Formation and development of rim-layer in WWER-440 fuel rod

The results of calculations of power density and burnup distributions over the WWER-440 reactor fuel rod radius depending on the cross-section mean burnup are discussed. The fuel rod cross section is divided into 20 zones with equal areas, and dependences of the fuel isotope composition change and relative power density on burnup are determined for each zone in the course of calculations. A fuel assembly with neutron-physical characteristics averaged over the reactor core is considered in calculations. Those are the following: specific power density is 86.28 W/cm2, the fuel temperature is 900 K at any burnup value, 135 Xe and 149 Sm poisoning is stationary, reactor lattice pinch is 14.7 cm, mounting size is 14.4 cm, uranium dioxide fuel rod density is 10.27 g/cm3, the fuel rod radius is 3.86 mm, spacing grids are made of stainless steel, other structural elements are manufactured of zirconium alloy with wall thickness of 0.15 cm, the coolant temperature is 558 K, its density is 0.7506 g/cm3. The conclusion on satisfactory agreement between the experimental data and calculational results is drawn