Bill Gates’s next-gen nuclear plant packs in grid-scale energy storage

Wind, solar, geothermal, hydro, wave power… Sustainable resources are an essential pillar of any type of strategy to decarbonize the planet’s power generation sectors as well as eradicate fossil fuel usage. However, for several factors – intermittency, location dependence, land needs, and others – they can not accomplish it on their own.

A scalable form of zero-emissions energy that can reliably produce power all year round uninterrupted is needed to fully remove greenhouse gases from the world’s energy sectors. It would be especially better if it rapidly ramps its output up and down to help the power grid cope with load spikes and interruptions in renewable energy supplies. Currently, advanced nuclear power is the best candidate to fill this role.

Despite nobody wants their backyard to be associated with disasters such as Chernobyl and Fukushima, nuclear is verifiably one of the safest forms of energy generation. Nuclear power has caused only 0.07 fatalities per terawatt of energy supplied, including the high-profile disasters that have led to its marred reputation, while coal and oil-derived energy cause 24.6 and 18.4.

With a projected death toll of a 2°C temperature rise – somewhere between 300 million and 3 billion premature deaths spread over one to two centuries – the fourth generation of nuclear power is being reconsidered, given the many decades of development, advanced modeling, and materials technology on its side, its excellent safety is likely to improve.

The collaboration between Bill Gates’s Terrapower and GE Hitachi Nuclear Energy is a promising initiative that has been backed by heavy private investment, as well as the US Department of Energy. Thanks, in part, to an US$80 million DoE grant announced in October, Natrium (Latin for sodium) has the chance to demonstrate its “cost-competitive, sodium fast reactor with a molten salt energy storage system” at an adequate commercial scale.

By the mid to late 2020s, the Natrium’s demonstration plant will be fully operational and connected to the power grid in its as-yet-unknown location. Instead of using water as its reactor coolant, the plant’s fast-neutron reactor will use high-temperature liquid sodium.

The large 785-degree temperature range between its solid and gaseous states is one of the sodium’s key advantages; water, offering only a 100-Kelvin range, needs to be pressurized to handle higher amounts of heat energy. The high levels of pressure immensely increase the cost of the plant, as nuclear-grade high-pressure components are not affordable, and can have explosive consequences.

At normal atmospheric pressures, liquid sodium will transfer an impressive amount of heat away from the reactor. Additionally, it won’t dissociate into hydrogen and oxygen, nullifying the risk of Fukushima-style hydrogen explosions, and being non-corrosive sidesteps the issue that puts a question mark over molten salt reactors.

The Natrium design, like many of the next-generation nuclear reactors under development, will use High-Assay, Low Enriched Uranium (HALEU) as its nuclear fuel. The U-235 isotope represents around 0.7 percent of the natural uranium as it comes out of the ground, which is afterward split to generate nuclear energy, and using centrifugal processes or gas diffusion, the traditional Low Enriched Uranium (LEU) nuclear reactor fuel is enriched to contain 3-5 percent U-235, being further enriched, between 5 and 20 percent. Comparatively, nuclear weapons need uranium enriched to more than 90 percent.

By reprocessing fuel spent from traditional nuclear power plants, HALEU fuel can be produced, and its higher grade improves reactor performance and efficiency allowing advanced reactors to be much smaller than LEU plants. According to Natrium, it should be four times more fuel-efficient than light water reactors. 

Regarding safety, the natural circulation of the air will function as emergency cooling, and in the event of a power outage, the control rods will drop by themselves due to gravity. Unlike light water reactors, the plant doesn’t need an extensive containment shield thanks to the liquid sodium design, and to boost the safety factor while cutting down costs, the design places the reactor underground.

Outputting a constant 345 MWe in the form of heat, the Natrium plant is designed to run at 100 percent output, 24/7. The heat is transferred out through the liquid sodium cooling system and transferred to a separate molten salt thermal energy storage system similar to what’s been proven in many direct solar plants around the world. A set of steam turbines, located at the other end of this storage system, can take that constant power and generate enough electricity to power approximately 225,000 homes.

The Natrium design has an extraordinary benefit; its storage system means the Natrium plant can respond to demand spikes or intermittent renewable energy supply drops by harnessing that stored heat and ramping its turbines up to 150 percent of the nominal reactor power, pumping out 500 MWe for as much as 5.5 or more hours.

That stands for virtually a gigawatt-hour of extra on-demand energy storage; significantly more than even the greatest grid-scale battery projects under development. This is a huge advantage, specifically in the context of decarbonization, where load-reactive systems similar to this certainly play a crucial part supporting renewable energy sources through the optimals as well as troughs in their less foreseeable generation cycles.

The DoE demo plant funding is undoubtedly superb information for Natrium, which currently can develop and prove its abilities prior to moving to roll comparable plants out at scale, which will be considerably bigger as well as much more efficient too. It’s likewise somewhat of a payback for Terrrapower, which was preparing to construct an experimental nuclear reactor outside Beijing to test and show its distinct Travelling Wave Generator technology when United States Government assents on technology deals with China compelled it to discard the project in 2019.

If everything turns out, the Natrium design promises to be quick to build as well as commission, and to make use of much less nuclear-grade concrete than conventional designs – a big factor in keeping the cost low and minimizing the “eco-friendly premium” on the emissions-free energy. Will designs like this help place some light back on nuclear power? Opportunities for these business will certainly be tremendous as fossil fuels are reduced. Time will tell.