The construction of one of the most important power block localization safety systems – the outer reactor containment for the 2nd VVER-1200 power block – has been completed at the Leningrad NPP. The team has concreted its last layer and reached the final point of +70.200 meters.

The outer reactor containment is designed to protect the reactor call from any external impact. If needed, its durability can survive a detonation wave, a hurricane, an explosion or even a plane crash.

Taking into account how important this structure is for the safety of the power block, the environment, and the population, the containment construction activities went under tightened supervision. The quality of the construction materials and the services performed were controlled meticulously. ‘Multiple checks of control samples held at specially accredited labs have confirmed the following: in hypothetical extreme conditions, the outer containment can handle out-of-limit loads and protect the reactor, the steam generators and other safety-sensitive pieces of equipment’, Alexander Belyaev, the chief engineer of the Leningrad NPP-2, said.

Kirill Mazurin, the deputy chief engineer of construction and assembly works at the Leningrad NPP-2 capital construction department: ‘All in all, to concrete a cylindrical structure and the semi-spherical dome of the containment, we used almost 14,500 cubic meters of concrete. It is around 1,800 units of concrete delivery trucks. The total thickness of the reinforced monolithic concrete of the outer containment is 800 millimeters, which complies with the project requirements. At the moment, the team is working on compulsory activities to handle the consolidating mixture and controlling how the concrete strength is growing’.

In addition to the reactor outer containment, the innovative 3+ generation VVER-1200 power block construction projects stipulate the inner containment. The latter is required to prevent radioactive substances from reaching the environment. Its construction at the 2nd VVER-1200 power block was completed back in March 2019.

Double reactor containment is a unique feature of the Russian VVER-1200 power block design. This type of enclosure vessel boasts higher reliability compared to the previously developed structures and is a new era in promoting higher safety standards for nuclear power plants. VVER-1200 power blocks under Russian designs are being constructed both at home and in other countries, such as Belarus, Finland, Egypt and others.