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Oklo Relaunches NRC Licensing Process for Nuclear Microreactor

A rendering of the Aurora powerhouse, a 1.5-MW fission power system being developed by Oklo Inc. Source: Oklo Inc.

Oklo, the developer of the much-watched 1.5-MW Aurora microreactor, has submitted a recharged licensing project plan (LPP) with the Nuclear Regulatory Commission (NRC), launching a renewed effort that could help the advanced nuclear reactor developer set the stage for “effective and efficient” application reviews by the federal regulator.

The move is a significant step for Oklo, which in March 2020 submitted the first-ever combined license application (COLA) to the NRC for an advanced non-light water reactor (LWR) that it has proposed to build and operate at the Idaho National Laboratory (INL). The NRC staff in January, however, denied the application “without prejudice,” citing Oklo’s “failure to provide information” on additional technical information related to the maximum credible accident and the safety classifications of the reactor’s systems, structures, and components (SSCs). While the action ended the NRC’s review of the Oklo Aurora COLA, it left the door open for Oklo to submit a revised application in the future.

Oklo’s submittal of the new LPP to the NRC in early September marks a formal effort to relaunch the trailblazing licensing effort. The LPP, which is similar to regulatory engagement plans that other developers have developed, essentially outlines Oklo’s proposed engagement pre-licensing interactions with NRC staff. The approach is important because “it establishes a clear line of sight between Oklo and the NRC on the timing and selection of pre-application engagement to ensure both a successful and efficient review,” Caroline Cochran, Oklo’s co-founder and the chief operating officer told POWER on Sept. 16. 

Trailblazing on Licensing

The effort is being closely monitored by the nation’s power industry. While a recent industry survey suggests U.S. utilities expect to add up to 90 GW—including an estimated 300 new small modular reactors (SMRs)—of new nuclear generation by the 2050s to alleviate compounding decarbonization and reliability challenges, licensing has long been a significant hurdle for nuclear new builds.

Historically, the NRC has taken five years or more to conduct a license review and make safety determinations for large light water reactors (LWRs). To support advanced nuclear reactor deployment—including a burgeoning fleet of non-LWRs—within the next decade, Congress in the 2019–enacted Nuclear Energy Innovation and Modernization Act (NEIMA) directed the NRC to develop a performance-based, risk-informed, technology-inclusive licensing pathway for commercial reactors. NEIMA also notably requires the NRC to develop a licensing process for advanced reactors that is “predictable, efficient, and timely.” So far,  the NRC is currently developing a new licensing pathway, 10 CFR Part 53, and plans to complete the rulemaking by the end of 2024 to fulfill that mandate.

To meet near-term deployment timeframes, several non-LWR advanced reactor developers, like Oklo and Kairos, are spearheading applications under the NRC’s existing licensing pathways, Part 50 and Part 52. So far, all 92 commercially operating nuclear reactors at the nation’s 54 nuclear plants have been licensed under 10 CFR Part 50, which is a historical two-step process involving a construction permit and an operating license as the plant approaches completion. In the 1990s, the NRC approved a second pathway, 10 CFR Part 52, which allowed an applicant to receive a combined license for construction and operation. (See POWER’s brief explainer on NRC nuclear new-build licensing here: “Vogtle 3 Gets NRC’s Approval to Begin Operation in Significant Regulatory Milestone for U.S. Nuclear Industry.”)

Effectively navigating a regulatory frontier, advanced reactor developers have sought to customize these regulatory constructs to their technologies’ size and unique characteristics. When Oklo submitted its pioneering COLA in March 2020, it marked the first time the NRC received an application for a custom combined license (COL) not referencing a certified design. As Oklo noted at the time, the COLA followed a September 2018-submitted “pilot” application based on the NRC’s draft regulatory guide (DG-1353), which was designed to give regulators and technology developers more insight into permit, licensing, and certification applications. In its pilot application, Oklo pointed out that the NRC “does not require applicants to follow a certain structure for applications,” noting that the application structure uses for operating commercial LWRs was developed after several plants had been built. As Oklo CEO and co-founder Jacob DeWitte has noted, Oklo’s COLA was also pioneering because it is the first that was privately funded and the first to be submitted online.

