Nuclear reactor startup Transatomic Power is shutting down operations, after deciding it doesn’t see a viable path to bringing its molten salt reactor designs to scale. 

But the startup still wants its technology to play a role in the future of advanced nuclear reactors — so it’s making it all public. 

In a Tuesday announcement, Leslie Dewan, Transatomic’s CEO and co-founder, wrote, “We haven’t been able to scale up the company rapidly enough to build our reactor in a reasonable timeframe. It is therefore with a heavy heart that I must announce that Transatomic is suspending operations.”

Dewan also announced that the Cambridge, Mass.-based company will be “open-sourcing our intellectual property, making it available for any researchers — private, public or nonprofit — who want to continue the work we’ve started.” 

Transatomic is in discussions with the Department of Energy’s Gateway for Accelerated Innovation in Nuclear (GAIN) initiative to open its work to the public domain, Dewan said in a Tuesday interview. This will include the work it’s done with DOE’s national laboratories, as well as the patents on its zirconium hydride-based molten salt reactors. “We’re going to be working with the Department of Energy to make sure we’re complying with export controls for all of this,” she noted. 

Transatomic is also releasing its patents in the European Union, Russia and China for its particular version of liquid-fueled reactor designs, she said. “We’re going to be putting up all of our white papers, all of our technical reports we’ve done in conjunction with the national labs, all the patents that have been granted, and those that are still in process,” she said. 

The work in question centers on Transatomic’s research into “spectral shift reactor design,” she said. This design alters the amount of moderator, or material used to slow down neutrons to speeds capable of sustaining fission, as a function of time over the course of the reactor’s fuel cycle, she explained. 

Transatomic’s patents deal with the use of zirconium hydride as a moderator, combined with its particular version of molten salt-based reactor design, based on work done at Oak Ridge National Laboratory. It also holds patents on the manufacture of cladding, or the material used to prevent corrosion of its moderator by its liquid fuel, Dewan said. 

Transatomic’s current work doesn’t include its initial goal of using spent nuclear fuel to power its reactors, however. Dewan and co-founder Mark Massie launched the company in 2011, while they were doctoral candidates at the Massachusetts Institute of Technology, with the goal of creating a reactor that could use spent fuel rods and thus manage the challenges of safely disposing of this nuclear waste. 

This promise helped Transatomic raise $2 million in 2014 from Peter Thiel's Founders Fund, and raise another $2.5 million round in 2015 from Acadia Woods Partners, Founders Fund, and Daniel Aegerter, chairman of the Swiss fund Armada Investment AG. 

But in 2016, the company was forced to backtrack on its earlier claims, after an informal review by MIT professors found errors in its calculations. As first reported by MIT Technology Review, these errors included its initial claim that its design could produce "75 times more electricity per ton of mined uranium than a light-water reactor” of typical design — a figure that was downgraded to “more than twice” the usual reactor’s output per unit of uranium in a company report from November 2016. 

Transatomic also revealed in this paper that it was shifting its plans to a reactor that “does not reduce existing stockpiles of spent nuclear fuel,” but rather which would “reduce nuclear waste production by significantly increasing fuel burnup.”  

Dewan said Tuesday that the decision to turn away from a design that consumes spent nuclear fuel “was a real blow to me personally.” But the company’s investors supported the company’s post-2016 work on its molten salt and zirconium nitride design, because “for them, the main value proposition was the safety case of these molten salt reactors and their low cost compared to fossil fuels.” 

Dewan also noted that the number of advanced nuclear reactor efforts have grown from a handful when Transatomic was founded to about 70 worldwide today. “Some are doing incredibly well,” she noted.  

These include TerraPower, a startup backed by Bill Gates, which has partnered with DOE’s GAIN program and Southern Company to develop its molten chloride fast reactor design, and which is expected to invest $20 million in a test facility set to open next year. Terrestrial Energy, a startup using an integral molten salt reactor design, won $8 million in funding in 2016, and this month announced a two-year R&D project with DOE and Southern Company. 

NuScale Power, a startup with a small modular reactor design, in May won Phase 1 approval of its design from the U.S. Nuclear Regulatory Commission, and this month it picked Virginia’s BWX Technologies to begin engineering work to manufacture its units. 

“I’m still incredibly optimistic and enthusiastic about the future of advanced nuclear reactors,” Dewan said. At the same time, the time scales of these efforts underscore how challenging it is for a startup to bring its plans to fruition. 

NuScale has said its first operational products, for Utah Associated Municipal Power Systems, could be hooked up to the grid “by the mid-2020s." TerraPower and Terrestrial Energy are envisioning 2030 as a target for commercial operations.