Tests of a Two-Stage Core at the KV-1 Test Facility: Physical Aspects and Results

The physical aspects and main results of reactor tests of a two-stage core consisting of fresh fuel assemblies and a significant number of fuel assemblies from the previous core, which are left for re-burning on the KV-1 test facility in a 3+ run, are presented. In spite of the significant heterogeneity of the core and the complexity of its computational and experimental neutronics modeling, neutronics engineering codes made it possible to calculate the governing neutronics parameters with acceptable accuracy. The combination of re-burning and make-up fuel assemblies made it possible to test fuel assemblies with high power contrast, including in the natural circulation regime in a wide power range. The technical solutions implemented in the 3+ run made it possible to create a database for validating with minimal financial cost and test time the resource reliability of cores which are under construction and cores for future ship nuclear power facilities.