Radiological Impact of Routine Discharges - Report Example

EUROPEAN PRESSURISED REACTORS - EPRs (Radiological Impact of Routine Discharges) Full ID Number: of Name: Name of School (University) Word Count: 2,927 (of text only) Date of Submission: November 21, 2013 Introduction The world today is fast running out of energy; this situation is primarily due to the two reasons, which are the traditional fossil fuels are being depleted known in the energy industry as the “peak oil” phenomenon, and secondly, rising energy demand from fast-growing populations in newly-industrialising countries such as the BRIC (Brazil, Russia, India, and China). This has fueled, so to speak, a frantic search for new energy sources such as the renewable energy sources like solar, wind, and tidal power. Fossil fuels like crude oil and natural gas are produced in wells which have seen declining extraction yields; the theory of “peak oil” was first put forward and popularised by Marion King Hubbert, who was a geo-scientist working at Shell, which is now largely proven to be true as conceptualised and illustrated by the “Hubbert Curve.” Invention of a new but controversial technology known as hydraulic fracturing or also termed as “fracking” has given a new lease of life to the energy industry by allowing access to most previously-inaccessible gas deposits trapped in hard rocks or shale by injecting pressurised water and fragmenting the rocks to release the gas. This new method has made gas prices lower today, by as much as 86% cheaper, due to the suddenly-abundant natural gas supplies but this has raised opposition from environmentalists because of pollution-related issues with fracking. In the same manner, atomic energy offers the best hope for an energy-thirsty world but a lot of safety issues are being raised with nuclear reactors in producing electricity. There are renewed concerns with the safety of reactor designs in view of the fairly-recent event in Fukushima, Japan after a strong earthquake and subsequent tsunami destroyed its nuclear reactor and released radioactive materials. This paper tackles safety issues associated with EPRs. Discussion A European pressurised reactor (EPR) is a third-generation nuclear reactor design that is alternatively known as a pressurised water reactor (PWR). It has been developed by Electricite de France (EDF) and the Siemens AG conglomerate group of Germany. It is being sold to several countries worldwide but as of date, only four are under construction, in the countries of Finland and France (one for each country) and two units in China. It is also being considered in the countries of the United Kingdom (U.K.), the United States of America (U.S.A.), Saudi Arabia, Italy, India, and Abu Dhabi but is meeting some stiff opposition in these countries. The EPR, also known in international energy industry circles by the same acronym of EPR (evolutionary power reactor) is supposed to offer increased safety while enhancing its economic efficiency through a higher electrical power and thermal output through lower costs (17% more efficient in the use of uranium fuels) but safety issues continue to hound this new design despite claims it is significantly safer against any potential terrorist attack compared to presently-operational reactors. The EPR design uses several safety measures against accidents or meltdown resulting from either a terrorist attack or a natural calamity like in Fukushima. The main issue raised against the EPR is the reliability and adequacy of safety systems incorporated into the design in conjunction with additional measures to ensure independence of a nuclear reactor in case safety systems will fail and control is lost. This independence factor is the equivalent of redundant systems found in aircraft and on the operational capabilities of complex systems such as the Internet. The independence principle is invoked in nuclear-reactor designs to ensure any accidental meltdowns can be prevented by regaining control of a run-away reactor. Nuclear energy is supposed to be safe and virtually inexhaustible, a renewable energy source that is both sustainable and causing less carbon-emissions to the atmosphere if compared to the traditional thermal power plants using fossil fuels and helps to reduce global warming. But a persistent issue has always been its safety, with critics citing various serious accidents like the Three Mile Island (1979), the Chernobyl disaster (1986), and the Fukushima meltdown (2011) as prominent examples in what is termed as “The China Syndrome” which is used as a metaphor to indicate a meltdown which goes through the earths crust to the other side of the world. However, regardless of the safety and design issues raised with the EPR, this paper will take a different tack or perspective with regards to the commercial operations of an EPR. It will examine and discuss how an EPR impacts