Sunday, November 10, 2019
Nuclear Energy: How Fukushima Changed Everything
Nuclear Energy: How Fukushima Changed Everything. After the Chernobyl disaster of April 26th, 1986, it was often said that the nuclear industry no longer had the resilience to survive another major nuclear accident. The industry hoped that the sentiment behind the Chernobyl accident could be eased on the basis that it was the consequence of a flaw in design that was unique to the Soviet Unionââ¬â¢s reactors and that they had been operated in such a way that would not have been acceptable in the West.Then, Fukushima changed everything. That, at least, was the popular view adopted in the aftermath of March 11, 2011, by the press, media and across the Internet blogging community. A nuclear accident in such a densely populated and well-developed country would transform the way nuclear energy is perceived, as well as, determine the way it would be used, or not used, in the years to come. This analysis attempts to overview its causes, evaluate its impact, and understand its consequences on future nuclear development. CausesOn October 30th, 2011, the Fukushima Nuclear Accident Independent Investigation Commission (NAIIC) was enacted, creating an independent commission whose sole purpose was to investigate the Fukushima accident with the authority to request documentation and evidence required from whomever they saw fit. This independent commission was the first in the history of Japanââ¬â¢s constitutional government. Their main mandate was to investigate the direct and indirect causes of the Tokyo Electric Power Company Fukushima nuclear power plant accident that occurred on March 11, 2011 in conjunction with the Great East Japan Earthquake.This event triggered an extremely severe nuclear accident at the Fukushima Daichii Nuclear Power Plant, owned and operated by the Tokyo Electric Power Company (TEPCO). It was declared Level 7 (ââ¬Å"Severe Accidentâ⬠) by the International Nuclear Event Scale (INES). At the moment the earthquake struck, nuclear reactor u nits 1 to 3 were functioning under normal operating parameters and units 4 to 6 were undergoing periodic inspection. Emergency shutdown occurred right after seismic activity was identified. The seismic tremors damaged the electricity transmission facilities between the TEPCO Shinfukushima Transformer SubstationsNuclear Energy: How Fukushima Changed Everything. 2 and the Fukushima Daichii Nuclear Power Plant. This resulted in a total loss of off-site electricity. The back-up transmission line that was hooked up to nearby Tohoku Electric Power Company failed to feed reactor 1 due to mismatched sockets. The first of 3 tsunami waves was more than twice the height of the seawall which TEPCO had failed to replace after recommendations had been made by a group of government scientists back in 2009. TEPCO later stated that this recommendation was in the process of review at the time the tsunami hit.The seawater began flooding the building floor breaking walls and scattering debris. As the w ater rose, emergency diesel generators broke down, along with the seawater cooling pumps, electric wiring system and DC power supply for units 1, 2, 3 and 4. This resulted in a complete loss of power. Unit 5 lost all AC power and unit 6 stayed online due to a working air cooled emergency diesel generator. The loss of electricity resulted in the shutdown of monitoring equipment, lighting and communication devices. Decisions had to be made on the spot without the proper tools or manuals, making it difficult to cool down the reactors in an efficient way.The cooling reactors which were dependent on electricity for high-pressure water injection, depressurizing the reactors low pressure water injection cooling, depressurizing the reactor containers, and removal of decay, failed. Lack of access to these key locations due to debris pile up led to the inability of the personnel to react appropriately. In June, 2011, four months after the accident, the countryââ¬â¢s Nuclear Emergency Respo nse Headquarters confirmed the complete meltdown of reactors 1, 2, 3, and spent fuel pond of reactor 4.The conclusions held by the NAIIC stated that the direct causes of the accident were all foreseeable prior to March 11, 2011. The plants design was incapable of withstanding an earthquake and tsunami of that magnitude. In addition, operators (TEPCO), regulatory bodies (NISA and NSC) and the government body promoting the nuclear power industry (METI) all failed to ensure basic safety requirements, such as assessing the probability of damage, preparation for containing collateral damage and developing evacuation plans for the public in the case of a serious radiation release. Dr.Kurokawa of the Nuclear Safety Commission reserved his most damning language for his criticism of a culture in Japan that suppresses dissent and outside opinion, which he said might have prompted changes to the countryââ¬â¢s lax nuclear controls. Nuclear Energy: How Fukushima Changed Everything. 