Nuclear energy has so many uses besides generating electricity



Recently, the National Energy Administration released the statistical data of the national power industry from January to June. In the first half of this year, China's installed power generation capacity was about 2.44 billion kilowatts, of which 55.53 million kilowatts of nuclear power accounted for about 2.3%, up 6.5% year-on-year. As a clean energy source, nuclear power is playing an increasingly important role in China's economic and social development.

Although China's nuclear power development started late, it has formed a high-level industrial innovation chain and industrial chain from scratch and from small to large, and its technical level and comprehensive strength have ranked first in the world. In recent years, in addition to the production of electricity, nuclear energy is also used in urban heating, industrial steam supply, seawater desalination, synthetic fuel and many other scenarios.

Yu Kaizhi, deputy general manager of China Nuclear Power Development Division of China National Nuclear Power Group, said in an interview with this newspaper that the nuclear fission process releases a lot of heat energy, which can better match the demand for high-temperature process thermal parameters in the industrial production process. The comprehensive utilization of nuclear energy is to fit various application scenarios, or convert heat energy into electricity or directly provide high-temperature process heat, and realize scientific energy use through the cascade utilization of energy, which helps to improve energy utilization efficiency. In the future, nuclear energy will shift from "single player" to "all-round assistance" and contribute more "nuclear" power to green and low-carbon development.

For industrial steam safety and energy saving

Boiling water to generate electricity with nuclear energy has always been an interesting metaphor for nuclear power by many netizens, and this analogy essentially explains the power generation principle of nuclear power plants. Yu Kaizhi explained that nuclear power plants mainly rely on nuclear fission to release energy, heat water into steam, and thus drive steam turbines to generate electricity. Among them, steam can be used not only to generate electricity, but also in industrial production.

On May 27, after 3 months of pile foundation construction, the first tank of concrete was officially poured in the energy station of Tianwan nuclear power steam power supply project, marking the country's first industrial nuclear power steam supply project - CNNC Tianwan Nuclear power steam power project. The project is jointly carried out by Jiangsu Nuclear Power Co., LTD., Lianyungang Xuwei New Area petrochemical base, using CNPC Tianwan Nuclear Power unit 3, 4 steam as a heat source, the steam will be transported to Lianyungang petrochemical industry base for industrial production and utilization, is expected to be put into operation at the end of 2023 for steam supply. After the completion of the project, the annual steam supply will reach 4.8 million tons, which can reduce the burning of standard coal by 400,000 tons per year.

"High temperature and high pressure steam is an indispensable element of chemical production. At present, the industrial steam in China's chemical industry mainly comes from coal-fired power plants or self-provided coal-fired boilers, and the use of nuclear energy will effectively reduce energy consumption and carbon emissions." China Nuclear Group Jiangsu nuclear power maintenance general manager, project leader Liu Yongsheng said.

Many people are concerned about how to ensure the safety of nuclear power supply. Liu Yongsheng introduced that the heated industrial steam is transported through an independent isolation loop, which ensures the clean safety of nuclear energy steam supply from the design source. In the whole process, there is only heat exchange, there is no medium connectivity, to ensure that the nuclear energy steam supply is clean, safe and reliable. Moreover, through the pipeline prefabrication overhead steam insulation program and other measures, the temperature loss per kilometer can be controlled less than 2 ° C and the pressure drop is less than 0.03 Mpa, effectively controlling the temperature and pressure loss during the steam long-distance transmission process, and meeting the demand for industrial steam in Lianyungang Petrochemical Industry base.

Demand for industrial heat or steam is widespread, not just in the petrochemical industry. For example, in the paper industry, the heating of some chemicals in paper production requires the use of steam, and processes such as processing and molding are also inseparable from steam. In the textile printing and dyeing industry, whether it is dyeing, drying, sizing, printing and dyeing steps, it is inseparable from the support and cooperation of steam. In the rubber industry, the process of rubber rolling, vulcanization, drying and so on must use steam. In the pharmaceutical industry, it is necessary to use a large amount of industrial steam and pure steam to sterilize raw materials, instruments and equipment at high temperature, and the drying, tablet pressing, granulation and other processes also need steam support. In the non-ferrous metal industry, the manufacturing of new energy lithium batteries also requires the use of steam to ensure the reaction temperature.

