Comparative analysis of multiplicating properties of WWER-1000 spent fuel depending on assembly layout in the reactor core and their operation conditions

Spent nuclear fuel with the same burnup value can have different isotope composition, and, therefore, different multiplicating properties. This work has analyzed the impact on WWER-1000 spent fuel multiplicating properties of different operation conditions, such as the presence or absence of absorbers-rods in an assembly, changes in the concentration of the boric acid dissolved in the moderator (water) during the campaign, oscillations of fuel and/or moderator temperature during the campaign in different areas of the core, and changes in water amount at the periphery of an assembly due to its location in the central or periphery part of the core during the fuel campaign and/or due to changes in inter-assembly gaps. (author)