VVER-1000 radial reflector modeling by diffusion nodes

The two commonly used approaches to describe the VVER radial reflectors in diffusion codes, by core-reflector albedos and by a ring of diffusion assembly size nodes, are discussed. The advantages and disadvantages of the first approach are presented first, then the Koebke's equivalence theory is outlined and its implementation for the VVER radial reflectors is discussed. Results for the VVER-1000 reactor are presented.