Methodological Approaches to Determining the Forces Acting on the VVER-1000 Reactor Support Elements Under Power Unit Operating Loads

V. O. Posokh

SE “State Scientific Engineering Center for Control System and Emergency Response”, 64/56, Heroiv Stalinhrada ave., Kyiv, 04213, Ukraine



Approaches to taking into account the impact of power unit operating loads (normal operation, abnormal operation and emergency conditions) on the reactor support elements through interaction with the reactor vessel are described in the paper. The described approaches were first used in the calculations performed within justification of Khmelnytskyi nuclear power plant, Unit 1.
The approaches include two main steps.
At the first step the principle of calculating forces acting on the nozzles of the reactor vessel from the main coolant pipelines and the emergency core cooling system pipelines is provided. To obtain the needed forces, a 3D pipeline model is developed and then series of calculations with different input data (for the corresponding power unit operating loads) are provided.
At the second step the principle of recalculating the forces acting on the nozzles of the reactor vessel to the forces acting on reactor support elements by means of reactor beam model is shown. Reactor beam model accounts for reactor support elements, stiffness characteristics in horizontal, vertical and torsional directions which were preliminary determined.
These approaches allow to consider the impact of power unit operating loads on the reactor support elements through the interaction with the reactor vessel for further stress-strain state calculations required for the reactor support elements long term safe operation.

Keywords: reactor support elements, reactor vessel, lifetime extension, calculational substantiation of safe operation, power unit operating loads.


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