Containment shell in place for Chinese SMR

Monday, 6 November 2023

The reactor building for the ACP100 - also referred to as the Linglong One - consists of three parts: the internal structure, the steel containment shell and the outer concrete shielding shell. The steel containment shell consists of four parts: the bottom head, the lower cylinder, the upper cylinder and the top head. "Its shape is like an upright capsule that contains the internal structure of the reactor building," CNNC noted.

The containment vessel bottom head - which supports the steel containment shell - was assembled on-site from 50 pre-fabricated steel plates. The assembled component was hoisted into place by crane onto the plant's concrete foundation plate on 24 October 2021. The lower section of the containment shell - some 15 metres in height and weighing about 450 tonnes - was lowered into place upon the vessel bottom head on 26 February 2022, 46 days ahead of schedule. This was followed by the installation of the upper cylinder of the containment shell - about 15 metres in height and weighing about 720 tonnes - on 6 July last year.

The assembled top head prior to hoisting (Image: CNNC)

The containment top head for the ACP100 was moved into place on 3 November, the company said.

"The key structures are capped and the peak period of internal installation has begun," CNNC said. "This hoisting completed the final step of forming the steel containment vessel as a whole, providing a more complete and reliable protective barrier for the reactor core modules, internal components, voltage regulators and other important equipment that had been introduced in advance."

The containment dome is lifted into place (Image: CNNC)

According to CNNC, "The modular and open-top construction method adopted by Linglong One reduces construction costs and saves the construction cycle through standardised design and batch manufacturing of individual modules."

CNNC announced in July 2019 the launch of a project to construct an ACP100 reactor at Changjiang on China's southern island province of Hainan. The site is already home to two operating CNP600 PWRs, while the construction of the two Hualong One units began in March and December 2021. Both those units are due to enter commercial operation by the end of 2026.

First concrete for the ACP100 was poured on 13 July 2021, with a planned total construction period of 58 months. Equipment installation work commenced in December 2022 and the main internal structure of the reactor building was completed in March this year.

Under development since 2010, the 125 MWe ACP100 integrated PWR's preliminary design was completed in 2014. In 2016, the design became the first SMR to pass a safety review by the International Atomic Energy Agency.

Once completed, the Changjiang ACP100 reactor - which CNNC describes as "the world's first commercial land-based small modular PWR" - will be capable of producing 1 billion kilowatt-hours of electricity annually, enough to meet the needs of 526,000 households. The reactor is designed for electricity production, heating, steam production or seawater desalination.

The project at Changjiang involves a joint venture of three main companies: CNNC subsidiary China National Nuclear Power as owner and operator; the Nuclear Power Institute of China as the reactor designer; and China Nuclear Power Engineering Group being responsible for plant construction. For the demonstration plant, the reactor vessel is being supplied by Shanghai Boiler Works Limited, the steam generators by a CNNC subsidiary and other reactor internals by Dongfang Electric Corporation.