Comparisons with measured data of the simulated local core parameters by the coupled code ATHLET-BIPR-VVER applying a new enhanced model of the reactor pressure vessel
21st Symposium of AER on VVER Reactor Physics and Reactor Safety (2011, Dresden, Germany)
Reactor dynamics and safety analysis
The paper describes the performed comparisons of measured and simulated local core data
based on the OECD/NEA Benchmark on Kalinin-3 NPP: ‘Switching off of one of the four
operating main circulation pumps at nominal reactor power’. The local measurements of incore self-powered neutron detectors (SPND) in 64 fuel assemblies (FA) on 7 axial levels are
used for the comparisons of the assemblies? axial power distributions and the thermocouples?
readings at 93 FA heads are applied for the FA coolant temperature comparisons.
The analyses are done on the base of benchmark transient calculations performed with the
coupled system code ATHLET/BIPR-VVER. In order to describe more realistically the fluid
mixing phenomena in a reactor pressure vessel (RPV) a new enhanced nodalization scheme is
being developed. It could take into account asymmetric flow behaviour in the RPV structures
like downcomer, reactor core inlet and outlet, control rods? guided tubes, support grids etc.
For this purpose details of the core geometry are modelled. About 58000 control volumes and
junctions are applied. Cross connection are used to describe the interaction between the fluid
The performed comparisons are of great interest because they show some advantages by
performing coupled code production pseudo-3D analysis of NPPs applying the parallel
thermo-hydraulic channel methodology (or 1D thermo-hydraulic system code modeling).