Cold testing of HTR-PM reactors completed

04 November 2020

Cold functional testing was completed yesterday at the second reactor of the demonstration high-temperature gas-cooled reactor plant (HTR-PM) at Shidaowan in China's Shandong province. Such tests have already been completed at the plant's first unit.

The HTR-PM demonstration project at Shidaowan (Image: CNNC)

The aim of the cold tests 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. Those at the first reactor of the twin-unit HTR-PM began on 6 October and were completed on 19 October, when cold tests at the second unit were then begun.

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 whilst the pressure was maintained at 8.0 MPa 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.

China National Nuclear Corporation (CNNC) said the cold testing of the "dual reactor" primary circuit system of the HTR-PM "effectively tested the equipment manufacturing and engineering quality of the reactor's main system and laid a solid foundation for accelerating the industrialisation of high-temperature gas-cooled reactors".

Construction of the demonstration HTR-PM plant - which features two small reactors that will drive a single 210 MWe turbine - began in December 2012. Helium gas will be used as the primary circuit coolant. 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.

A further 18 such HTR-PM units are proposed for the Shidaowan site. 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.

Researched and written by World Nuclear News