Bai Chunli: Laser nuclear fusion has a long way to go before commercial power generation

Bai Chunli, president of the Greater Bay Area Science Forum and academician of the Chinese Academy of Science. [Photo/VCG]

Bai Chunli, an academician of the Chinese Academy of Sciences, honorary president of the University of Science and Technology of China, and former president of CAS, recently analyzed the large-scale application of low-carbon and renewable energy in the development trends of energy science and technology in the context of carbon neutrality.

Bai said that there are two ways of obtaining nuclear power: fission and fusion. Safety, continuous and stable supply of nuclear fuel, and safe disposal of fuel are the three main problems to be solved in nuclear fission. The research on controlled nuclear fusion includes magnetic confinement nuclear fusion and laser nuclear fusion. Laser nuclear fusion is a great distance away from commercial power generation.

Electrochemical energy storage is important for developing energy storage technology in the future. The lithium-ion battery technology, which is mature, has entered the stage of large-scale mass production. The Perovskite battery is a new direction of electrochemical energy storage, but it has two shortcomings: poor stability and efficiency loss in large area applications, which have become its current research directions.

Three problems to be solved in nuclear fission

Nuclear power has the advantages of high-energy density, stable energy supply and low-carbon emissions, and is a good stabilizer for volatile solar and wind power generation. It is estimated that the total power generation of nuclear power will reach 2.7 trillion kilowatts in 2060, and the installed capacity of nuclear power generation in China will be about 50 million kilowatts in 2021. There is still much room for improvement.

Bai said that China has discovered about 270,000 tons of uranium resources. According to the current level of nuclear power, domestic uranium resources should last for about 40 years, and the sustainable and stable supply of nuclear fuel needs to be solved urgently. At present, nearly 20,000 tons of spent fuel have been accumulated in China, and about 1,000 tons of new fuel is produced each year. The wet temporary storage method of spent fuel is mainly used at a cost of about 40,000 yuan/ton/year. The safe treatment and disposal of spent fuel also needs to be solved urgently.

With regard to the shortage of uranium resources, the Chinese Academy of Sciences has set up the "thorium-based molten salt reactor nuclear energy system (TMSR)" as a pilot project. The use of thorium as nuclear fuel has the advantages of rich resources, less nuclear waste, low toxicity and inherent nuclear non-proliferation. It can also reduce the loss of thorium resources and radioactive environmental pollution in rare earth mining, which is one of the important directions of nuclear energy development. However, Bai said that this is still a research project and has not reached the application level. 

Magnetic confinement fusion and laser fusion

Bai said that Chinese scientists are actively involved in the work related to the International Thermonuclear Fusion Experimental Reactor (ITER). In May 2021, the EAST built by the Chinese Academy of Sciences made progress in nuclear fusion research, achieving repeatable 120 million degrees Celsius 101 seconds and 160 million degrees Celsius 20 seconds plasma operation, thereby further proving the feasibility of nuclear fusion energy and laying a physical and engineering foundation for commercial development.

In February, the European Union for Nuclear Fusion Research and Innovation, the International Thermonuclear Fusion Experimental Reactor Program (ITER) and other units announced that they had achieved a new record of controlled nuclear fusion energy. They heated the hydrogen isotope deuterium and tritium to 150 million degrees Celsius and kept it stable for 5 seconds in the world's largest fusion reactor, the European Union Ring (JET). At that time, nuclear fusion reactions took place and atomic nuclei fused together, releasing 59 megajoules of energy. 

Bai said that JET is the only experimental device in the world that can realize "deuterium and tritium fusion" reaction while maintaining the record maximum energy output of nuclear fusion. EAST prefers magnetic confinement experimentation and has not realized nuclear fusion reaction. This is because there are only D nuclides (deuterium) and no T nuclides (tritium) in the plasma during EAST’s operation. The significance of the EAST experiments is mainly to study how to constrain the plasma stably for a long time to provide experimental support for the ITER project and the China Fusion Engineering Experimental Reactor (CFETR) that China participates in. Maintaining fusion reaction, solving the problem of material irradiation, energy conversion and T retention are not its research focus. The China Fusion Engineering Experimental Reactor (CFETR) prepared by China aims to achieve fusion energy and make research practical, which can make up for the shortcomings of EAST's inability to generate electricity.

Bai also said that as the first laser fusion ignition in the world, it is a landmark project attracting wide attention in the scientific community and society. Of course, at present, laser nuclear fusion has the characteristics of short time and low power generation efficiency, which is of scientific significance and can be applied in some special fields. There is still a long way to go to realize commercial power generation. In 2020, the Chinese Academy of Sciences also set up a project to deploy laser fusion research with different technology paths from the United States.

Perovskite battery is a new direction of electrochemical energy storag

eBecause renewable energy, represented by wind and photovoltaic power, is characterized by intermittency, volatility and randomness, energy storage is the key to achieving large-scale integrated utilization. China's energy storage capacity is estimated to reach 420GW (420 million kW) in 2060.

Bai said that 2021 was the year when China's energy storage industry changed from the initial stage of commercialization to large-scale development. According to statistics, in 2021, China's installed capacity of power energy storage projects put into operation was 46.1GW, accounting for about 22% of the total global market size, with a year-on-year increase of 30%. He said there is still room for development. For example, the National Energy Administration issued the Medium and Long-term Development Plan for Pumped Storage Energy (2021-2035) in August 2021. By 2025, China's total installed capacity of pumped storage energy will reach more than 62GW, and by 2030 will crest 120GW. At the end of 2021, the installed capacity of pumped storage was only 39.8GW. This means that there will be three times the growth space in nine years, a compound annual growth rate of 13%.

At present, the development of energy storage technology in China still faces some problems and challenges. On the one hand, China lacks basic, original and breakthrough innovation in the field of energy storage, and the research on the relevant mechanism, technology and system of energy storage transformation is not mature enough, especially in the development of software, design standards and concepts.

On the other hand, the promotion of large-scale energy storage technology is limited by the imperfect market mechanism of the power system, and there are problems such as the unclear status of the main body of the energy storage market and the imperfect market mechanism, which make it difficult to obtain reasonable compensation for the value and potential income of energy storage. At this stage, a mature competitive power market operating mechanism has not been established, and it is difficult to reasonably verify the price of various electric auxiliary services, which makes it difficult to connect the value and income of energy storage. Progress and improvement have been made in these aspects in recent years, but the problems remain prominent.