the environment through its routine discharges in small quantities of radioactivity to the environment in both aerial and liquid forms. This paper is therefore a critical review of how an EPR impacts the environment by trying to determine levels of radioactive discharges in terms of safe individual and collective doses of nuclides. In other words, this paper compares the EPR to other nuclear-energy reactor designs based on available scientific literature and further tries to make a risk-benefit analysis based on critical ratios. Among the relevant issues to be discussed are the physical, chemical, and radiological characteristics of these routine discharges, the methods used to assess the environmental impact, give a summary of various studies on prospective operations of an EPR, identify the possible exposure pathways of such radioactive discharges, and to also examine the various constraints in terms of legal and regulatory controls facing the various government agencies charged with assessment and regulation of this new nuclear reactor design and put all these in context. Aerial and liquid discharges from operation of a nuclear reactor – these discharges are small and normal such as aerial discharges due to evaporation and erosion through smoke stacks and liquid discharges from coolant water through disposal via waterways and also into sewerage systems. Although radionuclides are released through the entire six-stage nuclear fuel cycle, this paper focuses on the radionuclides released during the power generation phase of the reactor. Radioactive gaseous emissions – the main source of such emissions is from de-gassing the water in the primary circuit of the reactor. This is then directed to the main treatment system where waste gas is first dried and then passed through activated-carbon delay beds. After this primary filtration, it is further filtered through a high-efficiency particulate air (HEPA) filters before being discharged or released via the smoke stacks approximately sixty (60 meters height.1 Nuclide Main Source Production Mode Discharge Mode Carbon-14 Coolant gas Activation of coolant water Aerial Tritium Coolant water Fuel fission and the activation of boron Aerial Xenon-133 Coolant gas Fuel fission Aerial Xenon-135 Coolant gas Fuel fission Aerial Iodine-131 Coolant gas Fuel fission Aerial Iodine-133 Coolant gas Fuel fission Aerial Argon-41 Coolant gas Activation of argon Aerial On the other hand, a report from an advocacy group estimated the annual discharges in radioactive gaseous emissions to be unacceptably high in both individual and collective doses. This report was prepared by the groups external consultant on radioactivity in the environment.2 It was further assessed by the said consultant that aerial discharges are far more dangerous than liquid discharges because of its concentration and in terms of cumulative doses received from a variety of sources, such as breathing contaminated air, eating contaminated food, drinking the contaminated water, and by skin exposure primarily from tritiated water vapors from radioactive water that contained tritium, which is an isotope or the radioactive form of hydrogen (3H). These are the estimates made by Fairlie regarding the amount of radiation emissions of an EPR: Nuclides Tritium Carbon-14 Noble gases Radioiodines Air emission 500 GBq 350 GBq 800 GBq 50 MBq The above estimates contradict the assumptions given by the Environment Agency in the previous page, which states EPRs are safe to operate. In that government report, the Agency stated however both their preliminary and detailed assessments gave satisfactory ratings to EPRs in terms of their environmental impacts on air, sea, and land contrary to what critics claimed. In the same report, the Environment Agency admitted the disposal of radioactive wastes is the main concern because it has the highest profile in terms of possible public opposition to a new plant. In regard to tritium production as a by-product of nuclear-energy generation, there is no known proven technique that can abate in liquid effluent discharges, even in Hinkley Point C. The only way to abate somehow the production of tritium is by use of depleted lithium or an additional use of enriched boron which is known as the boron-lithium ratio (“low lithium”) formula although three different boron-lithium ratios are currently being studied on what ratio is best for minimising the production of tritium in the primary coolant at its source; this approach is considered as the best available technique (BAT) at this point in time. Radioactive liquid discharges - At any rate, the largest of aerial emissions are composed mostly of tritium in the form of tritiated water vapors and liquid discharges are likewise mostly of tritium also, in this case, several thousand times larger. These are the estimated liquid discharges of tritium once Hinkley Point C goes