Nuclear Reactors Essay, Research Paper

Nuclear Reactors

Using a nuclear reactor is an efficient way to produce large amounts of electricity. Nuclear reactors are used to provide power to a neighboring town or city. In a nuclear reactor, water is heated using nuclear energy to the point that it boils and the steam collects around a collection of spinning blades, called a steam turbine. The pressure from the steam turns these blades, which are connected to a dynamo, or generator. The generator is activated and produces electricity, which is sent to electrical power lines and distributed throughout the community.

The heat needed to create the large amounts of steam is created in the reactor s core. In the core are fuel rods made of stainless steel. These fuel rods contain pellets of U-235. There are also moderators made of carbon or heavy water (H20 and deuterium) which are used to slow down the flow of electrons to the fuel rods. If the electrons are moving slow enough, the neutron reaches the fuel rods containing the U-235 pellets and fission occurs. Fission takes place when an atom s nucleus splits and causes a nuclear reaction. When a free neutron splits a nucleus, energy is released along with other free neutrons. A free neutron from the nucleus that just split splits another nucleus, and so on and so on. This process is called a chain reaction. The fission process is used to create heat, which boils water inside the nuclear reactor. Fission happens while being carefully monitored by a plant manager. If the reaction is getting out of control, ten control rods are used to slow it down. Control rods are made of boron or cadmium stainless steel and easily absorb neutrons, disabling them from heightening the reaction. The insertion and excerption of the control rods into the core is controlled by

the control rod drive mechanism. The entire core is submerged in coolant, a heat absorber, so that it won t overheat.

The extremely hot, high pressured water flows through tubes that are located in the water boiler, where heat exchange occurs between the hot water in the tubes and the cold water in the water boiler. The water in the boiler boils and steam is produced. There is shielding that surrounds the water boiler and core. The internal shielding is made of stainless steel and the external shielding is concrete. This protects the people outside of the shielding from radioactivity and danger.

The steam produced in the water boiler rises and activates the steam turbine and then passes through a condenser. The condenser is a tube within a tube. The inner tube is coming from the steam turbine and the outer tube leads toward the cooling tower. Cooling towers are 55 stories high and cool the water without any pollutant wastes. Cold water is taken from a river and enters the outer tube of the condenser. The hot steam in the inner tube gets cold and condenses into water droplets, finding its way back to the water boiler, where it will be once again turned to steam. The water in the outer tube that was once cold is now warm and follows the tube to the cooling tower, where it falls from platform to platform, cooling with every drop until it reaches the river where it was originally taken from. At this point the water is river water temperature again, so no harm is done to the lake wild life. In past years, there were no cooling towers and the warm water was dispensed back into the river, and some fish such as trout died of due to the unusual fluctuation of water temperature.