Energy is a basis of life. All civilization comforts, all material spheres of man activities - from laundering till investigations of the Moon and Mars require power consumption, which will only increase in future. Today energy of atom is widely used in many branches of economics.
Powerful submarine and surface ships with nuclear power installations are under construction. The peaceful atom is used in prospecting for minerals. Radioactive isotopes have a wide application in biology, agriculture, medicine, in space exploration.
Nuclear power plants are the third "whale" in the modern world power system. Equipment of NPP undoubtedly is the great achievement of the scientific-technical progress. In the case of trouble-free operation, NPPs practically don't pollute the environment, besides thermal pollution. Actually radiation waste presenting a potential hazard is produced as a result of NPP (and nuclear fuel cycle enterprises) operation. However, the volume of radioactive waste is very small, they are very compact and one can store them in the conditions guaranteeing the absence of their leakage outside. NPPs are more economic than usual thermal power plants and the main advantage is that they are pure energy source in the case of their correct operation. At the same time, developing nuclear power for economics needs, don't forget about safety and health of people, since the mistakes can lead to catastrophe consequences.
More 150 incidents and accidents of different levels of complexity in 14 countries of the world occurred from the moment of the beginning of NPPs operation. The most representative of accidents are in Windscale (England) in 1957, in Santa Susana (USA) in 1959, in Idaho Falls (USA) in 1961, at Three Mile Island NPP (USA) in 1979, at Chernobyl NPP (USSR) in 1986.There are various technogenic influences on the environment, when constructing and operating NPPs. The most essential of them are as follows:
Appearance of powerful heat source in the kind of cooling towers, cooling ponds during NPP operation changes significantly microclimatic characteristics of the adjacent districts. Movement of water in the system of external heat removal, discharges of technological water containing various chemical components have a traumatic influence on populations, flora and fauna of ecosystems. The spreading of radioactive materials in the environment is of great importance. Safety problems of NPPs, which will replace fossil fuel thermal power plants, have a great public significance in the complex of environment protection issues.
It is recognized that NPPs under their normal operation are 5-10 times "purer" than coil thermal power plants (TPP) from an ecological viewpoint. However, during accidents NPPs can make essential radiation influence on people, ecosystems. So providing safety of ecosphere and protection of the environment against harmful effects of NPPs is a large-scale scientific and technological task providing future of nuclear power.
NPP and other industrial enterprises of region make various influences on complex of natural ecosystems forming ecosphere region of NPP. Evolution of ecosystem occurs with time and changes in the states of dynamic equilibrium are accumulated and fixed as a result of these influences of constant operating NPPs or accidents, other technogenic influences. And people do care, which way these changes in ecosystem go, how they are invertible, what margins of stability are up to significant perturbations. Normalization of anthropogenic loadings on ecosystems is designed to prevent all unfavorable changes in them and to guide these changes in a favourable direction best of all. For reasonable regulation of relations of NPPs with environment, of course, it is necessary to know reactions of biogenesis on disturbing influences of NPP. The approach to normalization of antropogenic influences can be based on ecological - toxicogenic concept, i.e. on the necessity of preventing "poisoning" of ecosystem by harmful substances and their degradation due to extreme loads.
In other words it is impossible not only to poison ecosystem, but to deprive them of the opportunity to develop freely, loading by noise, dust and waste, limiting their areals and food resources. In order to avoid hurting ecosystem, some limiting introductions of harmful substances into organisms of individuals and other limits of influences, which could cause unacceptable consequences at the level of populations, should be defined and fixed as standards.
Ecological capacities of ecosystems should be also known, the values of which shouldn't be exceeded under technogenic effects. The ecological capacities of ecosystems for various harmful substances should be defined by intensity of these substances introduction, at which critical situation will arise even in one of biocenose components, i.e., when accumulation of these substances is approaching to the dangerous limit, the critical concentration will be achieved. Of course, cross-effects should be taken into account in the values of limiting concentrations of toxicogenes, including radionuclides. However, it is apparently insufficient. To protect the environment effectively, it is necessary to introduce a principle legislatively limiting harmful technogenic influences, in particular, emissions and discharges of dangerous substances. It may be said that by analogy with the principles of radiation protection of man, the principles of environment protection are that unjustified technogenic influences should be excluded, accumulation of harmful substances in biocenoses, techogenic loads on ecosystem elements shouldn't exceed dangerous limits, introduction of harmful substances into ecosystem elements, technogenic loads should be so low as possible taking into account economic and social factors. NPP has thermal, radiation, chemical and mechanical influences on the environment.
To provide safety of biosphere, it is necessary to have enough protection means. Necessary protection of the environment means a system of measures directed at compensation of possible exceeding of admissible values of temperatures of mediums, mechanical and dose loads, concentrations of toxicogenic substances in biosphere. Thus, sanitation standards of limiting admissible concentrations (LAC), admissible temperature, dose and mechanical loads should be a criterion of the necessity to carry out measures for protection of the environment. A system of detailed standards for limits of external irradiation, limits of radioisotopes and toxic substances content in components of ecosystems, mechanical loads could fix the standard boundary of limit critical influences on ecosystem elements for their protection against degradation.
