Theory and calculation of 135Xe concentration time evolution for the nuclear power plant CNA II

In this report the theory to describe 135Xe and 135I concentration time evolutions is developed, for calculations applied to systems like nuclear reactors at power plants. Here, different from most of theories utilised, the 135I concentration time evolution equation is corrected to iodine absorption. Reasons for both the occurrence of the xenon peak after a reactor power change and the reactor power limit value for the existence of this peak are also explained. Results for xenon and iodine concentrations performed for nuclear power plant CNA II agree with other calculations and previous works done for this installation.

► Theory for 135-Xe and 135-I time evolution concentrations after power changes.
► Analysis of 135-Xe and 135-I for power cycles in NPP CNA II.
► Conditions for xenon peak occurrence and limit concentrations of both isotopes for a CNA II type nuclear reactor.