On December 7, the civil works of the Jinping Underground Laboratory Phase II Extremely Deep Underground Extremely Low Radiation Background Frontier Physics Experiment Facility (hereinafter referred to as "Jinping Facility") were completed and the experimental conditions were met. This marks the official launch of the world's deepest and largest ultra-deep underground laboratory. The first batch of 10 experimental project teams from Tsinghua University, the Ministry of Ecology and Environment, Beijing Normal University, China Institute of Atomic Energy, Shanghai Jiaotong University, Sichuan University, University of Chinese Academy of Sciences, and the Fifth Institute of Electronics of the Ministry of Industry and Information Technology were stationed in the world's deepest and largest extremely deep underground experimental space.
The Jinping Facility is a major scientific and technological infrastructure priority for the construction of the country during the "13th Five-Year Plan" period, the project started construction in December 2020, and in 2021, as a forward-looking leading national major scientific and technological infrastructure, it was listed as the national "14th Five-Year Plan". Jinping Facility is the first infrastructure construction project of an extremely deep underground laboratory in China, and it is also the largest comprehensive experimental facility with a very low radiation background in the world. After the experimental project team settles in, it will make every effort to break through key core technologies, produce a number of major original scientific research achievements as soon as possible, enhance the national strategic scientific and technological strength, and inject strong impetus into China's response to the international scientific and technological competition in deep science and technology and the realization of high-level scientific and technological self-reliance and self-reliance.
Build a world-class deep scientific research center and accelerate the realization of high-level scientific and technological self-reliance and self-reliance.
Jinping Underground Laboratory is the first extremely deep underground laboratory in China, and Jinping Facility is the second phase of China's Jinping Underground Laboratory project. The laboratory is located 2,400 meters underground in the middle of the Jinping Mountain Tunnel of Jinping Hydropower Station in Liangshan, Sichuan, with Jinping Mountain as the natural platform and the deep buried long tunnel of the hydropower station as the foundation. Compared with other underground laboratories in the world, the Jinping Underground Laboratory in China has the deepest rock coverage, the smallest cosmic ray flux, the lowest radiation background, the largest available space, and also has the advantages of convenient transportation, sufficient power and water sources, and complete infrastructure.
The construction of the Jinping underground laboratory dates back to the beginning of this century. In 2003, jointly funded by the State Development and Investment Group and Sichuan Investment Group Co., Ltd., the Yalong River Basin Hydropower Development Co., Ltd., which is controlled by the State Investment Group, began to build two world-class hydropower stations on the Yalong River - Jinping Class I Hydropower Station, the world's highest dam and Jinping Class II Hydropower Station, the world's largest long-diversion hydropower station. The Jinping Mountain Tunnel, which connects the two power stations, is 17 miles longWith 5 kilometers and 2,400 meters of vertical rock cover, it is the thickest underground tunnel in the world, making it an ideal place for deep laboratory construction. The construction of the Jinping Mountain Tunnel is extremely difficult, and it has encountered many high-pressure and large-flow water surges during the construction, and has encountered more than 1,200 large-scale rockbursts, which is called the "cancer" in the construction of underground engineering by experts at home and abroad. On August 8, 2008, the Jinping Mountain Tunnel broke through, which received the attention and reports of the news. Tsinghua University, which was struggling to find a research site for dark matter, was keenly aware that it was an excellent place to conduct dark matter research, and quickly contacted Yalongjiang to propose a joint construction of a deep earth laboratory. At that time, the tunnel had been completed, and the expansion and construction of the laboratory on this basis would cause rockburst and collapse again, causing huge damage to the original tunnel and even affecting the construction of hydropower projects. In the face of risks and challenges, Yalongjiang resolutely supported the national basic scientific research and jointly built a laboratory with Tsinghua University. Through scientific demonstration and careful organization of construction, the safety risk was solved, and the two sides completed the first phase of the construction of the laboratory in only one and a half years.
In December 2010, China Jinping Underground Laboratory (Phase I) was completed and put into operation, becoming the first underground laboratory in China and the deepest in the world. In 2014, Tsinghua University and Yalongjiang planned to build the second phase of the laboratory project, increasing the available experimental space underground from 4,000 cubic meters to 330,000 cubic meters. On the basis of the second phase of the project, the two sides proposed to build a major national scientific and technological infrastructure - the "Jinping Large Facility" project, which was approved by the state and became a new national important weapon.
Cheng Jianping, director of the laboratory and secretary of the Party Committee of Beijing Normal University, said that the construction of Jinping facilities is highly in line with the "four aspects" requirements put forward by the general secretary. As a "national important instrument" in the field of particle physics and nuclear physics, Jinping Facility provides extremely low radiation background experimental conditions for cutting-edge physical science research such as dark matter, neutrinos, and nuclear astrophysics. As an open and shared large-scale scientific facility, the Jinping Facility also provides an excellent research platform for deep-earth sciences such as deep-earth rock mechanics and deep-earth medicine. In the future, the laboratory will become a multidisciplinary world-class deep earth science research center, which is of great significance for our country to explore the unknown world, discover the laws of nature, realize scientific and technological changes, and promote scientific and technological innovation.
