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CVN 003 aircraft carrier - Propulsion

SSN-688 Los Angeles 6,900 tons35,000 shp
SSN-21 Seawolf9,100 tons52,000 shp
SSN-774 Virginia7,800 tons40,000 shp (30 MW)
Although nuclear-powered submarines and nuclear-powered aircraft carrier reactors can use highly mature pressurized water reactors, the two are the same in principle and technically have similarities. However, it cannot be simply assumed that nuclear-powered submarines can be manufactured, and conventional-powered aircraft carriers can be easily changed to nuclear-powered aircraft carriers. In theory, a nuclear reactor capable of building a submarine should be able to build a nuclear reactor for an aircraft carrier. However, the power of the two is different, the specific design details and requirements are different, so the manufacturing difficulties are also different. Therefore, special aircraft carriers should be studied. reactor. the development of aircraft carrier nuclear reactors needs to break through many technical problems. The first is the high-power marine reactor technology. At present, only the United States can master this technology well. Russia and France still have a certain gap. The second is nuclear fuel technology. Carrier nuclear reactors do not require replacement of nuclear fuel for a long time. At present, the United States can basically achieve no replacement for about 30 years. The third is the nuclear reactor control technology. The carrier speed is different, and power and steam must be provided. The energy output must be controlled reasonably. Fourth, the auxiliary power system has high requirements, and nuclear energy must be efficiently converted into mechanical energy. Fifth, security protection technology must improve its ability to resist strikes.

A Chinese nuclear powered aircraft carrier would probably require a new power reactor, but Chinese industry is surely adequate to the task at hand.

In the US Navy, the CVN-68 Nimitz class larger aircraft carriers had an installed power of about 280,000 shp, while the new CVN-78 Ford class carriers had an installed power plant rated at 520,000 shp, much of the increase reflecting the increased electrical power requirements of the electromagnetic launcher catapults. China has built new generation nuclear reactors for each of three successive generations of atomic submarines. These reactors are poorly characterized in the open literature. Based on American precedent, the reactors powering the Shang Type 093 / 09-III and Sui Type 095 / 09-V attack submarines, both of which displace about 8,000 tons, probably have a power output of about 40,000 shp. China would need at least 6 such reactors to match the power of the CVN-68 Nimitz and at least 12 such reactors to match the CVN-78 Ford. In the USA, the first nuclear powered aircraft carrier, the Enterprise, had 8 reactors.

The IEA notes that since 2012, China has been the country with the largest installed power capacity, and it has increased this by 14% since then to reach 1,245 GWe in 2014, or 21% of global capacity, slightly ahead of the United States (20%). The age structures of the power plants in these two countries differ remarkably: in China almost 70% (865 GWe) was built within the last decade, whereas in the United States half of the fleet (580 GWe) was over 30 years old.

The adaptation of nuclear energy to global naval power assets revolutionized the thought process behind this crucial sector. The US navy had all but one of the world's nuclear-powered aircraft carriers, with 10 in service after the USS Enterprise was deactivated in December. The only operating aircraft carrier outside the US is France's Charles de Gaulle, also the first French nuclear-powered surface vessel.

While the United States hasn't built a civilian nuclear power plant since 1980, the rest of the world continued to develop this technology.

On 20 February 2013 China Shipbuilding Industry Corp, one of the two dominant shipbuilders in China, said in an online news release that one of its research institutions had received State approval and funding to formally begin research on core technologies and safety for nuclear-powered ships. The company did not disclose further details about the project. The replationwhips between this announcement and China's nuclear powered aircraft carrier [and dusbmarine] project is unknown. It is reasonable to believe that the publicly acknowledged program is either being conducted in parallel with the military program, or as a cover for it.

China's polar expedition ships may use nuclear propulsion in the future, experts said, after one of the country's leading shipbuilders announced it has begun developing key technologies for nuclear-powered vessels. "Compared with ships that use conventional propulsion, nuclear-powered ships can travel farther and are more reliable, factors that make the ships a reasonable choice for polar expeditionary missions," Du Wenlong, a senior researcher at the People's Liberation Army's Academy of Military Science, told China Daily on 21 February 2013.

The International Atomic Energy Agency (IAEA) defines 'small' as under 300 MWe, and up to about 700 MWe as 'medium' including many operational units from 20th century. Together they are now referred to by IAEA as small and medium reactors (SMRs).

The Gerald Ford-class carriers have more powerful and simpler A1B reactors reported to be 25% more powerful than A4W, hence about 700 MWt each. A figure of 550 MWt each is quoted for two A4W units in the Nimitz-class carriers, and these supply 104 shaft MW each (USS Enterprise had eight A2W units of 26 shaft MW and was refuelled three times). Nimitz-class CVNs have 64 MWe electric generating capacity. Ford-class CVNs were expected to have 300 MWe generating capacity.

