|
You have a gun barrel, some of the toughest steel around, which required to contain the supercritical mass long enough to allow for an efficient chain reaction. You stick a cone shaped object down the open end of the gun, and weld, or screw it into place with enough mechanical strength to stop an artillery round and keep it from exiting. More than 1/2 of the critical mass is likely here, with the air gap around it helping to keep the neutron flux low, for the time being. It is likely there is a neutron initiator on the very tip of the conical slug projecting into the barrel. (Think of shoving a ice cream cone into a pipe, narrow end first) On the breech end, you insert a large "hollow point" slug of the rest of the critical mass. (an empty ice cream cone, open end first) The hole in the middle helps keep the neutron flux low, for now. Following this slug is the cordite explosive which will push the slug down the barrel at great speed. The charge is set off, the slug rushes down the barrel, and gets wedged against the sides, in the process it breaks the neutron initiator, crushing it, and setting off a rush of neutrons, into the now complete, supercritical mass. The temperatures and pressures in the gun barrel begin to rise exponentially as the chain reaction takes off, within microseconds it is just the inertia of the barrel that helps keep things in place, the melting and even vaporization temperatures have been passed, but the contents have yet to disassemble completely, the chain reaction reaches its peak as the temperature climbs past 50,000,000 degrees, and then everything spreads outwards, 7/10ths of a gram of mass (the weight of about 3 rain drops) has been converted to energy, yielding the explosive yield equivalent of 15,000 tons of TNT. |