Ally Winning, European Editor, PSD
In general, nuclear reactors are one of the safest methods of generating electricity. The problem is that when things do go wrong, the effects are disastrous, long lasting and very visible. Currently, the type of reactor used in the majority of nuclear generation is a light water reactor designs. These reactors operate by splitting uranium atoms to make energy. The reaction generates massive amounts of heat. They use solid fuel rods, which are cooled by water. If the cooling isn’t working efficiently, then the rods can overheat, causing a meltdown, which can contaminate the surroundings for many decades. This has happened twice in living memory, at Fukushima in 2011 and Chernobyl in 1986. There are also other incidents that have come close to meltdown.
Nuclear reactors would be an ideal solution for our energy needs, at least in the short to medium term until we can develop 24/7 renewable power. The main problem is the size, cost and the perception of the general public that nuclear power is unsafe. If there was a way to prevent the worst outcome, that would go a long way to convince the public of its safety. One method of nuclear generation has the potential to be safer uses molten salt instead of fuel rods. Although the theory behind molten salt reactors has been understood since the 1950s, getting one working in practice has proven much more difficult. Brigham Young University (BYU) professor Matthew Memmott and his colleagues have now brought a practical solution closer with a new design that also has other significant benefits.
When the nuclear reaction occurs in the new reactor, the radioactive byproducts are dissolved into molten salt. Ordinarily, during the cooling process, nuclear elements can emit heat or radioactivity for hundreds of thousands of years. The salt used in the new reactor has an extremely high melting temperature of 550°C. The salt takes a short amount of time to fall beneath the melting point and crystalize, and once it has set it remains solid. When that occurs, the radiated heat is absorbed into the salt, negating the danger of a nuclear meltdown. Additionally, the new reactor has the potential to eliminate nuclear waste as the byproducts from the reaction are safely contained within the salt. Many of those products are valuable, and can be safely removed from the salt to be repurposed. For example, molybdenum-99 is an extremely expensive element used in medical imaging. It can be safely extracted from the salt, making it more affordable. Other elements that can potentially be extracted include cobalt-60, gold, platinum, and neodymium, resulting in potentially no nuclear waste.
The new molten salt reactor is also much smaller, measuring only Memmott’s 4 ft x 7ft, and does not need a large safety zone around the reactor as there is no risk of meltdown. It is compact enough to be able to fit on a truck and can power around 1000 homes.
Memmott’s colleagues on the project include BYU professors Troy Munro, Stella Nickerson, John Harb, Yuri Hovanski, Ben Frandsen, and BYU graduate student Andrew Larsen.