Nuclear power: clean energy that should not be misunderstood
Source: Economic Daily. Date: 2014-12-24.
Why "nuclear fog staining" is nonsense
Recently, there are articles that the smog in North China is related to the use of uranium-based radioactive elements in Inner Mongolia and the newly discovered large uranium resources in the Daying area of Inner Mongolia. It is said that the haze that persists throughout the day is caused by the ionization of a large number of air molecules and dust particles by the radioactive uranium dust emitted from coal combustion, which led to the term "nuclear fogging". Is this statement credible?
Radiation has been ubiquitous on Earth since ancient times. Natural radiation comes from cosmic rays in outer space and the crust itself. The average radiation exposure to the public in China is about 3.1 mSv / year, of which 0.36 mSv / year comes from cosmic rays, and the other 2.74 mSv / year comes from radioactive materials in the earth's crust.
Thorium is one of the natural radioactive materials. 99.3% of natural uranium is uranium-238. Its half-life is more than four billion years, which means that its radioactivity is very small. The concentration of uranium in the air is extremely low. The dose produced by inhalation of all nuclides in uranium and actinides (except for plutonium and plutonium) is only about 6 microsieves per year, which is only one-fifth of the total dose. Human beings thrive and develop in the natural radiation environment, and they are irradiated by various rays every moment. Natural uranium produces less than one-thousandth of the total dose and is unlikely to have an impact on health.
The average uranium content in thorium in China is 130 becks / kg, Beijing is 121 becks / kg, and the highest in Xinjiang is 951 becks / kg. The average content of uranium in China's soil is 81 becks / kg, the lowest in Beijing is 40 becks / kg, and the highest in Guangdong is 145 becks / kg. It can be seen that, in Beijing with frequent haze, the uranium concentration in coal is not high, and the uranium concentration in soil is the lowest. It can be seen that the haze is not related to the uranium concentration in the air.
From the above analysis, we can see that the term "nuclear fog staining" is totally nonsense, without any facts or scientific basis. The causes of haze are many and need to be studied and demonstrated by the whole society, but it is unfounded to link haze and radiation. China has established a strict radiation monitoring network and a sound radiation supervision system, which can guarantee public health and safety.
What is the relationship between nuclear power and air pollution control?
This year, severe haze weather broke out again in most parts of central and eastern China, affecting an area of about 1.43 million square kilometers, accounting for about 15% of the country's land area. Of the 161 cities that have carried out the monitoring of new air quality standards across the country, 36 cities have suffered severe pollution and above, which seriously affected the health of the people.
In September last year, the State Council issued the "National Ten Articles" on air pollution prevention and control, and proposed the national and key regions (Beijing-Tianjin-Hebei, the Yangtze River Delta, and the Pearl River Delta) to reduce PM2.5 / PM10 in the next five years and 10 prevention measures. . The core prevention and control measures in the energy field are to control the total coal consumption, increase the use of natural gas, and vigorously develop alternative energy sources such as nuclear power and renewable energy.
According to estimates, if 10 million kilowatts of nuclear power are installed in the surrounding areas of Beijing-Tianjin-Hebei, the Yangtze River Delta, and the Pearl River Delta, or 10 million kilowatts of nuclear power will be delivered to the region through external power transmission, the PM2.5 in these regions can be 2.5 years. The average concentrations decreased by 3.4, 1.7, and 4.0 micrograms per cubic meter respectively, which is equivalent to reducing the annual average concentrations of PM2.5 in these three regions by 3%, 2.5%, and 9%, respectively, on the current basis. Five years later, these nuclear power installations contributed 12% (about 1/8), 12.5% (1/8), and 60% of the local average annual PM2.5 concentration reduction targets.
Compared with hydropower, wind power, and solar power, nuclear power has obvious advantages in improving environmental quality. Nuclear power has a large stand-alone capacity, stable operation, high utilization hours, and can be used as the base load of the power grid. The production process has basically zero emissions to the environment, and the effect of improving the environment is very significant. It is estimated that for every 40 million kilowatts of nuclear power built, it can replace standard coal consumption of 100 million tons per year. The substitution effect of 1 million kilowatts of nuclear power on standard coal is equivalent to 2 million kilowatts of hydropower, 3.5 million kilowatts of wind power, and 4.7 million kilowatts of photovoltaic power (measured according to the annual utilization hours of nuclear power 7000, hydropower 3500, wind power 2000, and photovoltaic power generation 1500) .
