Pan Ziqiang Jiang Ziying: Nuclear power is the best low-carbon energy source at this stage
Source: China Environmental News Date: 2014-02-20
China's air pollution is serious, and energy is the main source of air pollution. Fossil fuels, especially coal, are the main source of energy pollution. While improving the environmental impact of the coal power fuel chain, accelerating the development of nuclear power is a realistic and effective way to reduce environmental pollution and greenhouse gas emissions in China.
的 Comparison of environmental pollution and greenhouse gases produced by different energy sources should be systematic and comprehensive. It is inappropriate to just compare power plants, and even to say that electricity itself is not appropriate; for example, some people say that the use of electric vehicles can solve the problem of pollution, and China's electricity is mainly from coal-fired power plants, which are the main source of air pollution. The use of electric vehicles may reduce pollution in some areas, but it may increase pollution as a whole.
Take nuclear power as an example, which means not only the nuclear power plant itself, but also the entire process including mining → water smelting → conversion → concentration → component manufacturing → power generation processing → waste disposal. Comprehensive comparison refers not only to the comparison of the systems themselves, but also includes the processes of building these systems and the equipment and raw materials used to produce them, that is, the environmental pollution and greenhouse gases generated throughout the life cycle.
Tritium nuclear power chain has little impact on the environment
The radiation exposure of the Yancoal power chain to the public is about 50 times that of the nuclear power chain
Based on the comparison of the environmental hazards caused by the coal and nuclear power chains in China in the mid-1990s, from the perspective of atmospheric pollutant emissions, under normal circumstances, coal-fired power generation emits SO2, NOx, PM and other atmospheric pollution to the environment. Material directly causes environmental impacts such as acid rain and dust fall, causing obvious harm to human health, forests, crops, and ecosystems. Nuclear power does not generate any atmospheric pollutants, and no appreciable environmental impact is found. From the perspective of radioactive effluent emissions, Coal contains naturally occurring native radionuclides, and the natural radionuclides in coal are discharged into the environment through the airborne soot of coal-fired power plants; while the nuclear power chain discharges to the environment after approval by the regulatory authority, which is far below the natural background level The gaseous and liquid effluent produced a small amount of solid waste for closed treatment and no effluent; the radioactive effluent emissions from the coal power chain produced about 40 times more radiation to the public than the nuclear power chain.
From the perspective of public health impact, the evaluation results of the normalized collective effective dose (2001-2005) caused by the radioactive effluent from nuclear fuel cycle facilities and nuclear power plants in our country are: 0.81 people in uranium mining and smelting · Sv / GWa (Collective dose is 0.81 people · Sievert per gigawatt year), uranium conversion 3.50 × 10-4 people · Sv / GWa, uranium enrichment 4.81 × 10-4 people · Sv / GWa, component manufacturing (1996 ～ 2000) 2.09 × 10-3 persons · Sv / GWa, PWR nuclear power plant 2.91 × 10-3 persons · Sv / GWa, heavy water reactor nuclear power plant 1.84 × 10-1 persons · Sv / GWa. The evaluation result of the normalized collective effective dose of the residents around the power plant caused by the discharge of airborne effluent from coal-fired power plants in China was 16.5 people · Sv / GWa (about 7.0 × 103 people · Sv / GWa for stone coal power plants). Coal carbonized brick buildings caused a collective annual effective dose of about 3.1 × 103 people · Sv / GWa.
It can be seen that the radioactive emissions of coal-fired power plants and their radiation exposure to the public are much higher than the contribution of nuclear power plants; since the content of radioactivity in coal slag is higher than other natural building materials and other materials, the doses received by residents living in housings containing coal slag building materials It is also significantly higher; in general, the radiation exposure of the coal power chain to the public is about 50 times that of the nuclear power chain.
The nuclear power chain is the power chain with the lowest greenhouse gas emissions
温室 Greenhouse gas emissions from the nuclear power chain are only about 1% of the coal power chain
In 2011, the Chinese Academy of Engineering carried out research projects on greenhouse gas emissions from different power generation energy chains. The main results are as follows: The actual greenhouse gas emissions in the first part of China's nuclear fuel cycle (including uranium mining and smelting, uranium conversion, uranium enrichment, component manufacturing, and nuclear power plants) The normalized emissions are 6.2g · CO2 / kWh (the carbon dioxide emissions are 6.2 grams per kilowatt-hour), and the total normalized greenhouse gas emissions after taking into account the nuclear fuel cycle (spent fuel reprocessing and waste disposal) are 11.9g · CO2 / kWh. For the coal power chain, the direct and indirect emissions of greenhouse gases in the four life cycle stages of coal production, coal transportation, coal-fired power station construction, operation and decommissioning, and power transmission and distribution were studied. The result was 1072.4g · CO2 / kWh. The hydropower chain is between 0.81 and 12.8g · CO2 / kWh, the wind power chain is between 15.9 and 18.6g · CO2 / kWh, and the solar energy is between 56.3 and 89.9g · CO2 / kWh. From the perspective of greenhouse gas emissions, the nuclear power chain is only about 1% of the coal power chain. The nuclear energy chain is also very low in various power generation energy chains. Nuclear power generation itself does not generate greenhouse gas emissions, but energy and materials are consumed during the construction of nuclear power plants and the fuel and equipment required to produce nuclear power plants. The production of these energy sources and materials requires greenhouse gas emissions, and China's energy mainly comes from coal-fired power stations. Therefore, it can also be said that the greenhouse gas emissions from the nuclear power chain are also derived from coal power plants.
