China Huaneng said the first batch of nuclear fuel was successfully loaded into unit 1 the demonstration high-temperature gas-cooled reactor plant (HTR-PM) at Shidaowan, in China's Shandong province on 21 August. This followed the issue the day before of an operating licence for the two-unit plant by the National Nuclear Safety Administration. The two small reactors will drive a single 210 MWe turbine. Helium gas is used as the primary circuit coolant.
China Huaneng is the lead organisation in the consortium building the units (with a 47.5% stake), together with China National Nuclear Corporation subsidiary China Nuclear Engineering Corporation (CNEC) (32.5%) and Tsinghua University's Institute of Nuclear and New Energy Technology (20%), which is the research and development leader. Chinergy, a joint venture of Tsinghua and CNEC, is the main contractor for the nuclear
The initial fuel loading of plant is divided into two stages, China Huaneng noted. The fuel elements are first loaded into a temporary fuel storage tank, and then transferred to the core through the fuel loading and unloading system. Over a period of some 30 days, it is estimated that about 104,000 fuel elements will be installed after which the unit will achieve criticality. A full load for a single reactor requires approximately 420,000 fuel elements. The first reactor has now officially begun operation and will be connected to the grid before the end of the year.
China Huaneng said the plant uses a fully ceramic coated particle spherical fuel element indigenously developed. Each sphere contains 7 grammes of uranium enriched to 8.5% with graphite as the matrix material. The core height is 11 metres and a diameter of 3 metres. There are two independent reactivity control systems: the primary one comprising 24 control rods in the side graphite reflector, and the secondary one of six channels for small absorber spheres falling by gravity, also in the side reflector. Fuel elements are released into the top of the core one by one with the reactor operating. Some graphite moderator pebbles the same size are included. They are correspondingly removed from the bottom, broken ones are separated, the burn-up is measured, and used fuel elements are screened out and transferred to storage.
Cold functional tests were completed at the HTR-PM's two reactors in October and November 2020 using Hot functional tests began in January to simulate the thermal working conditions of the plant and verify that nuclear island and conventional equipment and systems meet design requirements. Testing of the steam turbine took place earlier in August.
China has been developing high temperature gas-cooled reactor (HTGR) technologies for more than 40 years, mainly at the Institute of Nuclear and New Energy Technology (INET) of Tsinghua University in Beijing. Since the late 1980s, the National High-tech R&D Programme has designed, constructed, commissioned and operated a 10MW thermal power test reactor (HTR-10).
Based on the HTR-10 achievements, INET began development of a commercial nuclear power plant comprising modular HTGRs. The demonstration HTR-PM project was launched in 2001 and construction of the plant began in December 2012. A further 18 HTR-PM units are planned for the Shidaowan site.
China is also planning a larger HTGR. The HTR-PM600 will have a 650 MWe turbine driven by some six HTR-PM reactor units. Feasibility studies on HTR-PM600 deployment are under way for Sanmen, Zhejiang province; Ruijin, Jiangxi province; Xiapu and Wan'an, in Fujian province; and Bai'an, Guangdong province.
Photo: Fuel loading has begun at China’s HTR-PM (Photo credit: CNNC)