Gas Cooled Fast Breeder Reactors example essay topic

Heat is produced in a nuclear reactor when neutrons strike Uranium atoms causing them to fission in a continuous chain reaction. Control elements, which are made of materials that absorb neutrons, are placed among the fuel assemblies. When the control elements, or control rods as they are often called, are pulled out of the core, more neutrons are available and the chain reaction speeds up, producing more heat. When they are inserted into the core, more neutrons are absorbed, and the chain reaction slows or stops, reducing the heat. Reactors can be used for research or for power production.

A research reactor is designed to produce various beams of radiation for experimental application; the heat produced is a waste product and is dissipated as efficiently as possible. In a power reactor the heat produced is of primary importance for use in driving conventional heat engines; the beams of radiation are controlled by shielding. Research and test reactors -- also called "non-power" reactors -- are nuclear reactors primarily used to conduct research, development and education. These reactors contribute to almost every field of science including physics, chemistry, biology, medicine, geology, archeology, and environmental sciences. A breeder reactor is defined as a reactor that both consumes and produces fissionable fuel. Generally breeder reactors produce more fuel than they consume.

Breeding is the process by which new fissionable material is created by capturing neutrons from fissions in fertile materials. Fast breeder reactors are reactors where the fission reaction is sustained by fast neutrons. Fast breeder reactors do not require a moderator, allowing for a variety of working fluids. Two types of fast breeder reactors are Gas-Cooled Fast Breeder Reactors (GCB Rs), often cooled by pressurized helium, and Liquid Metal Fast Breeder Reactors (LMF BRs), which are cooled by molten sodium. The reactor core, at its center, has concentrations of ~20% Pu-239 and 80%.

Surrounding fuel rods are 100%. The reactor has a high concentration of fissile material at its core, allowing a chain reaction to be sustained even with fast neutrons, despite the lower probability of fast neutrons causing fissions than slow neutrons. A consequence of operating with fast-moving neutrons (hence the common name Fast Breeder Reactors, or FBR) is that there is a higher chance of transmuting U-238 (uranium- 238) to Pu-239 (Plutonium-239). After a year's worth of operation, the center rods will have concentration of 15% Pu-239 and 85% U-238, with the surrounding material having 95% U-238 and 5% Pu-239. This results in a net of 7% more Pu-239 than the starting configuration. The initial development of atomic energy during and immediately after the second world war was to produce bombs.

An early concern when the atom was harnessed for controlled civil use was that this nuclear power should not enable more countries to acquire nuclear weapons. Through the United Nations, procedures were set up to ensure this, and in fact they have been perhaps the most conspicuous success of that body. No nuclear materials such as uranium from the civil nuclear fuel cycle have ever been diverted to make weapons. In fact today the whole picture is reversed in that a lot of military uranium is being brought into the civil nuclear fuel cycle to make electricity, which is widely seen as a positive development, unimaginable 40 years ago. One tenth of US electricity is made from Russian military warheads. When you compare and contrast the two reactors, fissile and breeder you " ll see that they " re the same thing but only one is more efficient and because of the differences in the processes the breeder reactor may have more danger.

That is the cost of efficiency.