Energy Encyclopedia

Nuclear Energy

High-Temperature Gas-cooled Reactor

A helium-cooled, graphite-moderated reactor using coated-particle fuel, aimed at high outlet temperatures.

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Labelled system

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Original ENERGY ATLAS diagram of High-Temperature Gas-cooled Reactor

Original ENERGY ATLAS schematic. Interactive 3D is opt-in on this page.

Ceramic coatings retain fission products.

Overview

HTGRs (and related VHTR concepts) use TRISO or similar coated particles. Helium does not boil and is chemically inert. High temperatures can support process heat as well as electricity.

How it works

Fuel pebbles or prismatic blocks contain coated particles. Helium transfers heat to a steam generator or, in some concepts, a gas turbine. A large graphite inventory provides thermal inertia.

Components

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