Just on July 15, Zhejiang Haiyan Nuclear energy heating demonstration project (second stage) industrial heating project started smoothly, is expected to be completed by the end of August this year, can provide 24-hour heat supply security, annual industrial heating about 288,000 GJ. This is equivalent to saving about 10,000 tons of standard coal and reducing carbon dioxide emissions by about 24,000 tons, which will achieve a win-win situation for industrial development and energy conservation and carbon reduction. In the future, more and more industries will use nuclear steam.

Heating for residents clean and warm

Similar to the principle that provides steam for industry, nuclear power also provides heating for residents in the winter. The first stage of Zhejiang Haiyan nuclear heating demonstration project is the civil heating project. In fact, two small towns in north and south China - Haiyan in Zhejiang Province and Haiyang in Shandong province - used nuclear energy to heat their homes last winter.

On November 9, 2021, Haiyang entered the heating season ahead of schedule, and residents in the new and old urban areas used nuclear energy for heating, with a heating area of 4.5 million square meters. Relying on the clean heat provided by "warm core No. 1", Haiyang City bid farewell to the history of coal-fired heating that lasted for many years and became the first zero-carbon heating city in the country.

As a national initiative, the nuclear heating project has no ready-made experience to refer to, and every step of technical research is creating history. Can "clean electricity" produce "clean heat"? In order to accumulate experience and create a model, Shandong Nuclear Power gathered the China Nuclear Energy Industry Association, Tsinghua University, Electric Power Planning and Design General Institute and other "big coffee level" expert team to review the engineering feasibility report, after intense questioning and discussion, the technical program was unanimously approved by experts.

On July 10, 2019, the Haiyang Nuclear heating phase I project officially started, including the construction of the first station for nuclear heating and heat exchange and the laying of a 15-kilometer main network, which was completed on September 30 of that year. In the heating season of 2019-2020, a total of 7,757 households of 700,000 square meters in Lingang, resort areas and nuclear power industrial Park in Haiyang City used nuclear energy for heating. The whole heating season ran smoothly, was in good condition, and the user's room temperature was suitable, which was praised by the majority of users and all walks of life. In 2020, Shandong Nuclear Power has opened the research work to promote large-scale long-distance heating. On November 9, 2021, the warm current brought by the comprehensive utilization of nuclear energy was transported to thousands of households in Haiyang City.

"Just after the heating, the temperature in the house reached 23 ° C." Haiyang Jinyang coastal garden community resident Cheng Jingzeng said. With nuclear energy heating, the heating cost of residential buildings has also been reduced from the original 22 yuan/square meter to 21 yuan/square meter.

Then, on December 3, 2021, the first phase of the first nuclear energy heating project in southern China - Zhejiang Haiyan Nuclear energy Heating Demonstration Project was officially put into operation, with a heating area of 460,000 square meters. Nearly 4,000 residents of the three residential areas of Haiyan Nuclear Power New Village, Nuclear Power Nanyuan and Maple Leaf New Village took the lead in "pioneering", using zero-carbon, clean and efficient "nuclear heating". This also means that southern China has opened the history of nuclear energy heating, and from now on, winter and cold resistance no longer rely on "shaking".

As of April 2022, the demonstration project has completed the first heating season task, and has continued to provide heating for nearly 4,000 households for 100 days in a safe and stable manner, and the heating price has been reduced by about 1/3 compared with the past while the heating quality has been improved. It is estimated that by the end of the "14th Five-Year Plan", after the project is completed and put into operation, it can meet the heating demand of about 4 million square meters of Haiyan, which can save 196 million degrees of electricity consumption per year compared to the electric heating method in the southern region.

Nuclear heating is not only clean, but also safe. "Nuclear heating is the extraction of part of the steam from the nuclear power unit, and the heat is heated several times through the heat exchange station, the whole process only two steps: steam heating water and water heating water." Huang Qian, secretary of the Party Committee and chairman of the Qinshan Nuclear Power plant, said that there are multiple loops between the nuclear power plant and the user, only the transfer of heat between each loop, there is no exchange of water, there will be no radioactive substances into the heating pipe, and the hot water is only closed in the community, isolated from the nuclear power plant layers, without any contact.

In the view of Zou Zhengyu, general manager of Qinshan Nuclear Power Plant, the nuclear heating project uses the surplus thermal power of the units of Qinshan Nuclear Power Base in winter to provide large-scale safe, zero-carbon and economic nuclear heating for public facilities, residential communities and industrial parks in Haiyan County without affecting the original generation and safety performance of the units. It has truly achieved a win-win situation for local residents, local governments, nuclear power enterprises and ecological environmental protection.

