TRISO-X Completes Vertical Construction Of TX-1 Fuel Fabrication Facility
The title of this post, is the same as that of this news item from X-energy.
These two bullet-points act as sub-headings.
Completion of vertical construction marks major milestone for first-in-the-nation commercial scale advanced nuclear fuel fabrication facility
Project advances into interior buildout, fuel fabrication equipment installation and construction of supporting facilities
These two paragraphs add more detail.
TRISO-X, LLC (“TRISO-X” or the “Company”), a wholly-owned subsidiary of X-Energy, Inc. (Nasdaq: XE) (“X-energy”), today announced the completion of vertical construction at TX-1, its first-in-the-nation advanced nuclear fuel fabrication facility in Oak Ridge, Tennessee. The milestone completes the primary building structure of the 214,000-square-foot facility and enables the project to advance fully into its next phase of construction, including interior buildout, installation of fuel fabrication equipment and continued construction of supporting facilities.
“Completing vertical construction is a major milestone for TX-1 and another tangible demonstration of the progress our team is making in Oak Ridge,” said Joel Duling, President of TRISO-X. “We are moving from constructing the core and shell of the facility to building out the interior utilities, installing manufacturing equipment, and constructing key support capabilities. Every milestone brings us closer to establishing a new domestic source of advanced nuclear fuel and supporting the deployment of the next generation of American nuclear reactors.”
Note.
- Oak Ridge is one of the United States premier nuclear facilities.
- It would be like building a similar facility for specialist nuclear reactor fuel at Harwell in the UK.
This is without doubt a very professional start to the X-energy programme.
I also feel that the fourth paragraph has important information.
Once operational, TX-1 is expected to produce approximately 700,000 TRISO-X fuel pebbles annually, equivalent to 5 metric tons of uranium (“MTU”), with capacity to provide fuel for up to 11 Xe-100 reactors. The U.S. Nuclear Regulatory Commission (“NRC”) granted TRISO-X a 40-year Special Nuclear Material License for the facility earlier this year, the first-ever NRC Category 2 fuel fabrication license issued for the processing of high-assay low-enriched uranium. TX-1 is expected to be the first new commercial-scale advanced U.S. nuclear fuel fabrication facility built in more than 50 years.
Note.
- TX-1 will be able to support eleven Xe-100 reactors.
- Four Xe-100 reactors will be built initially at Dow’s Seadrift site.
- In Hartlepool Nuclear Reactor Moves To UK Regulatory Assessment, I said that Hartlepool will eventually be a 12-pack site.
I can envisage a fuel strategy based on TX-1, which is something like this.
TX-1 will provide the TRISO fuel for the four reactors at Dow’s Seadrift site.
TX-1 will provide the TRISO fuel for the initial reactor or reactors at a new site like Hartlepool, or for other licensees like Amazon or North Western.
TX-1 will be cloned as necessary to create TX-2, TX-3, TX-4 etc. as more Xe-100 reactors are built.
I am sure, that there is relevant expertise to make TRISO-X fuel pebbles safely in Japan, Korea and the UK of the known partners of X-energy.
The Wikipedia entry for the Dragon reactor finishes with these three paragraphs.
The choice of helium coolant was made after a long debate within the UKAEA between proponents of helium and carbon dioxide, with helium ultimately selected. Groundbreaking occurred in 1960. It operated from 1965 to 1976, and is generally considered extremely successful.
Dragon’s construction was followed by similar work in the US, leading ultimately to the much larger Fort Saint Vrain Nuclear Power Plant. This suffered from a number of problems due to corrosion and the customer soured on the design. Contracts for similar models in the US that were being signed were cancelled, and although Dragon suffered none of these issues, no orders were forthcoming in Europe either. By this time the market had largely standardized on the pressurized water reactor (PWR) for the large buildout that occurred during the 1970s and 80s, and the decision was made to shut down Dragon.
As of 2023, Dragon is being decommissioned.
Note.
- It appears only two reactors using TRISO fuel have been constructed.
- The 20 MW Dragon reactor was extremely successful.
- The 330 MW Fort Saint Vrain reactor had corrosion problems.
- Both reactors used helium gas as a coolant.
- The Wikipedia entry for the Fort Saint Vrain reactor details the corrosion problems.
- According to Google AI fuel for Fort Saint Vrain was fabricated at the General Atomic Fuel Fabrication Facility in San Diego, California.
- According to Google AI fuel for the Dragon reactor was fabricated on-site at Winfrith.
After writing these seven points, I have concluded that TRISO-fueled helium-cooled nuclear reactor designs better suited to small reactors?
