Insertion time

• To start with a subcritical system
• To create a super prompt critical system
• To make the change between these two states in a length of time which is shorter than the time between the random appearance of a neutron in the fissile material through spontaneous fission or by other random processes.
• Also at the right moment in time, neutrons must be injected into the fissile material to start up the fission process. This can be done by several methods.
• * Alpha emitters such as polonium or plutonium-238 can be rapidly combined with beryllium to create a neutron source.
• * Neutrons can be generated using an electrostatic discharge tube, this tube uses the D-T reaction.