Nuclear Plants and Their Impact on the Environment - Essay Example

Nuclear Plants and Their Impact on the Environment Background Greenhouse gas emissions from nuclear fission power has a "catastrophic risk" potential when containment fails. Failure in containment can emanate from over-heated fuels melting and releasing huge quantities of fission products into the environment. Nuclear waste must be isolated from humans and the immediate environment that could pose harm to other organisms in an ecosystem for many hundred years. Enormous campaigns have ensured public awareness and increased resistance to careless disposal of nuclear waste. Nuclear power has at least four waste streams that could harm the environment: 1. Spent nuclear fuel at the reactor site 2. Tailings and waste rock at uranium mines and mills 3. Releases of small amounts of radioactive isotopes during reactor operation 4. Releases of large quantities of dangerous radioactive materials during accidents (Cracolice & Peters, 1997). Disasters Accidents from nuclear reactors in the late 1970s and early 1980s led to end to the initial rapid growth in nuclear power capacity. These comprised the 1979 Three Mile Island accident (USA) and the 1986 Chernobyl disaster (Ukraine) (Cracolice & Peters, 1997). In 2011, a hard-hitting tsunami led the Fukushima I Nuclear Power Plant to leak, resulting in hydrogen gas explosions and partial meltdowns. In order to caution the immediate populations from the adverse effects of the disasters, the Ukraine government enacted a 30 kilometers no-settlement policy around the Chernobyl power plant while the Japanese government implemented a 20 kilometers cautionary zone around the Fukushima I plant (Hoeve & Jacobson, 2012; Bennett, Bouville, Hall, Savkin & Storm, 2000). Radioactive Decay Used up nuclear fuel from uranium-235 and plutonium-239 nuclear fission contains more than 100 carcinogenic radionuclide isotopes such as strontium-90, iodine-131 and caesium-137, and includes some of the most long-lived transuranic elements such as americium-241 and isotopes of plutonium. Disposal of these wastes in engineered facilities, or repositories, located deep underground in suitable geologic formations is currently the best disposal solution fronted (Cracolice & Peters, 1997). Nuclear Accidents and Concerns Debate over the reliability, durability and quality maintenance of old nuclear installations has emerged following leakage of radioactive water in over twenty US nuclear power plants. Tritium is a radioactive isotope of hydrogen that emits a low-energy beta particle. It may be present in water emanating from a nuclear plant (Casas et al, 2004; Cracolice & Peters, 1997). The main concern over tritium is the high possibility of its entry into drinking water, in addition to the subsequent presence in crops that depend on tritium-contaminated waters. Uranium is mainly mined for use in nuclear power plants. The 1979 Church Rock uranium mill spill in New Mexico led to the flow of over 1,000 tons of solid radioactive waste and 93 millions of gallons of acidic, radioactive tailings solution into the Puerco River. The Three Mile Island accident that occurred four months earlier had a lower magnitude in terms of the spilled contents flowing uncontrollably into the rivers and surroundings. The spill contaminated groundwater, rendering it unusable for local populations (Rong & Victor, 2012). Closed minefields can remain harmful for up to 250,000 years. Till now, many U.S. uranium mining sites used during the arms race have not been cleaned up. According to the Environmental Protection Agency, there are 4000 mines with known uranium production and 15,000 locations with uranium existence in 14 western states (Rong & Victor, 2012; Younos, 2009). The Uranium Mill Tailings Radiation Control Act gave the Environmental Protection Agency the authority to establish health and environmental standards for the stabilization, restoration, and disposal of uranium mill waste. Examples of Recent Nuclear Reactor Disasters Fukushima The March 2011 hard-hitting tsunami and earthquake across Japan led to explosions and partial meltdowns at the Fukushima I Nuclear Power Plant. Radiation levels immediately rose to over 1000 mSv/h (Buesseler, 2014). Considering the fact that exposure to a 1mSv/h level of radiation is likely to result in a radiation-induced illness in a human’s future, the levels of radiation at the plant can be described as having been too dangerous for human survival. Consequently, people living and working within 20 kilometers from the plant were evacuated, and those within up to 30 kilometers were advised to stay indoors to avoid excessive exposure to harmful radiation. The UK and France would later lead a host other countries in calling on their nationals to leave Tokyo altogether in anticipation of spreading contamination (Buesseler, 2014; Hoeve & Jacobson, 2012). Indeed, the fears were confirmed when Japanese officials stated that levels of the radioactive iodine-131 unbearable for infants were detected at 18 water purification plants in Tokyo and five other regions soon after the Fukushima I accident. The fallout from the Daiichi power plant was blamed for the complicated search of possible victims of the earthquake (Hoeve & Jacobson, 2012). According to the Japanese Ministry of Science and Education, areas in the temporary 12 miles (19 km) radius evacuation zone around Fukushima were found to be heavily contaminated with radionuclides. The town of Okuma was hardest hit, recording radiation levels 25 times above the