One of the major problems with renewable energy such as wind and solar is the fact that they are intermittent. A lot of interesting schemes have been hatched and some prototypes developed to address this issue. Water could be pumped up hill, large heavy blocks could be lifted and lowered, underground caverns could be utilized, etc. Now the ability to serve a clearer but more variable grid has become part of the PR around a technology that has been in development for decades but has not yet been applied commercially.
Molten salt reactors which have been heavily promoted recently by major investors such as Bill Gates who says that it is necessary to develop and deploy the technology to provide on-demand, low-carbon energy.
The existing U.S. fleet of commercial nuclear power reactors consists of what are called light water reactors. Developers of what are referred to “advanced reactors” are working to combine several revenue streams into a package that might be attractive to potential customers. One of these is what is called load following. This will help the national grid deal with the intermittency of renewable sources. A load following reactor can turn its output up or down as the demand changes. Another one of the elements would be the ability to start providing power to the grid without external power needed. This is called a “blackstart capability”. A third source of revenue would be the ability to supply heat to residential and commercial buildings.
The people working on advanced reactors think that these additional abilities of their new reactors could allow the nuclear industry to escape from the struggle with high costs of construction which make it extremely difficult to find investors to launch new reactor projects in North America and Europe in the near future.
Simon Irish is the CEO of advanced reactor developer Terrestrial Energy. He said in an interview “We are innovating to solve what we believe is the biggest limit on new nuclear builds in the west — conventional technology is unaffordable and non-cost-competitive.”
Molten salt is just one of the new “advanced” reactor designs with serious support. The ability to store a great amount of heat at extremely high temperatures is touted as particularly applicable to the U.S. grid.
Jeff Nevin is the TerraPower Director of External Services. He said in an interview, “Having the ability to sell ancillary services, the ability to sell heat on the side – that really helps the economics of the reactor.”
U.K. and Canadian developer Moltex Energy is developing what it calls a “Stable Salt Reactor” (SSR). The company says the new SSR will eventually be able to store energy in the form of heat for eight hours or more.
Various companies have been trying to launch reactors that are not light water based. It was the passage of the Nuclear Energy Innovation and Modernization Act (NEIMA) that gave the U.S. nuclear industry a much needed boost that will give unconventional reactor designs a better chance of being developed. President Trump signed NEIMA into law in early 2019.
The new law orders the Nuclear Regulatory Commission to create a new regulatory structure by the end of 2027. This new regulatory framework will make it easier for new reactor designs to be approved. The Nuclear Innovation Alliance, a non-profit think tank that supports advanced reactors issued a statement when the bill was passed. The law “will improve the path to commercialization for advanced reactors that can play an important role in addressing climate change and global energy needs.”