Energy Infrastructure
Kairos Power Pushes to Make Nuclear Construction Repeatable
Sector participant collaboration in Oak Ridge, Tenn., will develop and qualify precast, additive manufacturing and advanced welding methods for future reactor fleets
Alameda, Calif.-based Kairos Power launched an east Tennessee collaboration Aug. 18 to develop and qualify construction and manufacturing methods needed to build advanced nuclear reactors faster and in greater numbers.
Called The Nuclear Center for Advanced Manufacturing and Precast, or NuCAMP, it will initially operate under a 12-month agreement led by Kairos with Oak Ridge National Laboratory, Barnard Construction, the University of Tennessee-Knoxville, the Institute for Advanced Composites Manufacturing Innovation and regional education partners. Samsung C&T Engineering & Construction Group and Cambridge Vacuum Engineering also are exploring advisory roles.
Kairos Power uses test units and reactors to gain experience before larger deployment under its Google deal. Click to enlarge.
Work will focus on precast concrete for safety-related nuclear structures, large-format additive manufacturing of forms used to cast precast components, wire-arc additive manufacturing of large metal components and electron-beam welding. The partners plan to develop technical data to meet code, regulatory and licensing requirements that currently limit some methods in safety-related nuclear construction.
"Delivering affordable advanced reactors at scale will require more than a strong design," Kairos Chief Technology Officer Ed Blandford said in announcing the collaboration. He said deployment also requires manufacturing processes, a technical basis to qualify them under nuclear codes and a workforce trained to use them.
NuCAMP participants told ENR in an Aug. 26 email that the qualification work is intended to establish pathways that other nuclear developers could eventually use, rather than methods specific to Kairos projects.
Testing New Ways to Build
Barnard is general contractor for Kairos' Hermes 1 and Hermes 2 reactor projects at Oak Ridge. ENR reported in 2024 that the contractor was also building a nonnuclear engineering test unit so crews could develop supply-chain, construction and operating experience before applying lessons to safety-related reactor work. Kairos plans to fabricate reactor equipment modules at its Albuquerque, N.M., manufacturing campus and ship them to Oak Ridge for assembly.
Kairos has used that test program to rehearse specific construction operations. Before Barnard began installing 51 safety-related, 6-ft-dia drilled piers extending about 40 ft to bedrock for Hermes 1, crews built a full-scale test pier and installed 70 piers for the company's third engineering test unit. Kairos said crews reached production of as many as six piers per day during that work.
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Foundation work advances for Kairos Power’s Hermes reactor at its Oak Ridge, Tenn., campus. Crews first practiced the drilled-pier installation on a nonnuclear engineering test unit before applying the process to Hermes’ safety-related foundation.
Photo courtesy Kairos Power
Concrete construction is another target.
"Construction has been a major bottleneck for advanced reactors," Ahmed Hassen, ORNL's composites innovation group leader, said in describing the laboratory's work with Kairos.
One challenge was forming complex concrete bioshield structures planned for Kairos reactors. Conventional steel molds would be costly and difficult to fabricate, while wood forms could not provide the required geometric tolerances, according to Ryan Dehoff, director of Oak Ridge National Laboratory's manufacturing science division.
The labiratory and its partners instead produced reusable composite molds using large-format additive manufacturing. Conventional steel molds can require six to eight weeks to fabricate; the team designed, printed and delivered the composite versions in about two weeks, according to the lab..
The molds achieved tolerances of 1/16 in. on critical surfaces and were reused for four bioshield-column pours and three shielding-panel pours without measurable loss of quality, Oak Ridge National Laboratory said. The laboratory estimates concrete structures like radiation shielding can account for up to 60% of nuclear-project schedule risk.
Barnard told ENR it sees an opportunity to shift more concrete work into a factory setting and turn the reactor site increasingly into an assembly operation using off-site fabricated components. On-site precast production and storage also could make assembly schedules more predictable by reducing transportation-related delays, the contractor said.
NuCAMP's challenge is to transition these techniques from successful demonstrations to safety-related construction. Existing nuclear concrete codes generally assume structures are homogeneous and cast monolithically in place, NuCAMP participants told ENR. ASME Section III, Division 2 and ACI 349 do not contain explicit provisions for modular precast joints and 3D-printed concrete, they said.
New methods must therefore be tested to demonstrate they meet existing code requirements. For precast construction, for example, NuCAMP participants said structures assembled from multiple components must be shown to perform like monolithic concrete structures.
Kairos' existing and planned Oak Ridge facilities will host precast production and modular system assembly, the company told ENR. Kairos also is exploring expansion of the campus to add manufacturing capabilities but did not provide size, cost or schedule details.
From First Reactors to Fleets
Kairos broke ground April 17 on Hermes 2, which the company describes as its first commercial-scale reactor and the first project under its multi-plant agreement with Google. Barnard is general contractor. The demonstration plant is designed to supply up to 50 MW to the Tennessee Valley Authority grid and will use precast concrete, modular construction and a seismically isolated foundation. Kairos told ENR it is now piloting precast construction at small scale in Oak Ridge and plans to ramp up production for Hermes 2 and future commercial reactors.
Crews place concrete for the foundation of X-energy’s 215,000-sq-ft TRISO-X nuclear fuel fabrication plant in Oak Ridge, Tenn. Clark Construction is general contractor for the facility, part of a growing nuclear manufacturing buildout in the region.
Photo courtesy X-energy
The Google agreement calls for Kairos to build and operate a series of projects totaling up to 500 MW by 2035, creating a potential pipeline for construction methods developed on the Hermes projects and through NuCAMP.
