Fuel utilization in VVER-1000: Status and prospects

The status and prospects for increasing the fuel utilization efficiency of VVER-1000 reactors are reviewed. It is shown that the main trends in the development of water moderated and cooled reactors are reflected in an improved design with a four-year fuel run, different variants of which are now being implemented in nuclear power plants operating in Russia, Ukraine, and Bulgaria: weakly neutron-absorbing materials are used in the fuel assemblies, part of the excess reactivity of the core is compensated by an absorber (gadolinium) which is integrated with the fuel, the fuel load is designed with a reduced radial neutron leakage, and the number of refuelings is increased. Promising directions for improving fuel utilization are noted: increasing the energy content of the fuel load, operating the reactor with reduced values of the parameters at the end of a run after the reactivity excess has been exhausted on burnup, and reusing (recycling) the uranium and plutonium contained in the spent fuel.