3 Impacts on Health & Environment The Fukushima Daiichi nuclear accident resulted in the release of fission products to the environment, including the contamination of air, water, soil, animals, fish, milk and crops. In addition, it generated radiation levels that caused the necessary evacuation of people within a 20 to 30 km range of the facility.A study on the effects of the Fukushima nuclear meltdown on the environment and public safety by Dr. med. Alex Rosen of the University of Dusseldorf came up with a series findings. The atmospheric emissions of more than 30 radioactive isotopes occurred through the explosions in reactors 1 to 3, the spent fuel pond of reactor 4 and the venting of reactors to relieve pressure and enable cool down. The total emission of iodine 131 was estimated to be 20% of the quantity emitted in the Chernobyl accident and 40% to 60% of cesium-137 emissions.Although, these are both naturally occurring elements, both of these radioactive isotopes are found to have dang erous impacts to human health under high doses. A dozen other radioactive substances including strontium-90, xenon-133 and plutonium-139 were spread throughout the region as radioactive fallout following the incident. Geography Radioactive fallout occurred mainly in the Northern Pacific (79%) and about 19% of the fallout contaminated the Honshu island, which includes the densely populated Tokyo metropolitan area. Overall, it was determined hat 1000 km2 were highly contaminated with radioactive isotopes. This led to the evacuation of an estimated 200,000 people in the immediately impacted zone in a radius of 20 km2 to 30 km2. Furthermore, an estimated 70,000 people are said to have stayed within 870 km2 radius of the plantââ¬â¢s highly contaminated land outside of the evacuation zone. These people were exposed to 100 times the natural background radiation expected within a year following the accident. Health Risks The risk of developing cancer and other radiation-induced diseases increased proportionally to the amount of radioactive exposure.According to Dr. Rosen, even the smallest amounts of Nuclear Energy: How Fukushima Changed Everything. 4 radioactivity can cause tissue damage and genetic mutations. Children have been found to be the demographic class with the highest risk in relation to radioactive exposure due to a greater level of sensitivity. Soil Contamination Following the nuclear disaster at Chernobyl 25 years ago, the Soviet government chose long-term evacuation over extensive decontamination. As a result, the area is non habitable and remains severely contaminated by radioactive fallout.In Japan, large areas of farmland and forests were contaminated following the accident. Lacking land for resettlement and facing public outrage, the Japanese government chose to embark on a decontamination effort of unprecedented scale. Japanese workers, power-sprayed buildings, scraped soil off fields, and removed fallen leaves and undergrowth from the woods ne ar houses, in an attempt to make Fukushima livable again. The Japanese Ministry of Environment estimated that Fukushima would have to dispose of 15 to 31 million cubic meters of contaminated soil and debris by the end of the econtamination process, with costs exceeding one trillion yen. The decontamination efforts were focused mostly on the radionuclides caesium-134 and caesium-137, with half-lives of 2 and 30 years, respectively. Although other radionuclides have been found in Japan, these two pose the greatest long term threat to human health through ingestion and external exposure. Radiocaesium has been found in all of Japanââ¬â¢s prefectures, but most highly concentrated within a 50 kilometer area northwest of the plant, and to a lesser extent throughout eastern and central Fukushima Prefecture.Marine & Groundwater Back flow and deliberate discharge of radioactive wastewater were released from the plant. Approximately 15 to 27 PBq (petabecquerel) of radioactive marine dischar ge resulted in the worst radioactive contamination of the Japanese coast in recorded history. The effect of dilution of the radioactive marine discharge may substantially reduce the impact radioactive fallout, but will inevitably to a greater area being contaminated at a lower concentration. Proceedings from the National Academy of Sciences of the U. S. A. ublished major findings on the detection of Fukushima-derived cesium-134 and cesium-137 throughout waters 30ââ¬â600 km offshore, with Nuclear Energy: How Fukushima Changed Everything. 