China's total greenhouse gas emissions are among the highest in the world, and the amount of energy demand is huge and has increased sharply. The total amount of greenhouse gas emissions caused by energy use will further increase. Nuclear energy is a low-carbon, intensive energy source. The potential contribution of nuclear power generation to coal-fired power generation to reduce greenhouse gas emissions is very obvious. Accelerating the development of nuclear energy is a reasonable and effective choice for China to build a low-carbon energy structure and cope with climate change.
The nuclear power chain is a safe industry
Fukushima Prefecture adults receive a lifetime dose of about 10 mSv (millisievert) or lower, without increasing the risk of cancer
The probability of accidents in the nuclear power chain is very small. Even if catastrophic accidents such as the Fukushima Daiichi Nuclear Power Plant and Chernobyl occur, the overall situation cannot change the nuclear energy is a safe and environmentally friendly industry. in conclusion.
The United Nations Scientific Committee on the Impact of Atomic Radiation (UNSCEAR) collects, analyzes, and evaluates data provided by various countries and published literature, including data provided by the Japanese government, measurement results provided by UN member states, and UN agencies (CTBTO, FAO, IAEA, WHO And WMO) data, as well as articles published in scientific journals and independent analysis, etc., researched and analyzed the radiation levels and effects of the Fukushima nuclear accident, and discussed them at the 60th session from May 27 to 31, 2013 The report "The level and impact of radiation exposure caused by the nuclear accident caused by the Great East Japan Earthquake and Tsunami in 2011" was approved. Based on published data at home and abroad, the radiation levels and effects of the Fukushima nuclear accident are:
Judging from the doses received by members of the public, the highest doses received by members of the public who live in the 20km evacuation zone and the cautious evacuation zone. The effective dose received by adults before and during evacuation is less than 10mSv. 5mSv. For children under 1 year, the dose to the thyroid is about 50 mGy (milligray). Adults living in Fukushima receive a dose of approximately 4 mSv in the first year. The estimated dose for a one-year-old child is approximately 1 to 2 times higher. Residents living in other areas of Fukushima Prefecture receive roughly the same or lower doses. Residents in other parts of Japan receive lower doses. Assuming that no remedial measures will be taken in the future, it is expected that the lifetime dose of residents who have been living in Fukushima Prefecture in the future will be about 170 mSv. Obviously this estimate is too high. The actual absorbed dose of the thyroid gland may be 3 to 5 times lower, and the systemic dose may be approximately 10 times lower. In general, the doses generated by the Fukushima nuclear accident are roughly the same as those produced by natural radiation sources. The annual effective dose of natural radiation sources received by the Japanese is about 2.1 mSv, and the lifetime dose is about 170 mSv. The radiation dose of neighboring countries and other regions of the world is much lower than Japan, and the annual effective dose is less than 0.01mSv.
From the doses received by workers, emergency workers, municipal workers, and volunteers, by the end of October 2012, about 24,500 workers had participated in the work related to the Fukushima nuclear accident, of which about 15% were from Tokyo Electric Power Company. Employees, others are contract workers. About 34% of the staff have accumulated effective doses not exceeding 10mSv, and about 0.7% (mainly TEPCO staff) exceed 100mSv. The six Tokyo Electric Power staff members have accumulated effective doses higher than 250mSv, the highest dose being about 680mSv, and 90% of its dose comes from internal irradiation (mainly radioactive iodine). The maximum external exposure of contract workers is about 200mSv, and the total dose is about 240mSv. For the measurement of iodine 131 in the staff, the independent effective dose evaluation is consistent with the report of Tokyo Electric Power Company within a reasonable range. The contribution of some short-lived nuclides, especially iodine 133, is not considered, which may underestimate the dose by about 20%. Due to the delayed monitoring, no iodine 131 was detected in the staff's thyroid. For these staff, there are uncertainties in the estimation of internal exposure. Except for the thyroid gland, staff organ dose data do not have sufficient information. One of the most important is the dose of beta radiation to the eye lens.
From the perspective of radiation effects on workers, the vast majority of 24,575 workers are less than 100mSv. The effective dose received by 167 people was between 100 mSv and 680 mSv, with an average of about 140 mSv. Among them, the absorbed dose of thyroid in 12 workers was in the range of 2 Gy to 12 Gy (Gray), and there was an increased risk of thyroid cancer, but the risk was very low. For other 155 workers less than 250mSv, the effective dose is mainly from external radiation. The relevant cancer should be within the statistical fluctuation range of cancer incidence, and it is very difficult to find.
