A closed-cycle gas turbine is a turbine that uses a gas (e.g. air, nitrogen, helium, argon, [1] [2] etc.) for the working fluid as part of a closed thermodynamic system. Heat is supplied from an external source. [3] Such recirculating turbines follow the Brayton cycle. [4] [5]
The initial patent for a closed-cycle gas turbine (CCGT) was issued in 1935 and they were first used commercially in 1939. [3] Seven CCGT units were built in Switzerland and Germany by 1978. [2] Historically, CCGTs found most use as external combustion engines "with fuels such as bituminous coal, brown coal and blast furnace gas" but were superseded by open cycle gas turbines using cleaner-burning fuels (e.g. "gas or light oil"), especially in highly efficient combined cycle systems. [3] Air-based CCGT systems have demonstrated very high availability and reliability. [6] The most notable helium-based system thus far was Oberhausen 2, a 50 megawatt cogeneration plant that operated from 1975 to 1987 in Germany. [7] Compared to Europe where the technology was originally developed, CCGT is not well known in the US. [8]
Gas-cooled reactors powering helium-based closed-cycle gas turbines were suggested in 1945. [8] The experimental ML-1 nuclear reactor in the early-1960s used a nitrogen-based CCGT operating at 0.9 MPa. [9] The cancelled pebble bed modular reactor was intended to be coupled with a helium CCGT. [10] Future nuclear (Generation IV reactors) may employ CCGT for power generation, [3] e.g. Flibe Energy intends to produce a liquid fluoride thorium reactor coupled with a CCGT. [11]
Closed-cycle gas turbines hold promise for use with future high temperature solar power [3] and fusion power [2] generation.
They have also been proposed as a technology for use in long-term space exploration. [12]
Supercritical carbon dioxide closed-cycle gas turbines are under development; "The main advantage of the supercritical CO2 cycle is comparable efficiency with the helium Brayton cycle at significantly lower temperature" (550 °C vs. 850 °C), but with the disadvantage of higher pressure (20 MPa vs. 8 MPa). [13] Sandia National Laboratories has a goal of developing a 10 MWe supercritical CO2 demonstration CCGT by 2019. [14]
A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from nuclear fission is passed to a working fluid, which in turn runs through steam turbines. These either drive a ship's propellers or turn electrical generators' shafts. Nuclear generated steam in principle can be used for industrial process heat or for district heating. Some reactors are used to produce isotopes for medical and industrial use, or for production of weapons-grade plutonium. As of 2022, the International Atomic Energy Agency reports there are 422 nuclear power reactors and 223 nuclear research reactors in operation around the world.
A nuclear electric rocket is a type of spacecraft propulsion system where thermal energy from a nuclear reactor is converted to electrical energy, which is used to drive an ion thruster or other electrical spacecraft propulsion technology. The nuclear electric rocket terminology is slightly inconsistent, as technically the "rocket" part of the propulsion system is non-nuclear and could also be driven by solar panels. This is in contrast with a nuclear thermal rocket, which directly uses reactor heat to add energy to a working fluid, which is then expelled out of a rocket nozzle.
The pebble-bed reactor (PBR) is a design for a graphite-moderated, gas-cooled nuclear reactor. It is a type of very-high-temperature reactor (VHTR), one of the six classes of nuclear reactors in the Generation IV initiative.
A combined cycle power plant is an assembly of heat engines that work in tandem from the same source of heat, converting it into mechanical energy. On land, when used to make electricity the most common type is called a combined cycle gas turbine (CCGT) plant. The same principle is also used for marine propulsion, where it is called a combined gas and steam (COGAS) plant. Combining two or more thermodynamic cycles improves overall efficiency, which reduces fuel costs.
The Pebble Bed Modular Reactor (PBMR) is a particular design of pebble bed reactor developed by South African company PBMR (Pty) Ltd from 1994 until 2009. PBMR facilities include gas turbine and heat transfer labs at the Potchefstroom Campus of North-West University, and at Pelindaba, a high pressure and temperature helium test rig, as well as a prototype fuel fabrication plant. A planned test reactor at Koeberg Nuclear Power Station was not built.
A supercritical fluid (SCF) is any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist, but below the pressure required to compress it into a solid. It can effuse through porous solids like a gas, overcoming the mass transfer limitations that slow liquid transport through such materials. SCF are superior to gases in their ability to dissolve materials like liquids or solids. Also, near the critical point, small changes in pressure or temperature result in large changes in density, allowing many properties of a supercritical fluid to be "fine-tuned".
