1.29 x 1012
1 x 1020atoms
3 x 1013
4.3 x 1022 cm2
1 x 1024 cm2
1 x 107 watt sec
1.602 x 106erg
3.12 x 1010fissions
Reactor Theory (Neutron Characteristics)
To find the microscopic cross section, replace
with (N x
) and solve
Reactor Power Calculation
Multiplying the reaction rate per unit volume by the total volume of the core results in the total
number of reactions occurring in the core per unit time. If the amount of energy involved in each
reaction were known, it would be possible to determine the rate of energy release (power) due
to a certain reaction.
In a reactor where the average energy per fission is 200 MeV, it is possible to determine the
number of fissions per second that are necessary to produce one watt of power using the
following conversion factors.
1.602 x 10 ergs
1 x 10 watt-sec
This is equivalent to stating that 3.12 x 10 fissions release 1 watt-second of energy.