3D numerical investigation of natural circulation between the reac- tor pressure vessel and the cooling pond of a VVER-440 type reac- tor in incidental conditions during maintenance

摘要

During the annual maintenance of the VVER-440 type reactors, the reactor pressure vessel, the cooling pond and the transfer pond form a connected flow domain. The reactor is cooled by the natural circu- lation, which develops in one or two main loops. The cooling pond has its own cooling loops. CFD calculations have been performed with the code CFX-4.3 to investigate whether it is possible to cool the reactor core in case the main loops are lost and other emergency systems are not available. The results point out that the cooling sys- tem of the cooling pond ins not capable of cooling the reactor core with the present connection.