Thorium Fuel Cycle Reaction Initiation

[DLHill]

In an liquid fluoride thorium reactor, how is the reaction started? My assumption would be a piece of fissile material would be somehow inserted into the fuel to introduce neutrons to the solution, but I have not found any information to show if this is how the reaction is started. If this is not it, how do the reactors begin breeding and fissioning the U 233?

 

[Astronuc]

In an liquid fluoride thorium reactor, how is the reaction started? My assumption would be a piece of fissile material would be somehow inserted into the fuel to introduce neutrons to the solution, but I have not found any information to show if this is how the reaction is started. If this is not it, how do the reactors begin breeding and fissioning the U 233?

An LFTR would start with U-235 with U-233 increasing as it is produced in the system. U-233 would be chemically separated from the recirculating solution. Likely there would be 'neutron sources' placed in the reactor system.

One can look at the operation of the MSR at ORNL.

 

[QuantumPion]

The liquid fuel becomes critical as it flows through graphite moderator channels, sort of like an RBMK.