Oklo’s pioneering COLA approach was focused on a rigorous engagement with NRC staff. When the NRC abruptly dismissed Oklo’s application in January, the company said it was blindsided. “Although Oklo responded to every request for information, and the last thing we heard from the NRC was that the information we submitted was helpful, the NRC has denied our first application on the basis of not having submitted information,” it said in a candid blog post in January. “Yes, it was surprising. And there are elements that were frustrating and even angering.”

Oklo, however, remains “energized,” and has even found “silver linings” in the dismissal. “The NRC actions are catalyzing a new wave of support, momentum, and introspection from those that support advanced fission. This might not have happened in the same way had we proceeded on what we and everyone imagined would be a slow process of many smaller ‘paper cuts,’ ” it said. While the company acknowledges it wasn’t “perfect on [its] first try,” it said it would resubmit a COLA based on what it learned through the first review.

A Renewed Strategy

The new LPP will be pivotal to Oklo’s path forward, Cochran said. While Oklo submitted numerous LPPs in advance of the 2020 COLA, “This LPP builds on the pre-application lessons learned, as well as NRC staff feedback, from the submittal of the Aurora COLA, to ensure clear alignment and resolution of any potential technical or policy questions in advance of our next license application submittal,” she said.

The company hasn’t yet pinned down when its next license application submittal will be made, but the new LPP will serve to enable efficiency, Cochran added. “Reaching resolution on these topics can reduce COLA review times in the future, supporting our initial timeline for deployment of our reactor at INL,” she said.

Oklo’s DeWitte on Tuesday, meanwhile, noted that the company has already checked off some key NRC requirements, including approval for its quality assurance program description in 2020. It has also identified unique licensing considerations: The 2020 COLA contained more than “200 novel licensing items” that the company developed. “Oklo’s reactor design has excellent safety characteristics and robust performance features. We are working to present these features in a manner similar to what the NRC is used to from licensing Light Water Reactors,” DeWitte said. “To achieve a transparent and effective review process, Oklo has responded to every NRC request for information promptly, and we look forward to continuing to engage with NRC as we prepare for upcoming application submissions,” he said.

Effective and efficient engagement is a key aspect of the streamlined approach. “Our interactions, including in-person discussions, and our LPP submission set the pace for successful reviews while ensuring feedback from those interactions is incorporated into future regulatory interactions,” explained Tracy Orf, Oklo’s senior licensing manager. “We enjoyed productive and constructive pre-application engagements with the NRC leading up to our Aurora Idaho National Laboratory COLA from 2016 through 2020, and our use of LPPs was a valuable tool in guiding that process,” she said. Oklo will now leverage “decades of operational data” and “experience and familiarity” with NRC staff to pursue “intentional and focused licensing interactions,” she said.

Learning Lessons From Recent Industry Triumphs

Oklo’s renewed licensing process will also reap industry winds stemming from significant regulatory triumphs by other advanced reactor developers. In July 2022, the NRC certified NuScale’s 50-MWe (160 MWth) SMR designIn December 2021, the NRC accepted Kairos Power’s construction permit application (CPA) for its Hermes non-power demonstration reactor, which the firm has proposed to build at the East Tennessee Technology Park Heritage Center site in Oak Ridge, Tennessee, and begin operating by 2026. And in August 2022, the NRC gave Southern Nuclear Operating Co. the green light to load fuel and begin the operation of an AP1000 nuclear reactor—a Generation III+ reactor—at Vogtle Unit 3 in Georgia. The authorization moves Vogtle 3 out of the NRC’s construction reactor oversight program and into the operating reactor oversight process—effectively making Vogtle 3 the first reactor in the nation to reach the milestone as part of the regulator’s Part 52 combined license process.

