At the end of 2017, Japan's Mitsubishi General Materials data fraud incident broke out. At the press conference, the company's executives bowed and apologized to the whole society in response to the fierce public criticism. Mitsubishi Materials admitted that they had tampered with data on unqualified products in order to achieve the smooth flow of products, and these problematic products have flowed to many industries such as aviation, automobiles and electromechanics. The most serious is the two companies under the Kansai Electric Power Company of Japan. Nuclear power plants, nuclear reactors used fake "sealing rings" from Mitsubishi, which caused the two nuclear power plants to still have potential safety risks until now.
Thirteen years ago, China's Qinshan Nuclear Power Plant launched a bidding process for the gasket parts project of the nuclear reactor. The Chinese local sealing material technology company, NBTS Sealing Material Technology Company, won the bidding with American companies with great advantages. But no one thought that afterwards, China’s Qinshan Nuclear Power Plant directly changed the winning bid and decided to adopt sealing parts from American companies. This result not only made Li Xinggen, a senior engineer of NBTS, angry, but also the staff of China’s Qinshan Nuclear Power Plant. I felt aggrieved because the American company forcibly required China's Qinshan Nuclear Power Plant to use their gaskets and other parts on the grounds of "no longer providing C-shaped sealing rings."
At that time, if the C-shaped sealing ring was caught by this American company, it would undoubtedly be a fatal blow to China's Qinshan Nuclear Power Plant or all nuclear power plants in China. At that time, apart from the United States, no company in China or even the world could produce this "nuclear power seal C ring". For more than half a century, China has been dependent on imports. So what exactly is a C seal ring and why can nuclear power plants be inseparable? Open it?
Nuclear leakage has always been a global problem that plagues nuclear power in various countries. At present, nuclear power plant reactors have set up three safety barriers. First of all, the first protection is fuel cladding, which wraps nuclear fuel such as uranium and plutonium with metal zirconium. The second protection is the pressure vessel, which is used to store nuclear fuel rod stacks. The third line of protection is the steel and concrete plant of the nuclear power plant. The "inner containment shell" of the plant is composed of 6mm steel lining and over 1 meter thick concrete. The outer containment shell is also made of pouring concrete to prevent impacts from external forces. These three safety barriers are the key to preventing nuclear leakage.
The second barrier, the pressure vessel where the nuclear fuel reactor is placed, can be divided into two parts: the upper cylinder cover and the lower cylinder, and the joint surface of the cylinder cover and the cylinder must be sealed with a C-shaped sealing ring. When the nuclear reactor is in operation, it will release a lot of heat, causing high temperature and high pressure inside the container. When the container expands, the cylinder cover and the cylinder body will separate, and the C-shaped sealing ring will also be stretched. When the nuclear reactor is closed, the cylinder cover and the cylinder body are restored to their original state. At this time, the C-shaped sealing ring must have a memory function and then restore to its original state, ultimately achieving the effect of preventing nuclear leakage.
It can be seen how difficult it is to manufacture metal seal rings with a diameter of several meters. For more than half a century, the processing technology of C-shaped seal rings has been monopolized by American companies. This is an important part related to the safe operation of nuclear power plants. Being forced to import at high prices, this has seriously affected the autonomy of China's domestic nuclear power equipment, and has also given American companies a decisive bargaining chip in the beginning. Li Xinggen, a senior engineer at the NBTS Seal R&D Center at the time, after learning about the practices of American companies, assured Chinese nuclear power personnel:
"Within five years, I must conquer this sealing ring."
It was also in the same year that Lixinggen led the Tiansheng company’s R&D team to start the research and development of O-rings and C-type sealing rings. Within a few years, the Lixinggen team’s sealing mechanism, material selection and manufacturing process for the sealing ring , Carried out countless research experiments, until 2011, the Reedinggen team finally made a breakthrough in technology.
In 2015, China completed the development of the first C-shaped seal ring made in China. The product was used in the No. 1 nuclear power unit of Fangjiashan, China's Qinshan Nuclear Power Plant. China-made C-shaped seal ring began to be put into commercial use. During a test cycle from December 2015 to September 2016, the success or failure of China's domestically produced C-type sealing ring is not yet known. When Unit 1 was shut down for refueling, it was witnessed by a large number of companies such as China Nuclear Power and Tiansheng. The first C-shaped sealing ring made in China was slowly taken out. After the verification by the expert group, the inner and outer rings of the C-shaped sealing ring were not damaged. It fully complies with the operating standards of nuclear power plants. The level is advanced in the world, and some indicators are in the world. Leading, this marks China has become the second country after the United States to be able to manufacture C-shaped sealing rings.
With the commercialization of China-made C-shaped sealing rings, the price of a single set of such cutting-edge parts has dropped directly by 90%, and in terms of mature technology, performance, quality and life, China-made sealing rings have already met the seal of Hualong No. 1 Environmental design requirements have greatly promoted the localization of China’s nuclear power equipment.
Li Xinggen has spent more than 30 years developing the seal ring, and he won the second prize of the National Science and Technology Progress Award. Today, more than 70% of the equipment in the Qinshan Nuclear Power Plant, Lianyungang Nuclear Power Plant and Guangdong Nuclear Power Plant are equipped with Chinese-made seals. As a key part of the nuclear power plant's primary equipment, the C-shaped seal ring is an important guarantee to prevent nuclear leakage. As China's nuclear power enters the third generation and makes up for shortcomings in core components, China's nuclear safety can not be controlled by others.