Atomic Show #322 – Westinghouse’s eVinci micro reactor
Westinghouse’s eVinci is a 15 MWth, 5 MWe micro reactor. Westinghouse often refers to it as a nuclear battery.
Unlike conventional nuclear power plants, eVinci uses no water and doesn’t produce steam. The eVinci is not “just another way to boil water.”
There are no pumps in the system that moves heat out of the reactor. Instead, the system uses ~24′ long heat pipes to transfer fission heat to a heat exchanger.
That device serves the same function as a combustor (burner) in a fossil fuel heated Brayton cycle gas turbine. Atmospheric air is compressed and sent through the heat exchanger where it gets hotter and more energetic. That hot, compressed gas gets expanded through a turbine, causing it to rotate. The rotating turbine is connected to a generator that produces electricity with an efficiency of about 33%.
An eVinci will use an open air Brayton cycle gas turbine like those that are in a wide range of commercial applications. Gas turbines are not only well-understood devices, but they have a diverse supply chain and an experienced workforce with tens of thousands of builders, operators and maintainers. They are often manufactured by the thousands.
In another departure from the conventional way of doing things, eVinci uses rotating control drums instead of insertable control rods to adjust core reactivity and operating temperature. Shutdown rods are used during transport and to provide a secondary means of shutdown.
The fuel is TRISO coated particle fuel with high assay, low enriched uranium in the particles. The reactor operates in the thermal neutron spectrum with graphite as the moderator. The core isn’t in a pressurized fluid.
With its simple controls, small size and passive safety case, the eVinci is designed to be able to operate autonomously. Each core will last eight years or more.
Leah Crider, Westinghouse’s Vice President of Commercial Operations to the eVinci micro reactor, visited the Atomic Show to provide a system overview and to answer questions about the reactor, its history, its future, its applications and its potential impact on the energy market.
I think you’ll learn something from this show. Please participate in the comments and let us know what you think, especially if you have questions that were not addressed during the show.
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Thanks Mr. Adams: There certainly could be a lot of applications for a continuous 5 MW thermal power source. Pumping came to my mind. As various aquifers around the world become depleted and the warming planet causes enhanced evaporation, the need for irrigation water will continue to grow. Another application could be pumped hydro to meet peak usage during the day or to meet needs when wind and solar are slack. If these units are inexpensive enough they can free industrial customers from the local utility while giving predictable power costs. As the weather cools, Winter heating will soon be upon us. These units could provide district heating. I hope they achieve the goal of becoming an inexpensive clean power source.
Advantages over high-temperature gas-cooled reactors?
One advantage provided by using heat pipes to move heat out of the reactor is that the gas used in the Brayton cycle power conversion system isn’t exposed to a neutron flux.
For eVinci that allows the use of a conventional open cycle, air-breathing machine. Those are commerical products with deep supply chain capacity.
HTGRs using Brayton cycle power conversion typically use less mature concepts like closed cycle helium turbines or supercritical CO2, also in a closed cycle.
Only developers and customers can tell us if the benefit outweighs the cost and manufacturing challenges of hundreds of heat pipes.
The Westinghouse offering is to be taken more seriously than all the offerings from Aalo to Xenergy. The sheer caliber and array of guns that Westinghouse can train on any problem is only duplicated by foreign state franchises. Despite a bankruptcy and new owner every 5 years, the depth of talent, analytical methods, fabrication and maintenance skills and experience make Westinghouse ‘god of Nuclear’ (lowercase g, capital n).
I am glad they have moved on from the early concepts with pellets pressed into a monolith, but I do not understand why it is not a bundle of rods and heat pipes banded like a fasces, maybe with interstitial sodium bonding. Maybe they’ll figure that out if/after a single prototype is built. I have a very short position on these devices being adopted at any scale. They are certainly can’t have an EROI comparable to a big LWR or CANDU. Remind me again: Are there a bunch of Eskimos that want a nuclear reactor up in the Arctic, to keep their fridges cold?
Trying this again.
Hi, Rod. I am conversing with Elon M. on power generation needs for a Mars surface application. We are using a GCR as the basis but could use the Westinghouse design. We consider using CO2 or CFCs as the working fluid. I have come up with a divergent electric end after the turbomachine. We would welcome your inputs and participation.
John Kessler
Hi Rod,
Fascinating program on e-Vinci with Leah Crider.
Looking at the Westinghouse website, there is shielding on one end of the core, but that’s it. I’d be interested in how much shielding is required. Nothing is shown in the little videoclip on the website.
And what is the rough cost of loading it with Triso fuel?
Cheers,
Geoff
Could this be used to make the Australian Navy’s upcoming Ghost Shark drone submarines almost unlimited range?
https://www.youtube.com/watch?v=0HTdytBojsM&t=4s
*Just realised that it is using an open air brayton cycle turbine, which won’t work underwater! I guess it could work with some closed cycle turbine eventually…
How can it use a Brayton cycle if it doesn’t get output heat at 1200 Celsius?