Nuclear power plants—which emit zero greenhouse gas emissions and have very low emissions during their entire lifecycle—can contribute significantly to addressing climate change. However, many reactors have been retired, with more to follow. In many cases, these reactors are being supplanted by natural gas, which can result in a large increase in greenhouse gas emissions, especially when methane leakage is taken into account. As the Union of Concerned Scientists recently concluded, “the resulting emissions set back national efforts to achieve needed emissions reductions.” Many energy experts believe that a commitment to thorium-based nuclear reactors might help to turn the tide for nuclear over the course of the next couple of decades.
Thorium reactors could provide a number of benefits over current reactors, which might help substantially enhance the viability of nuclear energy production in the United States. Thorium reactors generate significantly less radioactive waste. Separated uranium can be reused, rendering the reactors self-sufficient. Liquid fluoride thorium reactors, a type of molten salt reactor, would be significantly safer than current reactors, including creating a significantly safer working environment for operators. Leftover radioactive waste also can’t be used to create nuclear weapons. Finally, fuel costs would be significantly cheaper than solid-fuel reactors.
Thorium can be used as a nuclear fuel in a number of different reactors, including many that have already entered into operation, such as heavy water reactors, high-temperature gas-cooled reactors, and boiling light water reactors. However, many nuclear energy proponents believe that the greatest prospects may be for molten salt reactors, which are still in the design stage but are well-suited for using thorium as a fuel.
However, significant challenges remain in the deployment of thorium-based reactors, especially advanced systems using molten salt. This includes the development of post-processing chemical facilities to separate uranium from molten salts for re-use, and capital to purchase highly-enriched uranium to start reactors. It has been estimated that an investment of approximately $5 billion could produce a viable reactor solution in the United States over the next five years.