Concreting of the dome for the internal containment shell (ICU) has been completed at unit 2 of Russia’s Kursk-II NPP. This is the final stage of construction of one of the physical barriers of defence in depth. In total, about 3,500 cubic metres of concrete mixture were laid into the structure of the dome, which has a height of 19.4 metres and an internal diameter at the base of 44 metres. The ICU is a key element in the safety system. It protects the reactor compartment and also provides support for pipeline penetrations and the polar crane used to service the reactor.

“Completing the concreting of the unit 2 internal containment shell is one a significant events for the Kursk NPP-2 construction site,” explained Rosatom First Deputy Director for the Construction of New Units Andrey Osharin. “This enables the start of preparations for the next stage of work in the reactor building – the installation of a containment prestressing system, which greatly enhances the strength of the internal containment shell.”

Throughout the entire concreting process, laboratory quality control of the concrete mixture was carried out. Only when the required technological characteristics were confirmed, was the concrete mixture put in place.

“We made use of similar experience at unit 1,” said Oleg Shperle, vice-president and project director for the construction of the Kursk NPP at ASE JSC. “This allowed us to optimise the work process. Concreting was carried out continuously in day and night shifts with the participation of about 80 contractor specialists.”

Kursk II will replace the currently operating Kursk NPP, which comprises four ageing RBMK reactors (one of which is already closed). Units 1&2, currently under construction, will have VVER-TOI reactors – a development of the VVER-1200 reactor design. The VVER-TOI has increased power and improved technical and economic indicators, as well as increased resistance to extreme external influences. Currently work is being carried out at 156 facilities on the Kursk-II site. The number of construction and installation personnel in August totalled more than 8,500.

Image: Concreting of the dome for the internal containment shell at unit 2 of Russia’s Kursk-II NPP (courtesy of Rosatom)