Leslie Dewan and Mark Massie are Ph.D. students in nuclear engineering at MIT. For most of their peers, the options upon graduating are pretty simple: teach, or work for one of the national labs. Dewan and Massie, though, decided on an unconventional path: like a couple of Stanford grads, they’ve formed a start-up. Incorporated in 2011, it’s called Transatomic Power, and its mission is to transform the nuclear power industry.
Transatomic’s product is called a “Waste Annihilating Molten Salt Reactor.” If you’ve read my book, SuperFuel, you’ll recognize it as an update on an old reactor technology that was pioneered at Oak Ridge National Laboratory, in the 1950s and 60s. SuperFuel focused on another type of molten salt reactor, a Liquid Fluoride Thorium Reactor, or LFTR. Dewan and Massie’s design is fuel-agnostic in the sense that it can run on either uranium or thorium; as the name implies, its signal feature is that it can consume spent fuel from conventional light-water reactors. Transatomic joins a growing list of start-ups, including Flibe Energy, that are trying to revolutionize nuclear power by bringing back alternative fuels, including thorium, and alternative reactor designs.
(A quick note on the uranium fuel cycle: Most uranium in the ground is the isotope uranium-238 (U238), which is not fissile, and thus is no good for producing power. Conventional reactors require fuel in which the percentage of the isotope U235 has been enriched up to 3% to 5%, or “reactor-grade” uranium. Uranium that is enriched to around 20% U235 is weapons-grade. That’s why it’s a relatively easy step for countries with enrichment capability, like Iran, to build nuclear weapons programs. Thorium requires no enrichment.)
‘A Leapfrog Move’
“Nuclear power is in a cul de sac,” Russ Wilcox, the CEO and co-founder of Transatomic, told me in a phone interview. “The nuclear industry knows it’s in trouble, it’s not quite sure what to do, and it’s just trying to survive for the moment. It’s a fabulous time to do a leapfrog move.”
Wilcox was one of the founders of E Ink, which commercialized electronic paper materials originally developed at MIT’s Media Lab and ended up licensing the technology to Amazon, for the Kindle, to Barnes & Noble’s Nook, and so on. (Wilcox also points out that the ink for E Ink-based readers continues to be made at a state-of-the-art facility in Boston that employs around 100 skilled workers.) E Ink was sold to Taiwanese company Prime View for nearly half a billion dollars in 2009. Transatomic’s plan is to build a prototype reactor in 5 years, commercialize the technology in 15 years, and have reactors come online by around 2030. The company doesn’t plan to build and operate nuclear power plants, but to license its reactor technology.
Molten salt reactors (MSRs) can achieve much higher burn-up factors than conventional uranium reactors. In other words, while conventional reactors harness only around 3% of the available energy in a given volume of uranium, MSRs can capture much higher percentages – up to 98%, according to Transatomic (I should note that the nuclear experts I consulted for SuperFuel believe that burn-up factors of 50% are more realistic). Beyond that, the company is not releasing details of its patented reactor technology.
Liquid-fuel reactors, such as MSRs, also offer inherent safety advantages: because the fuel is liquid, it expands when heated, thus slowing the rate of nuclear reactions and making the reactor self-governing. Also, they’re built like bathtubs, with a drain in the bottom that’s blocked by a “freeze plug.” If anything goes wrong, the freeze plug melts and the reactor core drains in to a shielded underground container. Essentially, if Transatomic’s design works as advertised, MSRs could solve the two problems that have bedeviled the nuclear power industry: safety and waste.
Noting that China plans to build a liquid-fuel reactor (likely powered by thorium) within 5 years, Wilcox says that he and Dewan and Massie – currently the entire staff of Transatomic – would prefer to build the prototype MSR in the United States, but will consider another country if the licensing or financing proves too difficult here. (The Nuclear Regulatory Commission recently licensed a two-reactor nuclear plant in Georgia, the first new reactors to be licensed in this country since 1978. The reactors are conventional light-water uranium powered models.)
In SuperFuel I noted that the nuclear power industry has a generational problem: most of the leading executives in the industry are now in their 60s. It will take a new generation of scientists and technologists to spark a revival in nuclear power technology. Transatomic Power is an encouraging sign that this is beginning to happen.