The scientific principles behind thorium reactors have existed for many decades. In the early days of the nuclear industry there were numerous studies supporting the notion that “thorium could be used as a precursor to nuclear fuel to run electricity-generating power plants.” And yet, today 100% of U.S. nuclear power is derived by Light Water Reactors (LWRs), which use the highly radioactive and volatile element of uranium to produce power at high pressures. Looking forward, while nuclear power has generated about 20% of U.S. energy since 1990, a 2016 report from Idaho National Laboratory estimates a drop to 10% of U.S. energy generation as old LWRs are shut down, due to old age, while a combination of regulatory hurdles, cost pressures, and a lack of research prevent the development of new nuclear power generation.
And yet, despite years of stagnation in U.S. nuclear power use and projections of steep declines in its future use, the U.S. nuclear industry has been reluctant to pursue new forms of nuclear energy generation, such as thorium powered molten salt reactors (MSRs). As a result, proponents of thorium energy have had no choice but to turn to U.S. rivals to continue R&D with this technology. The potential risks to U.S. energy security and U.S. competitiveness of falling behind in next-generation nuclear power are clear; but the lack of financial support in the U.S. continues to restrict engineering projects that could lead to wide-scale development of thorium reactors.
There are numerous potential benefits to thorium based nuclear power. Thorium is far less radioactive than uranium, it produces much less waste which is also less radioactive, it is three to four times more abundant than uranium, and it is much more challenging and costly to weaponize. Thorium reactor designs are also, at least theoretically, much safer due to the fact that they cannot melt down, at least not to the extent that a LWR can, and they have the potential to be much more energy efficient than uranium reactors.
In the past, political obstructions, defense industry preferences, and regulatory hurdles may have played a role in hindering thorium energy’s development. That has resulted in a lack of long term operational experience that continues to plague the technology to this very day and makes it incredibly difficult to compete with uranium powered LWRs. However, today the main issues plaguing the technology have much more to do with the exorbitant cost of getting the technology off the ground, especially considering the numerous engineering difficulties that still need to be addressed. From an engineering perspective, thorium is more challenging to process than uranium since it melts at much higher temperatures than uranium dioxides, and, during reprocessing, thorium becomes more radioactive than uranium. From a costs perspective, R&D and large scale construction of new reactors is immensely expensive and risky. Thorium works best in Molten Salt Reactors but few of them have been produced and design modifications are still struggling to address the highly corrosive nature of sodium at high temperature.
In the face of these challenges, there has been a lack of interest from the nuclear energy industry and a lack of financial backing from investors in the U.S. for thorium energy. As a result, the U.S. Department of Energy turned to China and signed a ten year Cooperative Research and Development Agreement in 2015, that builds on a previous Memorandum of Understanding, and allows the Oak Ridge National Laboratory and the Shanghai Institute of Applied physics to work together on the development of thorium powered molten salt reactors. China has plentiful reserves of thorium and is looking to develop emissions free energy sources that can meet their growing demand for energy. Additionally, China is not constrained by regulatory hurdles, initial costs, or the political blow-back of expanding nuclear power generation. According to Oak Ridge nuclear engineer Jess Gehin, “The Chinese, being relatively new to it, need technical support…[but], if they follow through and build a test reactor, there’s a lot of useful information that we could get from that.” However, this collaboration comes with substantial risks to U.S. energy security and future U.S. competitiveness.
While there are numerous obstacles that need to be overcome, the potential benefits and the lack of alternative options for emissions free base-load electricity generation presents a strong argument for at least moderate U.S. efforts at pursuing thorium powered nuclear energy. And yet, what seems like a no brainer of potentially safer, cheaper, and cleaner energy is being resisted in the U.S. because of the financial costs, engineering challenges, and a lack of long-term thinking in the nuclear power industry. As a result, nuclear proponents have been turning to countries like China to continue the development of this promising energy technology. If the U.S. wants to protect its status as the center of technological innovation and ensure its long-term energy security it must be willing to take the lead in next generation energy technologies before countries like China get too far ahead.