Vilensky O.Yu., Lapshin D.A., Malygin M.G., Pristrom S.A.
Afrikantov Experimental Design Bureau for Mechanical Engineering, Nizhny Novgorod, Russia
The paper provides the main results of deformation process analysis and assessment of consequences of roof block dropping on the BN-600 reactor under operation.
The dropping scenario, regarded as abnormal operation initiating event, has been defined.
Dropping computational analysis is carried out using dynamic analysis module LS-DYNA of certified ANSYS program package. The LS-DYNA module is intended for computational analysis of highly linear dynamic processes using explicit scheme of dynamic equation integration. The paper describes computational and experimental methods aimed at analyzing models of deformation of structural ma-terials under the impact of static and dynamic loads and defines based on experimental studies the parameters of Jonson-Cook model from LS-DYNA library.
Mathematical analysis employs a verified model of behavior of the structural material used in BN-600 reactor pressure vessel.
The obtained results made it possible to analyze the dropping process, define the plastic deformations that occur in all component parts of the reactor and the loads acting upon the support structures.
The assessment of the consequences of roof block dropping on the reactor allowed us to conclude that the reactor vessel and in-vessel structures preserve their integrity and remain operable under internal dynamic impacts.
The application of a comprehensive approach implemented in this computational analysis made it possible to solve the problem related to reactor operation safety assurance under conditions when equipment falls onto the reactor applying moderate conservatism.
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