MSR-100
About
The MSR-100 is a 100 MWe MSR that uses fuel dissolved in liquid fuel salt that also serves as its coolant. The MSR-100 can be used in flexible and remote electricity production. It operates at about 650 degrees Celsius, making it well suited for hydrogen production and industrial refining.
| Developer | Natura Resources |
|---|---|
| Country of Origin | United States |
| Size | Small |
| Type | Molten Salt Reactor (MSR) |
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Analysis
2
Deployment Timescale
Score Justification
Natura Resources is still in the pre-application stages of regulatory engagement for the MSR-100. No similar MSRs have been previously deployed, which limits the clarity of the design’s regulatory and developmental timeline.
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) - 1/5 Supply Chain
How mature and available are suppliers for key reactor components and fuel services? (30% of total score)
4
Overnight Cost
Score Justification
The MSR-100’s Overnight Cost expectations benefit from the absence of large pressure vessels, steam generators, and high-pressure coolant systems. However, specialized materials for molten salt handling systems offset some construction advantages.
By indicator
- 3/4 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)
3
Operational Cost
Score Justification
The MSR-100’s Operational Cost is shaped by molten salt fuel handling and chemistry control and high fuel costs for HALEU. Staffing and decommissioning costs are low, given the small size of the reactor.
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) - 3/4 Maintenance Cost
What is the expected annual maintenance cost for the reactor and balance of plant systems, including consumables? (25% of total score) - 4/5 Staffing Level
How many full-time personnel are required to safely operate and maintain the reactor unit? (40% of total score) - 3/5 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) - 4/5 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 MSR-100’s Cost Predictability is constrained by first-of-a-kind risk, but a full-scale demonstration reactor is under construction at Abilene Christian University in Texas. Modular construction strategies are expected to reduce long-term uncertainty, but early deployments are likely to face learning-curve effects related to salt systems and materials qualification.
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)
4
Security
Score Justification
The MSR-100 uses HALEU fuel. Its thermal spectrum is not optimized to produce weapons-usable nuclear material. Publicly available design information does not explicitly reference the incorporation of security-by-design principles. The reactor is not currently designed for integrated reprocessing, however, Natura has alluded to this potential. Adopting integrated reprocessing would decrease the MSR-100’s Security score.
By indicator
- 2/3 Fuel
What is the enrichment level and composition of the reactor fuel? (40% of total score) - 4/4 Nuclear Material Production
What is the potential for the reactor to produce weapons-usable nuclear material? (40% of total score) - 0/1 Security by Design
Has the reactor developer built in security by design? (20% of total score)
3
Safety
Score Justification
The MSR-100 employs low-pressure operation and molten salt fuel with high temperature tolerance. Reactivity control includes control rods and a passive drain tank-based shutdown mechanism. The design relies on a functional confinement approach with multiple barriers, but it does not include a traditional high-pressure steel containment structure because the reactor operates at low pressure. A regulator has not approved the MSR-100’s safety case because the reactor has not yet been certified.
By indicator
- 0/2 Safety Case
How mature and publicly established is the reactor’s safety case with the regulator? (40% of total score) - 2/2 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) - 2/4 Coolant Reactivity
How chemically reactive is the reactor coolant? (10% of total score)
3
Spent Fuel & Radioactive Waste Management
Score Justification
The MSR-100 can support a compact on-site storage footprint because of its modular plant layout. Waste management involves multiple waste streams associated with liquid fuel salt, off-gas treatment systems, and activated materials such as graphite. Its molten salt fuel form has a low spent fuel volume, which eases the storage burden.
By indicator
- 0/1 Spent Fuel Licensing Precedent
Has the spent fuel form been previously licensed for disposal? (20% of total score) - 2/4 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) - 2/2 Time to Interim Storage
What is the average time until spent fuel can be transferred to interim storage? (15% of total score)
1
Supply Chain
Score Justification
Supply chain maturity is a key constraint for the MSR-100. Nuclear-grade molten salt heat exchangers, corrosion-resistant alloys, and fuel salt preparation remain limited to pilot or research scale. Although efforts are underway to address commercial supply, HALEU availability and fuel fabrication infrastructure remain constrained.
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) - 1/4 Fuel Availability
Are suppliers available for both fuel fabrication and enrichment required by the reactor design? (40% of total score)