China has independent intellectual property rights of fourth generation nuclear power commercial demonstration plant Rongcheng, Shandong is gradually forming. According to the China Nuclear Engineering and Construction Corporation (under construction, said Chinese nuclear) official website news, March 20, the world's first fourth-generation nuclear energy systems have security features 200,000 kilowatts HTR nuclear power plant - Rongcheng, Shandong Shidaowan high temperature gas cooled reactor nuclear power plant demonstration project, the reactor pressure vessel successfully hoisting.

The reactor pressure vessel lifting done as a circuit core nuclear island equipment, 27.5 meters high, weight 594 tons, is the world's largest size, the weight of the heaviest of the reactor pressure vessel, reactor high temperature gas-cooled nuclear power plant is also the largest single weight device of. Successful hoisting of the pressure vessel, the master HTR nuclear power plant demonstration project equipment installation work has laid a foundation, but also accelerated the HTR nuclear technology success pace of the world.

Compared with the hundreds of large million-kilowatt pressurized water reactor, nuclear power plant HTR demonstration project is only 20 million kilowatts. But because of its outstanding inherent safety, plus power efficient, versatile and so, HTR was included in one of the next six candidate Reactors Generation IV technology. HTR is one of the world's most secure type of nuclear reactor in 2006, it was listed as a national major science and technology.

Reactor pressure vessel successfully hoisting

Reactor pressure vessel successfully hoisting

Independent four generations of nuclear power: a large number of core melt and release radioactive accident does not occur under any circumstances

Science and Technology Daily has reported in 1994 occurred at Tsinghua University's INET 10 MW (1 MW = 1000 kilowatts) HTR nuclear safety demonstration: Let staff by operating reactor coolant circulating fan to stop working immediately to reactor the ability to transfer heat lost outside. You know, after the shutdown of the nuclear reactor will continue to produce heat, rather than after the boiler flame no longer generate heat. If this heat is not cooled, the reactor core melt can occur, radioactive leakage serious accident, which is the main technical challenge of nuclear safety. Just a circulating fan stops working, the alarm will be sounded Laer, Chinese and foreign guests stare staring changes on the display, we saw a sharp decline in the curve of the normal operation of the reactor thermal power produced by more than 3000 kilowatts reduced to a few hundred kilowatts Finally, heat the reactor was maintained at about 1.5% in normal operation. This indicates that the heat through the reactor pressure vessel surface is automatically distributed to the surrounding environment, without the need for any additional cooling system.

This experiment demonstrates one of the most important characteristics of modular HTR: In the case of any accident, including loss of all cooling, do not take any artificial intervention and machine, the reactor to maintain a safe state. China has mastered the technology.

Depending on the moderator and coolant, nuclear power plants can be divided into different reactor type. Operation of nuclear power, the nuclear fuel used to trigger a chain reaction speed neutrons generally require moderation, we need to moderator (except fast reactor outside); nuclear fuel requires cooling and heat transfer do work, you'll need coolant. PWR is currently more mainstream low-enriched uranium as a raw material, water as moderator and coolant. HTR works, the use of ceramic coated particle fuel elements in high temperature graphite as moderator, chemically inert helium gas as a coolant.

Molten core is the most serious nuclear power plant accident conditions that may arise. Three Mile Island, Chernobyl, Fukushima nuclear accident three cases have emerged in the core melted. Therefore, if the exclusion of the core melt, the probability of the occurrence of nuclear accidents can be greatly reduced.

According to experts, China's self-developed design and production of spherical fuel element diameter of about 6 cm from the ultra-high purity graphite, graphite clouds about 12,000 tiny coated fuel particles; each small particle diameter of less than 1 mm, there pyrolytic carbon layer, a silicon carbide layer and other multilayer coating to protect the uranium dioxide fuel core. Such layers of coating technologies and processes, make fuel pellets of radioactive material inside the case will not harm public health.