Innovation goes far beyond that. On the basis of more than 50 years of safe and stable operation of swimming pool research reactor, CNNC has independently developed a safe, economic and green stacking product for urban heating in northern China - "Yanlong" swimming pool reactor. Yu Kaizhi introduced that "Yanlong" swimming pool stack has outstanding characteristics such as high inherent safety, clean environmental protection, and strong pipe network adaptation. A 400 MW "Yanlong" low-temperature heating reactor, heating construction area of 20 million square meters, can cover 200,000 families.

At present, the demonstration project of "Yanlong" swimming pool type low-temperature heating reactor has been included in the "14th Five-Year Plan" of Jilin Province. Experts said that in some areas where there is no nuclear power plant nearby, the pool type low-temperature heating reactor is very suitable, its high safety factor can meet the heating demand within a certain range, but also can solve the air pollution problem caused by loose coal heating.

Inject nuclear energy into various fields

Not long ago, the world's first commercial reactor carbon-14 irradiation production target, in the Qinshan Nuclear Power Plant No. 2 heavy water reactor unit, which is controlled by China Nuclear Power Group, began commercial reactor production of carbon-14 isotopes, is expected to begin to supply to the market in 2024, and the output can meet domestic demand. This is another important breakthrough in the comprehensive utilization of nuclear energy.

What is carbon-14? What can it be used for? What does it have to do with our lives? Originally, the carbon that exists in nature, such as common graphite, diamonds, pencil leads, etc., are carbon-12. In addition, it has some isotopic brothers, such as carbon-11, carbon-13, and carbon-14, which all have six protons in their nuclei and different numbers of neutrons. Carbon-12 is stable, carbon-14 is radioactive.

"The use of carbon-14 radioactive labeling and detection can detect Helicobacter pylori and carry out pharmacokinetic studies." Meng Zhiliang, senior engineer of Qinshan Nuclear Power Plant of China National Nuclear Corporation, said carbon-14 is often used as a marker and is widely used in agriculture, chemistry, medicine, biology and other fields. For example, by adding carbon-14 to pesticides, the residual amount of pesticides can be determined by detecting the content of carbon-14 on crops in the later stage.

China has previously used small reactors for experimental research to produce carbon-14, but the output is small and the production is not continuous, unable to form a stable supply, said Fan Shen, a senior engineer at China National Nuclear Group's Qinshan Nuclear Power Plant. The use of commercial nuclear power units can maintain long-term high power stable operation and continuous production of carbon-14.

"Take the diagnosis and tracking of Helicobacter pylori, the current annual demand for Helicobacter pylori testing in China exceeds 30 million people, and the market cannot be underestimated." Yu Kaizhi said that the major breakthrough made by CNNC in the production of medical isotopes will effectively solve and alleviate the problem of domestic carbon-14 isotope supply, and make new contributions to the establishment of a stable and independent medical isotope supply security system and improve people's health.

In addition to making full use of existing nuclear power units to carry out comprehensive utilization of nuclear energy, CNNC also actively develops advanced nuclear energy systems through scientific and technological innovation, and expands more new scenarios for comprehensive utilization of nuclear energy. For example, on July 13, 2021, CNNC's Hainan Changjiang Multi-purpose modular small Reactor technology Demonstration Project officially began construction, becoming the world's first onshore commercial modular small reactor to start construction.

Yu Kaizhi introduced that "Linglong 1" (ACP100) technology is a multi-functional modular small pressurized water reactor type independently developed by CNNC through more than 10 years and with independent intellectual property rights. It is characterized by miniaturization, modularity, integration, and passive, and can be used as a clean distributed energy source. At the same time, it can meet the application needs of seawater desalination, district heating, industrial heating (cold) and other fields.

In the view of Wang Shoujun, chairman of the Chinese Nuclear Society, nuclear energy not only has the characteristics of zero carbon emissions of renewable energy, but also continues the characteristics of uninterrupted and stable service of fossil energy, which fits the energy demand of mass manufacturing process, should give full play to the advantages of large pressurized water reactors, high temperature gas cooled reactors, modular small reactors, low temperature heating reactors and other advantages, and closely integrate with the comprehensive energy consumption demand of users. The establishment of a multi-energy complementary and multi-energy integrated regional energy system integrating power supply, residential heating, industrial steam supply, hydrogen production, seawater desalination and isotope production will inject nuclear energy into China's green and low-carbon development in the future.