Engineering Disasters - Essay Example

Engineering Disasters College: Engineering Disasters Since 1980, numerous engineering disasters have occurred causing serious lossesand fatalities, with some disasters having their effects still experienced today. Though engineering has been attributed to the rapid development in industrial innovations and provision of better ways to solve problems in the society, engineering has its fair share of accidents that have resulted in fatalities, and some of which are recorded as the worst disasters in history. An important requirement in all engineering systems is precision, ability to hold the load for which the system is designed with a good safety factor, ability to withstand adverse environmental effects and the ability to prevent possible errors in systems by providing ways through which any error can be corrected before a disaster occurs. In engineering, most disasters that have occurred portray a possibility of overlooking one or more provisions of safety with some being caused by poor decision-making and ignorance. The Chernobyl Power plant disaster The Chernobyl Nuclear power plant disaster of April 26, 1986 although blamed on negligence on the part of operators had some engineering aspects that could have contributed in the disaster, in addition to the operation negligence. The Chernobyl plant used RBMK reactors that have been blamed for a number of negative features that may compromise the safety of the reactors and their operations. The RBMK reactors have neutron fields with high sensitivity levels towards movement of control rods, which results from having a high number of absorbers in the reactor core aimed at compensating for any extra reactivity (Malko, 1991). When some absorbers are withdrawn, especially affecting most of the absorbers in the peripheral zones, there results a local criticality. Moreover, RBMK reactors involve occurrence of huge positive reactivity that leads to a reduction of the period required to achieve stabilization of the power produced at the core to about 3 minutes (Medvedev, 1990). These factors make operations of a RBMK reactor problematic and uncertain in maintaining the safety of the reactor. Frankel (2010) observed that the Chernobyl reactor was designed to use graphite moderators that were typically unsafe, in addition to use of graphite rods. As a result, any possible loss of water in such a RBMK reactor posed great danger. Contrary to the operations of Pressurized Water Reactors (PWR), any water that circulates in the pipe network is only required to serve the purpose of cooling the reactor core only and not to moderate the core and cool it (Frankel, 2010). In PWR reactor cores, removal of the core cooling water would cause the entire chain reaction to abort. However in an RBMK-0100 reactor such as the one used in Chernobyl, in case water is lost due to closure of the supplying pumps as was the case, the graphite moderating rods continue to propagate and facilitate nuclear chain reactions (Frankel, 2010). Such mechanism, when considered alongside the loss of cooling water in the nuclear reactor core, would lead to overheating of the core in the shortest time possible. In such a case, the event of a core meltdown becomes the only possible event. In addition, in the Chernobyl RBMK reactors, the control rods were not designed as drastic safety features. Control rods are necessary for absorbing neutrons towards reducing or stopping chain reactions from taking place. However, in the Chernobyl RBMK reactors, control rods required about 20 seconds to reach the bottom of the core from their highest position (Medvedev, 1991). This was contrary to modern reactors that have well designed control rods, which require one second or less, to reach the core of a nuclear reactor stopping any chain reaction. Therefore, in Chernobyl nuclear reactor, the design and engineering of the entire core overlooked key safety mechanisms that could have prevented possible meltdown. The result of overlooking these safety considerations was the 1986 disaster. This was an engineering failure that could have been prevented through proper design and elaborate safety mechanisms in such reactors. The Titanic The titanic, a luxurious cruise ship, was one of the major disasters that have ever happened in the history of engineering. The ship was among the largest, and most luxurious ocean liners and debate has been raging as to the exact cause of the ship’s sinking. Most of the research studies carried out to this effect blamed the sinking of the ship on some of the materials that were used in the ship’s construction. This is had been envisioned from the fact that the impact of the ship with the iceberg caused the steel making the hull and the rivets fixing the hull plates together to develop brittle failure (Kelly, 2013). In most engineering materials, there is a tendency of brittle failure to occur rapidly even without developing some plastic deformations in the process (Kelly, 2013). Research has identified such types of failure to result from high impact forces, low temperatures and high sulphur content in structural materials, three factors that have been blamed for the sinking the Titanic (Basset, 1998). In examining the causes of the disaster, engineers relayed on studying the steel plates and the Charpy impact test used to test the extent of brittleness in the structural material making the Titanic. The results indicated that the hull steel behaved in a completely brittle manner when exposed to the conditions that Titanic was exposed. The possible conclusion in the investigation was that there were high chances that the materials used in the construction lacked enough ductility to withstand impact loads, which led to the drastic and rapid flowing of the ship’s hull and its sinking (Felkins, Leighhly & Jankovic, 1998). Impact