In short, no radiation-related deaths and acute radiation sicknesses occurred; because the doses received were below the threshold for a deterministic effect, no deterministic effect was possible; nor was it possible to observe an increase in the incidence of cancer.
From the perspective of the radiation effects on the public, the doses received by the public are usually not large or low. The lifetime effective dose for adults in Fukushima Prefecture is about 10 mSv or lower, and the dose received in the first year is about 2 to 3 times lower. Such low doses do not cause an increased risk of cancer. No excess thyroid cancer was found in children under 1 year old who lived in Fukushima Prefecture at the time of the accident.
From the perspective of radiation effects on non-human species, there may be short-term effects on plants and animals. For acute effects, no acute effects on marine and terrestrial organisms were observed because the dose was too low. Impacts may be observed in smaller areas where radioactive material deposits are large, such as where radioactive sewage is discharged into the ocean. In other areas, the impact is not obvious.
The Chernobyl accident is the largest catastrophic accident in the history of nuclear power. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) submitted research reports on the aftermath of the Chernobyl accident to the UN General Assembly in 2000 and 2008. The main conclusions are:
"The Chernobyl accident caused many severe radiation effects almost immediately. Of the 600 workers who appeared at the scene of the accident on the morning of April 26, 1986, 134 were exposed to high doses (0.7Gy to 13.4Gy) and Radiation sickness. Of these people, 28 died in the first 3 months, and two others died immediately in the accident for other reasons. "" Of the 134 patients with acute radiation sickness, 19 have died by 2006. There are various reasons for this, but they are generally not related to radiation exposure. "
"Between 1986 and 1987, approximately 200,000 recovery workers received doses ranging from 0.01 Gy to 0.5 Gy." "Among hundreds of thousands of emergency workers and recovery workers, leukemia was observed in people exposed to higher doses And there are no signs of an increase in the incidence of cataracts and no health effects attributable to radiation exposure. "" In children and child care at the time of the accident, observations were made from Belarus, Ukraine, and the four regions that were more heavily polluted in Russia. With the increase in thyroid cancer, only 15 people died by 2005. For all residents considering relatively small doses and doses similar to natural background radiation, although patterns have been predicted to increase the incidence of solid cancer Reported, but the Commission decided that due to the uncertainty of the predictions, no model was used to estimate the absolute number of effects in people exposed to low doses. "
"There have been no reports of extinction of local populations of a species due to radiation exposure after the Chernobyl accident. In all regions, populations survived chronic chronic exposure conditions. In the following 2 to 2.5 years, populations were obtained Recovery. No sustained severe effects on animal populations or ecosystems have been observed. "
多年 More than 20 years after the Chernobyl accident, nuclear power plants operating around the world have maintained safe and stable operation, and the design, construction and operation of newly built nuclear power plants have achieved a higher level of safety. After the Fukushima nuclear accident, the world has summarized the experience and lessons of the accident, and has achieved higher safety goals in many aspects such as accident prevention, emergency response, safety foundation, and safety culture. It can be seen that the direct radiation hazards (to human health and the environment) caused by the radioactive release of the Chernobyl accident and the Fukushima nuclear accident are relatively limited, and the conclusion that "nuclear power is a clean and safe energy source" has not been changed. However, although the impact of the Chernobyl accident and the Fukushima nuclear accident on human health and the environment is limited, the economic losses are huge and the social impact is unacceptable. Effective measures must be taken to prevent such accidents.
Nuclear power is one of the energy sources with the largest emission reduction effect
百万 One million kilowatt electric power nuclear power plant can reduce carbon dioxide emissions by more than 6 million tons per year
In summary, the nuclear power chain is a clean energy with minimal impact on the environment. The nuclear power plant itself does not emit air pollutants such as SO2 and PM. The radiation exposure of radioactive materials in the effluent of nuclear power plants to surrounding residents is generally much lower than the local Natural background level. Nuclear energy is a low-carbon energy source. Compared with a coal-fired power plant, a million-kilowatt electric power plant can reduce carbon dioxide emissions by more than 6 million tons per year, which is one of the energy sources with the largest emission reduction effect.
The Chinese government promises that by 2020, the proportion of non-fossil energy in primary energy consumption will reach about 15%, and carbon dioxide emissions per unit of GDP will fall by 40% to 45% compared to 2005. Developing nuclear power is a realistic way to achieve this goal. The safety of nuclear power is guaranteed. Compared with other energy sources, the number of nuclear deaths is the smallest. Nuclear power has low external costs and has strong economic competitiveness and alternative capabilities for coal power.
At present, the nuclear power plants that have been put into operation and approved in China are located in coastal areas, mainly because of the developed coastal economy in the east and the lack of conventional energy resources. With the social and economic development of the central and western regions and the constraints of resource, energy and environmental issues, the construction of inland nuclear power stations should be actively promoted. There is no essential difference between inland nuclear power and coastal nuclear power, and inland nuclear power plants have stricter standards than coastal nuclear power plants. The construction of nuclear power plants inland can not only guarantee the energy needed for socio-economic development