Static and Dynamic Multiplication Factors and Their Relation to the Inhour Equation

The theory of the stable period of a fixed-fuel reactor is developed by considering the gross conservation of neutrons in the reactor. The resulting inhour equation directly relates the dynamic multiplication factor to the actual delayed-neutron fractions. It is shown that the inhour equation may also be written in terms of the conventional multiplication factor if so-called “effective” delayed neutron fractions are introduced. The results are shown to be in agreement with those of the perturbation method.