breeder reactor
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What is a breeder reactor?
A breeder reactor is a nuclear reactor that produces more fissionable material than it uses to generate energy, extending the nuclear fuel supply for electric power generation. Unlike conventional reactors that primarily use uranium-235, breeder reactors utilize uranium-238 or thorium, which are more abundant.
There are two main types of breeder reactors:
* Fast breeder reactors convert uranium-238 into plutonium-239 using artificial radioactive decay. The plutonium-239 is then bombarded with high-speed neutrons to create a self-sustaining chain reaction, releasing heat that is used to generate electricity.
* Thermal breeder reactors employ thorium-232, converting it into fissionable uranium-233. These reactors use ordinary water as a coolant and have simpler technology than liquid-metal fast breeders.1 Britannica SourceCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How does a breeder reactor differ from a regular nuclear reactor?
A breeder reactor differs from a regular nuclear reactor because it produces more fissionable material than it consumes while generating energy, extending the nuclear fuel supply for electric power generation. Conventional nuclear reactors can only use the readily fissionable isotope uranium-235 for fuel, while breeder reactors use uranium-238 or thorium, which are more abundant. Breeder reactors can utilize approximately 70 percent of uranium-238 for power production, whereas conventional reactors can extract less than one percent of its energy.
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What is the main purpose of a breeder reactor?
A breeder reactor is a nuclear reactor that produces more fissionable material than it uses to generate energy, extending the nuclear fuel supply for electric power generation. Unlike conventional nuclear reactors that rely on the scarce uranium-235, breeder reactors utilize uranium-238 or thorium, which are more readily available. Approximately 70 percent of uranium-238 can be used for power production in breeders, whereas conventional reactors use less than one percent.
The first experimental breeder reactor, EBR-1, was developed in 1951 by U.S. scientists in Idaho. Other countries like France, Great Britain, Japan, and the Soviet Union also constructed experimental breeders. Although interest in breeder reactors decreased after the 1960s due to the discovery of additional uranium reserves, countries like Russia, China, India, and Japan still have breeder reactors in operation. A thermal breeder reactor uses thorium-232 as fuel, converting it into fissionable uranium-233.
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How does a breeder reactor produce more fuel than it uses?
A breeder reactor produces more fuel than it uses by converting fertile materials, such as uranium-238 or thorium, into fissionable materials like plutonium-239 or uranium-233. Unlike conventional reactors that primarily use the scarce uranium-235, breeder reactors utilize the more abundant uranium-238 and thorium. During the operation of a breeder reactor, fertile materials capture neutrons and undergo a series of nuclear reactions that transform them into fissile isotopes, thus generating more fuel than is consumed in the process of generating power. The technology of thermal breeder reactors is simpler than that of liquid-metal fast breeder reactors.
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What materials are commonly used as fuel in breeder reactors?
Breeder reactors utilize specific materials to generate more fissionable material than they consume, extending the nuclear fuel supply.
Fast breeder reactors commonly use uranium-238, which is converted into plutonium-239, a fissionable isotope, through artificial radioactive decay. The plutonium-239 is then bombarded with high-speed neutrons to create a self-sustaining chain reaction. Mixed uranium-plutonium dioxides or metal fuels can also fuel liquid-metal reactors.
Thermal breeder reactors employ thorium-232 as their fertile material, which is converted into uranium-233, a fissionable material capable of creating a chain reaction.
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What are the advantages and challenges of using breeder reactors for energy production?
Breeder reactors offer the advantage of extending nuclear fuel supply by using uranium-238 or thorium, which are more abundant than uranium-235 used in conventional reactors. They convert these materials into fissionable isotopes like plutonium-239 or uranium-233, thereby producing more fuel than they consume.
However, challenges exist. Fast breeder reactors, like liquid-metal fast breeder reactors, involve the handling of liquid sodium, which can be hazardous. Thermal breeder reactors, such as the liquid fluoride thorium reactor, are simpler but still experimental. Interest in breeder reactors has fluctuated with the discovery of uranium reserves.
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breeder reactor, nuclear reactor that produces more fissionable material than it consumes to generate energy. This special type of reactor is designed to extend the nuclear fuel supply for electric power generation. Whereas a conventional nuclear reactor can use only the readily fissionable but more scarce isotope uranium-235 for fuel, a breeder reactor employs either uranium-238 or thorium, of which sizable quantities are available. Uranium-238, for example, accounts for more than 99 percent of all naturally occurring uranium. In breeders, approximately 70 percent of this isotope can be utilized for power production. Conventional reactors, in contrast, can extract less than one percent of its energy.
The first experimental breeder reactor, designated EBR-1, was developed in 1951 by U.S. scientists at the National Reactor Testing Station (now called Idaho National Engineering Laboratory), near Idaho Falls, Idaho. France, Great Britain, Japan, and the Soviet Union subsequently built experimental breeders. Although interest in breeder reactors waned after the 1960s as a result of the discovery of additional uranium reserves, Russia, China, India, and Japan have breeder reactors in operation.
Types
Fast breeder reactors
In the early 21st century, all large power plants using fast breeder reactors employed liquid-metal fast breeder reactors, which convert uranium-238 into the fissionable isotope plutonium-239 by means of artificial radioactive decay. The plutonium-239 is then bombarded with high-speed neutrons. When a plutonium nucleus absorbs one such free neutron, it splits into two fission fragments. This fissioning releases heat as well as neutrons, which in turn split other plutonium nuclei, freeing still more neutrons. As this process is repeated again and again, it becomes a self-sustaining chain reaction, yielding a steady source of energy, chiefly in the form of heat, which is transported from the reactor core by a liquid sodium coolant to a system of heat exchangers. This system utilizes the heat to produce steam for a turbine that drives an electric generator.
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Proposed fast breeders include gas-cooled fast reactors, which are cooled with helium, and sodium-cooled and lead-cooled fast reactors. Additionally, a supercritical water fast reactor has been proposed that would operate at a supercritical pressure to utilize fluid water that is neither steam nor liquid.
Thermal breeder reactors
Another type of breeder, the thermal breeder reactor, employs thorium-232 as its basic fuel, or fertile material. It converts this isotope into fissionable uranium-233, which is capable of creating a chain reaction. In the thermal breeder, whose technology is much simpler than that of the liquid-metal fast breeder, ordinary water is employed as a coolant to remove the heat produced by the continuous series of fission reactions.
An experimental thermal breeder known as the liquid fluoride thorium reactor (LFTR) employs molten fluoride salt to transfer heat to the turbines. Such reactors do not require fuel rods, and interest in developing the technology has grown in the early 21st century.