IHX and Steam Generators

IHX stands for Intermediate Heat eXchanger. There are two IHX's for each reactor vessel. The purpose of the IHX is to prevent radioactive Sodium from leaving the reactor vessel. The IHX is positioned just above the core so that hot Sodium leaving the core can enter the inlet and transfer heat to the Sodium in the secondary piping. After the Sodium passes over the piping , it exits through the reactor downcomer. After the secondary Sodium has been heated, it passes through into the steam generator. This secondary Sodium is called the Intermediate Heat Transfer Sodium (IHTS).

Two steam generators supply superheated steam to the steam generators and a single steam turbine. The steam generators must have the ability of being isolated from the secondary Sodium in case a rupture in the water pipes causes Sodium-water interactions. This isolation prevents the reactions from spreading through the entire supply of Sodium in the reactor.