Does a nuclear power plant endanger public health?
Inland nuclear power plants are relative to nuclear power plants built on the seashore, meaning nuclear power plants built on inland rivers, rivers, and lakes. The construction of nuclear power plants inland will not affect the environment and public health.
China's nuclear power safety standards are consistent with the latest standards of the International Atomic Energy Agency. Inland nuclear power plants use secondary cycle cooling technology, and their fresh water consumption will not affect the water resources in the basin. The quality of water downstream of inland nuclear power plants can reach the drinking water standard.
Inland domestic nuclear power plants, water, gas and other emission indicators meet high international standards, and the increase in radiation impact on the environment is far lower than the radiation level of the environmental background, which will not affect the environment and public health. For example, in an airplane, the radiation we receive in an hour at 10,000 meters is 5 micro-Sieves, but next to the nuclear electric field, if we work here for a long time, the maximum radiation we receive in a year is a few micro-Sieves.
As for the impact of severe accidents on inland nuclear power plants on water resources safety, China's proposed inland nuclear power projects have good site selection conditions, and serious accidents similar to the Fukushima nuclear power plant in Japan cannot occur; further engineering measures can be taken to ensure that Water resources safety and public health under severe accidents; serious accidents of inland nuclear power plants pose less public health risks than other human activities. Even in the unlikely event of a nuclear accident, inland nuclear power plants can take measures to achieve the "storable", "blockable", "treatable" and "can (and water bodies)" of radioactive wastewater under severe accident conditions. ) Entity isolation ".
The practice of developing nuclear power in many countries around the world has proven that there is no essential difference between coastal nuclear power plants and inland nuclear power plants, and they are all safe. The proportion of inland nuclear power in France and the United States accounted for 69% and 61.5%, respectively. The Mississippi River Basin in the United States has 32 nuclear power plants; in some countries, such as Switzerland, Ukraine, and Belgium, its nuclear power plants are all built inland.
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What is the third generation nuclear power technology
In response to public concerns about the safety and economics of nuclear power, the American Institute of Electric Power, with the support of the US Department of Energy and the Nuclear Regulatory Commission, conducted a study on the feasibility of further vigorously developing nuclear power, and formulated the "User Requirements" based on its research results. "Documents (URD)" put forward requirements for the safety, economy and advanced nature of new nuclear power plants. Subsequently, Europe also issued the European User Requirements Document (EUR), which expresses similar requirements to URD documents.
At the end of the 20th century, the United States Department of Energy proposed the development of third-generation nuclear power technology, and achieved consensus around the world. The third generation nuclear power technology refers to a new generation of advanced nuclear power plant technology that meets URD or EUR and has better safety. It has the advantages of being able to compete economically with combined cycle natural gas generating plants and adopting a large number of second-generation mature technologies in energy conversion systems. The most fundamental difference between the third-generation technology and the second-generation technology is that the third-generation nuclear power technology regards installation prevention and mitigation of serious accidents as requirements that must be met in the design of nuclear power plants. In other words, the three generations of nuclear power have "designed pockets" on safety issues.
At present, there are roughly six reactor types of representative third-generation nuclear power technologies. They are the Advanced Passive Pressurized Water Reactor (AP1000) of Westinghouse Electric Company of America, the European Pressurized Water Reactor (EPR) of Areva of France, the Advanced Boiling Water Reactor (ABWR) of General Electric Company and the Economic Simplified Boiling Water Reactor (ESBWR) ), Mitsubishi Corporation ’s Advanced Pressurized Water Reactor (APWR), and Korea Electric Power Engineering Corporation ’s Korea Advanced Pressurized Water Reactor (APR1400). China's self-designed CAP1400 and "Hualong One" are also third-generation nuclear power technologies.
From the current situation of nuclear power development, the third generation nuclear power technology has become the mainstream of nuclear power development in the world today. Almost all nuclear power developed countries in the world that have started construction and are applying for construction permits are of the third generation. Among the three generations of nuclear power plants currently under construction, the United States occupies four, Russia has two, France and Finland each have one, and China has six (of which four AP1000 are located in Sanmen, Zhejiang and Haiyang, Shandong, and two EPR are located in Taishan, Guangdong).