The work is taking place amid a broader nuclear manufacturing buildout around Oak Ridge. Clark Construction began vertical construction last year on X-energy's 215,000-sq-ft TRISO-X nuclear fuel manufacturing plant there, ENR previously reported. X-energy acquired about 70 additional acres adjoining the campus this month for expansion and received an $11-million Tennessee economic-development grant for the facility.
Oak Ridge National Laboratory Director Stephen Streiffer told ENR last year that building new nuclear facilities would provide the experience needed to reduce risk on subsequent deployments.
"Learning from building those plants is the key to the future," he said.
Fuel from X-energy's Oak Ridge manufacturing operation is intended to support its Xe-100 reactor fleet, beginning with the planned four-reactor Long Mott Generating Station at Dow's Seadrift, Texas, chemical complex.
Other advanced-reactor developers also are moving from first-of-a-kind projects toward repeatable delivery. Bechtel is EPC contractor for TerraPower's estimated $4-billion, 345-MW Natrium plant in Kemmerer, Wyo., where nuclear construction began in April following Nuclear Regulatory Commission permit approval, ENR previously reported.
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TerraPower on Aug. 14 selected Hyundai Engineering & Construction as EPC contractor for as many as eight future Natrium reactors. The framework includes completion, price and performance guarantees that TerraPower says are intended to support conventional financing of subsequent plants.
Kairos is nearing the transition from construction processes to full-scale deployment. Methods tested on engineering units—now applied to Hermes reactors—must still meet nuclear code and regulation standards before they can be used for larger reactor construction programs.
Facts Only
* Kairos Power launched a collaboration on August 18 in East Tennessee.
* The collaboration is called NuCAMP and operates under a 12-month agreement led by Kairos with Oak Ridge National Laboratory, Barnard Construction, the University of Tennessee-Knoxville, and other partners.
* Work will focus on precast concrete for safety structures, large-format additive manufacturing of forms, wire-arc additive manufacturing of metal components, and electron-beam welding.
* The goal is to develop technical data to meet code, regulatory, and licensing requirements limiting some current methods in safety-related nuclear construction.
* Kairos has used test units and reactors to gain experience before larger deployment.
* Barnard was the general contractor for Kairos' Hermes 1 and Hermes 2 reactor projects at Oak Ridge.
* Crews practiced drilled-pier installation on a nonnuclear engineering test unit before applying it to Hermes safety-related foundations.
* Reusable composite molds were produced using large-format additive manufacturing, achieving tolerances of 1/16 in. on critical surfaces for concrete structures.
* Barnard suggests shifting concrete work into a factory setting with off-site fabricated components to improve predictability.
* Kairos is piloting precast construction at small scale in Oak Ridge and plans to ramp up production for Hermes 2 and future reactors.
Executive Summary
Kairos Power initiated a collaboration in August to develop and qualify construction and manufacturing methods for advanced nuclear reactors, focusing on speed and increased numbers. This initiative involves The Nuclear Center for Advanced Manufacturing and Precast (NuCAMP), operating under a 12-month agreement led by Kairos with Oak Ridge National Laboratory, Barnard Construction, the University of Tennessee-Knoxville, and other partners. The work will focus on methods such as precast concrete for safety structures, large-format additive manufacturing forms, wire-arc additive manufacturing of metal components, and electron-beam welding to develop technical data that meets current nuclear codes.
The collaboration aims to establish qualification pathways for these novel methods applicable to future nuclear deployments beyond Kairos' specific projects. Experience gained from prior work, such as developing construction methods on nonnuclear test units, is intended to create transferable knowledge for the broader industry. Furthermore, there is an observed trend where companies are looking to shift construction away from traditional on-site methods toward factory-based assembly using off-site fabricated components to address bottlenecks in project timelines.
Full Take
The narrative illustrates a tension between rapid technological development, demonstrated by advanced manufacturing techniques, and the highly conservative, codified requirements of the nuclear safety industry. The push to implement additive manufacturing and precast methods directly addresses significant project bottlenecks in concrete fabrication, suggesting that speed and reduced risk in construction are directly tied to achieving scalable energy goals. The challenge is bridging the gap between successful laboratory or test-unit demonstrations and formal regulatory acceptance under existing, monolithic structural codes like ASME Section III and ACI 349, which were not explicitly written for modular construction.
This dynamic reveals a pattern where private industry innovation attempts to create new pathways that must then be vetted by established governance structures—the nuclear codes themselves. The focus on creating "pathways" rather than specific project methods suggests an awareness that broad adoption requires systemic change in code-making, not just incremental application of new techniques. The implication is that if the manufacturing process proves its equivalence to monolithic performance under stringent safety criteria, regulatory frameworks must evolve to incorporate modularity and 3D-printed materials.
The larger context involves the industrialization of nuclear deployment, moving from first-of-a-kind demonstration projects to repeatable fleets. The move toward factory assembly for components—as suggested by the contractor and laboratory findings—points toward a future where predictable supply chains reduce risk more effectively than incremental safety checks on every component installation. The pattern suggests that true advancement in energy infrastructure relies not just on engineering breakthroughs but on achieving consensus within regulatory bodies regarding the structural integrity of novel construction methodologies, which requires establishing formalized precedent before mass deployment.
Bridge questions: What specific, verifiable code amendments or test protocols are required to formally recognize modular and 3D-printed concrete joints as equivalent to monolithic structures? How will regulatory bodies balance the need for rapid energy deployment against the imperative for unprecedented safety assurance in novel construction methods? What mechanisms exist to ensure that qualifications developed under NuCAMP transition smoothly into enforceable, standardized procedures across all nuclear developers?