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Energy and Environment
Published in T.M. Aggarwal, Environmental Control in Thermal Power Plants, 2021
Opponents believe that nuclear power poses many threats to people and the environment. These threats include the problems of processing, transport and storage of radioactive nuclear waste, the risk of nuclear weapons proliferation and terrorism, as well as health risks and environmental damage from uranium mining. They also contend that reactors themselves are enormously complex machines where many things can and do go wrong; and there have been serious nuclear accidents. Critics do not believe that the risks of using nuclear fission as a power source can be fully offset through the development of new technology. They also argue that when all the energy-intensive stages of the nuclear fuel chain are considered, from uranium mining to nuclear decommissioning, nuclear power is neither a low-carbon nor an economical electricity source.
The wider perspective of decommissioning
Published in Martin J. Pasqualetti, Nuclear Decommissioning and Society, 2019
More general environmental hazards are likely to receive greater attention in future as the decommissioning of nuclear and North Sea facilities gets under way and environmental implications become more apparent. Nuclear decommissioning, for example, will produce large quantities of radioactive waste: the US NRC estimates that 4 years of decommissioning will produce a volume of waste comparable with that produced in a 30-year period of reactor operation. The as yet unresolved problems of radioactive waste management are therefore bound to act as a constraint on the decommissioning of nuclear facilities. Dismantling of offshore structures, in contrast, will have to be subject to stringent precautions to minimize the risk of serious marine pollution and such measures must add significantly to the cost of the operation. Furthermore, all major decommissioning projects will have to include contingency provision for an unanticipated or catastrophic turn of events; an example might be the ‘champagne effect’ – the possibility that a gravity platform will float uncontrollably, and very dangerously, to the surface once its base has been loosened from the sea bed. This is a foreseeable problem; by definition, many contingencies are not.
The problem of radioactive wastes
Published in Matthew Cotton, Nuclear Waste Politics, 2017
In the United Kingdom, the total physical volume of radioactive waste has been estimated to fill the Royal Albert Hall approximately 20 times and of this volume, high level waste (HLW) represents a comparatively tiny proportion of the total. According the 2013 UK Radioactive Waste Inventory (Nuclear Decommissioning Authority, 2013) by volume of total radioactive waste is: 63.2 per cent VLLW (2,840,000 m3)30.5 per cent is LLW (1,370,000 m3)6.4 per cent is ILW (286,000 m3)<0.1 per cent is HLW (1,080 m3) However, physical volume is not of course the only property of waste that poses a challenge to management decisions and the socially constructed nature of these volumes is discussed in the subsequent section of this chapter. For example, changes to waste management practices have altered the composition of waste types – i.e. decreasing ILW volumes have resulted in rapid growth in LLW volumes as shown in Figure 1.3. One of the issues discussed in this book, is the extent which the scale of this problem is socially constructed by different actors embedded within the policy process. Whereas the nuclear industry is keen to emphasise the comparatively small volumes of waste produced, particularly of spent fuel, environmental organisations have often argued the opposite. ENGOs commonly point to the very small amounts of highly active wastes needed to cause illness in an individual or a population. There is no single picture to which all actors within the debate adhere, and so the scale and nature of the problem is a matter of social construction.
Using the swelling rate calculated from the swelling index test to evaluate the influence of concrete alkali concentration and temperature on bentonite swelling properties
Published in Journal of the Chinese Institute of Engineers, 2023
Wei-Chien Wang, Jia-Chen Xue, Chung-Hao Wu, Kao-Hao Chang
In terms of studies regarding the influence of normal concrete pore solutions on bentonite, highly alkaline solutions usually used to simulation testing of concrete pore solutions (Bauer et al. 2006; Fernández et al. 2006; Sun et al. 2018; Ye et al. 2014). While studies of the influence of low-pH concrete on bentonite mostly use models for research (Fernández, Cuevas, and Mäder 2009; Lehikoinen 2009; Watson, Benbow, and Savage 2007), some directly used low-pH concrete blocks to contact bentonite for research (González-Santamaría et al. 2018; Lerouge et al. 2017). Few studies have used the concrete pore solution to directly erode bentonite. Besides, the radioactive decay of HLW in the disposal site results in heat output, and the maximum temperature of the disposal tank can reach 80°C within five years (Nuclear Decommissioning Authority 2010). Therefore, research for high-temperature environments is also necessary.