X-Energy Reactor Company, a developer of advanced nuclear reactor and fuel technology, has completed an upsized Series C-1 financing round, raising $700m.

The investment includes participation from Segra Capital Management, Jane Street, Ares Management funds, and Emerson Collective, among others. These investors join previously announced backers such as Amazon.com’s (Amazon) Climate Pledge Fund, an affiliate of Citadel Founder and CEO Ken Griffin, affiliates of Ares Management Corporation, NGP, and the University of Michigan.

X-energy founder and executive chairman Kam Ghaffarian said: “We are proud to have gained the additional support from our industry, government, and investment community since X-energy was founded more than 15 years ago.

“We look forward to continuing to advance and scale our technology and realize our vision of fulfilling the growing energy needs of future generations.”

The funding will support the completion of X-energy’s reactor design and licencing, as well as the first phase of its TRISO-X fuel fabrication facility in Oak Ridge, Tennessee.

It will also facilitate future carbon-free projects incorporating the company’s Xe-100 advanced small modular reactors (SMRs).

X-energy’s Xe-100 reactor and TRISO-X fuel are designed to be among the safest and most reliable clean energy technologies available. Each Xe-100 reactor unit is engineered to generate 80MW of electricity, with multi-unit plants ranging from 320 MW to 960 MW.

The modular design is road-transportable and aims to enhance geographic scalability, shorten construction timelines, and provide more predictable project costs.

The company is currently developing its first Xe-100 plant at Dow’s UCC Seadrift Operations manufacturing site on the Texas Gulf Coast. This initiative, supported by the US Department of Energy’s Advanced Reactor Demonstration Program, is expected to be the first grid-scale advanced nuclear reactor deployed to serve an industrial site in North America. The plant will deliver zero-carbon electricity and high-temperature steam to the facility.

Additionally, X-energy and Amazon are collaborating to bring over five gigawatts of new power projects online across the US by 2039. Their efforts include direct project investments in development, licencing, and construction, as well as long-term power purchase agreements to supply Amazon’s operations. X-energy and Amazon also plan to establish a standardised deployment and financing model in partnership with infrastructure and utility stakeholders.