Reactor Theory (Reactor Operations)
If the term M in Equation (4-2) is replaced by the expression 1/1-keff from Equation (4-1), the
following expression results.
A reactor contains a neutron source that produces 110,000 neutrons per second. The
reactor has a keff of 0.986. Calculate the stable total neutron production rate in the
The neutron production rate is calculated using Equation (4-3).
7.86 x 106
To this point it has been necessary to know the neutron source strength of the reactor in order
to use the concept of subcritical multiplication. In most reactors the actual strength of the
neutron sources is difficult, if not impossible, to determine. Even though the actual source
strength may not be known, it is still possible to relate the change in reactivity to a change in
Consider a reactor at two different times when keff is two different values, k1 and k2. The
neutron level at each time can be determined based on the neutron source strength and the
subcritical multiplication factor using Equation (4-3).