Liquid sodium in primary systems, often with an intermediate sodium or other isolated heat-transport circuit.
Fission System • Liquid-Metal Fast Reactor
Sodium Fast Reactor
A sodium-cooled fast reactor uses liquid sodium to move heat from a fast-spectrum core. Pool-type and loop-type arrangements have both been developed, and many plants use an intermediate heat-transport circuit to isolate primary sodium from the power-conversion system.
Liquid Sodium CoolantFast SpectrumOperating + Demonstration HeritageAdvanced Development
Phase 4 • Page-Specific Technical Summary
What this reactor category means
System definition
A fast-neutron reactor family using liquid sodium as the primary heat-transport medium.
A fast-neutron reactor family using liquid sodium as the primary heat-transport medium.
Intended applications
Electricity, fast-reactor fuel and materials research, actinide-management studies, and high-temperature energy-system development.
Electricity, fast-reactor fuel and materials research, actinide-management studies, and high-temperature energy-system development.
Public boundary
Technology classification, system relationships, maturity, and engineering challenges only. No design parameters, calculations, control logic, procedures, procurement data, or build instructions.
Technology classification, system relationships, maturity, and engineering challenges only. No design parameters, calculations, control logic, procedures, procurement data, or build instructions.
System Architecture • Public-Level Component Map
Major Components
A second view separates the principal system functions for Sodium Fast Reactor. The rendering and callouts are conceptual and intended for public engineering orientation.
- Primary pool or loop and core region
- Primary sodium circulation
- Intermediate heat exchangers
- Intermediate heat-transport system
- Steam generator or alternative conversion interface
- Power conversion and heat rejection
Component boundaries vary by vendor, plant arrangement, coolant choice, power-conversion cycle, site constraints, and licensing basis.
Phase 4 • Concise Comparison
Engineering comparison
Fast-neutron spectrum without a conventional moderator.
Substantial experimental and demonstration heritage, limited operating deployment, and continued advanced development.
Fast-spectrum electricity and fuel-cycle missions, with high-temperature heat transfer at low coolant pressure.
Sodium-air and sodium-water chemical reactivity, leak detection, opaque-coolant inspection, materials compatibility, steam-generator or conversion-interface design, fuel-cycle policy, licensing, cost, and maintainability.
Application Context
Where the family fits
Fast-Reactor Electricity
Grid-power demonstrations and development programs built around sodium’s heat-transfer characteristics.
Fuel & Materials Research
Fast-neutron environments for fuels, structural materials, and reactor-physics validation.
Actinide-Management Studies
Selected closed-fuel-cycle concepts examine resource utilization and long-lived actinide management under national policy controls.
10-Phase Reactor Program • Phase 2
Standardized fission technical specification
Standardized public-safe fields support comparison across every fission and fusion family. Values are intentionally qualitative; licensing data, dimensions, operating windows, calculations, control logic, and build instructions remain offline.
Liquid sodium, usually with an isolated intermediate circuit
Fast spectrum
Metallic or oxide fuel depending program and fuel-cycle mission
Demonstration and limited-deployment fast-reactor plant
Intermediate heat transport to steam or alternative conversion
Substantial experimental and demonstration heritage
Fast-spectrum recycling can improve uranium use and transmute selected actinides, but it does not consume every radionuclide or remove fission-product waste and repository needs.
Specification boundary: Family-level technology classification and lifecycle context—not a vendor datasheet, safety analysis, procurement specification, or construction package.
Ten-Phase Reactor Program · Phase 5
Safety, licensing and public-trust boundary
Sodium chemical reactivity and fire, decay-heat removal, opaque-coolant inspection, leak detection, fuel and core feedbacks, intermediate heat transport, maintenance, and severe-event mitigation.
U.S. advanced-power candidate: Parts 50 and 52 remain available, and the NRC issued Part 53 as an additional risk-informed, technology-inclusive pathway. The exact design, fuel, mission, and site control the route.
Apply nuclear-material control and accounting, physical protection, cybersecurity, transport security, insider-risk controls, and international safeguards as applicable to the exact material and jurisdiction. Do not publish Safeguards Information or adversary-useful detail.
Eligible SMR, non-light-water, and non-power facilities may use the performance-based 10 CFR 50.160 framework. Emergency-planning scope and zone are consequence-informed and design-specific—not automatically the site boundary.
May say the family has a defined operating or research history and can be evaluated through an applicable licensing pathway. State the exact maturity and unresolved design-specific gates.
Do not claim inherently safe, meltdown-proof, waste-free, proliferation-proof, walk-away, unguarded, zero-emergency-zone, automatically cheaper, or licensed because a related reactor operated.
Classification only: This is not a safety finding, licensing opinion, emergency plan, security plan, or legal determination. Exact obligations belong to the applicable regulator and project authority.