5 the highest radioactivity associated with near-shore eddies and the Kuroshio Current acting as a southern boundary for radioactive transport. Researchers concluded that even though cesium isotopes are elevated 10 to 1000 times over prior levels in waters off Japan, radiation risks due to these radionuclides are below those generally considered harmful to marine animals and human consumers, and even below those from naturally occurring radionucl ides.Food & Vegetation Radioactive contamination was found in fruits and vegetables grown in the affected region. Meat products originating from animals grazing on contaminated soil and destined to human consumption was found to be contaminated. Contamination was also detected in milk and tea, as well as, tap water in the Tokyo metropolitan area (the worldââ¬â¢s largest city in terms of population). It has been determined that eating 500g of contaminated vegetables can cause internal exposure of 100 times the normal amount of radioactive food content for adults and more than 200 times for children.Fish and seafood caught in the North Pacific region was contaminated and showed clear accumulation of radioactivity in sea life higher up in the food chain within the months following the accident. Washout and bioaccumulation will continue to cause the radioactive contamination of marine animals for years to come due to the extended half life of certain radioactive elements. Although it is quite clear that this accident has had significant impacts on human health, soil, food, animal and marine life, it is still too early to accurately determine the full extent of the accidentââ¬â¢s environmental impacts and the proper approach to remediation.Impacts on Nuclear Energy Development Nuclear power provides global carbon-free dispatchable base load generation and its continued growth is a major component in many forecasts for future greenhouse gas emissions (GHG) reductions. Nuclear energy accounts for 13. 5% of global electricity production as of 2012. This GHG reduction potential is one of the reasons for the much discussed ââ¬Å"renaissance of Nuclear Energy: How Fukushima Changed Everything. 6 nuclear powerâ⬠.It has been acknowledged that nuclear power represents a potential source for large quantities of carbon-free electricity production from plants that do not share the intermittency issues of solar and wind energy production. Two potential forces could adversely affect nuclear production projections postFukushima accident. Foremost, the accident may affect safety criteria and procedures for existing and new nuclear generating units. These changes could lead to increased associated costs. Second, the accident may have adverse affects on public opinion and potential political support for nuclear power.Hence, some countries could ultimately move away from nuclear energy on a political basis, making relicensing of new plants more difficult, leading to tighter safety criteria and delays in regulatory decisions. Determining what the long run responses will be globally and how they will affect the economics of nuclear power generation, as well as the politics associated with acceptance of nuclear power in different countries will remain uncertain for years to come. Prior to the Fukushima accident, it appeared that there was growing political acceptance of nuclear energy.In the worldââ¬â¢s 3 largest nuclear economies (U. S. , France, J apan), extensions to licensing were in progress and associated operating lines of most existing plants were proceeding without much political opposition. In particular, Unit #1 of the Fukushima Daichii plant had just received a 10 year extension on its operating license months before the incident. As for new construction, major nuclear vendors were heavily promoting the latest generation 3 design as being safer and more economical than previous generations.Construction was beginning on new nuclear units in Finland and France, and commitments were being made to build new units in the U. K. China had also just made a major commitment to increase its production from 1% to 6% by 2020. India was also in the midst of piercing into the nuclear market, with the help of the U. S. , France and Russia. Additional construction was anticipated in South Korea, Japan and Taiwan. A number of developing countries were also beginning to show interest in integrating nuclear energy as a part of their e nergy portfolios.These countries included Abu Dhabi, Saudi Arabia, Turkey, Egypt, Israel, Jordan, Chile, Venezuela and Vietnam amongst others. A number of considerations were driving this interest. Policies to promote low to zero carbon emitting energy sources and the intent of reaching C02 emissions reduction targets by Nuclear Energy: How Fukushima Changed Everything. 