safe limit of 20 millisieverts per year (Buesseler, 2014). Three Mile Island (TMI – March 1979) The problem started when reactor number 2 at the TMI experienced partial meltdown. The situation was then broadcast all over the country, creating fear among the populations. A series of errors led to the overall outcome. Initially, there was a minor problem that resulted in a rise in the temperature of the main coolant. The instantaneous response was a shutdown of the reactor. Upon shutdown, a relief valve that should have automatically closed failed to. The primary coolant drained away leading to serious damage on the primary coolant. There were ensuing gas leaks. Plant operators and experts took one month to completely shut down the plant. However, the readings following the accident did not indicate the presence of toxic amounts of iodine. A registry of the 30000 residents living within a five-mile radius was performed. Follow-up studies have not indicated the presence of abnormal rates of cancer that would normally come with substantive exposure to radioactive emissions (The History Channel, 2015). The Stationary Low-Power Number One (SL-1) Meltdown The SL-1 was a US army nuclear power reactor that underwent steam explosion and meltdown in 1961. The explosion killed three operators. Upon investigation, it was established that the primary cause of the accident was the improper withdrawal of the central control rod that absorbs neutrons in the core of the reactor. The accident led to exposure to toxic levels of iodine-131 (Radiation Works, 2012). However, the remote location of the plant shielded the populations from exposure. Analysis of the Chernobyl Nuclear Reactor Disaster Up to now, the Chernobyl nuclear reactor disaster is still the world’s largest nuclear power plant accident. It is not yet known how many people died from the accident, with figures ranging between 62 and 25000 deaths. For some analysts, deaths that are imminent for some people who were affected by the radiation, which partly accounts for some of the higher figures in the estimates. The effect that the accident had on the populations cannot be underestimated. Apparently, the radiation is bound to keep affecting people’s lives up to 2065, which explains why some scientists have opted to calculate the total fatalities with the inclusion of predicted, foreseeable deaths (Cracolice & Peters, 1997). Thyroid cancer has been found to increase in the region surrounding the Chernobyl power plant. According to the UN figures provided by the World Health Organization (WHO), 4000 to 9000 former Soviet citizens out of the 6.9 million who suffered the most exposure will die of radiation-resultant cancer. However, other researchers think that inclusion of populations that were affected by the radiation worldwide is paramount, capping the global fatality estimates from the Chernobyl accident at 25000. The accident was occasioned by massive spread of contamination across Europe. In particular, cesium and strontium contaminated many agricultural products, livestock and large portions of land. As a result of the Chernobyl disaster, the entire population living in the city of Pripyat was evacuated alongside over 300000 residents of Kiev. The immediate portion of land was rendered unusable for human purposes for an indefinite period of time (World Nuclear Association, 2014). Decay of radioactive material results in the release of harmful particles that could easily harm the body and cause cancer. The most dangerous of these are cesium-137 and iodine-131. In the Chernobyl disaster, releases of cesium-137 contaminated land. Some settlements, including the entire city of Pripyat, were abandoned permanently. Many more who consumed milk that had been contaminated with iodine-131 developed thyroid cancer (World Nuclear Association, 2014). The piece of land up to 30 kilometers in radius from Chernobyl is still laden with very high quantities of cesium-137, which will die away in about 300 years (about 10 half-lives). Due to the bioaccumulation of cesium-137, some mushrooms as well as wild animals which feed on them may have levels of the chemicals beyond agreed safety levels for humans (Nuclear Energy Agency, 2002). In recognition of the growing challenge, mandatory testing for sheep bred and reared in areas that could be having high contamination levels was put in place (though the requirement has been relaxed since 2012). Conceding that the 50000 hectares of land surrounding Chernobyl are still unsafe for human inhabitation, the Ukrainian government declared the entire acreage within the Chernobyl Exclusion Zone a zoo in 2007. Due to the long abandonment period, there has been an increase in the number of wild animals living in the area, especially those wolves, bison and moose. At the same time, some other species, including spiders and ban swallows are thought to have reduced (Buesseler, 2014). This makes the question of whether Chernobyl is, indeed, an animal reserve, contestable. In order to clear the air on whether higher levels of radioactive radiation that find their way into the atmosphere result in increased risk of acquiring cancer, numerous studies have over time embarked on the prevalence of certain types of cancer (especially thyroid) among nuclear reactor workers or people living in the areas surrounding such plants. However, it is accidental releases that appear to cause the most numbers of such cancerous infections. The Chernobyl case is one such accidental release. Equally prone to higher prevalence of cancer are workers in