The main components of the reactor shaft have been installed at the reactor compartment of unit 4 at the Akkuyu NPP under construction in Türkiye. These include the dry reactor shielding and a support truss.
Akkuyu, Türkiye’s first NPP, will eventually host four Russian-designed VVER-1200 reactors. The pouring of first concrete for unit 1 took place in April 2018, for unit 2 in June 2020, for unit 3 in March 2021, and for unit 4 in July 2022. Rosatom is constructing the reactors according to a build-own-operate model. Unit 1 is expected to begin operation in 2025. In July Akkuyu NPP reported that some 70% of the equipment and systems installed at unit 1 had already undergone commissioning.
The dry reactor shielding ensures reliable operation of the NPP even under extreme loads, such as in case of an earthquake of 9 points on the MSK-64 scale. The support truss is designed to fasten the reactor vessel in the concrete cavity, and protects the reactor against external impacts. Installation of the components using a heavy caterpillar crane took eight hours.
The dry shielding surrounds the nuclear reactor vessel and represents a thick-walled, cylindrical steel structure filled with a special concrete that withstands high temperatures (up to 500°С). The dry shielding is chiefly designed to reduce thermal loads and ionising radiation, which affect the concrete reactor cavity. The structure of the dry reactor shielding, which weighs 30 tonnes (without a filler), has an outer diameter of 6.7 metres and a height of more than five metres. It was manufactured by Russia’s Tyazhmash factory in Syzran City. The support truss is a structural component of the reactor cavity, which weighs 145 tonnes (without a filler), with an outer diameter of more than 10 metres and a height of more than 1.5 metres.
“Installation of such large-size structures is complex and requires the highest qualification of the personnel and detailed calculation,” said Sergei Butskikh, CEO of project company Akkuyu Nukleer. “making use of the experience gained during similar work at previous units, enabled the specialists to complete the installation right on time. We are continuing intensive construction works on the reactor cavity of unit 4.”.
Other construction work on the reactor shaft at the unit 4 is continuing uninterrupted. In particular, work on pre-assembly, cavity concreting, and installation of measurement channels are almost complete.
