China National Nuclear Corporation (CNNC) says construction has been completed of the main internal structure for the reactor building at the ACP-100 small modular reactor (SMR) demonstration project at the Changjiang NPP in Hainan Province. The multi-purpose, 125 MWe SMR (also known as Linglong One) is a pressurised water reactor designed for electricity generation, urban heating, urban cooling, industrial steam production, or seawater desalination.

CNNC said pouring concrete for the wall panels at an altitude of more than seven metres above the internal structure of the reactor building “has created good conditions for the subsequent commissioning of the main equipment and for lifting the steel upper part of the protective shell".

Compared with traditional nuclear technology, the outstanding features of the ACP-100 are its “compactness, modularity, and integral design”, CNNC noted. "The main body is placed in a steel protective shell, and the total thickness of the concrete floor is more than 7.5 metres. It has dense steel rods and many pre-installed elements, a small spatial structure and other characteristics, making its design is extremely complex.”

CNNC began development of the Linglong One in 2010, and it was the first SMR project to pass an independent safety assessment by International Atomic Energy Agency experts in 2016. Its integrated pressurised water reactor (PWR) design was completed in 2014 and it was identified as a key project in China's 12th Five-Year Plan. The design, which has 57 fuel assemblies and integral steam generators, was developed from the larger ACP1000 PWR. It incorporates passive safety features and could be installed underground.

China's state council approved the ACP100 Science & Technology Demonstration Project in 2021 and first concrete was poured in July that year. The lower section of the containment shell of was hoisted into place on in February 2022 and the last tank of concrete for the nuclear island's underground retaining walls was poured the following August.

The project is owned by CNNC Hainan Nuclear Power Company, a subsidiary of China National Nuclear Power (CNNP – itself a subsidiary of CNNC). The projected start-up date is May 2025. Once completed, the project will produce enough power to meet the needs of 526,000 households, CNNC said.

There are already two operating CNP600 power units at the Changjiang site, and construction of the two Hualong One power units began in March and December 2021 for operation by the end of 2026.

Image: Construction of the ACP100 at the Changjiang nuclear power plant in China (courtesy of CNNC)