mines that have radioactive products such as uranium. However, this problem has been addressed in recent years, though those who did uranium mining in the 1980s and before have recorded significantly higher cancer prevalence rates (Pflugbeil, Paulitz, Claussen & Schmitz-Feuerhake, 2011). There is no consensus on which types of cancers are caused by normal operations at nuclear plants. As a result, academic debate is still ongoing in this field. Other studies indicate that people who live near nuclear plants are more prone to cancer. At the moment, one of the contentious findings is that leukemia is more prevalent among children born near nuclear power plants. Owing to the controversial findings across several studies, the US Nuclear Regulatory Commission has requested the National Academy of Sciences to oversee a state-of-the-art study of cancer risk in populations near NRC-licensed facilities (Pflugbeil et al, 2011; Casa et al, 2004). Accidents at nuclear reactor plants usually cause the release of a variety of isotopes into the environment. The health impact of each radioisotope depends on a variety of factors. For instance, iodine-131 is potentially a significant source of ill health in accidental discharges because of its higher prevalence and because it settles on the ground. When this isotope is released, may be inhaled or consumed when it ends up in the food chain, primarily through contaminated fruits, vegetables, milk, and groundwater. When it gets into the body, iodine-131 rapidly accumulates in the thyroid glands, and starts emitting beta radiation from there. The Fukushima-Daiichi nuclear disaster displaced 50,000 households as people sought safety from the contamination that had leaked into the air, soil and sea (Buesseler, 2014). In order to enhance the security of human populations, governments embarked on banning some products, such as fish and vegetables that appeared to have higher concentrations of contamination from nuclear waste than is acceptable. The fuel cycle for production and conversion of uranium into usable state routinely exposes uranium workers to higher levels of decaying radon, which emits high doses of gamma radiation. Such high doses of gamma radiation contribute to leukemia. At present, research into the effects of gamma radiation on the prevalence of other hematological cancers is still ongoing (Buesseler, 2014). Remediation One of the major remediation steps in the management of radioactive waste is the construction of sustainable sites and enactment of programs that will oversee safe transition of nuclear material into safe disposal. Some of the common repositories of radioactive material include the containers enclosing the waste, engineered barriers around the containers, tunnels housing the containers, and geologic makeup of the surrounding areas. The ability of natural geologic barriers to isolate radioactive waste is demonstrated by the natural nuclear fission reactors at Oklo, Gabon (Casas et al, 2004). There is a sustained skepticism that geological disposal can be safe, technologically feasible and environmentally safe. At the moment, experts are still trying to convince the general public and other players that repositories will more unlikely remit contamination to places that will hurt the general population. Despite the processing steps that accompany the production phase, the need for a repository still remains real. However, the processing phase gradually reduces the amount of waste that requires disposal. Similarly, locating worthy sites for repositories is a challenge. For instance, they cannot be located at a place that has the potential of attracting populations in the future; including potential mine fields. Public consultation has been a remarkable starting step when selecting a site for a repository. In reality, communities fear having to play host to nuclear waste repositories due to the notion that they could suffer the effects of radiation for generations. The US is host to three low-level waste disposal sites. They are located in Utah, South Carolina, and Washington (Hoeve & Jacobson, 2012). Environmental groups have claimed that uranium mining companies are attempting to avoid cleanup costs at abandoned uranium mine sites. Once a mine becomes inactive, remediation is deemed a necessary step in preventing the contamination of the environment from radioactive material. It has been observed that uranium mining companies have resorted to time-to-time reactivation of old minefields in order to avoid clean-up responsibilities (Pflugbeil et al, 2011). Financial Costs Waste heat. Nuclear power generators have a lower thermal efficiency compared to coal-fired power plants. There is, therefore, tremendous loss of heat. Consequently, cooling is required more often, which explains why most nuclear power plants are located near reliable sources of water. This factor tends to overrule all other considerations, despite standing the potential of raising costs significantly. Still, some plant managers prefer to undergo the expense of constructing artificial lakes. An example is Shearon Harris Nuclear Power Plant or the South Texas Nuclear Generating Station. Shearon Harris uses a cooling tower but South Texas does not and discharges back into the lake. In order to increase efficiency, waste heat is sometimes used for industrial applications (Pflugbeil et al, 2011). Water consumption and risks. Inevitably, the process of nuclear power generation is accompanied by massive usage of water. It is this water that is heated by the large amounts of