The installation of the core melt localization device, or the “core catcher”, has started at Tianwan NPP Unit 7.
The first element of the device - the core catcher casing - has been installed in the design position. The core catcher casing is a tank weighing over 156 tons, with the total weight of the device being over 800 tons. Besides the casing, the main components of the core catcher include block-cassettes filled with special non-metallic materials, maintenance platform, cantilever truss and bottom plate.
Alexey Bannik, ASE JSC Vice President for NPP construction in China, pointed out that the core catcher casing is the first large-size long lead manufacture equipment installed in the reactor compartment of Tianwan Unit 7. The core catcher has been adapted for the site conditions and it complies with all the up-to-date safety requirements”, said A.Yu. Bannik.
The core catcher is a Russian invention, it is part of the passive safety system, which is intended for prevention of release of radioactive substances into the environment in the event of a severe accident accompanied by the destruction of the reactor pressure vessel. The core catcher is capable of containing liquid and solid fragments of the core and the structural materials of the reactor for an indefinitely long time keeping the power plant safe for the environment and the people. This operation is one of the critical path activities under the schedule, after which further construction of the reactor pit becomes possible. For the first time, the core catcher was installed at Tianwan NPP Unit 1. Currently, all the power units of Novovoronezh NPP-2, Leningrad NPP-2, Belarus NPP and Kudankulam NPP in India are equipped with this device.