Fort Lewis College students are determining the best ways to monitor and work with liquid sodium, a silvery molten metal, which could help develop the next generation of nuclear power plants.
Liquid sodium can be used to cool nuclear reactors and reduce the amount of time radioactive waste produced by a reactor is dangerous from tens of thousands of years to dozens of years – solving one of the biggest problems with nuclear power, said Billy Nollet, thermal hydrolysist and associate professor of physics and engineering.
“If we can solve the spent-fuel problem, then we potentially can tap into the cleanest and safest energy on record,” he said.
Public perception of nuclear power safety was hurt most recently in 2011 by an accident at the Fukushima Daiichi Nuclear Power Station in Japan, when a tsunami disabled the power supply and cooling systems for three reactors. No one died in the Fukushima accident.
Despite criticism of nuclear power, Nollet said far fewer deaths happen during its production than during the generation of power through other means, such as coal.
Nuclear power is also an appealing source of energy because it doesn’t produce greenhouse gases and it can run regardless of the weather, unlike solar or wind power, he said. However, all the nuclear reactors in the United States rely on water-cooled systems, which lead to long-lasting radioactive waste.
Liquid sodium, an alternative to a water-cooled system, has been used in the U.S. power plants before.
But it has been decades since any liquid sodium-cooled reactors operated in the U.S., and the professionals who ran those plants have either retired or died. So research is needed to re-establish the expertise required to operate those plants, Nollet said.
At Fort Lewis, students working with Nollet are focused on understanding the properties of liquid sodium. They do not work with nuclear materials.
Liquid sodium is challenging to work with because it can’t be seen or touched by an instrument while it is moving through systems, Nollet said.
At Nollet’s Thermal Hydraulics Lab, students are, for example, learning how to measure how fast the metal moves and understanding its corrosive properties. The system they work with has high electrical voltage, high temperature and high volatility, he said.
“The stakes are real, in terms of the real-world work experience,” he said.
To better understand liquid sodium and its corrosive properties, FLC students designed a system to control the level of oxygen in the metal because oxygen is the biggest contributor to corrosion.
Students have also designed a pump that employs spinning magnets to create alternating magnetic fields to pull the liquid sodium through a duct, Nollet said.
The work has drawn investment from the Department of Energy’s Office of Nuclear Energy and the department’s Nuclear Energy University Program, according to FLC.
“It shows a federal interest and the American people as a stakeholder in the quality of education that Fort Lewis provides,” he said.
Before Nollet started his program in 2013, it was unheard of for undergraduate students to participate in this type of work, he said.
“I think that our undergrads, and undergrads in general, are much more capable than people think,” he said.
About 30 students have worked with Nollet since he opened the lab. About five students have gone on to pursue doctoral degrees at established research schools, such as the University of Wisconsin-Madison. His students have also gone to work for the Argonne National Laboratory, a science and engineering research center run by the Department of Energy.
“I can’t produce enough students to keep up with the demand,” he said.
FLC engineering junior Wiley Kirks joined Nollet’s lab in recent weeks and expects the work experience will help him decide between graduate school and entering the workforce.
“This is kind of a taste of grad school,” he said.
While the future of nuclear energy in the U.S. is uncertain, the skills that Nollet’s students gain can be applied to many different industries, such as solar energy and rocket propulsion, he said.
“Thermal hydraulics is an extremely coveted field,” he said.