When Dr. Rusty Towell talks about the cutting-edge work being done with molten salt at Abilene Christian University, he can’t stop smiling as he speaks with a mixture of excitement and anticipation in his voice.
The work the 1986 graduate of Abilene High School is leading has the potential to literally change the world by providing clean, safe, and affordable energy; clear and abundant water; and potentially providing medical isotopes that can lead to cures for cancer.
Towell, professor of engineering and physics and director of the Nuclear Energy eXperimental Testing Laboratory (NEXT Lab) at ACU, oversees the staff and students who are attempting to use molten salt reactors to provide life-changing answers in the search to make the world a better place.
Towell moved to Abilene from Kentucky in the fall of 1982, just in time to start the eighth grade at Franklin Junior High School. He then moved on to AHS where he first met physics teacher Ron Esman, who encouraged him to think about a career in physics. Towell followed his advice and began at ACU in 1986, although he had intentions of going somewhere else after his first year.
Instead, he spent four years at ACU, graduating in 1990 and earning his Ph.D. in Physics from the University of Texas in 1999. He spent four years as a Lieutenant teaching math, physics, and Reactor Principles at the Naval Nuclear Power School in Orlando, Florida, and two more years as a Postdoctoral Research Fellow at the Los Alamos National Laboratory.
He returned to Abilene in the fall of 2001 as a professor of physics and engineering, and in 2016 was tabbed as the director of the NEXT Lab. He and his wife, Amy, have five children – all of whom graduated from Abilene High School – and three grandchildren, all of whom live in Abilene.
But instead of winding down his career, Towell seems to be just getting started with a second act.
Back in 2004, ACU’s first physics department chair, Dr. Charles Ivey, began working on Towell to read a book about producing clean water, affordable energy, and medical breakthroughs using molten salt reactors. It wasn’t until 2015 that Towell read the book and, after doing some other research, became a believer.
While on a sabbatical in 2015, he gave an 18-minute at talk at the first TEDxACU event about the benefits of such a reactor. In the room that day was a group of ACU donors who agreed to fund and support the idea. After acquiring their support, Towell and those working on the project began small, building a loop and flow meter.
Shortly after that, he spoke to a small group of ACU donors – the President’s Venture Council – and caught the attention of Doug Robison, J.D., who had served on the Texas Energy Planning Council. He was impressed with what Towell was doing at ACU and asked him what he could do if he was fully funded and how much that would cost. After a couple of weeks, Towell went back to Robison with the number, $3.2 million, which Robison agreed to give through his foundation and salt flowed through the molten salt loop for the first time.
Officials from the U.S. Department of Energy toured NEXT Lab and requested follow-up visits in Washington, D.C., by Towell and ACU President Dr. Phil Schubert. In June 2019, the U.S. Department of Energy awarded an $800,000 grant to NEXT Lab for molten salt research, and the DOE issued a Letter of Support.
In July 2020, Natura Resources announced funding of $30.5 million to NEXTRA over the next three years, with $21.5 million going to ACU and the remaining $9 million to the other consortium universities (University of Texas, Texas A&M University, and Georgia Institute of Technology). Also in 2020, NEXT Lab received its first patent for a high-temperature flow meter to help monitor the flow of molten salt through a pipe at temperatures as high as 700 degrees Celsius.
After ACU purchased the old Taylor Elementary School property, construction began in 2021 on the Gayle and Max Dillard Science and Engineering Research Center. This 28,000-square-foot facility will include a 6,000-square-foot research bay that will house the molten salt reactor. ACU still must get government approval to build and use the reactor, and once that is done, the reactor will become operational. Towell’s earliest estimate on that is December 2025, but most likely sometime in 2026.
Towell recently sat down with us for a question-and-answer session to discuss how molten salt can literally change the world, if having a nuclear reactor inside the city limits is safe, and how it all works.
Q: When did you know this was the career you wanted, and what or who led you to that realization?
Towell: I remember my chemistry and physics teacher at Abilene High School (Ron Esman) and it was between my junior and senior years, he took a group of students to Austin for an energy symposium, and I was invited to go on that trip. So I got to listen to lectures from scientists talking about different kinds of energy, how they impacted our lives, and how important energy was, and I remember a talk on nuclear fusion and how it would save the world. So, I asked Mr. Esman what I needed to major in college if I wanted to work on nuclear energy and he told me physics, even though I liked chemistry better because the labs were better; you got to blow stuff up. I showed up at ACU to be a physics major. It wasn’t my intention, but I find myself back working with nuclear energy and am so blessed to have this opportunity to be doing this now.
