Aurora
About
Aurora is a first-of-a-kind SFR with an electrical output of approximately 75 MWe. Aurora is designed for small-scale electricity production and process heat applications, such as district heating and desalination.
| Developer | Oklo |
|---|---|
| Country of Origin | United States |
| Size | Small |
| Type | Sodium-Cooled Fast Reactor (SFR) |
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Analysis
2
Deployment Timescale
Score Justification
The Aurora has completed a readiness assessment in preparation for a combined license application, but it is not yet in formal regulatory review. Although fast reactors are not new, Aurora has several design features that differ from prior deployments. Once licensed, the design’s modularity can expedite deployment; however, timelines remain dependent on the availability of a fuel supply chain.
By indicator
- 1/4 Regulatory Engagement
To what extent has the reactor developer engaged with a recognized nuclear regulatory authority in the licensing process? (30% of total score) - 3/6 Technology Precedent
Has the reactor design, or a sufficiently similar design, been certified anywhere in the world? (10% of total score) - 3/3 Modularity
What share of total reactor systems can be manufactured off-site in controlled factory environments rather than constructed on-site? (15% of total score) - 3/4 Specialization
To what extent do construction activities and components require lengthy qualification processes? (15% of total score) - 2/5 Supply Chain
How mature and available are suppliers for key reactor components and fuel services? (30% of total score)
5
Overnight Cost
Score Justification
The expected overnight cost of the Aurora reactor unit itself — excluding fuel-cycle infrastructure — is relatively low owing to its small footprint and modular construction approach.
By indicator
- 4/4 Component Cost
What is the expected cost of the reactor’s major components? (40% of total score) - 5/6 Construction Cost
To what extent does the design reduce construction cost and risk through modular fabrication and limited nuclear-grade specialization? (60% of total score)
4
Operational Cost
Score Justification
The Aurora’s non-fuel-related costs associated with reactor staffing, maintenance, and systems operation are expected to be relatively low. However, its fuel and waste management costs are expected to be high.
By indicator
- 1/3 Fuel Cost
What is the estimated cost of nuclear fuel per unit of electricity generated, including enrichment, fabrication, and back-end costs? (15% of total score) - 4/4 Maintenance Cost
What is the expected annual maintenance cost for the reactor and balance of plant systems, including consumables? (25% of total score) - 5/5 Staffing Level
How many full-time personnel are required to safely operate and maintain the reactor unit? (40% of total score) - 2/5 Spent Fuel & Radioactive Waste Management Cost
What are the expected operational costs associated with managing spent fuel, including interim storage, transport, disposal, or recycling? (10% of total score) - 5/5 Decommissioning Cost
What are the total lifetime contributions required for decommissioning, regardless of funding mechanism? (10% of total score)
2
Cost Predictability
Score Justification
The modular construction approach of the Aurora reactor is intended to support repeatability over time. While Cost Predictability for the Aurora remains limited due to the lack of a prototype, Oklo intends to complete a demonstration reactor through the Reactor Pilot Program.
By indicator
- 0/5 Prototype
To what extent has the reactor design been built, demonstrated, or commercially deployed in practice? (75% of total score) - 3/3 Modularity
What share of total reactor systems can be manufactured off-site in controlled factory environments rather than constructed on-site? (25% of total score)
2
Security
Score Justification
The planned use of a reprocessed, plutonium-bearing fuel for Aurora would introduce weapons-usable material into the fuel cycle, creating additional nuclear security considerations relative to designs optimized for a once-through fuel cycle. Plutonium-bearing fuel, including plutonium comingled with other transuranics, poses significant security risks.
By indicator
- 1/3 Fuel
What is the enrichment level and composition of the reactor fuel? (40% of total score) - 3/4 Nuclear Material Production
What is the potential for the reactor to produce weapons-usable nuclear material? (40% of total score) - 1/1 Security by Design
Has the reactor developer built in security by design? (20% of total score)
2
Safety
Score Justification
The Aurora uses liquid sodium coolant, which is chemically reactive but allows the reactor to operate at low or near-ambient pressure. Shutdown is achieved through gravity-aided control rod insertion supported by inherent negative reactivity feedback. The design incorporates a sealed core configuration and relies on passive heat removal through natural convection, enabling decay heat removal without operator intervention. These features support passive safety performance while introducing some material-specific handling and design considerations associated with sodium coolant.
By indicator
- 0/2 Safety Case
How mature and publicly established is the reactor’s safety case with the regulator? (40% of total score) - 1/2 Shutdown Mechanism
How diverse, independent, and passive are the reactor’s shutdown systems? (20% of total score) - 1/1 Fuel With Safety Characteristics
Does the reactor use fuel with accident tolerance or inherent safety characteristics? (10% of total score) - 2/4 Pressure & Containment
How well does the reactor’s containment strategy protect from the release of radioactive material? (10% of total score) - 3/3 Passive Heat Removal
How long can the reactor remove core heat without operator intervention? (10% of total score) - 1/4 Coolant Reactivity
How chemically reactive is the reactor coolant? (10% of total score)
2
Spent Fuel & Radioactive Waste Management
Score Justification
The Aurora’s use of a closed fuel cycle may reduce the volume of spent fuel requiring disposal, but it creates extra waste streams that complicate management and final disposition of waste. The footprint needed for a geologic repository is a function of heat load, not volume.
By indicator
- 0/1 Spent Fuel Licensing Precedent
Has the spent fuel form been previously licensed for disposal? (20% of total score) - 1/4 Waste Streams
How many distinct waste streams require separate conditioning or handling pathways? (20% of total score) - 3/3 On-Site Storage
How much on-site area is required for interim spent fuel storage? (10% of total score) - 3/3 Spent Fuel Volume
What volume of spent fuel is produced per unit of electricity generated? (15% of total score) - 1/2 Decay Heat
What is the decay heat output of spent fuel at the 50-year interim storage milestone? (20% of total score) - 1/2 Time to Interim Storage
What is the average time until spent fuel can be transferred to interim storage? (15% of total score)
2
Supply Chain
Score Justification
The Aurora lacks a commercial supply chain for its fuel, inclusive of both HALEU fuel and reprocessed plutonium-bearing fuel options. Whereas commercial suppliers exist for many reactor components, supply chains for nuclear-grade sodium coolant and associated systems remain limited and would require further development to support deployment at scale.
By indicator
- 1/2 Key Component Availability
To what extent are commercial or pilot-scale suppliers available for the reactor’s major components? (60% of total score) - 2/4 Fuel Availability
Are suppliers available for both fuel fabrication and enrichment required by the reactor design? (40% of total score)