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Gas plants are often used to overcome the hurdle. But what if that could also be decarbonised?
That is one of the aims of Seattle firm Ultra Safe Nuclear Corporation (USNC). The company’s micro modular reactor (MMR), currently in development, is designed to deliver ‘safe, clean, and cost-effective’ electricity to urban areas, large industrial users, and off-grid locations.
Using encapsulated Triso particle fuel and cooled by helium, the MMR will be partially manufactured using a new 3D-printing method that uses binder jet printing as the additive manufacturing technique, and a ceramic production process called chemical vapour infiltration. Together, the processes can print refractory materials, which are highly resistant to extreme heat and degradation, into components with complex shapes. The engineering multinational Jacobs is supporting design and development of the reactor, which could start demonstrating nuclear power in 2026.
Extreme temperatures
“People are converging on this Triso particle as the way forward, and Ultra Safe Nuclear are probably one of the leading companies doing that,” said Professor Simon Middleburgh at the Nuclear Futures Institute at Bangor University.
The particles have tiny, uranium-based fuel kernels in the centre, surrounded by layers of silicon carbide and graphite to contain radioactive fission products. The main reason they are used is the high reaction temperatures they enable, said Middleburgh.
“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,” he said. “The higher the temperature, the higher the temperature difference, which means you can get more effective energy out of your system.”
Low uranium density means the particles are not the most efficient nuclear fuel, he added, but this also means easier handling, as well as potential application in otherwise risky environments close to population centres or onboard rockets. Their robustness means radioactive material should be contained within the coated kernels.
“For everything we’ve looked at, this is exactly how they perform, and this is why they’re so exciting,” said Middleburgh. “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.”
To the Moon
Using gas plants will not be “socially acceptable” in the near future so replacing them with MMRs is a tempting proposition, said Middleburgh. “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 making electricity via nuclear is using big reactors, he said, but they are more expensive. Micro reactors are typically less efficient, but they can be very cheap and quick to build. This could also make them suitable for speedy deployment in disaster zones or on the Moon, he claimed.
The UK government hopes the reactor could be well-suited to production of hydrogen or sustainable aviation fuel. The Department for Energy Security and Net Zero awarded USNC a grant of up to £22.5m to develop the MMR.
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