Operation

The material used for the reactor is uranium-238 and uranium-235 in the form of ceramic pellets packaged into a tube about 6mm in diameter and a few meters long. According to Dr. David Brenner, Director of the Center for Radiological Research, “A nuclear reactor can’t operate with natural uranium. It has to have a bigger proportion of uranium-235 to operate.” Uranium-235 is naturally found in concentrations of about 0.7%. Through a process called enrichment, Uranium-235 is boosted to a concentration of 3%. These rods are inserted into the reactor to maintain the required mass. In order to control the reaction, control rods are inserted and removed to slow or accelerate the chain reaction. The rods full of uranium are separated by water.


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Pressurized Water Reactors

In a pressurized Water Reactor, there are three separate, interacting water systems. The first system is the water surrounding the uranium rods. This water absorbed the immense amount of heat energy that is generated from the fission. The water in this system is kept under such high pressure that it is able to absorb all that heat while remaining in liquid form. Instead, it circulates through a pipe system that passes through a steam generator which contains the second closed water system. Heat is then transferred from the initial water system to the second which causes the water to turn into the vapor used to turn the turbine. The vapor then cools down in the heat exchange chamber (which contains the third water system) condenses, and repeats the process. The water in the third system take the heat from the second system and removes it via the cooling tower.


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Boiling Water Reactors

A boiling water reactor uses only two water systems. The first water system surrounds the core of the reactor and absorbs the heat. The water then vaporizes and turns the turbine on the generator, thus producing electricity. The steam then flows into the cooling system where its heat is absorbed by cool water and the cycle repeats.


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