A vision of nuclear energy buoyed by molten salt

Years before he put foot on MIT university, Kieran P. Dolan participated in researches performed at MIT’s Nuclear Reactor Laboratory (NRL). Being an undergraduate pupil majoring in atomic engineering within University of Wisconsin at Madison, Dolan worked on elements and detectors for MIT Reactor (MITR)-based experiments integral to designing fluoride-salt-cooled high-temperature nuclear reactors, called FHRs.

These days, as second-year doctoral pupil in MIT’s Department of Nuclear Science and Engineering, Dolan is really a hands-on detective during the NRL, deepening his analysis wedding with this variety of next-generation reactor.

“i am thinking about higher level reactors for quite some time, therefore it is already been really nice to remain using this project and study from men and women working here on-site,” states Dolan. 

This a number of scientific studies on FHRs is part of the multiyear collaboration among MIT, the University of Wisconsin at Madison, in addition to University of Ca at Berkeley, funded by an incorporated scientific study (IRP) Grant through the U.S. division of Energy (DOE). The nuclear energy community views great vow in FHR concept because molten sodium transfers temperature very efficiently, enabling these types of higher level reactors to perform at greater temperatures in accordance with a few special protection features set alongside the present fleet of water-cooled commercial reactors.
“Molten salt reactors provide an approach to nuclear power this is certainly both financially viable and safe,” states Dolan.

For the functions of this FHR task, the MITR reactor simulates the most likely operating environment of the working advanced reactor, filled with large conditions inside experimental capsules. The FHR concept Dolan is testing envisions billiard-ball-sized composites of fuel particles suspended within a circulating circulation of molten sodium — a special blend of lithium fluoride and beryllium fluoride labeled as flibe. This sodium lake continuously absorbs and distributes the heat made by the gasoline’s fission reactions. 
But there is however a formidable technical challenge on salt coolants found in FHRs. “The salt responds because of the neutrons circulated during fission, and produces tritium,” explains Dolan. “Tritium is one of hydrogen’s isotopes, that are notorious for permeating metal.” Tritium is really a potential threat if it gets to water or environment. “The stress usually tritium might escape as being a fuel via an FHR’s temperature exchanger or other metal components.”

There’s a potential workaround to the issue: graphite, that could capture fission items and suck up tritium before it escapes the confines of a reactor. “While individuals have determined that graphite can absorb an important level of hydrogen, no body understands with certainty where in fact the tritium could end up in the reactor,” states Dolan. Therefore, he’s concentrating their doctoral study on MITR experiments to determine just how effortlessly graphite performs as being a sponge for tritium — a vital factor needed to model tritium transportation in the complete reactor system.  

“we should predict where tritium goes in order to find the greatest option for containing it and extracting it safely, therefore we can perform optimized performance in flibe-based reactors,” he says.

Whilst it’s early, Dolan is examining the outcome of three MITR experiments exposing a lot of different specialized graphite examples to neutron irradiation inside existence of molten salt. “Our dimensions thus far suggest a significant amount of tritium retention by graphite,” he states. “We’re in correct ballpark.”

Dolan never ever likely to be immersed into the electrochemistry of salts, however it quickly became central to their study portfolio. Enthused by mathematics and physics during high school in Brookfield, Wisconsin, he swiftly focused toward atomic engineering in university. “we liked the idea of making of use devices, and I also was especially contemplating nuclear physics with useful programs, like energy flowers and energy,” he claims.

At UW Madison, he earned a spot within an manufacturing physics material study group involved with the FHR task, and he assisted in purifying flibe coolants, creating and building probes for calculating sodium’s corrosive influence on reactor components, and experimenting on electrochemical properties of molten fluoride salts. Performing with Exelon Generation as a reactor professional after college persuaded him he was even more suited to study in next-generation tasks compared to the day-to-day upkeep and procedure of the commercial atomic plant. 

“I happened to be interested in development and increasing things,” he says. “I liked becoming the main FHR IRP, and while i did not have a passion for electrochemistry, we understood it might be fun focusing on a remedy which could advance a new type of reactor.”

Acquainted with the goals for the FHR project, MIT facilities, and workers, Dolan surely could jump quickly into researches examining MITR’s irradiated graphite examples. Under the guidance of Lin-wen Hu, his consultant and NRL study director, including MITR engineers David Carpenter and Gordon Kohse, Dolan emerged to speed in reactor protocol. He is found on-site participation in experiments thrilling.

“Standing towards the top of the reactor because begins and also the sodium gets hot, anticipating whenever tritium comes out, manipulating the device to check out different places, and watching the dimensions appear in — becoming involved with this is certainly truly interesting in a hands-on way,” he claims. 

When it comes to immediate future, “the primary focus is getting information,” claims Dolan. But sooner or later “the information will anticipate what the results are to tritium in numerous problems, that ought to end up being the main driving force identifying what to do in real commercial FHR reactor styles.”

For Dolan, causing this next phase of advanced reactor development would prove the perfect next thing after their doctoral work. This past summer time, Dolan interned at Kairos Power, a nuclear startup organization created because of the UC Berkeley collaborators on two DOE-funded FHR IRPs. Kairos Power will continue to develop FHR technology by using major strategic investments that the DOE made at universities and national laboratories, and has now recently begun collaborating with MIT.  

“i have developed most expertise in FHRs thus far, and there’s lots of interest at MIT and beyond in reactors utilizing molten salt ideas,” he says. “i’ll be thrilled to apply what I’ve discovered to simply help accelerate a new generation of safe and efficient reactors.”