#Third Eye on China#
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Recently, the Jiangnan Shipyard and Dalian Shipyard successively held a launch ceremony for an aircraft carrier, showing that the numbers on the model are 20 and 21 respectively, there is no chimney on the model, and professionals look at the typical characteristics of a nuclear-powered aircraft carrier. Perhaps two nuclear-powered aircraft carriers were built at the same time.
Model of a nuclear-powered aircraft carrier
At the same time, some media exposed the marine model of Linglong No. 1. The nuclear reactor has a diameter of 10 meters and a height of only 15 meters, and the parameters are perfectly suitable for equipping the aircraft carrier. The output of this model reaches 125 megawatts, which is 25 megawatts higher than the current output of the US nuclear-powered aircraft carrier Nimitz's 100 megawatts. In terms of power, Linglong One is superior.
Usually, before a nuclear power unit can be equipped with an aircraft carrier, a nuclear reactor must be built and tested. Let's take a look at the world's first onshore commercial modular small nuclear reactor Linglong No. 1 built in Changjiang, Hainan.
After welding the integrated reactor pressure vessel and steam generator assembly, the primary side hydrostatic test was successful
(This article is all textbook science knowledge, does not involve any confidential or confidential information, please feel free to read!)
(i) About Linglong No. 1
Linglong No. 1, also known as ACP100, started construction in Changjiang, Hainan on July 13, 2021, and is a multi-functional modular small pressurized water reactor type developed on the basis of CNNC Hualong No. 1 (ACP1000) and with independent intellectual property rights. It is also the world's first onshore commercial modular small PWR.
It is mainly composed of nuclear reactors, steam generators, steam turbines and related system equipment.
Ordinary pressurized water reactor working principle diagram
Linglong No. 1 uses pressurized light water (ordinary water) as a coolant and moderator to ensure that the water does not boil in the pile. The reactor is fueled with 3 per cent LEU. The reactor is 14 meters high and 10 meters wide.
According to the size of the power generation, the pressurized water reactor can be divided into three categories: large, medium and small. Pressurized water reactors with power generation power greater than 600 MW are large pressurized water reactors, PWRs with power generation power of 300 mega~600 MW are medium-sized PWRs, and PWRs with power generation less than 300 MW are small PWRs. Linglong No. 1 has a single-seat electric power of 125 MW and belongs to a small pressurized water reactor.
(ii) Characteristics of Linglong No. 1
◆Integrated reactor technology
In order to achieve miniaturization, Linglong No. 1 eliminated the traditional main circuit piping and directly placed the steam generator in the reactor pressure vessel, and the shielded pump was connected to the reactor pressure vessel through a short nozzle. The entire reactor module consists of reactor pressure vessel, DC steam generator, shielded pump, reactor reactor internal components and integrated reactor top structure.
Integrated reactor module
◆Inherently safe plus passive safety
(1) Reduce failures by simplifying the safety system.
(2) Adopt a completely passive safety system, including passive emergency core cooling, passive emergency waste heat discharge, containment air cooling, automatic pressure relief and passive combustible gas control.
(3) In the event of an accident, the safety of the reactor is achieved through natural forces, and safety-related emergency AC power supply is not required, so that it can be long-term without human intervention. Thus, major nuclear power plant accidents similar to those that occurred in Chernobyl and Fukushima were avoided.
◆Modular high-efficiency DC steam generator technology
The built-in modular high-efficiency DC steam generator is adopted to reduce heat dissipation loss, high heat exchange efficiency and compact structure. The secondary side of the DC steam generator has a small water load, the consequences of the main steam pipe rupture accident are light, and reactor overcooling will not occur.
◆Air-cooled containment
The containment is air-cooled, without system capacity limitations, eliminating complex air deflectors, eliminating containment overpressure accidents.
◆Underground arrangement of reactors
The use of rock mass soil as a natural radioactive isolation barrier. The entire reactor is located underground, with high earthquake resistance, strong resistance to terrorist attacks and environmental friendliness, which helps to increase public acceptance of small nuclear energy and facilitate the deployment of Linglong 1 close to cities and users.
◆ Higher degree of main system modularity
The reactor and reactor coolant system are integrated as reactor modules, which are assembled from multiple sub-modules to achieve modular manufacturing, modular transportation, and rapid assembly in the field.
◆High maturity
The main equipment miniaturization is all using proven technology in engineering practice. The main key technologies have all been solved, and a variety of design verification, test verification, simulation verification and third-party verification have been carried out. A number of special equipment for Linglong No. 1 have also been developed.
(3) Application scenarios of Linglong No. 1
Linglong No. 1 can easily provide stable power to remote areas such as islands, mining areas, Gobi deserts and mountain valleys far from the city.
