Paks II. Ltd. submitted the production license application for the core catcher to the Hungarian Atomic Energy Authority on 11 February. This is the second long-lead item for which the approval process has been initiated by the authority. Earlier, on 16 November 2021, the reactor pressure vessel documentation was received by the HAEA. The submission of this application is another significant step towards entering the implementation phase.
The upgraded 3+ generation VVER-1200 units use a number of new technical solutions to increase safety. One of these is the core catcher, which is a special tank located below the reactor vessel and capable of receiving the zone melt in the event of its damage. The core catcher serves to absorb the melt when the reactor core is melted, to reduce the consequences, to prevent the zone melt from interacting with the base plate concrete, and to reduce hydrogen generation and the release of radioactive materials into the environment. The total height of the core catcher is 15,24 meters, its largest part - 11 meters - is the support ring. The total weight of the core catcher parts is 732,7 tons.
The core catcher contains a melt charge containing alumina and iron oxide which, when mixed with the zone melt, reduces the specific heat of the melt. Gadolinium is also added to the melt charge, which, due to its neutron-absorbing properties, prevents the formation of a nuclear chain reaction in the melt. The steel tank of the core catcher can be cooled with boron water from the outside in the event of a serious accident.
Construction of new CEB buildings might start
Another four buildings of the construction and erection base received construction licenses from the Hungarian Atomic Energy Authority on 9 and 10 February: a canteen for 300 people and three two-storey service buildings, each with a floor area of 1600 square meters, which are for the social needs of the staff of the subcontractors involved in the construction. Paks II. Ltd. also obtained a construction license for the construction of a 4200 square meter waste storage area.