Estimation of Void Swelling in VVER-1000 Baffle Using Benchmark in LR-0 Reactor

Reactor pressure vessel internals have a multipurpose task that is mainly to ensure optimal coolant flow, to form and support the active core, and to shield, guide, and support the in-core instrumentation. The VVER-1000 reactor internal components are in an environment with high radiation doses, boric (H3BO3) acid dissolved in water, high temperatures, and gamma heating. These effects, together with the high moderator flow rate, form strongly inhomogeneous temperature fields in vessel internal components and induced internal stresses. In the case of the VVER-1000 reactor baffle, the main potential limiting factor for prolongation of the reactor operational lifetime is a void swelling of the Russian-type titanium stabilized stainless 08Cr18Ni10Ti steel used to construct the baffle surrounding the active core. This paper presents a VVER-1000 mock-up model validation for the thermal neutron and gamma fluence in the region of the baffle and a precise gamma heating as well as a displacement-per-atom estimation in a one-sixth section of the reactor baffle. Obtained results on the mock-up are scaled to the VVER-1000 nominal power and used in ABAQUS code for void swelling estimation.