Gas turbine modular helium reactor
Encyclopedia
The Gas Turbine Modular Helium Reactor (GT-MHR) is a nuclear fission
power reactor design under development by General Atomics
. It is a helium
cooled, graphite
moderated
reactor and uses TRISO fuel compacts in a prismatic
core
design.
has been used to better manage the excess of reactivity. The reactor and containment structure are 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.
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
, which is what coal-fired power plants use. Commercial LWRs average 32% efficiency, again as of 1995.
(EM2), in 2010. The EM2 uses fast neutrons
and is a gas-cooled fast reactor
, enabling it to reduce nuclear waste considerably by transmutation
.
Nuclear fission
In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts , often producing free neutrons and photons , and releasing a tremendous amount of energy...
power reactor design under development by General Atomics
General Atomics
General Atomics is a nuclear physics and defense contractor headquartered in San Diego, California. General Atomics’ research into fission and fusion matured into competencies in related technologies, allowing the company to expand into other fields of research...
. It is a helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
cooled, graphite
Graphite
The mineral graphite is one of the allotropes of carbon. It was named by Abraham Gottlob Werner in 1789 from the Ancient Greek γράφω , "to draw/write", for its use in pencils, where it is commonly called lead . Unlike diamond , graphite is an electrical conductor, a semimetal...
moderated
Neutron moderator
In nuclear engineering, a neutron moderator is a medium that reduces the speed of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction involving uranium-235....
reactor and uses TRISO fuel compacts in a prismatic
Prism (geometry)
In geometry, a prism is a polyhedron with an n-sided polygonal base, a translated copy , and n other faces joining corresponding sides of the two bases. All cross-sections parallel to the base faces are the same. Prisms are named for their base, so a prism with a pentagonal base is called a...
core
Nuclear reactor core
A nuclear reactor core is the portion of a nuclear reactor containing the nuclear fuel components where the nuclear reactions take place.- Description :...
design.
Construction
The core consists of a graphite cylinder with a radius of 4 m and a height of 10 m which includes 1 m axial reflectors at top and bottom. The cylinder allocates three or four concentric rings, each of 36 hexagonal blocks with an interstitial gap of 0.2 cm. 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 located at about 0.2 eV. The QUADRISO fuel concept conceived at Argonne National LaboratoryArgonne National Laboratory
Argonne National Laboratory is the first science and engineering research national laboratory in the United States, receiving this designation on July 1, 1946. It is the largest national laboratory by size and scope in the Midwest...
has been used to better manage the excess of reactivity. The reactor and containment structure are 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 cycleBrayton cycle
The Brayton cycle is a thermodynamic cycle that describes the workings of the gas turbine engine, basis of the airbreathing jet engine and others. It is named after George Brayton , the American engineer who developed it, although it was originally proposed and patented by Englishman John Barber...
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
Rankine cycle
The Rankine cycle is a cycle that converts heat into work. The heat is supplied externally to a closed loop, which usually uses water. This cycle generates about 90% of all electric power used throughout the world, including virtually all solar thermal, biomass, coal and nuclear power plants. It is...
, which is what coal-fired power plants use. Commercial LWRs average 32% efficiency, again as of 1995.
Energy Multiplier Module (EM2)
General Atomics presented a new version of the GT-MHR, the Energy Multiplier ModuleEnergy Multiplier Module
The Energy Multiplier Module is a nuclear fission power reactor under development by General Atomics. It is a modified version of the Gas Turbine Modular Helium Reactor and is capable of converting spent nuclear fuel into electricity and industrial process heat, without separative or conventional...
(EM2), in 2010. The EM2 uses fast neutrons
Fast neutron reactor
A fast neutron reactor or simply a fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons...
and is a gas-cooled fast reactor
Gas-cooled fast reactor
The Gas-Cooled Fast Reactor system is a nuclear reactor design which is currently in development. Classed as a Generation IV reactor, it features a fast-neutron spectrum and closed fuel cycle for efficient conversion of fertile uranium and management of actinides...
, enabling it to reduce nuclear waste considerably by transmutation
Nuclear transmutation
Nuclear transmutation is the conversion of one chemical element or isotope into another. In other words, atoms of one element can be changed into atoms of other element by 'transmutation'...
.
See also
- Energy multiplier moduleEnergy Multiplier ModuleThe Energy Multiplier Module is a nuclear fission power reactor under development by General Atomics. It is a modified version of the Gas Turbine Modular Helium Reactor and is capable of converting spent nuclear fuel into electricity and industrial process heat, without separative or conventional...
- Gas-cooled fast reactorGas-cooled fast reactorThe Gas-Cooled Fast Reactor system is a nuclear reactor design which is currently in development. Classed as a Generation IV reactor, it features a fast-neutron spectrum and closed fuel cycle for efficient conversion of fertile uranium and management of actinides...
- Pebble bed reactorPebble bed reactorThe pebble bed reactor is a graphite-moderated, gas-cooled, nuclear reactor. It is a type of very high temperature reactor , one of the six classes of nuclear reactors in the Generation IV initiative...
- Very high temperature reactorVery high temperature reactorThe Very High Temperature Reactor , or High Temperature Gas-cooled Reactor , is a Generation IV reactor concept that uses a graphite-moderated nuclear reactor with a once-through uranium fuel cycle. The VHTR is a type of High Temperature Reactor that can conceptually have an outlet temperature of...