated. The integration of the fuel and coolant is fundamentally safe from severe accidents caused by a loss of coolant. Because an MSR operates at atmospheric pressure and high temperature compared to pressurized water reactors, the reactor structure is simple and thermal efficiency is excellent. An MSR can be deployed at any scale from a small micro-reactor to a large commercial nuclear power plant. At a time when the role of nuclear power is growing dramatically more significant for achieving “2050 Carbon Neutrality”, the MSR technology draws attention due to its superior safety and efficiency as well as an expectation that can resolve the spent nuclear fuel issue. This article briefly introduces the characteristics and the R&D status of MSRs.