The Gas Turbine Modular Helium Reactor (GT-MHR) is a class of

nuclear fission Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactiv ...

power reactor designed that was under development by a group of Russian enterprises ( OKBM Afrikantov,

Kurchatov Institute The Kurchatov Institute (, National Research Centre "Kurchatov Institute") is Russia's leading research and development institution in the field of nuclear power, nuclear energy. It is named after Igor Kurchatov and is located at 1 Kurchatov Sq ...

, VNIINM and others), an American group headed by General Atomics, French

Framatome Framatome () is a French nuclear reactor business. It is owned by Électricité de France (EDF) (80.5%) and Mitsubishi Heavy Industries (19.5%). The company first formed in 1958 to license Westinghouse's pressurized water reactor (PWR) designs ...

and Japanese Fuji Electric. It is a

helium Helium (from ) is a chemical element; it has chemical symbol, symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert gas, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is ...

cooled,

graphite Graphite () is a Crystallinity, crystalline allotrope (form) of the element carbon. It consists of many stacked Layered materials, layers of graphene, typically in excess of hundreds of layers. Graphite occurs naturally and is the most stable ...

moderated reactor and uses

TRISO Nuclear fuel refers to any substance, typically fissile material, which is used by nuclear power stations or other nuclear devices to generate energy. Oxide fuel For fission reactors, the fuel (typically based on uranium) is usually based o ...

fuel compacts in a

prismatic An optical prism is a transparent optics, optical element with flat, polished surfaces that are designed to refraction, refract light. At least one surface must be angled—elements with two parallel surfaces are ''not'' prisms. The most fami ...

core Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (laboratory), a highly specialized shared research resource * Core (manufacturing), used in casting and molding * Core (optical fiber ...

design. The power is generated via a gas turbine rather than via the more common steam turbine. A conceptual design was produced by 1997, and it was hoped to have a final design by 2005, and a prototype plant commissioning by 2010.

Construction

The core consists of a graphite cylinder with a radius of and a height of which includes axial reflectors at top and bottom. The cylinder allocates three or four concentric rings, each of 36 hexagonal blocks with an interstitial gap of . Each hexagonal block contains 108 helium coolant channels and 216 fuel pins. Each fuel pin contains a random lattice of TRISO particles dispersed into a graphite matrix. The reactor exhibits a

thermal A thermal column (or thermal) is a rising mass of buoyant air, a convective current in the atmosphere, that transfers heat energy vertically. Thermals are created by the uneven heating of Earth's surface from solar radiation, and are an example ...

spectrum with a peak neutron energy located at about 0.2 eV. The

fuel concept allows the reactor to be inherently safe. The reactor and containment structure is located below grade and in contact with the ground, which serves as a passive safety measure to conduct heat away from the reactor in the event of a coolant failure.

Advantages

The Gas Turbine Modular Helium Reactor utilizes the

Brayton cycle The Brayton cycle, also known as the Joule cycle, is a thermodynamic cycle that describes the operation of certain heat engines that have air or some other gas as their working fluid. It is characterized by isentropic process, isentropic compre ...

turbine arrangement, which gives it an efficiency of up to 48% – higher than any other reactor, as of 1995. Commercial light water reactors (LWRs) generally use the

Rankine cycle The Rankine cycle is an idealized thermodynamic cycle describing the process by which certain heat engines, such as steam turbines or reciprocating steam engines, allow mechanical work to be extracted from a fluid as it moves between a heat sour ...

, which is what coal-fired power plants use. Commercial LWRs average 32% efficiency, again as of 1995.

Legacy

Energy Multiplier Module (EM2)

In 2010 General Atomics conceptualized a new reactor that utilizes the power conversion features of the GT-MHR, the Energy Multiplier Module (EM2). The EM2 uses

fast neutrons The neutron detection temperature, also called the neutron energy, indicates a free neutron's kinetic energy, usually given in electron volts. The term ''temperature'' is used, since hot, thermal and cold neutrons are moderated in a medium with ...

and is a gas-cooled fast reactor, enabling it to reduce

nuclear waste Radioactive waste is a type of hazardous waste that contains radioactive material. It is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, nuclear decommissioning, rare-earth mining, and nuclear ...

considerably by transmutation.

References

External links