TMSR-LF1


About

The TMSR-LF1 (Thorium Molten Salt Reactor-Liquid Fuel 1) is a thermal molten salt experimental reactor that operates at 2 MWt. The TMSR-LF1 relies on a thorium fuel cycle and incorporates online reprocessing. Although the TMSR-LF1 is an experimental reactor, SINAP plans for it to be the first step to commercializing the technology. The TMSR-LF1 is not designed to produce electricity at this stage, but later versions of the design could. It operates at 600 degrees Celsius, making it well suited for process heat applications like industrial refining, hydrogen production, and district heating.

DeveloperSINAP (Shanghai Institute of Applied Physics)
Country of OriginChina
SizeMicro
TypeMolten Salt Reactor
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Analysis

3

Deployment Timescale

3%

Score Justification

The TMSR-LF1 has obtained an operating license, reflecting regulatory progress for molten salt reactor technology. While the molten salt supply chain remains limited, the design relies on relatively simple construction techniques and does not require a high proportion of nuclear-grade components, supporting shorter construction timelines despite limited modularity.

By indicator

  • 4/4 Regulatory Engagement
    To what extent has the reactor developer engaged with a recognized nuclear regulatory authority in the licensing process? (30% of total score)
  • 6/6 Technology Precedent
    Has the reactor design, or a sufficiently similar design, been certified anywhere in the world? (10% of total score)
  • 1/3 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)

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4

Overnight Cost

4%

Score Justification

The small footprint of the TMSR-LF1 lends itself to inexpensive overnight costs. A more modular design would further decrease costs. 

By indicator

  • 4/4 Component Cost
    What is the expected cost of the reactor’s major components? (40% of total score)
  • 3/6 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)

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4

Operational Cost

4%

Score Justification

Operational Cost for the TMSR-LF1 is driven by the reactor’s use of thorium-based fuel in molten salt form, and the additional waste management and safeguards requirements associated with online reprocessing. The production and handling of uranium-233 introduce added security, monitoring, and accounting costs. 

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)
  • 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)
  • 5/5 Decommissioning Cost
    What are the total lifetime contributions required for decommissioning, regardless of funding mechanism? (10% of total score)

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2

Cost Predictability

2%

Score Justification

As a prototype reactor, the TMSR-LF1 provides an initial cost baseline, but further deployments will increase confidence in the cost. 

By indicator

  • 2/5 Prototype
    To what extent has the reactor design been built, demonstrated, or commercially deployed in practice? (75% of total score)
  • 1/3 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)

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1

Security

1%

Score Justification

Publicly available information does not explicitly reference the incorporation of security-by-design principles in the TMSR-LF1 design. The reactor’s thorium fuel cycle and online reprocessing result in the production of separated uranium-233, a weapons-usable material that requires enhanced monitoring, material accountancy, and physical protection measures compared with conventional LWR designs.

By indicator

  • 1/3 Fuel
    What is the enrichment level and composition of the reactor fuel? (40% of total score)
  • 1/4 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)

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4

Safety

4%

Score Justification

The TMSR-LF1 incorporates multiple fully passive shutdown mechanisms. In addition to negative reactivity feedback, the reactor employs a passive freeze-plug system that allows the fuel salt to drain into a subcritical configuration if temperatures exceed design limits, providing an inherent shutdown response without operator intervention.

By indicator

  • 2/2 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)

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3

Spent Fuel & Radioactive Waste Management

3%

Score Justification

The TMSR-LF1’s online reprocessing results in multiple, complex waste streams that require specialized handling and security arrangements. Reprocessing also contributes to the accumulation of long-lived actinides and fission products, which can increase decay heat at longer storage timescales, including around the 50-year milestone.

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)
  • 2/2 Time to Interim Storage
    What is the average time until spent fuel can be transferred to interim storage? (15% of total score)

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1

Supply Chain

1%

Score Justification

Elements of a molten salt reactor supply chain exist, but further development would be required to support commercial-scale deployment of integrated molten salt reactors.

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)
  • 0/4 Fuel Availability
    Are suppliers available for both fuel fabrication and enrichment required by the reactor design? (40% of total score)

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