ML-1 was an experimental nuclear reactor built as part of the US Army Nuclear Power Program between 1961 and 1965. It was intended to provide truck-mounted nuclear power that could accompany troops from place to place and provide power to command and communication centers, evacuation hospitals, depots, and radar and weapons systems.
The Fort St. Vrain Nuclear Power Plant is a former commercial nuclear power station located near the town of Platteville in northern Colorado in the United States. It originally operated from 1979 until 1989. It had a 330 MWe High-temperature gas reactor (HTGR). The plant was decommissioned between 1989 and 1992.
The sulfur–iodine cycle is a three-step thermochemical cycle used to produce hydrogen.
Supercritical carbon dioxide is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure.
A high-temperature gas-cooled reactor (HTGR) is a type of gas-cooled nuclear reactor which use uranium fuel and graphite moderation to produce very high reactor core output temperatures. All existing HTGR reactors use helium coolant. The reactor core can be either a "prismatic block" or a "pebble-bed" core. China Huaneng Group currently operates HTR-PM, a 250 MW HTGR power plant in Shandong province, China.
The gas-cooled fast reactor (GFR) 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. The reference reactor design is a helium-cooled system operating with an outlet temperature of 850 °C (1,560 °F) using a direct Brayton closed-cycle gas turbine for high thermal efficiency. Several fuel forms are being considered for their potential to operate at very high temperatures and to ensure an excellent retention of fission products: composite ceramic fuel, advanced fuel particles, or ceramic clad elements of actinide compounds. Core configurations are being considered based on pin- or plate-based fuel assemblies or prismatic blocks, which allows for better coolant circulation than traditional fuel assemblies.
The Gas Turbine Modular Helium Reactor (GT-MHR) is a class of nuclear fission power reactor designed that was under development by a group of Russian enterprises, an American group headed by General Atomics, French Framatome and Japanese Fuji Electric. It is a helium cooled, graphite moderated reactor and uses TRISO fuel compacts in a prismatic core design. The power is generated via a gas turbine rather than via the more common steam turbine.
The Aircraft Nuclear Propulsion (ANP) program and the preceding Nuclear Energy for the Propulsion of Aircraft (NEPA) project worked to develop a nuclear propulsion system for aircraft. The United States Army Air Forces initiated Project NEPA on May 28, 1946. NEPA operated until May 1951, when the project was transferred to the joint Atomic Energy Commission (AEC)/USAF ANP. The USAF pursued two different systems for nuclear-powered jet engines, the Direct Air Cycle concept, which was developed by General Electric, and Indirect Air Cycle, which was assigned to Pratt & Whitney. The program was intended to develop and test the Convair X-6, but was canceled in 1961 before that aircraft was built. The total cost of the program from 1946 to 1961 was about $1 billion.
The steam-electric power station is a power station in which the electric generator is steam driven. Water is heated, turns into steam and spins a steam turbine which drives an electrical generator. After it passes through the turbine, the steam is condensed in a condenser. The greatest variation in the design of steam-electric power plants is due to the different fuel sources.
A gas-cooled reactor (GCR) is a nuclear reactor that uses graphite as a neutron moderator and a gas as coolant. Although there are many other types of reactor cooled by gas, the terms GCR and to a lesser extent gas cooled reactor are particularly used to refer to this type of reactor.
A gas-fired power plant, sometimes referred to as gas-fired power station, natural gas power plant, or methane gas power plant, is a thermal power station that burns natural gas to generate electricity. Gas-fired power plants generate almost a quarter of world electricity and are significant sources of greenhouse gas emissions. However, they can provide seasonal, dispatchable energy generation to compensate for variable renewable energy deficits, where hydropower or interconnectors are not available. In the early 2020s batteries became competitive with gas peaker plants.
The liquid fluoride thorium reactor is a type of molten salt reactor. LFTRs use the thorium fuel cycle with a fluoride-based molten (liquid) salt for fuel. In a typical design, the liquid is pumped between a critical core and an external heat exchanger where the heat is transferred to a nonradioactive secondary salt. The secondary salt then transfers its heat to a steam turbine or closed-cycle gas turbine.
The Energy Multiplier Module is a nuclear fission power reactor under development by General Atomics. It is a fast-neutron version of the Gas Turbine Modular Helium Reactor (GT-MHR) and is capable of converting spent nuclear fuel into electricity and industrial process heat.
{{cite web}}: CS1 maint: archived copy as title (link)MIT-ANP-Series, MIT-ANP-TR-100 (2004)