What does Google AI think?
I asked Google AI “Are TRISO-fueled helium-cooled nuclear reactor designs better suited to small reactors?” and received this reply.
TRISO-fueled, helium-cooled reactor designs are exceptionally well-suited for small and micro-modular reactor applications because their physical properties scale down efficiently to provide inherent safety and high-temperature operation.
Why They Suit Small Reactors
Inherent Safety (Walk-Away Safe): Each TRISO fuel particle acts as its own tiny containment system, capable of withstanding extreme temperatures (well over 1,600°C) without melting or releasing radioactive fission products. In a small reactor design, the high surface-area-to-volume ratio allows residual decay heat to dissipate passively through the reactor vessel walls, meaning the reactor cannot suffer a catastrophic meltdown even if active cooling completely fails.
Simplified Helium Cooling: Helium is chemically inert and does not absorb neutrons or become radioactive. In smaller reactor configurations, helium’s single-phase gas state eliminates the high-pressure water loops and massive containment structures required by traditional large light-water reactors.
High-Temperature Process Heat: Because helium can operate at very high temperatures without boiling off, small TRISO-gas systems can deliver high-grade industrial heat (useful for chemical plants or hydrogen production) alongside electricity.
Compact Footprint: Small modular reactor (SMR) and microreactor developers (such as X-energy and Ultra Safe Nuclear Corporation) leverage these traits to design factory-fabricated units that can be transported and sited near urban or off-grid industrial locations.
Key Challenges
Power Density and Size: Helium has a lower volumetric heat capacity than water, meaning gas-cooled cores can be physically bulkier per megawatt than water-cooled equivalents, placing a premium on optimizing core geometry for micro-scales.
Supply Chain and Cost: High-Assay Low-Enriched Uranium (HALEU) and specialized TRISO manufacturing face immature supply chains and higher first-of-a-kind costs.
The more I read about X-energy’s technology, the more I like it.
With Federal Funding Windfall, X-energy Advances Small Nuclear Reactor
The title of this post, is the same as this article on Canary Media.
This is the sub-heading.
The Amazon-backed firm is aiming to build up to 144 of its novel Xe-100 reactors as the U.S. government seeks to revitalize an industry beset by rising costs
These three initial paragraphs add more detail.
The federal government has thrown its weight into reviving America’s long-stagnant nuclear industry, and X-energy’s first-of-a-kind reactor project is among the biggest beneficiaries so far.
The U.S. Department of Energy last month said it would award $1 billion to X-energy, an Amazon-backed advanced nuclear startup working to bring four novel 80-megawatt electric reactors online at a Dow Chemical facility in Seadrift, Texas, in the early 2030s.
The award nearly doubles the federal government’s commitment to X-energy, following a $1.2 billion investment in early 2021. Both tranches were structured as 50-50 cost-sharing agreements under the DOE’s Advanced Reactor Demonstration Program, launched in 2020 to commercialize next-generation nuclear technologies.
Note.
- It looks like X-energy are well-funded.
- It also looks like they have received funding under two different presidents.
- I like Dow’s concept of using nuclear to power a chemical complex, which needs both lots of electricity and heat.
- If they build 144 reactors, this will be twelve of the 12-pack power station, that they have said they will build at Hartlepool and I wrote about in Hartlepool Nuclear Reactor Moves To UK Regulatory Assessment.
The next phase would appear to be up to the regulators.
The article on Canary Media is well worth giving a full read.
These are some important highlights.
Dow Seem Enthusiastic And Would Be An Ideal First Customer
In any large project the first customer is always important.
- Dow seem to fit the part well.
- I also suspect, that as Dow turned over around $40 billion in fiscal year 2025, they know what they want.
Even in nuclear power, the customer is generally right.
Has X-energy Found Any Customers For The Xe-100?
I asked Google AI, this question and received this answer.
Yes, X-energy has secured major commercial customers and strategic partners for the Xe-100 reactor.
Key Customers and Partners
Dow: Partnering to deploy an Xe-100 four-pack plant at the Seadrift chemicals manufacturing site in Texas to provide low-carbon heat and power.
Amazon: Bankrolling and collaborating on up to 12 Xe-100 units via Energy Northwest in Washington state, alongside broader clean energy scaling for AI infrastructure.
Centrica: Partnering in the UK to deploy a potential fleet of up to 6 GW (10 to 20 reactors), targeting the Hartlepool site.
Energy Northwest: A Washington public power utility working collaboratively on project deployment frameworks.
Note.
