China’s quest for a high-temperature reactor began in the 1970s with fundamental research into the technology. Construction of a 10MW high- temperature gas-cooled reactor (HTR-10) was approved in 1992, and started in 1995. The project achieved first criticality in 2000 and started operation in 2003. A decade later, first concrete was poured for a 200MW commercial demonstration power plant (HTR-PM) based on the HTR-10 technology. Now China is looking ahead to the next phase of high- temperature gas-cooled reactor programme.

At the end of 2016, China’s Tsinghua University released plans for the construction of a 600MW high-temperature gas-cooled reactor. The programme is the follow-up to the 200MW HTR-PM project, which was launched in Rongcheng city, Shandong Province in December 2012. China Huaneng is the lead organisation (47.5%) in the consortium building the demonstration units together with China Nuclear Engineering Corporation (32.5%) and Tsinghua Holding Co. (20%).

The HTR-PM comprises 2x105MW reactors that will utilise pebble fuel and helium coolant. The project is currently in the installation and commissioning phase. The reactor vessel was installed in unit 1 in March 2016, and later that year in unit 2. This April the graphite moderator elements were loaded into the reactor, and in July the thermal hydraulic parameters of the steam generator were validated (see boxes). HTR- PM is expected to be connected to the grid and start electricity generation around 2018, according to INET.

Plans for a subsequent 600MW reactor are based on China’s technical and manufacturing capability resulting from the project in Rongcheng city. The new reactor will use the same major equipment design and have the same operating parameters as the demonstration project and will be “as safe” as HTR-PM, according to INET. 

The 600MW power plant will have six reactor modules connected to one steam turbine/generator set. The thermal power
of each module is 250MWt, so the six-unit station will have a power of 1500MWt, which equates to an electric power of 655MW at a generating efficiency of 43.7%. The power plant will cover almost the same area as a pressurised water reactor power plant. Upon completion, the project will be the world’s first commercial high-temperature gas-cooled reactor.

The aim of the 600MW HTGR is to improve project economics while ensuring safety. Based on the current design, costs are expected to be similar to those for a PWR. “By standardising the design of the main equipment and expanding the scale of nuclear fuel production, we can reduce the cost of construction and operation of the reactor,” said Zhang Zuoyi, chief scientist of the HTGR demonstration project.

With the HTGR project, China has mastered all the core reactor technologies and has achieved several ‘firsts,’ including the establishment of the first large-scale factory for spherical fuel elements containing ceramic-coated particles and the first helium circulator with electromagnetic bearings. China has produced the key equipment for the HTR units, including the reactor pressure vessel and steam generator and holds the full proprietary intellectual property rights for the HTR-PM. Zhang Zuoyi said that technological advances in the reactor design were made possible through the efforts of several generations of Tsinghua people, as well as the collaborative innovation of several major domestic nuclear power enterprises.

Due to the high temperature and characteristics of the steam produced by HTGR, the reactor has strong promise for replacing coal-fired plants, combined heat and power generation and hydrogen production. At the same time, the 600MW HTGR is an important part of China’s strategy to go global with nuclear power. China has already signed a memorandum of cooperation on HTGRs with countries such as Saudi Arabia and Indonesia. 

Kun Yuan, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, P. R. China