tests carried out on materials making the Titanic portrayed that the steel used broke into two pieces in a highly brittle manner. This was in contrast to the current steel that portrays high rates of ductility when exposed to a high impact load. Moreover, research has revealed the steel used for the ship hull was not tested to determine its performance at very low temperatures, the conditions that Titanic was exposed to (Hooper & Tim, 2008). Research today has indicated that the steel used was not suitable for such low temperatures. Comparing the steel material making the Titanic to today’s steel composition, the modern steel contains much higher manganese composition with much lower sulphur content. The ratio of manganese to sulphur in today’s steel has made it possible to reduce the ductile-brittle temperatures to a good level (Felkins, Leighhly & Jankovic, 1998). Moreover, the Titanic material had substantially high phosphorus levels, which contributed to its brittleness (Jankovic, 1991). From the figure below, the material making the ship had large pearlite structures, ferrite grains and other non-metallic inclusions, all which pointed to the use of plain carbon steel in the ship’s manufacturing process. Plain carbon is brittle and cannot withstand similar impact loads. Etched surface of the Titanic hull An investigation into the composition of the rivets in the hull steel revealed a shocking detail of the presence of 3 times more slag than would be expected in wrought iron; the rivets had their interior heads missing (Kelly, 2013). Considering the slag orientation, there were high chances that the rivets lost their heads at impact, which caused them to move out of their holes along the joints (Broad, 2008). The ship had more than 3 million rivets and the failure of some rivets transferred the load to the remaining rivets, which could have increased the stress levels in rivets around the impact area to a failure point (Berg, 2012). These notable engineering faults led to sinking of one of the most luxurious cruise ships in history. The challenger Another significant engineering disaster that shook the space exploration missions was the disintegration of the Challenger space shuttle in 1986 in the face of cameras and thousands of friends and families. The Challenger explosion soon after launch was mainly caused by both engineering and decision-making errors. The O-rings of the vessel failed to seal properly as after interacting with cold temperatures (Jarman & Kouzman, 1990). The result was leakage of gas, which encountered the firing booster, and the intense heat of the booster ignited the gas causing an explosion that ended the mission soon after launch (Roger, 1992). O-rings had a long history of problems dating back to 1977, though NASA engineers assumed that the shuttle was safe relying on secondary or primary seal for backup in case any of the seals failed. NASA had rejected the use of the O-rings before, and even engineers were aware of the technical problems facing the O-rings and objected to the launch of the challenger (Fisher, 1993). Engineers had assumed that a foam debris piece had no significant effect to pose any danger to the wing, and that the two O-rings offered backup to one another (Fisher, 1993). In preceding launches, O-ring erosion had been noted, but the mission went on successfully, which aggravated the above assumptions, making engineers reluctant to solve the problem (Columbia Accident Investigation Board, 2010). Therefore, the accident was caused by wrong decision making, in addition to mechanical problems involving malfunctioning of the O-rings. As illustrated, most disasters in engineering do not happen by chance, but are caused by a series of events. These events range from poor design, ignorance from engineers and poor management in emphasizing on safety of the systems. With proper designs and effective emphasis on the processes, it would be possible to prevent some of these engineering disasters. References Broad, W. J. (2008, April 15) In Weak Rivets, a Possible Key to Titanic’s Doom. The New Columbia Accident Investigation Board (2003). History as Cause: Columbia and Challenger. Report Volume 1, 195-204. Felkins, K, Leighly, H. P. & Jankovic, A. (1998). The Royal Mail Ship Titanic: Did a Metallurgical Failure Cause a Night to Remember? JOM, 50(1), 12-18. Fisher, C. W. (1993). NASA’s Challenger and Decision Support systems. CCSC Journal, 9(2), 145-152. Frankel, V. (2010). Environmental and human-health consequences of the Chernobyl nuclear disaster in Belarus. Master Thesis, University of Pennsylvania. Foecke, T. (1998). Metallurgy of the RMS Titanic. NIST-IR 6118. Hooper, J. & Foecke, T. (2008). What Really Sank the Titanic: New Forensic Discoveries Reviews. New York: Citadel Press. Jankovic, A. (1991). Did Metallurgy Sink the Titanic? Senior Project Report, Department of Metallurgical Engineering, University of Washington, Seattle. Jarman A. & Kouzmin, A., (1990). Decision pathways from crisis. A contingency-theory simulation heuristic for the Challenger Shuttle disaster. Contemporary Crises,14(4). Kelly, H. (2013).The sinking Of the Titanic. Journal of Undergraduate Engineering Research and Scholarship. Memorial University, St. John ’s, NL. Paper Code (PT-13 - Kelly). Malko, V. M. (1997). The Chernobyl Reactor: Design Features and Reasons for Accident. Retrieved from. http://www.rri.kyoto-u.ac.jp/NSRG/reports/kr79/kr79pdf/Malko1.pdf Berg, C. (April 12, 2012). The Real Reason for the Tragedy of the Titanic, The Wall Street Journal. Medvedev, G. (1991). The Truth about Chernobyl. NY: Basic Books Inc. Medvedev, Z. A. (1990). The Legacy of Chernobyl: 1st American Edition. New York: W.W. Norton. Roger D. L. (1992). Toward an Understanding of the Space Shuttle: A Historiographical Essay. Air Power History, 39(4). York Times. Read More