Installation of solar panels and wind turbines is increasing around the globe. Critics claim that renewables alone are not enough to fully decarbonize the electrical grid because of the issue of intermittency.
     Natural gas plants are often used to deal with intermittency. Is it possible to decarbonize such plants?
     The Seattle firm Ultra Safe Nuclear Corporation (USNC) is working on the possibility of replace gas fired furnaces with USNC’s micro modular reactors (MMRs) which are currently in development. MMRs are designed to deliver ‘safe, clean, and cost-effective’ electricity to urban areas, large industrial users, and off-grid locations.
     The MMR will utilized encapsulated Tristructural-isotropic (TRISO) nuclear particle fuel cooled by helium. It will be manufactured with a new 3D-printing method that uses binder jet printing as the additive manufacturing technique. A ceramic production process called chemical vapor infiltration will also be used. Together, the processes can print refractory materials into components with complex shapes which are highly resistant to extreme heat and degradation. The engineering multinational company Jacobs is supporting design and development of the new reactor. The MMR could begin demonstrating nuclear power in 2026.
     Professor Simon Middleburgh is at the Nuclear Futures Institute at Bangor University. He said, “People are converging on this Triso particle as the way forward, and Ultra Safe Nuclear are probably one of the leading companies doing that.”
     The TRISO particles have tiny uranium fuel kernels in their centers which are surrounded by layers of silicon carbide and graphite to contain radioactive fission products. The main reason they are used in the MMRs is that they can enable high reaction temperatures.
     Middleburgh said, “Even if you go to extremely high temperatures beyond your normal operating temperature, what happens is these little kernels just sit there and they absorb that heat, and they hold those fission products.  higher the temperature, the higher the temperature difference, which means you can get more effective energy out of your system.”
     Low uranium density in the TRISO particles means that they are not the most efficient nucleal fuel. However, this also means easier handling. They have potential applications in otherwise risky environments close to population centers. They may also be of use in rockets.
     Middleburgh added that, “For everything we’ve looked at, this is exactly how they perform, and this is why they’re so exciting. Not necessarily the most efficient in terms of volume, but the safest way to do it. That’s why we’re pushing quite hard on this now.”
     He went on to say that using gas plants will not be socially acceptable in the new future so replacing them with MMRs is an attractive proposition. “We need to take those off the grid as soon as possible, and having reactors that can essentially act as buffers to renewables, when you’ve got a high-renewable grid, is brilliant.”
     The most efficient way of generating electricity via nuclear power is using big reactors. However, they are more expensive than MMRs. MMRs are typically less efficient but they can be very cheap and easy to build quickly.
     The U.K. government hopes that the MMRs could be well-suited to production of hydrogen or sustainable aviation fuel. The U.K. Department for Energy Security and Net Zero granted the USNC up to 29 million dollars to develop MMRs for that purpose.