World’s first high temperature gas-cooled reactor starts up in China


State-run power generator China Huaneng Group (CHGC) announced earlier this week that the company has started up its high-temperature gas-cooled HTR-PM small modular reactor (SMR) at the Shidao Bay nuclear power plant in northeast China’s Shandong province. Being cooled by helium gas, the HTR-PM can be used in inland areas away from large bodies of water. 

With this start up achieved on September 12, 2021, as per a China Huaneng release, the HTR-PM became the world’s first pebble-bed modular high-temperature gas-cooled reactor (HTGR), and is scheduled to be connected to the grid before the end of this year. The HTR-PM is a Generation 4 reactor design and is a part of the nation’s drive to make China carbon-neutral by 2060.

The China Huaneng statement said the company “will continue to standardise the follow-up commissioning and trial operation of the demonstration project to ensure the first grid-connected power generation in 2021.” It also said the demonstration project will now conduct zero-power physical tests to verify the core and control rod performance and the availability of nuclear instrument monitoring system equipment.   

According to the company, the demonstration project used more than 2,000 sets of equipment for the first time, and more than 600 sets of innovative equipment, including the world’s first high-temperature gas-cooled reactor spiral coil steam generator. It also features the first high-power, high-temperature thermal electromagnetic bearing structure for the main helium fan, as well as the world’s largest and heaviest reactor pressure vessel. 

“We’ve mastered a series of global and industrial bottleneck technologies, and verified their engineering transformation. Features such as the inherent safety of the HTGR will hopefully expand nuclear power from coastal to inland regions”, said a China Huaneng vice president Wang Wenzong.  

This unit is the first of the two high-temperature gas-cooled reactors at the demonstration HTR-PM plant at Shidao Bay. The company aims to develop the two HTR-PM reactors to jointly power a 210 MW turbine. 

The Chinese nuclear regulator, the National Nuclear Safety Administration, issued an operating license for the HTR-PM last month, which was followed by the loading of the first spherical fuel elements into the first reactor.  A total of 18 such reactors are planned at Shidao Bay. China is also proposing a scaled-up version called the HTR-PM-600, in which one large turbine will be driven by six HTR-PM units to generate 650 MW electricity. 

According to the International Atomic Energy Agency (IAEA), being cooled by helium and capable of reaching temperatures as high as 750 degrees Celsius, makes the HTMR suitable for non-electric applications such as district heating and hydrogen production. The reactor is also designed with inherent safety features that reduce the risk of radioactive releases. 

An IAEA report says that safety is also a matter of fuel design and how the nuclear fission reaction is controlled in the reactor core. According to the agency, modular high-temperature gas-cooled reactors (MHTGR) being small in size, with predesigned geometrical restrictions and limitations of the reactor and fuel elements, are inherently safe owing to their design features. Besides, their power density is low, while minimal fuel is available in the reactor. Moreover, the chances of core damage of the MHTGR are nil, according to the IAEA. 

Among the Asian nations, taking the case of India which has plentiful thorium reserves, the IAEA has specifically pointed out that small thorium-based gas cooled high temperature reactors in the 20MW-40MW range are completely safe with a core damage frequency rate of zero. The agency has reiterated that such SMRs merit introduction in India not only for their innovative technology, but also for other economic benefits of the STGRs. An IAEA report says that “for 10,000 STGRs in India, the combined core damage frequency (CDF) will still be 0.” 

China is poised to unveil the design for a commercial molten salt reactor (MSR) that uses thorium as fuel. A 2 MW prototype reactor is expected to be completed this month, with the first tests slated for September 2021, which will pave the way for building the first commercial 100 MW MSR scheduled for construction by 2030. China leads global MSR research, that includes work in this area by countries such as France, India, Japan, Norway, and the US.