Siemens Energy Poised to Partner with Oklo on Aurora Nuclear Reactor

Siemens Energy may be poised to become a crucial equipment and consulting partner for Oklo’s Aurora powerhouse, a liquid metal-cooled fast nuclear reactor.

A memorandum of understanding (MOU) Oklo unveiled on Dec. 19 designates Siemens Energy to become Oklo’s potentially preferred supplier for the rotating equipment in the conventional island of the Aurora powerhouse, including its steam turbine generators. Oklo noted the agreement would also position Siemens Energy to “provide consulting to support” the design and integration of the powerhouse’s conventional island.

For Oklo, the agreement marks a strategic partnership that allows the company to “secure an efficient, reliable, and scalable supply chain for converting that heat into power in our Oklo Aurora powerhouses,” said Alex Renner, senior director of Product at Oklo, in a statement.

Oklo’s Aurora Powerhouse is a vertically oriented compact passive fast-spectrum reactor derived from the Experimental Breeder Reactor-II (EBR-II) that uses liquid metal as a coolant. The company recently uprated its design’s capacity offerings to 15 MWe and 100 MWe. The compact fast reactor uses a high-assay, low-enriched uranium (HALEU) metallic uranium-zirconium fuel enriched to about 19%.

Developing a well-established and reliable supply chain is crucial for deployment scale-up and reliability of Oklo’s power plants, the company added. “Most importantly, this partnership accelerates the commercialization of Oklo’s advanced fission energy solutions, addressing the global need for clean, reliable, and affordable energy sources,” it said.

A Nuclear Legacy

The potential contract signals new momentum for Siemens Energy’s foray into advanced nuclear power. Long before Siemens AG spun off its gas and power business in 2020, forming Siemens Energy, Siemens AG was a full-range nuclear power generation supplier with broad nuclear fuel experience. Under its 1969-founded Kraftwerk Union business (which was eventually reintegrated into Siemens in 1987), Siemens built Germany’s 17 nuclear power plants and supplied reactors to Argentina, Austria, and Brazil. In 2001, Siemens merged its nuclear activities with Framatome (to form Framatome ANP, later AREVA), but in 2009, Siemens announced it would sell its 34% in AREVA.

In 2011, influenced partly by the nuclear downturn after the Fukushima accident, Siemens AG entirely withdrew from nuclear plant building and financing. However, the company continued to make conventional steam turbines and other conventional parts, a business now housed at Siemens Energy. Today, Siemens Energy has more than 60,000 steam turbines worldwide.

While Siemens Energy confirmed its nuclear strategy has remained unchanged since 2009, Siemens Energy has acknowledged nuclear’s significant role in future decarbonized power systems. The company’s annual report, issued on Dec. 6, suggests that in accordance with the European Union’s (EU) taxonomy rules, the company is actively undertaking, funding, or is engaged in research and development of “innovative electricity generation facilities that produce energy from nuclear processes with minimal waste from the fuel cycle.” The annual report also suggests the company carries out, funds, or has exposures to building and operating new and existing nuclear installations.

Siemens Energy’s recent deals in the advanced nuclear space include a November 2021 contract with Terrestrial Energy, developer of the Integral Molten Salt Reactor (IMSR), for the manufacture and supply of steam turbines and other balance-of-plant equipment, such as transformers, switchgear, and motor drive systems, for the IMSR.

“The clean power generated by advanced nuclear is one of the key steps to reaching a net zero future and Siemens Energy’s thermal energy components and services complement the powerhouses being developed by Oklo,” said Tobias Panse, senior vice president of Industrial Steam Turbines and Generators with Siemens Energy, on Tuesday. “Working with Oklo as a preferred supplier will bring us closer to advanced nuclear deployments and our net-zero targets.”

A Deliberate Design Philosophy

Oklo, notably, already has an agreement with Idaho National Laboratory (INL) to demonstrate down-blended HALEU in a commercial-scale Aurora reactor within a 2026 or 2027 timeframe, and it is seeking licensing for the Idaho Falls project. The company is also spearheading the development of the second and third commercial 15-MWe Aurora Powerhouse reactors, which are planned on a land parcel in Piketon, Ohio.

The company has also trailblazed on licensing, though those efforts have been challenging. In March 2020, Oklo submitted the first-ever combined license application (COLA) to the NRC for an advanced non-light water reactor (LWR) for the INL project. While NRC staff in January denied the application “without prejudice,” Oklo, in September 2022, formally relaunched the licensing effort with the submittal of a licensing project plan.

In August 2023, POWER reported that the U.S. Air Force tentatively selected Oklo, issuing a Notice of Intent for its first nuclear microreactor planned for Eielson Air Force Base in Alaska to Oklo. But in September, the Air Force issued a Notice of Rescission “to give further consideration to the agency’s responsibilities” under the governmental acquisition rules.

Oklo CEO Jacob DeWitte told POWER that the action doesn’t constitute an outright “rescission of the contract because there’s no contract yet.” Part of the Notice of Intent award “is to kick off contract negotiations, and part of that process often involves things where the Notice of Intent, because of federal acquisition rules and requirements, are withdrawn and updated,” he said.

The Air Force remains “pretty consistent that they see this as a very exciting, very important part of what they’re doing,” DeWitte said. “But it also includes some things that are a little new, and it’s got some pathfinder elements,” he noted. While the setback poses a probability “that there’s going to be some more delays,” the opportunity “ultimately represents a lot of appetite for even more projects from other elements in the Defense Department,” he said.

Oklo’s projects in Idaho and Ohio are progressing “pretty positively” DeWitte noted. “Structurally, we’ve intentionally built a business that has a significantly differentiated business model and approach that allows you to separate a lot of things,” he said. That aspect is rooted in Oklo’s overall design philosophy, which has targeted the “long game,” he said.

“At the end of the day, we’ve tried to focus on solving from the ground up about how to do some stuff differently,” he said. “There’s a lot of talk about innovation that’s been pretty prevalent in the nuclear industry for the last 10 years and really gotten [more prevalent], especially in the latter part of the last decade going into this one. I think that’s really exciting,” he said. “But it was kind of … tunnel-vision focused on technology alone. That’s part of it, but [it also includes] business model, financing model, it’s go-to market strategies, it’s regulatory strategies. All of that is really important,” he said. “And now I think we’re starting to see the value of why that differentiation is important.”

—Sonal Patel is a POWER senior associate editor (@sonalcpatel, @POWERmagazine).