Chernobyl Nuclear Disaster - Coursework Example

Name Course Tutor Date Chernobyl Nuclear Disaster Chernobyl nuclear disaster is believed to be one of the worst engineering disasters ever. Unlike most of the nuclear reactors which were water cooled, the RBMK-1000 was designed to use graphite in order to moderate the core reactivity. As per the intended design, graphite was also meant to prevent continuous nuclear reaction from occurring at the core. The continued heating and subsequent production of steam bubbles led to higher reactivity in the core also referred to as positive void coefficient. This positive coefficient is what led to this engineering disaster and this paper looks into this design flaw. In addition, the professional engineers Ontario code of ethics, section 77 of the O. Reg 941-77 is discussed in accordance to this issue and how it might help curb such eventualities. The continued operation of this site and the inherent risks posed despite of the contamination until closure is an unethical act that is also discussed herein. RBMK-1000 Design Flaws Before delving into the flaw that led to this engineering disaster, is important to highlight some of the reactor’s basic features. The RBMK-1000 reactor was built to gross up to 1000MW of electricity as the nominal capacity. This was a boiling water reactor that was enriched with uranium as fuel with water as the coolant and graphite as the core moderator. This kind of reactors were built and operated in the United Soviet with the first commissioning carried out in 1974. Replicas of this reactors were built and operated along the first ones commissioned translating to same eventualities if operation continued. Table 1 below shows some of the principal characteristics of RBMK-1000 that made it stand out among the nuclear reactors ever built. Table 1: The typical characteristics of the RBMK-1000 reactor (Malko). Figure 1 below gives a basic schematic layout of this disastrous reactor. Figure 1: RBMK-1000 reactor layout (Malko). According to Malko (2012), the large positive steam coefficient is blamed greatly for this accident. In studies carried out in 1970s, the steam void coefficient was found to increase by up to which subsequently decreases the number of absorbing rods within the core. This simple process was meant to increase the fuel burn up process which in turn reduced the period of power stabilization at the core to three minutes. This translated the nuclear process of the RBMK-1000 to a more dangerous one owing to the inability to auto-control the system after a bout of uncontrolled power excursions took place. Although it was known to the nuclear scientists by the time of the Chernobyl disaster that the positive steam-void is controlled by adding absorption rods to the core, nothing of this nature was carried out in a case of utter negligence. Core enrichment of up to 2.4% was also important if the accident had to be avoided – this is together with addition of 80 resident absorbers (Malko). Another negative feature that was discovered to have led to this disaster are the enhanced neutron fields which were used for moving the control rods. This led to a large number of absorbers whose core compensation required a large reactivity surplus. A low criticality was further created when the absorbers within the peripheral zones were withdrawn. This led to a big challenge in controlling the RBMK-1000 when compared to other nuclear reactors that had been discovered as of that time. The geometry of the RBMK-1000 is also blamed for the fatalities that occurs as withdrawal of SAR gave ER and MR extreme top core positions which caused a water height deficit of around 1.25m. The end rods effect as this was referred to in this type of reactors attributed largely towards the positive reactivity surge (Malko). Series of Events Leading To the Disaster Prior to the incident that occurred at unit 4 on the 26th of April 1986, it is evident that a study had been scheduled to help seek possibilities of tapping the slowing turbine’s mechanical power after steam cut-off. The tests were carried out from 0106Hrs on 25th April 1986 during which the nominal power was identified to be at 3200MW. The slowing turbine could give 1600MW at 0347Hrs and 15t00MW at 0413Hrs although the turbine continued operating to 1236Hrs. At 0710Hrs, the operation reactivity surplus had fallen way beyond the engineers’ expectations and the manual absorbing rods had apparently reached 13.2. Switching off the turbo generator TG7, the engineers chose an option of connecting the circulating pumps to turbo generator TG8 (Malko). The chosen connection configurations were to be utilised at 6-8 operating rods which were considered safe in case of a power surge and would only take 20 seconds to shut down the reactor. During the test however, the automatic trip which could have shut down the reactor had been circumvented leading to instability. Adjustments had to be made every few moments in order to maintain the power output at a constant value. The slowing water pumps could not on the other side provide enough cooling water to the reactors thus this exaggerated the levels of instability due to increasing steam production in the cooling channels. Due to the negligence of the operators, the positive void coefficient had gone up beyond their control and the power output grown 100fold. This led to rupture of the fuel causing it to react with water leading to steam explosion which spoilt the reactor core and gave in to explosions (OECD). Professional Engineers of Ontario Code of Ethics in Relation to Public Welfare According to the professional engineers of Ontario code of ethics in relation to public welfare, “A practitioner shall regard the practitioner's duty to public welfare as paramount”. The bitter truth is that the engineers involved in the experimentation exercise were not fully current to the art of the poorly designed reactors. This can be viewed from the way they ignored the power surges that were taking place only for them to keep on regulating periodically until the major explosion occurred at a time the steam production had grown by up to 100 times of the accepted levels. The lack of safety culture within this plant is highly attributed to the ignorance of the operators who only sort to benefit from this dangerous experiment and ended up blowing the reactor which in turn released nuclear debris that led to many fatalities (Chernobyl Documentary Video). While the reactor design was also faulted as poor, however the engineers at this site did not comply with the basic set of procedures meant for operation. Was continued Operation of RBMK Ethical? Why is the World Exposed to Such Risk? The continued operation of these reactors having been concluded as poorly designed was not ethical. The reason as to why the exposure of the public to such risks continued is due to the commercial viability and the expensive nature of the nuclear reactors. The negligence that emanates from such engineering acts can be costly in terms of fatalities and economic implications. The rules and guidelines that govern such government projects are however faulted by public panels making them obsolete whenever such decisions favour them. It is unfortunate that the world has not reached a consensus when it comes to standardising nuclear equipment as experiments continue day and night in a bid to outdo each other. This has made it altogether difficult to pursue the nuclear issues and other engineering matters that are out of geographical boundaries. When such disasters happen, they affect the whole world thus such practices should be standardised in pacts or treaties that are held periodically across the globe for purposes of elimination of such risks as it is done for the global warming or climate issues. Works Cited Chernobyl Documentary Video. n.d. Harder, Douglas Wilhelm. PEO Code of Ethics. 2010. Website. 8 October 2014. Malko, Mikhail V. "The Chernobyl Reactor: Design Features and Reasons for Accident." Joint Institute of Power and Nuclear Research (2012): pp 11-27. Electronic. OECD. Chernobyl: Assessment of Radiological and Health Impact . 2002. Website. 8 October 2014. jfjfjfhAAHHHhfdhdhfgfgfg Read More