It can be built as a distributed power source in locations close to industrial areas and densely populated areas to achieve urban district heating and cooling, industrial steam supply and industrial process heating.
It can also be used as a mobile power supply to power marine resource development, etc., and can be used for seawater desalination and heavy oil extraction.
Linglong 1 has passed the safety certification of the International Atomic Energy Agency. In the future, such small modular reactors can be built in countries along the Belt and Road, especially in the Middle East, Central Asia and other places, to solve the local power problem. Once the problem of electricity consumption is solved, the cost of building urban supporting facilities will be much lower, and the difficulty of building related transportation networks will be lower, and China's One Belt, One Road initiative will be better and faster.
In short, Linglong No. 1 will drive the high-level development of the mainland's nuclear energy-related industrial clusters and form another important reactor brand. At the same time, it is of great significance to open up the international small reactor market and achieve the strategic goal of going global.
(iv) Whether Linglong-1 can be used on nuclear-powered aircraft carriers
The development of the nuclear reactor power unit for China's first nuclear-powered aircraft carrier is a state military secret and cannot be found from publicly available information. According to the development line of China's military science and technology: first military, then popularized civilian. Based on the technical analysis of Linglong-1, we can infer that China already has the capability to build a small nuclear power unit for nuclear-powered aircraft carriers.
Liaoning aircraft carrier
Given the operational problems of the pressurized water reactors of nuclear-powered aircraft carriers already in service in the United States and France, the mainland is likely to choose the most advanced nuclear reactor technology that is one or two generations ahead of the technology. The preferred estimate is the technically most mature third-generation PWR. In addition, Continental is a global leader in the development of high-temperature gas-cooled reactors and molten salt fuel reactors.
■ High temperature gas-cooled reactor
It adopts ceramic coated granular fuel element, high-temperature resistant graphite as moderator, and chemically inert helium as coolant, which is recognized by the international nuclear energy community as a reactor with good safety characteristics.
Schematic diagram of the working principle of high-temperature gas-cooled reactor
Uranium fuel is made into small particles, each coated with a layer of low-density carbon, two layers of high-density carbon and a layer of silicon carbide, forming coated particles less than 1 mm in diameter. The coated particles are uniformly dispersed in the graphite-moderated material to create a spherical fuel element with a diameter of 6 cm. When a nuclear reaction occurs, the cladding layer can sufficiently retain the fission products produced in the coated particles in the particles.
Due to its outstanding inherent safety, coupled with the characteristics of high efficiency and wide range of applications for power generation, high-temperature gas-cooled reactors are included in the reactor type of fourth-generation nuclear energy system technology.
■ Molten salt fuel reactor
A reactor that uses liquid fuel in a nuclear fission reactor. It uses molten mixed salt as a nuclear fuel carrier and reactor coolant. When the reactor is running, the nuclear fuel and the fission products melted in the carrier salt circulate continuously with the molten salt in the circuit composed of the reactor core and heat exchanger, and the heat generated by the fission is continuously transported from the reactor to the outside of the reactor.
It can operate at high temperature and atmospheric pressure, which can obtain higher energy conversion efficiency and high intrinsic safety. Fuel can be pumped or replenished directly without stopping the reactor, and the extracted fuel can be returned to the molten salt reactor after online processing. The result is easier reactivity control of molten salt reactors and avoids large fuel reserves. Molten salt fuel reactors are also included in the reactor type of the fourth generation nuclear energy system technology.
Whether it is the use of the third generation of pressurized water reactors, or the use of high-temperature gas-cooled reactors or molten salt fuel reactors as the power unit of the mainland nuclear-powered aircraft carrier, it directly gives the mainland's nuclear-powered aircraft carrier the advantage of one to two generations ahead of the opponent in the power unit.
(5) Progress of the construction of Linglong No. 1
■ On July 13, 2021, Linglong No. 1 officially started construction at the Changjiang Nuclear Power Base in Hainan.
■ On October 24, 2021, the bottom head of Linglong No. 1 steel containment was hoisted ahead of schedule in Changjiang, Hainan.
■ In February 2022, the lower cylinder of the Linglong No. 1 steel containment was successfully hoisted into place.
■ On July 6, 2022, the upper body of the steel containment of the Linglong No. 1 reactor building of the Changjiang Nuclear Power Base in Hainan was hoisted into place.
■ On November 30, 2022, the installation of the pipeline support hanger of the Linglong No. 1 reactor building began. This marks the official start of the installation of the small reactor core island.
After completion, the annual power generation of each unit can reach 1 billion kWh.