The Nuclear Power Institute of China (NPIC), under China National Nuclear Corporation (CNNC), has designed a multi-purpose small modular reactor, the ACP100. It has passive safety features, notably decay heat removal, and will be installed underground. It has 57 fuel assemblies 2.15m tall and integral steam generators (287C), so that the whole steam supply system is produced and shipped a single reactor module. Its 310 MWt produces about 100 MWe, and power plants comprising two to six of these are envisaged, with 60-year design life and 24-month refuelling [unsuitable for marine applications].

In October 2015 the Nuclear Power Institute of China (NPIC) signed an agreement with UK-based Lloyd's Register to support the development of a floating nuclear power plant (FNPP) using the ACP100S reactor, a marine version of the ACP100. Following approval as part of the 13th Five-Year Plan for innovative energy technologies, CNNC signed an agreement in July 2016 with China Shipbuilding Industry Corporation (CSIC) to prepare for building its ACP100S demonstration floating nuclear plant, for 2019 operation. CNNC New Energy Corporation, a joint venture of CNNC (51%) and China Guodian Corp, is planning to build two ACP100 units in Putian county, Zhangzhou city, at the south of Fujian province, near Xiamen, as a demonstration plant.

China General Nuclear Group (CGN) has two small ACPR designs: an ACPR100 and ACPR50S, both with passive cooling for decay heat and 60-year design life. Both have standard type fuel assemblies and fuel enriched to < 5% with burnable poison giving 30-month refueling. The ACPR100 is an integral PWR, 450 MWt, 140 MWe, having 69 fuel assemblies. Reactor pressure vessel is 17m high and 4.4 m inside diameter, operating at 310C. It is designed as a module in larger plant and would be installed underground. The applications for these are similar to those for the ACP100.

The offshore ACPR50S is 200 MWt, 60 MWe with 37 fuel assemblies and four external steam generators. Reactor pressure vessel is 7.4m high and 2.5 m inside diameter, operating at 310C. It is designed for mounting on a barge as floating nuclear power plant (FNPP). Following approval as part of the 13th Five-Year Plan for innovative energy technologies, CGN announced construction start on the first FNPP at Bohai shipyard in November 2016 for trial operation in 2019, supplying power and desalination.

China is edging closer to building its first maritime nuclear power platform, which could sail to remote waters and provide stable power to offshore projects. It was reported 22 April 2016 that Bohai Shipbuilding Heavy Industry Company (BSHIC), a ship assembly enterprise under the CSIC, would be responsible for building China's first maritime nuclear power platform, and the CSIC will build about 20 such platforms "in the future."

The report said the National Development and Reform Commission had approved this, and the Bohai company convened with Liaoning Provincial Economy and Informatization Commission, Huludao Municipal Economy and Informatization Commission, the safety inspection team of CSIC's nuclear safety department and Wuhan Second Institute of Ship Design, also known by its code name Institute 719, to discuss the location and relevant viability issues of the construction.

Institute 719 has proposed two designs for the maritime nuclear power platform. The first is a floating nuclear power plant and the second a submersible nuclear power plant that could work under water. The CSIC had also been working with China General Nuclear Power Corp, a leading atomic power company in China. The latter is working on a small marine nuclear propulsion reactor, called ACPR50S. The 200-megawatt reactor can be installed inside a ship and is expected to be commissioned by 2020.

China is getting closer to building its first-ever floating nuclear power station, which will be installed in a vessel and could provide stable electricity to remote waters such as the South China Sea, a leading nuclear engineer said on 25 July 2016. The construction of China's first maritime nuclear power platform is due to be completed by 2018 and be put into operation by 2019.

"It won't take long (to construct) the maritime atomic propulsion project, because the technology is already mature, and we only need to work on the stability when it operates on a floating vessel," Lei Zengguang, chief engineer of China National Nuclear Corp, told China Daily.

Nuclear power plant operator CNNC is developing the homegrown ACP100S technology for China Shipbuilding Industry Corp, the vessel maker in charge of designing and assembling the platforms, and China State Shipbuilding Corp. China General Nuclear Power Corp, another State-owned nuclear giant, is also developing the small ACPR100 reactor with a capacity of 450 megawatts per unit, which can be installed inside a section of the ship, for some remote areas and large industrial clusters, as a supplement to the large-scale land-based nuclear power plants.




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Page last modified: 25-12-2019 18:42:45 ZULU