The reactor pressure vessel, steam generator and hot gas duct at unit 2 of China's demonstration high-temperature gas-cooled reactor plant (HTR-PM) have been paired and connected, China National Nuclear Corporation (CNNC) announced on 25 March.

The demonstration HTR-PM unit, at China Huaneng's Shidaowan site in Weihai city, Shandong province, features two small reactors and a turbine.

Construction began on HTR-PM in December 2012. The 700t reactor pressure vessel of the first HTR-PM reactor was installed within the containment building in March 2016, followed by the second later that year.

It is being built by China Huaneng, China Nuclear Engineering Corporation (CNEC) and Tsinghua University's Institute of Nuclear and New Energy Technology. Chinergy, a joint venture of Tsinghua and CNEC, is the main contractor for the nuclear island.

According to CNNC, the "pairing of the key nodes" of the second reactor was completed on 18 March. This enabled reinstallation of the low-temperature helium riser of the steam generator, as well as installation of the main steam detachable pipe section and the main helium fan.

CNNC said pressure vessel, steam generator and hot gas duct have been "rigidly connected in the form of a flange to form a primary circuit system for the thermal energy transmission of the reactor, which constitutes a second barrier to prevent the leakage of radioactive materials," CNNC said.


Photo: HTR-PM (Credit: CNNC)