Fukushima nuclear plant incident in 2011 Essay Example | Topics and Well Written Essays - 2000 words

Fukushima nuclear plant incident in 2011 - Essay Example This is the largest nuclear catastrophe recorded in the world after the 1986 Chernobyl disaster and it is believed to have released approximately 10 to 30% of radiation material of what Chernobyl incident emitted (Povinec, Hirose and Aoyama 2013, p. 9). In the event of the tsunami, the backup power equipment that was meant to cool the reactors was destroyed and this caused fuel melting, hydrogen outburst, and radioactive gases. This radioactive release at the Fukushima plant forced the neighborhoods up to 25 miles estimated at more than 100,000 residents were all evacuated away from the plant. The subsequent lack of AC power in Units 1 to three prohibited the valves and pumps from working normally which was necessary to eliminate heat and pressure that occurred due to radioactive decay from the nuclear fuel within the reactor hubs. The fuel rods therefore, overheated and in combination with the steam, huge quantities of hydrogen were generated causing an explosion. This is the explos ion that prevented the plant workers from cooling the reactors and the radioactivity spread rapidly (Elliott 2012, p.7). The Pollutant Source and Pathway The source of the Fukushima nuclear plant disaster is directly related to the earthquake of a 9.0 magnitude that hit Japan in 2011. This earthquake caused damage to the external power supply and the backup diesel emergency generators were flooded leading them to fail. After the failure of the diesel backup generators, the reactor operators initiated the emergency battery power but they run out after 8 hours of operation. The enduring heat therefore, could not be carried out and this led to fuel failure. Fuel failure occurs because of mechanical, chemical or even thermal failures when there is too much heat in the valves (Brook, 2011). The nuclear power plant workers had now to focus on managing the core while the heat was building up to allow the fuel cladding to keep going as much as possible. In reality, the reactor is made up of several independent and different cooling systems that operate to ensure smooth flow. These cooling systems include the reactor water clean-up mechanism, the decay heat exclusion, the core isolating cooling system, and also standby cooling mechanism among others. It is evident some of these cooling system failed and caused damage to the core and therefore, the disaster occurred (Elliott 2012, p.7). When the workers lost most of the cooling systems because of loss of power, they had to come up with other means of eliminating the heat. However, in a situation where the heat production is greater than its removal, the pressure immediately keeps rising as the boiling water builds steam. The operators now focused on keeping the temperature below 1200Â °C, while also maintaining a manageable level of the pressure. Maintaining a manageable pressure level is necessary to get rid of steam and this is done by pressure relief valves that are contained in the reactor (Elliott 2012, p.7). The process of maintaining pressure requires venting or emitting steam to keep the levels in a steady rate. It is important to note that steam and other gases eliminated are radioactive fission materials, which are in small quantities. In this case, when the workers at Fukushima nuclear plant were emitting steam, some form of radioactive emissions were released into the

Atmospheric Ozone Essay Example | Topics and Well Written Essays - 750 words

Atmospheric Ozone - Essay Example Although Ozone occurs naturally in the atmosphere it can be produced by numerous chemical reactions in a chemical laboratory. Atmospheric Ozone results from a mechanism when O2 absorbs Ultra Violet (UV) radiation at wavelengths of about 242 nanometers (nm) [1m = 109nm] but is removed by a phenomenon called Photo-dissociation from sunlight at wavelengths greater than 290nm (Ozone in the Atmosphere "n.d"). Ozone occurs in the atmosphere in Troposphere, Stratosphere, Mesosphere and Thermosphere. The amount of Ozone found in the atmospheric layers is dependent on the temperature. The troposphere which is the bottom layer of atmosphere has the lowest amount of ozone. The deterioration of the Ozone layer leads to a phenomenon known as the 'Greenhouse' effect. The effect is caused by greenhouse gasses known as chlorofluorocarbons (CFC's) including carbon dioxide and is a major cause of many environmental problems. Greenhouse gases are said to be the leading cause of Global warming (Ozone in the Atmosphere, "n.d"). The amount of ozone in the atmosphere is measured using Dobson units (Du), [1 mm of O3 thick layer = 100 Du] if compressed at sea level pressure. The threat to the atmospheric ozone balance has been on the increase as industrialization and modernization grows around the world. These events have significantly increased the rate of ozone removal, resulting in a gradual decline in the global ozone levels (Wikipedia, "n.d"). Ozone Depletion Man-made industrial activities produce massive amounts of CFC's. The dangerous and ozone depleting compounds are used in many industrial processes and can be found in many household products. CFC's are used as coolants in refrigerators and as propellants in various spray cans. These gases are also employed in the production of certain foam mixtures, in electronic and mostly in solvents (The Atmospheric Zone "n.d"). CFC's have a very long lifespan. A single molecule of a CFC gas can exist for centuries before it is eliminated once it escapes into the atmosphere. After their release into the air through a simple human activity like the spraying of a CFC containing can, studies have shown that the gases can reach the stratosphere between a 1-5 year periods. Once the released CFC reaches the ozone layer, it depletes it causing less UV rays to be absorbed by ozone layer. This happens when the CFC molecules breakdown upon reaction with UV rays from sunlight, the reaction releases free radical chlorine atoms and it these atoms that destroy and deplete atmospheric ozone layer. The depletion of the protective ozone layer and the subsequent passage of UV rays which are known to be harmful are the cause of various effects and illnesses. Skin cancer is said to be on the increase, various problems and diseases are plaguing crops around the world. Temperatures are rising around the earth leading to more floods, hurricanes like Katrina in 2005, and record braking heat waves in Europe. According to the Intergovernmental Panel on Climate change (IPCC) a United Nations Advisory body, environmentalists and researchers have linked (through the use of ground-based and satellite measurements) the depletion of the