What Happend Essay Research Paper In the

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What Happend Essay, Research Paper In the mid-1950s, nuclear physicists confidently predicted that nuclear energy would usher in a new age for humanity. The cost of energy would be so low it would be almost too cheap to meter. They predicted that by the year 2000 there would be thousands of commercial reactors producing unlimited amounts of power. Like the horse and buggy, oil and coal would become little more than historical curiosities. With such a bright outlook for the future the engineers and scientists started to get careless. Then on March 28, 1979, an event took place that rocked the nuclear power industry so badly that it has yet to recover. That event was the partial meltdown of one of the reactor cores at the Three Mile Island nuclear power plant in Londonderry

Township, Pennsylvania. The accident at Three Mile Island was a combination of equipment failures, design problems, and human error. It was even more that though it was a complacent attitude that the industry had as a whole as Harold Denton former Nuclear Regulatory Commission official said, We thought the plant was too well designed to have a serious accident. It was kind of like the Titanic. (CNN) It may surprise some people to find out how close we came to a major disaster and the shear amount of problems that occurred. To understand what went wrong you first need to understand how a nuclear power plant works. At the heart or every plant is it s radioactive core. The core is a nuclear furnace creating heat by the splitting of atoms during a controlled chain reaction. Control

rods that are raised and lowered into the core to control the rate the atoms split and there by controlling the amount to heat produced. To slow down the reaction the rods are lowered into the core, to speed it up they are raised or taken out of the core. Surrounding the core is the water in the primary loop. This water removes the heat generated by the core as it is pumped through the loop. Because the water in the primary loop comes in contact with the core it becomes radioactive. The heat is then transferred from the water in the primary loop to the water in the secondary loop. The water in the secondary then turns in to steam that steam turns a turbine that is connected to a generator that produces electricity. Pumps move the water through the secondary loop and back to where

the heat is exchanged. Because the water in the secondary loop never comes in contact with the radioactive water in the primary loop it is not radioactive. (PBS) At 4:00 A.M. on March 28, 1979 the main pumps in the secondary non-nuclear loop of the unit 2 reactor stopped working caused by a slight malfunction. The turbine and then the reactor shut down according to their design. Because water is no longer flowing through the secondary loop, heat is no longer being transferred from the primary loop to the secondary loop. The water temperature and pressure in the reactor raise, this is normal and no cause for alarm. To prevent the pressure from getting too high, a pressure relief valve opens to relieve some of the pressure and water to a drain tank. (Raso) All according to what was

supposed to happen in case of such an event. This is when things start to go wrong. The back up pumps for the secondary loop had had a test run on them 42 hours before the indent. Part of this test included a valve being closed and then reopened at the end of the test. But this time the valve was not reopened after the test. The valve being closed prevented the backup system from functioning. The plant workers discovered the valve closed in about eight minutes and reopened. Once the valve was open the back up system started to work correctly. Cooling water then flowed into the steam generators. (NRC) This solved one problem but a bigger one existed. Because the secondary loop was out of commission for about eight minuets the pressure relief valve had to open. The pressure relief