Full core reference
Historic graphite assemblies show the scale and channel logic behind moderated salt systems.
SourcesGraphite moderation
Shape the neutron spectrum and the core economics.
Graphite is not just a structural feature. In a thermal-spectrum MSBR, moderator geometry affects breeding potential, salt channel layout, power density, and replacement planning.
Core role
Thermal-spectrum breeding
The moderator slows neutrons into a range where the thorium cycle can be attractive. The tradeoff is material lifetime, dimensional change, inspection, and replacement strategy.
ThermalNeutron spectrum
CoreGeometry driver
Moderator decisions
Core design has to balance neutron economy against mechanical lifetime. The moderator should support salt flow, heat removal, inspection, and planned replacement without turning maintenance into a custom outage every time.
Channel geometryFuel salt passages control moderation ratio, hydraulic losses, and temperature distribution.
Lifetime planningGraphite dimensional change and irradiation effects must be designed into replacement economics.
Neutron economyModeration choices affect conversion, parasitic capture, and margin for online cleanup.
Inspectable modulesThe core should be planned around modular inspection and replacement pathways.
Next: fuel cycle
The moderator only matters commercially if it helps turn fertile material into reliable heat and long-term fuel value.