online or operational:3 Although cobalt 58/60 is also routinely discharged together the tritium in liquid radioactive waste, it is the tritium that is most abundant in these routine discharges and considered as the main radioactive danger. Annual limit for liquid tritium discharges Actual limit for liquid tritium discharges Percent Increases Combined Hinkley C and Oldbury B From 653 TBq to 983 TBq per annum From 105 TBq to 315 TBq per annum For annual limit (50% increase) and actual limit (300% increase) Tritium in water (tritiated water) behaves like normal water and is likely mixed with ordinary sea sprays and marine aerosols. Recent studies suggest tritium is not so benign after all, as it has been linked to radiotoxicity due to bio-accumulation from marine predation webs. Assessment of environmental impacts – besides pollution of the environment even far away from nuclear-power plants (NPP), there are many other environmental issues which affect the operation of any NPP. One of these critical issues is the proper disposal of radioactive waste, because these wastes often have very long half-lives before these decay completely. High-level nuclear waste from nuclear reactors are the most hazardous materials ever and most countries in the world are finding it difficult to find suitable permanent repositories of these wastes.4 It could also be very expensive in the long run to maintain these disposal sites with new waste generated. Another pressing issue is contamination of potable water supplies which compounds a problem. People living near NPP were found to have abnormally high rates of cancer incidence, especially that of leukemia among children. The patho-physiology on this aspect is not yet very clear but mounting data points to radiation as a very probable cause, based on extensive studies. Some radioactive materials have an extremely rapid distribution in the environment, together with its inherent tendency to be heterogeneously distributed within human tissues, and lastly, the apparent ability of radioactive materials to bind themselves with organic molecules resulting in a higher dose than what would normally be warranted under these circumstances. While backers of nuclear power promote it as a sustainable energy source that does not contribute to global warming, its critics point out these epidemics of cancers near nuclear power plants as proof that there is no safe threshold level to radiation exposure. Nuclear radiation is a cumulative process, and the greater the exposure over the long term, the greater the risks. Exposure pathways to radiation - modes of exposure to radiation are through the air, sea, and land. In the case of airborne radioactive effluents, the exposure follows inhalation of the contaminated air and also by external irradiation, then via deposition on the ground, followed by deposition on food crops, and deposition on vegetation which are then eaten by livestock such as cattle (ingestion by the animals). Radiation from liquid effluents can come via direct radiation from contaminated bodies of water such as rivers, lakes, estuaries, coastal waters, and oceans. It is furthered along by eating aquatic animals and other marine resources which had radiation from their food uptake along the food chain, and most often, by drinking contaminated water sources. Radiation exposure by land involves to ground areas contaminated with radiation from waste and other radioactive materials such as those coming from a de-commissioned nuclear-power plant.5 Exposure to radiation is a cumulative process and women face higher risk of developing and dying from cancer than men; for babies and young children, their risks are markedly higher, at three to four times more likely to develop cancers than adults due to their still developing bodies. The more scientists learned about nuclear radiation exposure, the more they got nervous and concerned as they repeatedly kept lowering the safe dose levels allowed when in reality, the consensus nowadays seems to be there is no safe threshold for radiation because it is cumulative in the human body.6 The computation for safe levels of radiation simply gives a false sense of security to most people who become unwitting victims of cancer epidemics due to the erroneous assurance they often received from government officials, regulators, and industry experts. Nuclear-energy advocates cite the human bodys ability to repair itself (homeostasis or to regain equilibrium or a healthy balance) will offset any possible adverse effects of the ionizing radiation that people received from the operation of NPPs.7 The argument has been that lowest possible doses and dose rates are below the considered safe thresholds of any radiation. This is shown by the following illustrative example of how ionizing radiation is considered “safe”: Annual Effective Dose Maximum Discharges (with an additional Read More