NUCLEAR POWERHow Molten Salt Could Be the Lifeblood of Tomorrow’s Nuclear Energy
Molten salt has caught the eye of the nuclear industry as an ideal working fluid for reactor cooling, energy transfer, fueling and fission product absorption. Many of the salts being considered are inexpensive, nontoxic, and easily transportable – and table salt is one of the constituents many reactor developers are choosing to use.
Salt isn’t just for popcorn anymore. In fact, molten salt has caught the eye of the nuclear industry as an ideal working fluid for reactor cooling, energy transfer, fueling and fission product absorption. Many of the salts being considered are inexpensive, nontoxic, and easily transportable. In fact, table salt is one of the constituents many reactor developers are choosing to use.
Heightened interest in molten salt reactors (MSRs) has led to increased investment in their research and development. Idaho National Laboratory has already dedicated efforts to establish comprehensive molten salt capabilities. In the coming years, these efforts will establish a molten salt characterization facility, irradiate fuel salt and, for the first time, start up an experimental “fast” reactor that runs on molten salt.
“Molten salt research is essential for the future of nuclear energy, and INL is the ideal resource for industry projects in this area,” said Advanced Technology of Molten Salts Manager John Carter. “MSRs are an attractive option for future power generation, and we are prepared to make significant progress toward full-scale operations.”
Why Salt?
Molten salt, as a coolant and nuclear fuel, offers numerous safety, efficiency and flexibility benefits.
Interestingly, molten salt fuel comes with an inherent safety feature. If the salt overheats, it naturally expands and makes the fission reaction less effective, which shuts down the reactor. The MSR reactor core naturally changes its power level to match heat removal for electricity production, allowing it to appropriately meet consumer demand.
Another benefit: fuel flexibility. Uranium, plutonium and thorium all form salts that can be used as fuel for MSRs. At reactor operating temperatures, the salt is liquid, which means new fuel can be introduced and in-use fuel can be cleaned, filtered and managed during operation. This eliminates the need for refueling outages.
Molten salt fuel opens a whole new world of possibilities to reactor designers. The characteristically high temperatures in MSRs translate into efficient electrical power conversion, but the low-pressure feature eliminates the need for costly, thick-walled pipes and tanks.
The use of fast neutrons has its own set of benefits as well.
What Are Fast Neutrons?
A fast-spectrum nuclear reactor uses fast, high-energy neutrons to sustain the nuclear reaction. Fast neutrons are more effective than slow neutrons at consuming certain waste products. This greatly reduces the amount of long-lived waste that must be isolated from the environment.