7 2020 and 2050 were having a positive effect on political decision making. In addition, significant improvements in the performance of nuclear plants in were enabling countries such as the U. S. to reach up to 90% capacity factors.Furthermore, the rise in fossil fuels and new generation reactors were promising higher safety ratings and lower construction costs. The reconsideration of Italy, Spain and Sweden on the use of nuclear power use and the growing interest in emerging countries to rapidly respond to increase in demand for electricity were also leading factors. All these reasons led experts into the optimistic belief that the world was on the verge of a new wave of investment in the nuclear energy sector. Since the Fukushima accident, detrimental impacts on expert optimism have been observed.Japan has permanently closed units 1-4 of the Fukushima Daichii plant and the status of units 5-6 remain uncertain. In addition, only 10 out of Japanââ¬â¢s 50 previously operational units are now operating, and there has been significant local opposition to returning them to service. Public support for Japanââ¬â¢s current nuclear power program is under considerable stress. Following the accident, most countries with major nuclear programs have moved quickly to perform short-term safety assessments of existing plants and have opted to launch longer term assessments of regulatory procedures and safety criteria.The situation in Japan remains uncertain. As the third largest nuclear program worldwide, a decision to move away from nuclear energy with Germany would have a definite material effect on f uture development trends. Any tightening of safety requirements resulting from the accident will only make the economic status of nuclear power less attractive. However, it has been observed that the Fukushima accident has had little effect on plans for unit construction in countries where significant nuclear programs were being planned prior to Fukushima.Some countries such as Taiwan, Chile, Israel and Venezuela have decided to not enter or re-enter the nuclear expansion business. On the other hand, current non-nuclear countries such as Turkey, Saudi Arabia, Vietnam and Abu Dhabi have recommitted to start building nuclear power plants. As for China, it is believed that its willingness to sacrifice on economics to meet energy security and environmental goals is still present. The setback is that China can not fail to meet safety requirements and this may constrain the rate at which its nuclear program can proceed. Nuclear Energy: How Fukushima Changed Everything. The Fukushima Daich ii nuclear accident will contribute to a reduction in future trends on the expansion of nuclear energy, but at this time these effects appear to be quite modest at the global level. For countries such as Germany, Switzerland and Japan, the effects are significant, but for most other countries, changes have not been currently made in their support for nuclear power. Due to significant loss of trust in reactor safety, the International Atomic Energy Agency reduced, in Juin 2011, the 2030 projection on the worldwide contribution of nuclear power by about 10%.Nuclear power has been the source of fear and excitement for decades, and what the Fukushima Daichii nuclear accident caused, first and foremost, was irreparable damage to the local communities of Japan and their surrounding environment. It is now clear that the international community may have dodged the bullet once again, however it seems as though they might not be getting a second chance. The potential for clean energy producti on with nuclear energy is undeniable, perhaps advancements in technology such as the development of Generation IV reactors will put nuclear energy back on the forefront of global energy production.Whether or not potential energy output outweighs the risks associated with future accidents differs based on personal perspective. The Gen IV International Forum will evaluate lessons learnt and integrate them in the design and safety criteria of the reactors under development, which are expected to be ready by mid-century. Inherent reactor safety features will become far more important as a result of the Fukushima accident. Furthermore, modular and smaller reactors, due to their lower in-core energy density, will probably gain in popularity.As we move forward, a dedicated and permanent effort is needed to regain trust by open, transparent and honest dialogue with the public on the risks and benefits of nuclear energy. Nuclear Energy: How Fukushima Changed Everything. 9 References Lincoln L. Davies. ââ¬Å"Beyond Fukushima: Disasters, Nuclear Energy, and Energy Law. â⬠Brigham Young University Law Review. (2011): 1937-1990. The Fukushima Nuclear Accident Independent Investigation Commission. ââ¬Å"The National Diet of Japan. â⬠(2012): 1-15. Dr. med. Alex Rosen. ââ¬Å"Effects of the Fukushima nuclear meltdowns on environment and health. â⬠(2012): 1-18. Paul L. Joskow & John E. Parsons. The Future of Nuclear Power After Fukushimaâ⬠. MIT Center for Energy and Environmental Policy Research. (2012): 1-30. Roland Schenkel. ââ¬Å"Nuclear Energy Acceptance and Potential Role to Meet Future Energy Demand. Which Technical/Scientific Achievements Are Needed? â⬠. European Commission, Joint Research Centre, Institute for Transuranium Elements. (2012): 356-364. Winifred Bird. ââ¬Å"As Fukushima Cleanup Begins, Long-term Impacts are Weighedâ⬠. Yale Environment 360. (2012): 1. Karl K. Turekian et al. ââ¬Å" Fukushima-derived radionuclides in the ocean and biota off Japanâ⬠. PNAS. (2012): 1-5. Nuclear Energy: How Fukushima Changed Everything. 10
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.