energy released during the process of induced nuclear fission. The water turns into steam and rotates a turbine, thereby generating electricity. Normally, nuclear plants need to collect about 600 gallons/MWh for this process, which explains the huge burden that would ensue if they were constructed far away from reliable sources of water (Pflugbeil et al, 2011; Younos, 2009). Like all other power generating plants, nuclear plants use special structures for efficient transmission of generated power. However, the efficiency of these structures is put to one further test in the generation of nuclear power – the prevention of small organisms that pass through the screens from getting into contact with toxic materials that accompany nuclear power generators. For non-nuclear generating plants, the main concern is prevention of debris from entering the containers (Younos, 2009). Due to the difficulty in implementing sustainable prevention mechanisms, many marine organisms (including fishes, turtles, and seals) that are important to the food chain are drawn into the cooling systems and destroyed. Response to Nuclear Disasters The world is coming to a point of convergence on ways to deal with nuclear reactor leakages. For instance, both the Ukrainian and Japanese governments (the Chernobyl and Fukushima disasters respectively) opted to evacuate their populations from within 30 and 20 kilometers of the point where the exploded reactors were. Similarly, the US government designated a ten-kilometer radius within which evacuation would be done. Each of these radiuses seems to be advised by the magnitudes of the respective accidents. The Chernobyl accident was by far the hugest, which understandably led to a wider evacuation region for the people living around the location of the reactor. As observed above, the international community responds both by sending in experts to fairly assess the magnitude of the problem and to also protect their own populations. This can be deduced in France and England’s call for removal of their nationals from Japan after the publication of the wide-spread contamination resulting from the leakage of the Fukushima I power plant. Disaster Control Steps by the United Nations and Other Agencies Researchers have embarked on establishing the feasibility of various disposal methods. For instance, the feasibility of thorium fuels and fuel cycles has been tested across various nuclear reactors and are showing encouraging results. At present, thorium is being considered as a possible replacement for uranium, whose risks and subsequent disposal are too expensive and complicated. Better still, thorium is about 400% more abundant than uranium, and is much safer to mine and transport. Estimates suggest that the current thorium reserves across the globe could sustain meaningful production for thousands of years. That, in essence, implies that thorium can be the next nuclear power generator for as many years. The existence of thorium close to the surface eliminates both the requirement for expensive ventilation mechanisms at the mines and exposure to the dangerous radon (Hoeve & Jacobson, 2012). Another advantage of thorium as a source of nuclear-generated power is that in the possible event of excessively high temperatures or power failure, the reactors would not go into a melt-down state. The reactor is designed such that the plugs will melt and drain the reactor fluid into an underground storage tank for safe storage (Buesseler, 2014). This way, catastrophes such as the ones experienced at Fukushima and Chernobyl would not be possible. This is in recognition of the high potential for human-made disaster that is nuclear power. References Bennett, B., Bouville, A., Hall, P., Savkin, M. & Storm, H. (2000). Chernobyl accident: Exposures and effects. Vienna. Buesseler, K. O. (2014). Fukushima and ocean radioactivity. Oceanography. 27(1): 92-105. Casas, I., De Pablo, J., Perez, I., Gimenez, J., Duro, L. & Bruno, J. (2004). Evidence of uranium and associated trace element mobilization and retention processes at Oklo (Gabon), a naturally radioactive site. Environmental Science and Technology. 38(12): 3310-3315. Cracolice, M. & Peters, E. (1997). Introductory chemistry: An active learning approach. Boston: Cengage Learning. Hoeve, J. E. T. & Jacobson, M. Z. (2012). Worldwide health effects of the Fukushima Daiichi accident. Energy and Environmental Science. Doi: 10.1039/c2ee22019a. Nuclear Energy Agency (2002). Chernobyl: Assessment of radiological and health impact. Retrieved from https://www.oecd-nea.org/rp/chernobyl/c0e.html. Pflugbeil, S., Paulitz, H., Claussen, A. & Schmitz-Feuerhake, I. (2011). Health effects of Chernobyl 25 years after the reactor catastrophe. Berlin: German Affiliate of International Physicians for the Prevention of Nuclear War. Radiation Works (2012). The SL-1 reactor accident. Idaho National Engineering Laboratory. Retrieved from http://www.radiationworks.com/sl1reactor.htm Rong, F. & Victor, D. G. (2012). What does it cost to build a power plant? San Diego: Laboratory on International Law and Regulation. The History Channel (2015). Nuclear accident at Three Mile Island. Retrieved from http://www.history.com/this-day-in-history/nuclear-accident-at-three-mile-island. World Nuclear Association (2014). Nuclear basics: Chernobyl accident 1986. Retrieved from http://www.world-nuclear.org/info/Safety-and-Security/Safety-of-Plants/Chernobyl-Accident/. Younos, T. (2009). The economics of desalination. Journal of Contemporary Water Research & Education. 132(1): 39-45. Read More