Reactor Theory (Reactor Operations)
Calculate the subcritical multiplication factors for the following values of keff.
keff = 0.6
keff = 0.986
The example above illustrates that the subcritical multiplication factor will increase as positive
reactivity is added to a shutdown reactor, increasing the value of keff. If the source strength of
this reactor were 1000 neutrons/sec, the neutron level would increase from 2500 neutrons/second
at a keff of 0.6 to a neutron level of 71,400 neutrons/sec at a keff of 0.986.
Effect of Reactivity Changes on Subcritical Multiplication
In a subcritical reactor, the neutron level is related to the source strength by Equation (4-2).
N (S) (M)
neutron source strength
subcritical multiplication factor