Cold tests completed at first HTR-PM reactor

Construction of the demonstration HTR-PM plant - which features two small reactors and a turbine - began in December 2012. China Huaneng is the lead organisation in the consortium to build the demonstration units (with a 47.5% stake), together with CNNC 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 island.

The pressure vessel of the first reactor was installed within the unit's containment building in March 2016. The vessel - about 25 metres in height and weighing about 700 tonnes - was manufactured by Shanghai Electric Nuclear Power Equipment. The second reactor pressure vessel was installed later that year. The demonstration plant entered the commissioning phase on 25 July this year.

The aim of the cold tests, which began at the first reactor on 6 October and were completed yesterday, is to verify the reactor's primary loop system and equipment as well as the strength and tightness of its auxiliary pipelines under pressure higher than the design pressure. CNNC noted the tests "mark the first comprehensive test of reactor performance".

Cold functional tests at other types of reactors use water, while those at the HTR-PM reactor used compressed air and a small amount of helium as the test medium. This air and helium was pressurised in stages to a maximum pressure of 8.9 MPa during the primary loop pressure boundary strength performance test. The leakage rate of the primary circuit was measured whist the pressure was maintained at 8.0MPa for more than 24 hours. At the same time, the deformation and displacement of the primary circuit pressure vessel under pressure was investigated, and the effectiveness of the supporting system verified.

CNNC said the test results "show that all indicators of the first reactor of the demonstration project meet the design requirements, effectively verifying the reliability of the manufacturing and installation quality of the nuclear island equipment."

The demonstration plant's twin HTR-PM reactors will drive a single 210 MWe turbine. Helium gas will be used as the primary circuit coolant. The steam generator transfers heat from helium coolant to a water/steam loop. The design temperature of the HTR-PM reaches 750 degrees Celsius.

Beyond HTR-PM, China proposes a scaled-up version called HTR-PM600, which sees one large turbine rated at 650 MWe 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.