Impact of shield elements on the WWER-440 reactor pressure vessel activation

Highlights: • Neutron flux and induced activities are estimated for RPV of WWER-440 reactor. • MCNP code and SCALE codes system are used for modelling. • Shield elements effect for RPV activation is demonstrated. - Abstract: The WWER-440 type nuclear reactor is one of the most common reactor types in the nuclear power plants (NPP) across Central and Eastern Europe. Most of the NPPs equipped with these reactors have reached or are approaching the end of their service lifetime and face decommissioning. Neutron activated components of these reactors (the largest being the reactor pressure vessel (RPV)) are the most hazardous radioactive waste arising during decommissioning. Some of these reactors were equipped with shield elements (dummy fuel assemblies) in order to reduce neutron flux affecting the RPV. Therefore, the induced activity of an RPV also depends on whether or not shield elements were used in a specific reactor. This paper presents the analysis of shield elements' influence on the induced activity of an RPV.