The provided diagram illustrates the production steps of how using steam to become a gas cooled.
The graph consists of the reactor itself and heat exchanger. The reactor contains the charge tubes for loading fuel elements which are surrounded on the top of reactor. Moreover, these elements are conducting with the boron control rods, which go inside the box until the graphite moderators where locate four uranium fuel elements. The box is made of pressure vesel and concrete rediation shielding, and have four tubes where gas goes.
From the reactor the hot gas flows through a duct into the heat exchanger which is outside the concrete radiation sheilding. In the heat exchanger, steam is generated in the second loop. There is a tube with water which is heated to steam, and it turns to the turbo-alternator. Meanwhile, the hot gas sinks to the bottom of reactor and goes through a gas blower which pushes to the cool gas duct and back to the reactor.