True or false? The "bullet" usually need to initiate the fusion of 235 U is a neutron.?

Question

On a related note, is it true that the capture of the neutron by the 235 U nucleus causes an unstable condition that leads to its disintegration?

Please help! Thank you.

Answer 1

True - although it is fission, rather than fusion.

The "Little Boy" bomb was a "gun-triggered" type fission bomb. The simplest way to bring the subcritical masses together is to make a gun that fires one mass into the other. A sphere of U-235 is made around the neutron generator and a small bullet of U-235 is removed. The bullet is placed at the one end of a long tube with explosives behind it, while the sphere is placed at the other end. A barometric-pressure sensor determines the appropriate altitude for detonation and triggers the following sequence of events:
The explosives fire and propel the bullet down the barrel.
The bullet strikes the sphere and generator, initiating the fission reaction.
The fission reaction begins.
The bomb explodes.

A fission bomb uses an element like uranium-235 to create a nuclear explosion. Uranium-235 has an extra property that makes it useful for both nuclear-power production and nuclear-bomb production -- U-235 is one of the few materials that can undergo induced fission. If a free neutron runs into a U-235 nucleus, the nucleus will absorb the neutron without hesitation, become unstable and split immediately.

As soon as the nucleus captures the neutron, it splits into two lighter atoms and throws off two or three new neutrons (the number of ejected neutrons depends on how the U-235 atom happens to split). The two new atoms then emit gamma radiation as they settle into their new states.

Answer 2

yes.Its true.But the neutron is THERMAL NEUTRON ( a slow moving neutron)as a fast neutron results in uncontrolled chain reaction which is further results in formation of very radio-active substances(like plutonium)due to BETA DECAY.

Answer 3

True, they fire a neutron into U235 to begin fission (not fusion)