Various technogenic influences on the environment are characterized by their frequency of repeat and intensity. For example, emissions of harmful substances have some constant component corresponding to normal operation and random component depending on probabilities of accidents, i.e. on a level of safety of facility under consideration. It is clear, the more severe and dangerous accident, the lower probability of its arising. Now we know by bitter experience of Chernobyl that pine forest has radio sensitivity similar to that for man, mixed forests and bushes have sensitivity 5 times lower. Measures of preventing dangerous influences, preventing influences under normal operation, creation of the opportunities for compensating these influences and for controlling harmful influences should be accepted at the stage of facility designing. It suggests to develop and create the systems for ecological monitoring of region, to develop methods for calculation forecasting of ecological damage, recognized methods for assessing ecological capacities of ecosystem, methods for comparing various type damages. These measures should develop the basis for active control for the environment state.Nuclear power acquires greater significance for diversification China's energy mix, improving safety and promoting sustainable development of the country. Technologies of nuclear power due to its relative purity, safety and economical efficiency play more important role in the strategy for sustainable development of China.
Development of nuclear power in China began at the beginning of 1980-ies. At that time nuclear power was considered as addition to other types of power. In the second half of 1990-ies the first three nuclear power units have been put into operation with total installed power of 2100 MW. By the end of 2001 nuclear power of Chine was approximately amounted to 1% of total volume of power generation in China. The first NPP- Qinshan (300 MW) in the north of Zhejiang province (designed and built by Chinese engineers and scientists by themselves) was connected into the grid in December 1991 and put into industrial operation in April 1992. The second NPP- Tianwan located in Guangdong province was put into industrial operation in the middle of 1990-ies. It was the largest investment project in nuclear power at that time. Qinshan and Tianwan NPPs are under stable safe operation regime with coefficient of using installed capacities of 84% and 76,5% correspondingly in 1997. By the end of 1997 total installed capacity of power facilities in China exceeded 250 GW with annual electricity generation of 1,135TW*h, in which nuclear power was amounted to 1,27%.
In 2004 Chinese government approved the projects to expand Qinshan Phase II in Zhejiang and Ling"ao NPP in Guangdong of extending NPPs, as well as the project of construction of new NPPs - in Sanmen of Zhejiang and Yangjiang of Guangdong.
Beginning from the middle of 1990-ies the strategy of nuclear power development in China began using the principle of "moderate development" and in other interpretation "corresponding development". Since China continued to consider coil as a key energy source, nuclear power branch was somewhat limited in its development during last 20 years. By 2006 nuclear power capacity in China was only 1,7% of total power generation by national electricity plants.However, now the situation changes and development of nuclear power in China has promising future. At present 9 power units are under operation in the continental part of China, the total power of which was achieved to 6998 MW. The nearest projects of Chinese nuclear power are as follows. Firstly, 2 power units with power of 600 MW will be constructed at NPP Qinshan on the basis of available infrastructure. Secondary, third generation nuclear technologies from abroad are involved through international tenders. Two 1000 MW nuclear power units will be constructed in Sanmen of Zhejiang province and Yangjiang city Guangdong province. Now hard work is going on estimating tenders. Simultaneously preliminary project of NPP with power units on the basis of light water reactor has been already prepared and considered by experts. Its design lifetime is 60 years. Investments in 1 kW of power will be less than 1300 $, and the price for electricity, when connecting to the grid, is less than 5 cents for kW*h. Soon Chinese preliminary project of NPP with power of 1500 MW will be prepared.
The considerations of guaranteed energy security in China's foreign policy and actual shortage of electricity have made Chinese government change its strategy of nuclear power development to "active development". In March 2006 China's National People's Congress (NPC) approved the 11th Five-Year Plan for Economic and Social Development (2006-10), in which the government set an ambitious goal to reduce total energy consumption per unit of gross domestic product (GDP) by 20% over the next five years. Chinese Premier Minister Wen Jiabao also announced during the meeting that China would strive to decrease its energy consumption rate by 4% in 2006.
As Chinese nuclear physicist Wang Naiyan confirms, beginning from June 2006, unanimous opinion was beginning to form regarding to the important role of nuclear power for sustainable development of China. The strategic plan "Active development" defined that nuclear power would be one of priorities of the strategy for power development for the next two decades.Safety, economic competitiveness of nuclear power and control for nuclear waste are vital important problems facing before all governments and public. The Chinese Atomic Energy Authority (CAEA) under the State Council is responsible for planning and controlling the peaceful use of nuclear power and developing of international cooperation. The National Nuclear Safety Administration (NNSA) under CAEA was established in 1984. It is licensing and regulatory body, which also provides fulfillment of international safety agreements. Now it is directly subject to the State Council. The State Environment Protection Administration (SEPA) is responsible for radiological monitoring and handling of radioactive waste. Power company suggesting construction of a new NPP presents feasibility study to CAEA for consideration, sends proposals to NNSA and SEPA (concerning environment issues). Since China's Ministry of health established the Centre of Medical Assistance in nuclear accidents in 1992, the Center has improved its medical response system to radiation and nuclear emergencies in China.China's Government accelerates paces of developing nuclear power of a new generation differing by increased safety and strives to master it itself. During the first two decades of the XXI century nuclear power in China will be used wider due to its safety, better economy and ecology.
In accordance with Chinese Government's plans, at least 1,8 GW nuclear power capacities are planned to put into operation annually during period up to 2020 so that total capacity of Chinese NPPs will increase up to 40GW that will be equal to 4% of total energy balance in China, i.e. China plans to increase nuclear power fraction almost 4 times during the next 13 years. It will allow to solve energy problems of the country and provide the sustainable development of economics. The state of the environment also depends on nuclear power development. In 2001 the capacity of nuclear power for the most heavily populated country on Earth was slightly less than in Finland. However, international nuclear industry "makes headway" to open doors of China. Asia is the growing market for nuclear power. Development of nuclear power becomes more important for diversification China's energy mix, improving safety and promoting sustainable development of the country.
SOURCE: Tsi Chunshen, AtomInfo.Ru
DATE: November 19, 2007