Final answer:
The number of detonators used to initiate a detonating cord in critical blasts depends on the specifics of the blast design and the explosive's properties. For complex operations such as detonating a plutonium bomb, precision is paramount, involving shaped charges and a neutron source, with careful timing for the initiation.
Step-by-step explanation:
The question pertains to the use of detonators in initiating detonating cord in critical blasts, such as in the case of controlled demolitions or precise military operations.
Due to the variety and complexity found in different situations where detonating cords might be used, there is no standard number of detonators recommended for all cases.
Instead, the number of detonators is determined by the specifics of the blast design, the type of explosive, its sensitivity, and other critical safety factors.
In the context of a critical blast involving nuclear materials, such as the implosion technique used in the plutonium bombs during World War II, this is especially sophisticated.
The precise initiation of a plutonium bomb involves surrounding a sphere of plutonium with shaped charges that implode the material into a smaller volume, exceeding the critical mass and starting a chain reaction.
This requires a precise timing mechanism and a neutron source initiator to be triggered at the exact right moment. The complexity of such an operation underscores the importance of expertly calculated use of detonators and shaped charges to ensure both efficacy and safety.