Overcome the extreme challenge of "2400 meters underground" and build the most "pure" laboratory.
The deep ground experimental facility project is an advantage for scientific experiments, but it is a challenge for engineering construction. At 2,400 meters underground, the thick marble of Jinping Mountain can isolate most of the cosmic radiation, but the rock mass will produce radioactive "radon gas", which affects the accuracy of the experiment. At the same time, the construction materials and mechanical and electrical equipment used in the construction of the Jinping facilities will also introduce new sources of radioactivity, which must be strictly controlled. In addition, the limited space and complex environment of the underground cavern further increase the difficulty of engineering construction.
Yalongjiang has carried out joint technical research with Tsinghua University, China Construction Third Engineering Bureau and other construction units, innovated waterproof and radon inhibition technology, developed low-background equipment and materials, and created "the world's deepest intelligent construction site". During the construction of the project, 10 layers of materials were innovatively used to fortify the surface of the 100,000-square-meter cavern layer by layer to shield the water and radon gas generated by the rock, and the radon gas inhibition rate reached 99. In order to achieve lower radiation background requirements, all equipment and materials are customized, and successfully developed and produced low-radiation cement, emery, rock wool and a number of low-radiation mechanical and electrical equipment, all of which are the first in the world, to maximize the control of laboratory radiation background, to create the most "pure" experimental environment. At the same time, all parties involved in the construction have further promoted the intelligence of engineering construction, realized the integration and collaboration of "smart construction site", "BIM collaborative design" and "intelligent transportation and environmental monitoring", and greatly improved the construction efficiency and quality control level. At present, the project has built the world's largest physical experiment liquid nitrogen constant temperature tank and polyethylene shielding cabin, and built the world's longest distance fresh air supply system, which effectively solves the problem of environmental radiation control in the underground experimental space and greatly promotes the technological progress of deep engineering construction.
Luo Qi, academician of the Chinese Academy of Engineering and chairman of the Chinese Society for Radiation Protection, said that through a series of key technical research and the application of intelligent construction technology, the Jinping large facility has been built into a world-class deep-earth laboratory with various advantages such as "extremely low ambient radon precipitation", "extremely low ambient radiation", "ultra-low cosmic ray flux" and "ultra-clean space", which has played a great role in promoting China's deep-earth basic scientific research and provided an international platform for China's radiation protection science.
Enterprise-school cooperation creates a new model of scientific research system and promotes the deep integration of industry, university and research.
Jinping Facility is the only major national science and technology infrastructure project jointly built by schools and enterprises in China, and it is a major initiative of Yalongjiang Company and Tsinghua University to promote national basic scientific research in the form of industry, learning and research cooperation, and has opened up a precedent for large state-owned enterprises to support national basic scientific research.
Since the start of the cooperation, the two sides have not only performed their own duties, but also collaborated on innovation. Over the years, Yalongjiang Company has invested a lot of manpower and material resources, given full play to the advantages of enterprise management, and established the Jinping Underground Laboratory Management Bureau, which is fully responsible for the construction, operation management, scientific research management, safety and other work of Jinping large facilities, and relies on the Jinping Hydropower Station to provide good comprehensive logistics support for each experimental project team, so that scientists can carry out scientific experiments without distractions; At the same time, it actively supports and participates in scientific research experiments through platforms such as Yalongjiang United**, Enterprise Technology Center, and Postdoctoral Workstation. Tsinghua University makes use of its strong academic appeal and scientific research innovation to bring together the top teams of deep earth scientific research in China to jointly carry out research on cutting-edge basic scientific research, forming a strong synergy to help the development of national basic scientific research. Since the laboratory was put into operation, high-quality scientific research achievements have been emerging, and a large number of outstanding talents have been cultivated, and more than 120 high-level articles have been published, including 2 articles in "Nature", 23 articles in "Physical Review Letters", one achievement won the first prize of natural science in 2022 by the Ministry of Education, and 6 "National Outstanding Young Scientists" and 1 "New Cornerstone Researcher" have been cultivated.
Qi Ningchun, Chairman of the Laboratory Management Committee, Secretary of the Party Committee and Chairman of Yalongjiang Company, said that Yalongjiang Company will give full play to the important role of Jinping Large Facility as a "great power and heavy weapon", and work together with Tsinghua University to build Jinping Large Facility into a model and model for giving full play to the advantages of the new first-class system and promoting national basic research through cooperation between enterprises and schools. At the same time, the company will continue to make efforts in basic research and key technology research, explore the deep integration of industry, university and research, promote the transformation of scientific achievements, help promote China's independent innovation ability and comprehensive scientific and technological strength in the field of basic research, and contribute the wisdom and strength of Yalongjiang to achieve high-level self-reliance and self-improvement and build a scientific and technological power.