Upgrading of RBMK fuel assembly design and production technology

At present there are 13 power units with RBMK-1000 and 2 power units with RBMK-1500 reactors in operation. In 1986 as a result of safety enhancement program 80--100 additional absorbers (AA) were installed in RBMK-1000 reactor and number of AA RBMK-1500 reactors increased by 54. This made possible to improve reactor safety and reduce void coefficient down to 0.6--0.8 β. At the same time, fuel burn-up was decreased by 30--35% as compared to its design value. Until 1986 a greater emphasis in RBMK fuel advancement has been focused on its reliability and efficiency. Starting from 1986 the main goal of design and calculation analysis was to upgrade fuel loading with a view to reduce void reactivity coefficient. Research activities demonstrated that the use of erbium oxide as AA in the fuel can be regarded as the advantageous approach for RBMK reactors