The Concept of Localization of the Corium Melt in the Ex-Vessel Stage of a Severe Accident at a Nuclear Power Station With a VVER-1000 Reactor

摘要

The concept of localization and cooling of he corium melt in the concrete reactor cavity underneath the reactor vessel is considered. This concept was developed for the protect of the Tyanvan NPS with VVER reactors. The basement plate and the cavity walls are protected by a heat exchanger whose cooled surface local- izes the melt entering from the reactor. The water is delivered into the heat exchanger and to the free surface of the melt by gravity from the storage tanks, whose capacity is sufficient to ensure operation of the cooling system for 24 h without any coolant makeup. Sacrificial material located in the melt-localization zone ensures forma- tion of the optimal structure and properties of the melt bath and subsequent crystallization of the melt.