On December 1, 2014, I talked with Leslie Dewan and Mark Massie, the co-founders of Transatomic Power, a tiny nuclear reactor design company started up less than 3 years ago. Several weeks ago, I published an article here titled Transatomic Power – Anatomy of Next. That article, as expected, generated a healthy discussion thread.

At the end of the initial article, I stated that I was arranging an interview with the founders. I’m not always the most prompt person, but I try to follow through on such promises.

Dewan and Massie have developed a conceptual design for a fluid fueled reactor that consumes actinides with a low concentration of fissile isotopes dissolved in molten salt to produce vast quantities of reliable heat. Using conventional heat exchangers, their system uses that heat to boil water and uses the resulting high temperature, high pressure steam to drive a turbine and produce electricity.

Aside: Like many nuclear engineers, Massie and Dewan have focused most of their early design efforts on the reactor portions of their system. The power production portion has received little attention so far. End Aside.

The initial concept of a molten salt reactor was developed and proven at the Oak Ridge National Laboratory in the 1950s, 1960s and 1970s.

The main innovations that Massie and Dewan have introduced are 1) using zirconium hydride for neutron moderation instead of graphite and 2) using LiF salt without any beryllium. LiF salt can dissolve a substantially higher concentration of actinides. The combination of those two innovations enables a smaller reactor to obtain and maintain criticality with a fissile isotope concentration of just 1.8% of the actinides in solution.

Aside: That concentration is a little lower than the material that is removed from light water reactors after producing 40,000 to 50,000 MW-days/ton of heavy metal. Up until a few years ago, that material was nearly always referred to as “spent nuclear fuel,” an appellation that implied it was just waste and had no future utility. Not long ago, more prescient people began referring to the material as “used nuclear fuel,” helping others to understand that the material still contained a large fraction of its initial potential energy. An even better term, especially in light of the innovative thinking of people like those at Transatomic Power, is reusable fuel. End Aside.

Massie and Dewan were interesting, cooperative and open about their current status, the difficulty of the challenge that they have chosen to address, and the long road that they must traverse in order to achieve their goals. They admit that they are a bit on the idealistic side, but have admirable youthful optimism about the power of innovation to address the technical challenges.

At the beginning of our discussion, we talked a little about the November 2011 TEDx talk that they gave in Boston. The Transatomic Power site hosts an embedded video of that talk.

Dewan and Massie expressed their concerns about the numerous strings that slow atomic energy development and are working to help leaders understand the vast potential that the US and much of the rest of the world is avoiding by its current regulatory construct. I believe their kind of thinking needs to be nurtured and encouraged. At the end of the show, they told me they wanted to participate in a well-moderated, professional discussion about their technology.

Atomic Insights should be a good place for such a discussion.

Keep it civil. Open up some minds to the fact that there is vast potential for creative problem solving in atomic energy technology. Challenge the myth that is propagated by the opposition that nuclear fission is old, obsolete technology. The reality is that fission the only really new power source discovered and usefully developed in the last century.

Correction: An earlier version of this article incorrectly stated that both Dewan and Massie have PhD’s in nuclear engineering from MIT. Though Dr. Dewan completed her PhD defense several years ago; Mr. Massie is still “a few weeks away from having his Ph.D. to be completely technically correct about it.”



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