Q: What other memories do you have of your time in the AISD and how did those moments help shape you into one of the world’s leading nuclear physicists?
Towell: The opportunities for those honors classes at Abilene High were huge for me because they pushed me. They also put me in a smaller class with the same students, so it was a comfortable learning environment for me.
Q: In laymen’s terms, what is molten salt, and how does a molten salt reactor work?
Towell: Molten just means it’s in a liquid state. The one substance we’re familiar with in everyday life is water. We understand in solid form it’s ice, in liquid form it’s water, and in its gaseous phase, it’s a vapor. We understand that if it’s cold it’s a solid, but if we raise the temperature, it’s a liquid, and if we raise it more it’s a vapor. And most every substance has those three phases, and many times the temperature ranges are outside of everyday life. For us, the thing that’s a solid at room temperature and then raises and goes to a liquid is candle wax. If you heat it up, it becomes a liquid, and we’ve all seen candle wax: it looks a little bit clear like water. But as soon as you heat it up and it gets out of the heat source, it cools down to room temperature and becomes a solid. That’s what we’re doing with molten salt. We take salt, and at room temperature, it’s a solid. If we raise the temperature – and we have to raise it more than for wax – but if we raise it quite a bit, it melts and becomes a liquid. The beautiful thing about it is it never becomes a gas or not until you have it at such a crazy high temperature that if you have it in a metal bucket, the bucket will melt before the molten salt becomes a gas. And the reason that’s a beautiful thing is that we’re using molten salt as a coolant in the reactor. The coolant moves heat from where it’s produced to where we need it.
Think about what happens to cars when you have a radiator leak. The anti-freeze moves heat from Point A to Point B. So, when a radiator gets in a hole in it, the anti-freeze immediately leaks out and flashes to steam, so we see all of that coming out from under the hood. That was the trick that water-cooled reactors used: how do you keep water in a liquid phase at the high temperatures you want, and the answer is high pressure. All we’re doing is taking the water loop that moves the heat and replacing it with a molten salt loop, and so now we’re able to work at very, very high temperatures – which is more efficient – but at low pressure. If there’s a leak, there’s no steam going off. If there’s a leak, there’s a drip. And as you would expect with wax dripping out, it drips down and becomes a solid.
Q: How is it viable in creating clean water, affordable energy, and medical isotopes to help in the cure for cancer?
Towell: We don’t really have a shortage of water in the world; we have a shortage of clean water. You just need the energy to take salt water and purify it. Because we’re using molten salt, we can run a reactor at high temperatures that will let us de-selenate water, which is one of the things we can do with high temperature or a lot of energy. One of the exciting things we think about when looking at deploying this technology is that we can deploy a reactor to, let’s say, the Gulf Coast of Texas. In a day when everyone’s running air conditioners, let’s use the reactor to produce electricity. At night, when we have electricity, let’s de-selenate water. We can run the reactor all the time, but it can do whatever is demanded.
Q: I’m sure you’ve been asked about the safety of having a nuclear reactor on campus and all the concerns that go along with that. How do you answer those questions?
Towell: Obviously if anyone ever has concerns, I’m happy to explain or give tours or whatever. I want everyone to be comfortable with what we’re doing, so we’ve had town hall events and will continue to do those types of things. Because salt can’t form into a gas, if it ever leaked out of the loop, it would immediately be cooled into a solid, which would then drip down into a safety pan, keeping all the potentially harmful fuel and radiation contained in the salt. (From an ACU Today Q&A, the answer to the question of whether the reactor is safe is explained like this: “It’s impossible for a molten salt reactor to cause a nuclear explosion and release of harmful radiation. The use of low-pressure coolants removes the largest single risk from current nuclear plants. The use of liquid fuel allows for a drain in the bottom of the small reactor. If anything were to go wrong with the plant, the fuel and coolant would drain to a passively drained sub-critical storage location where the salt would then solidify, safely containing all of the fuel and radioactive fission fragments.”).
Q: You’ve spoken at conferences all over the world, authored numerous journal articles, and worked in the most prestigious labs in the country, but now you’re embarking on a project with potential life-changing outcomes. Even though you’re a young man, is this the pinnacle of your career?
Towell: Oh, yeah, it doesn’t get any better than this. I talk to everyone working on the project about professional development because I want them to be able to go from working for NEXT Lab to anywhere they want because they’re continuing to grow. I’m not looking to grow and move anywhere else; I’m very, very happy right here. The opportunity I have is like nothing else. The ability to come back to my alma mater, build upon how it blessed me, and raise the academic stature of the university so that more people have this same opportunity is a wonderful thing.