By Andre Pienaar
When the Silicon Valley Defense Group (SVDG), backed by J.P. Morgan, released its 2025 NatSec100 rankings, most headlines focused on AI, autonomy, cyber and space. But one development should make national security leaders sit up: C5 Capital’s advanced nuclear energy portfolio company X-energy has been named a Top 10 company on this year’s list.
For a ranking long dominated by software and sensors, a clean-energy, advanced nuclear fuel and reactor company breaking into the top tier is not a curiosity. It is a strategic signal that energy security is now recognised as core national security – on a par with AI chips, counter-drone systems and space launch.
The NatSec100 is not a vanity list. It is a data-driven, momentum-based ranking of the top 100 venture-backed defence and dual-use companies contributing to the US National Security Innovation Base. SVDG relies on measurable indicators: capital raised, hiring, contracts, and engagement with the national security community.
The list is built around three ideas:
• Momentum, not hype – companies moving from concept to scale.
• Dual-use relevance – technologies with both commercial and defence applications.
• Strategic fit – alignment with US national security priorities and trusted ownership.
Historically, that has meant a heavy tilt towards AI, cyber, software and space. X-energy’s arrival in the Top 10 broadens that aperture and brings energy infrastructure squarely into the centre of the defence-tech conversation.
X-energy did not secure this position through marketing. It arrived in the Top 10 on the back of hard infrastructure, capital formation and execution.
In recent months, the company has:
• Closed an approximately $700 million oversubscribed Series D round, positioning itself to scale deployment of its Xe-100 small modular reactor (SMR) and TRISO-X fuel technology globally.
• Started vertical (above-ground) construction of its TX-1 advanced nuclear fuel fabrication facility in Oak Ridge, Tennessee – expected to be the first US facility dedicated exclusively to advanced SMR fuel, and the first new US fuel facility in more than half a century.
• Advanced a fuel-qualification campaign at Idaho National Laboratory, putting its TRISO-X fuel pebbles through the rigorous testing required for first-of-a-kind commercial deployment.
Once complete and licensed, TX-1 is designed to produce on the order of 5 metric tonnes of uranium per year, or roughly hundreds of thousands of TRISO fuel pebbles annually – enough to power a substantial fleet of Xe-100 reactors. This is not a pilot lab; it is a cornerstone of a new domestic advanced-fuel ecosystem.
On the deployment side, X-energy is driving two flagship projects:
• A multi-unit Xe-100 plant with Dow on the Texas Gulf Coast, under the DOE’s Advanced Reactor Demonstration Program, to provide clean power and industrial steam to a critical chemicals and materials hub.
• A major project with Energy Northwest in Washington State, with Amazon as a key partner, linking advanced nuclear directly to the resilience of hyperscale data centres and sovereign compute.
In other words, X-energy sits at the junction of defence, industry and digital infrastructure – exactly where 21st-century power security must be built.
X-energy’s top ranking has three major implications.
First, it confirms that energy resilience is a form of deterrence.
In an era of great-power competition and systemic cyber risk, a country’s ability to keep its factories, ports, bases and data centres powered may be as important as any single weapons system. Advanced reactors like the Xe-100, supplied by domestic fuel facilities like TX-1, can harden critical infrastructure against grid disruption and coercive energy tactics, reduce dependence on fragile fossil-fuel supply chains and contested sea lanes, and enable forward-deployed, energy-independent nodes for the US and allied forces.
Placing X-energy in the Top 10 is an acknowledgement that controlling the advanced fuel cycle is a strategic advantage.
Second, it highlights the gap – and opportunity – between private capital and public demand.
NatSec100 data shows tens of billions of dollars flowing from private investors into defence-relevant companies – far outpacing US government contracts and programmes. In capital-intensive sectors like nuclear, that imbalance is even more pronounced.
By elevating X-energy, the NatSec100 sends a clear message: investors see advanced nuclear as an investable, scalable solution, not a science project. Policymakers must now catch up, with long-term offtake commitments, export finance, insurance solutions and industrial policy that treats nuclear fuel and reactors as mission-critical infrastructure, not niche climate projects.
Third, it expands the definition of “defence tech”.
Defence technology is no longer confined to weapons and software. It now encompasses grid and data-centre power as a national security function; industrial decarbonisation as protection against geopolitical energy shocks; and fuel fabrication and nuclear supply chains as strategic choke points on a par with microelectronics and rare earths.
X-energy’s Top-10 status helps cement that broader view.
For America’s allies in Europe, the Gulf, Africa and the Indo-Pacific, X-energy’s NatSec100 ranking offers a clear shorthand. It signals a company vetted by the US national security innovation community, backed by substantial private capital, and building the reactors and fuel infrastructure that will underpin future industrial and digital growth.
For sovereign wealth funds, export credit agencies and development finance institutions, partnering with companies of this calibre is fast becoming a pathway into a shared, nuclear-enabled security architecture with the United States.
At National Security News, we have consistently argued that advanced nuclear energy and secure fuel supply chains belong at the centre of US and allied security strategy.
X-energy’s rise into the NatSec100 Top 10 is both validation and challenge: validation that serious, quantitative analysts now treat reactors and fuel plants as part of the core defence industrial base; and challenge to governments and allies to match private momentum with public commitment – in policy, procurement and partnership.
As concrete rises at TX-1 in Oak Ridge and Xe-100 projects advance from design to deployment, we should see X-energy not merely as a successful company, but as a test case for whether the United States and its allies are ready to build the energy backbone of a secure 21st-century order.
Andre Pienaar is an international investor in national security, a co-founder of the Directorate of Special Operations (DSO), Mandela’s elite law enforcement unit, and a member of the International Advisory Council of the US Institute for Peace.