Schematic representation of a single time step in our dynamic code. In this chart ρ₀ is the initial crust density, Y_e,0 is the initial electron fraction, Y(Z₀) is the initial chemical abundance of the crust, T₀ is the initial temperature, Z₀ is the initial atomic number and n₀ is the initial particle density of the crust. The neutron density (n_n) is first found using the secant method and then reaction network is solved using the Crank-Nicholson method. After solving the reaction network evolution of the density (ρ(t)), heating due to β and neutron decay and nuclear fission is calculated. The neutron density is then re-evaluated and finally the maximal temperature change criterion is checked before moving on to the next time step.