When, the four partners, of which I was one, started to develop the Artemis project management system, the salesman of the four, did a survey of who might buy.
A proportion of these became valuable clients.
As X-energy also has a world-class engineering partner from Japan and Korea, I feel that they have done their preparation thoroughly.
Where Is The TRISO Fuel To Be Made?
According to the Canary Media article, it will be made near Oak Ridge National Laboratory in Tennessee.
- This could be handy for support.
- It could ease recruiting some of the staff with the right experience.
- There may also be useful sub-contractors in the area, with the right experience and certification.
The location is an excellent one.
Has Centrica Been Recruited Because They Are British?
According to its Wikipedia entry, the Dragon reactor, which used TRISO fuel, was generally considered extremely successful.
So by inviting Centrica to be involved, will X-energy be able to get access to the British files concerning the details of the Dragon reactor?
Their interpretation may be the difference between success and failure of the project.
I wouldn’t be surprised that there is a very trustworthy and knowledgeable network of very elderly British nuclear engineers, who enjoy meeting in pubs, with only the best real ales.
Centrica, X-energy Advance Nuclear Plans As UK Regulators To Begin Design Review For Xe-100
The title of this post, is the same as that of this press release from Centrica.
This is the sub-heading.
On the one-year anniversary of the Centrica X-energy partnership being signed, the UK Government has directed regulators to accept the X-energy Xe-100 Advanced Modular reactor into the Generic Design Assessment, marking a significant step toward UK commercial licensing.
Under their partnership, the companies intend to deploy up to 6 GW of new nuclear capacity in the UK (10-20 Xe-100 power stations depending on size of each installation)
These first two paragraphs add some details.
Centrica and X‑Energy, Inc., a leading developer of advanced nuclear reactors and fuel technology, today announced that X‑energy’s Xe‑100 Generation IV advanced Small Modular Reactor (“SMR”) has been accepted into the United Kingdom’s Generic Design Assessment (“GDA”) process.
GDA acceptance formally triggers the process of assessing the design’s acceptability for deployment and operation ahead of the technical and environmental evaluations required for site‑specific licensing and permitting. The assessment is expected to take approximately three years and will be administered by the UK Office for Nuclear Regulation (“ONR”), the Environment Agency (EA), and Natural Resources Wales
To learn more, I asked Google AI for what it knows on the Xe-100 reactor and I received this.
The Xe-100 is an advanced Generation IV high-temperature gas-cooled pebble-bed small modular nuclear reactor developed by the American company X-energy.
Key Specifications & Design
Power Output: Generates about 80 megawatts of electricity (MWe) or 200 MW thermal per unit, and can be scaled up into a four-pack configuration yielding 320 MW.
Cooling System: Uses inert helium gas instead of water to remove heat from the core, reaching operating temperatures above 750°C.
Fuel Type: Runs on proprietary TRISO-X fuel pebbles, where each billiard-ball-sized pebble contains roughly 18,000 microscopic TRISO fuel particles that act as individual containment vessels.
Note.
- 320 MW may seem small, but you have to remember Sizewell A was two 210 MW Magnox reactors and it operated for forty years.
- I like the choice of helium for a coolant. Especially, as the gas is widely used for cooling superconducting magnets, so there must be plenty of expertise.
- Helium is also present in the atmosphere at 5.2 parts per million.
- I also like the concept of the fuel pebbles.
These are some of my questions.
Where Was TRISO Fuel Developed?
The Wikipedia entry for TRISO Fuel has a History section, which starts with this paragraph.
Coated-particle ceramic fuels were initially developed in the United Kingdom as part of the Dragon reactor project. During the development of the Dragon reactor, its designers became concerned by the need to purge gaseous fission products from the reactor core and their potential migration to other parts of the reactor This concern led to the choice of coated-particle fuel, where the fuel would be formed from small particles of uranium then coated with pyrolytic carbon. The inclusion of silicon carbide as a diffusion barrier was first suggested by D. T. Livey in 1961, in order to better retain fission products.
Note.
- The United States and Germany made contributions to the development of TRISO fuel.
- the first commercial reactor to use TRISO, was the 330 MWe Fort Saint Vrain Nuclear Power Plant
- The experimental High Temperature Test Reactor in Japan, constructed in 1998, uses prismatic UO2 TRISO fuel.
- Japan has the only TRISO-fueled reactor in commercial operation.
- Oak Ridge National Laboratory in the United States, developed the process used to make TRISO fuel.
The Wikipedia entry for the Dragon reactor is worth a read.
These are the first two paragraphs of its Wikipedia entry.
