Construction of the main structure of the cooling tower for unit 1 of China’s Lianjiang Nuclear Power Project in Guangdong Province has been completed paving the way for installation of the internal components of the tower, according to State Power Investment Corp (SPIC). “The successful completion of the cooling tower has accumulated valuable experience for the design and construction of ultra-large seawater cooling towers in China’s nuclear power field,” SPIC said.
This is the world’s largest NPP cooling tower with a height of 218.7 metres and a diameter at its base of about 175 metres. It comprises a foundation, inclined pillars, tower tube, and inlet. This includes a central water shaft, water distribution system, heat exchange filler, water collection system, main water collection tank, and water eliminator.
The final concrete for the circular foundation of the tower was poured in November 2023. The foundation is more than 10 metres wide and more than 2 metres thick. Its construction required 15,900 cubic metres of concrete. A further 137,400 cubic metres of concrete was used in the tower’s construction. The water spraying area of the tower is 20,000 square metres.
According to SPIC, unlike the “once-through circulation cooling” used in traditional NPPs, the “secondary circulation cooling technology” used in the Lianjiang 1 tower is a technical breakthrough. This technology replaces the direct discharge of seawater with the recycling of cooling water. It uses the atmosphere as the final heat trap and realises the recycling of cooling water through air-water heat exchange. This significantly reduces the water intake, greatly reducing the risk of an influx of marine organisms improving the safety and stability of power supply. The water discharge is significantly reduced to one-fortieth of that of traditional NPPs, and the temperature of the discharged water approaches that of natural seawater.
SPIC said the high-level water collection design adopted by the cooling tower is a key innovation to improve efficiency, which not only reduces the ventilation resistance increasing the cooling efficiency, but also lowers the temperature of water leaving the tower under the same spray area, which can indirectly increase power generation. At the same time, the operating noise is reduced by 4-8 decibels compared with a conventional cooling tower.
Construction of the first two CAP1000 reactors at Lianjiang NPP was approved by China’s State Council in September 2022. Excavation works for the units began in the same month, with the pouring of first concrete for the foundation of unit 1 completed at the end of September 2023 and for unit 2 in April 2024. Lianjiang unit 1 is expected to be completed and put into operation in 2028.
Once all six CAP1000 units planned at the site are completed, annual electricity generation will be about 70.2 TWh, which will reduce standard coal consumption by more than 20m tonnes. It will reduce carbon dioxide emissions by more than 52m tonnes, sulphur dioxide by approximately 171,000 tonnes and nitrogen oxides by approximately 149,000 tonnes. Lianjiang is the first NPP in China to adopt seawater secondary circulation cooling technology, and is the first to develop and use a super-large cooling tower.
