1. Assessments: why and for whom?

1.1 Background on neutronics

The aim of neutronics is to solve the equations that describe the neutron population in a reactor in operation, and the evolution of the isotopes present. These equations are mainly the Boltzmann equation, which describes the neutron population and its evolution over the lifetime of the reactor, and the Bateman system of equations, which calculates the evolution of the concentrations of isotopes present or created in the reactor and subjected to the neutron flux previously calculated.

The Boltzmann equation is written :