Аннотация:The results of four-year utilization of the fuel with increased (4.4%) enrichment in the WWER-440 reactor of the Kola NPP are analyzed. The power and temperature reactivity coefficients, worths of control element groups and boric acid, as well as fuel can state were investigated. The conclusion is made that the results of the full-scale experiment at the Kola NPP have confirmed the possibility of the WWER-440 reactor conversion into regime of four-year run with make-up fuel of increased enrichment; the universal diagram of its motion was developed. Such cycle introduction increases the designed efficiency of fuel utilization by 10.7%.