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 radio ...

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

Kurchatov Institute The Kurchatov Institute (russian: Национальный исследовательский центр «Курчатовский Институт», 'National Research Centre "Kurchatov Institute) is Russia's leading research and developmen ...

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

Fuji Electric , operating under the brand name FE, is a Japanese electrical equipment company, manufacturing pressure transmitters, flowmeters, gas analyzers, controllers, inverters, pumps, generators, ICs, motors, and power equipment. History Fuji Electric ...

. It is a

helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...

cooled,

graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on large ...

moderated reactor and uses TRISO fuel compacts in a

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

core 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 spectrum with a peak neutron energy located at about 0.2 eV. The TRISO 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 turbine arrangement, which gives it an efficiency of up to 48% – higher than any other reactor, as of 1995. Commercial

light water reactors The light-water reactor (LWR) is a type of thermal-neutron reactor that uses normal water, as opposed to heavy water, as both its coolant and neutron moderator; furthermore a solid form of fissile elements is used as fuel. Thermal-neutron reacto ...

(LWRs) generally use the Rankine cycle, 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 and is a gas-cooled fast reactor, enabling it to reduce nuclear waste considerably by transmutation.

References

External links