Monte Carlo Binary Collision Approximation

When uranium-235 undergoes fission, the average of the fragment mass is about 118, but it is more probable that the pair will have an unequal distribution in mass. A common pair of fragments from uranium-235 fission is xenon and strontium:

[math]^{235}U+n\rightarrow ^{236}U^{*} \rightarrow ^{140}Xe+^{94}Sr+2n[/math]