Dragon was an experimental high temperature gas-cooled reactor at Winfrith in Dorset, England, operated by the United Kingdom Atomic Energy Authority (UKAEA). Its purpose was to test fuel and materials for the European High Temperature Reactor programme, which was exploring the use of tristructural-isotropic (TRISO) fuel and gas cooling for future high-efficiency reactor designs. The project was built and managed as an Organisation for Economic Co-operation and Development/Nuclear Energy Agency international project. In total, 13 countries were involved in its design and operation during the project lifetime.
Originally conceived as a small research reactor, during the design phase it grew larger. The choice of helium coolant was made after a long debate within the UKAEA between proponents of helium and carbon dioxide, with helium ultimately selected. Groundbreaking occurred in 1960. It operated from 1965 to 1976, and is generally considered extremely successful.
Who Are The Technology Partners Of X-energy?
I had to ask Google AI this question and received this reply.
X-energy works with major technology, industrial, and energy partners to develop and deploy its advanced small modular nuclear reactors (SMRs) and TRISO-based fuel technology.
Key Technology and Strategic Partners
Amazon and AWS: A primary investor (through the Climate Pledge Fund) and customer, Amazon collaborates with X-energy on scaling nuclear energy for data centers and AI infrastructure. X-energy, Amazon Web Services (AWS), NVIDIA, and Idaho National Laboratory are founding members of Project Prometheus to apply AI to advanced nuclear deployment.
NVIDIA: A founding partner in Project Prometheus alongside AWS and Idaho National Laboratory, helping integrate AI accelerators and tools into nuclear design and operations.
Doosan Enerbility & Korea Hydro & Nuclear Power (KHNP): South Korean industrial partners collaborating to support multi-gigawatt deployments of Xe-100 reactors and manufacture key components.
Energy Northwest: A utility partner working on X-energy’s first-of-a-kind project development in Washington state.
Dow Inc.: Partnered with X-energy to deploy an initial four-unit Xe-100 plant at Dow’s Seadrift chemical manufacturing site in Texas.
Centrica: Partnered through a Joint Development Agreement to deploy Advanced Modular Reactors and pursue up to 6 gigawatts of new nuclear capacity in the United Kingdom.
IHI Corporation: Partnered to expand U.S.-Japan supply chain collaboration and commercial-scale manufacturing for reactor components.
Oak Ridge National Laboratory: Collaborates with X-energy’s fuel subsidiary, TRISO-X, on advanced nuclear fuel research.
Note.
- There are companies and organisations here from Korea, Japan, the US and the UK.
- Do Amazon and Centrica see an Xe-100 reactor as a reliable way of powering a data centre without a grid connection?
- The Korean and Japanese companies would be ideal to ensure the quality of reactor and other key compoonents.
- Chemical manufacturing sites use a lot of electricity and Dow’s contribution could define a widespread use of the Xe-100.
- Oak Ridge have been a client of mine in the past and like AWRE in England, I would trust their nuclear technology.
I also believe that if you put these companies in a joint venture, you’ll get out more ideas than you expect.
Who Are The Financial Partners Of X-energy?
I had to ask Google AI this question and received this reply.
Amazon & Climate Pledge Fund: Led major funding rounds (including a $500 million investment in 2024 and ongoing backing) and holds a significant stake in the company.
Jane Street: Led X-energy’s oversubscribed $700 million Series D financing round.
Ares Management: Provided financial backing and funds across multiple investment rounds alongside special purpose acquisition sponsorships.
Emerson Collective: Participated as a key venture capital backer across multiple funding rounds.
NGP Energy Capital Management: Contributed significant capital through multiple financing stages.
Segra Capital Management: Acted as an ongoing financial participant in major capital raises.
Other Investors: Includes ARK Invest, Point72, Galvanize, Ken Griffin (Citadel founder), XTX Ventures, Reaves Asset Management, and the University of Michigan.
Note that like the technology, the finance comes from a wide variety of sources.
This all sounds like a good positive start.
Will Centrica, X-energy Be Going For A Multi-Country Design Review For Xe-100?
There are four major countries with extensive nuclear power experience, with stakes in the Xe-100; Japan, Korea, the US and the UK.
There is also Oak Ridge in the US, which appears to be supplying the concept of the fuel.
If this group can’t convince the regulators in these four countries, that they have a safe and viable project, then they shouldn’t be in business.
Conclusion
It’s now mainly up to the regulators.
Unfortunately, you get stories with titles like this article on the BBC, which have a title of Green Party Leader Criticises Nuclear Reactor Plan.