In tandem, the NRC is in discussions with GE Hitachi on its BWRX-300 SMR design, as well as with the Tennessee Valley Authority for a construction permit and future operating license application for the Clinch River site in Tennessee. Separately, the NRC is engaging with SMR, a Holtec International subsidiary, on its SMR-160 SMR design. Several non-LWR reactor designers have also formally notified the NRC of their intent to engage in regulatory interactions.

These include General Atomics for its Energy Multiplier Module, Terra Power and GE Hitachi for their Natrium reactor, Westinghouse for its eVinci microreactor, Terrestrial Energy for its IMSR, X-Energy for its XE-100 design, Terra Power for its molten chloride fast reactor, and Ultra Safe Nuclear Corp. for its high-temperature gas-cooled test reactor at the University of Illinois at Urbana-Champaign. In addition, TRISO-X, a subsidiary of X-energy, in April submitted a license application for a high-assay low-enriched uranium fuel fabrication facility to produce tristructural isotropic fuel (TRISO). And in August, Ultra Safe Nuclear opened a pilot fuel manufacturing facility that will produce TRISO-coated fuel particles and the company’s proprietary fuel for use in its high-temperature gas reactor. The facility features “licenses for processing pilot-scale quantities of both natural and enriched uranium needed for fuel production,” the company said.

According to Oklo, these are big steps that underscore momentum for the advanced nuclear industry. “We are excited to see how the NRC has moved forward on the NuScale design certification and novel standard design approval applications, as well as the Kairos construction permit application for their non-power reactor,” said Cochran. However, Oklo’s next steps will be unique to its technology.

A key differentiator to a combined license application is the inclusion of not just design or construction-related information but all of the important operations-related information and all other information required for combined license applications,” Cochran noted. “The NRC has continued to advance their work in many important areas since Oklo first engaged in pre-application in 2016 and even since the first COLA application in 2020, including in the areas of security, operations, and environmental reviews. Additionally, in our interactions, the NRC has demonstrated improved flexibility in the mechanisms by which it enables information sharing and provides feedback. This improves pre-application engagements and leads to more effective reviews,” she said. 

Technology Development Continues at Oklo

Alongside its regulatory development, Oklo steadily working on technology development, including for the Aurora product line—though “any changes or updates were internally driven and not required based on feedback from the initial Aurora COLA review,” Cochran noted. 

The company is developing a compact fast reactor that it says could bring distributed, carbon-free, affordable, and reliable nuclear power to “high-cost power areas” in the U.S. Oklo’s technology uses a core comprising solid metallic uranium-zirconium fuel that produces heat. The heat is transported using heat pipes, which function as thermal superconductors. The design, notably, uses no pumps or valves that interact with the core, and it has no flowing coolant into and out of the core.

“It is designed to have very low burnup. The size of the reactor is similar to that of a research reactor. Because of this small size, the reactor decay heat power at 24 hours after shutdown is very small and manageable in comparison with larger reactors, being on the order of tens of kilowatts or on the order of a single running motorcycle engine. The materials used in the reactor have been designed to use materials with significant historical databases of testing data at appropriate temperatures and irradiation,” the company says.

Oklo in 2019 received a first-of-its-kind site use permit to build its Aurora plant, a fast reactor, at an INL site in Idaho Falls, Idaho, and in 2020 also became the first modern advanced reactor design firm to secure access to recycled high-assay, low-enriched uranium (HALEU) fuel from INL for demonstration purposes. The planned demonstration in a full-size Aurora microreactor is a big step that could accelerate the deployment of commercially viable microreactors.

Among Oklo’s more recent developmental milestones is an agreement signed in February 2022 with Argonne National Laboratory to commercialize electrorefining technology to recycle fuel for use in advanced fission power plants. In May, Argonne added new capabilities to support testing of liquid metal fast reactors. The national lab will run its first test with Oklo under a U.S. Department of Energy’s Gateway for Accelerated Innovation in Nuclear (GAIN) voucher.

Source: Power Magazine