How Is a Reactor Pressure Vessel Moved?

Short Answer — Reactor Pressure Vessel (RPV)

The reactor pressure vessel (RPV) is the thick-walled steel vessel in a pressurised water reactor that houses the fuel assemblies and internals and contains the hot, high-pressure coolant water. For the VVER-1200, this single-piece component weighs 330–350 tonnes and is 11–12 m long; it is usually shipped by special vessel from the manufacturer's quay directly to the power plant's jetty.

What does the reactor pressure vessel do?

The pressure vessel holds the core, the heart of the reactor. In the VVER-1200, the core consists of 163 fuel assemblies; the water in the primary circuit is kept at a pressure of about 16 MPa so that it can reach high temperatures without boiling. Because the vessel must withstand this pressure safely throughout a 60-year design life, it is manufactured by welding forged steel rings together, with hundreds of quality control steps. Akkuyu's first vessel was completed at Atommash in about three years, involving more than 750 manufacturing operations and more than 300 quality tests. The difference between a nuclear vessel and a conventional pressure vessel is covered in a separate entry.

What are its weight and dimensions?

Akkuyu unit	Weight	Dimensions	Status
Unit 1	330 tonnes	approx. 12 m long, 4.5 m diameter	Arrived on site in November 2020
Unit 2	343 tonnes	11.45 m × 5.6 m	Installed in September 2022
Unit 3	350 tonnes	11.45 m × 5.7 m	Arrived on site in November 2023

The diameter and width figures given in the sources may refer to different points on the vessel; the transport plan is always based on the widest point, i.e. the outer dimension including the nozzle and flange area.

How is it transported from the factory to the site?

Preservation and preparation: Nozzle and flange openings are sealed, internal surfaces are protected against moisture, and the vessel is secured horizontally in a transport cradle. Shock and tilt sensors that record impacts and inclination are fitted.
From the factory to the quay: In Volgodonsk, the vessel was moved by heavy-haul trailers to the factory jetty on the Tsimlyansk Reservoir; trolleybus lines along the road were temporarily removed for the passage.
Loading onto the vessel: It is lifted aboard with a heavy-lift crane and sea-fastened in accordance with the IMO Code of Safe Practice for Cargo Stowage and Securing (CSS Code).
Sea voyage: Akkuyu's first vessel travelled via the Don and the Sea of Azov into the Black Sea, then through the Turkish Straits into the Mediterranean, covering about 3,000 km in 20 days.
Discharge: The vessel is unloaded at the plant's Eastern Cargo Terminal and moved by on-site road to the storage area.
Incoming inspection and storage: Documents, sensor records and the condition of the vessel are checked; preservation conditions are maintained until installation.
Lifting and installation: At Akkuyu, the "open top" method was used: the vessel was lowered into the building from above with a heavy crane before the reactor building dome was closed. For Unit 1, this was done in June 2021.

Why heavy equipment arrives by sea rather than by road is explained in a separate entry.

Who checks what during transport?

The manufacturer is responsible for packaging and preservation, the ship's master for the safety of the cargo at sea, and the logistics company for the transfer points. On site, the plant owner's quality team carries out the incoming inspection. The installation quality of the Akkuyu Unit 3 vessel was reviewed by a commission made up of Akkuyu Nuclear, the independent inspector Türk Loydu and the Nuclear Regulatory Authority (NDK).

Common mistakes

Not matching lifting points and cradle position with the ship's stowage plan.
Not verifying the load-bearing capacity of the quay surface before discharge.
Not attaching the sensor records to the delivery documents.

How does Voltim Global support you?

Single-piece main equipment such as the reactor vessel arrives by the manufacturer's sea transport. Voltim Global, for its part, has handled more than 450 shipments since March 2024 in nuclear project logistics, running the flow of auxiliary materials and spare parts that accompany the main equipment by RoRo and road. The transport of equipment of similar weight is described in the entry steam generator.

Frequently Asked Questions

Can a reactor pressure vessel be transported by road?

Over short distances, yes. The legs from the factory to the quay and from the jetty to the plant building are carried out by road using modular hydraulic trailers or SPMTs. Road transport over hundreds of kilometres, however, is often not feasible because of bridge capacities, overpass heights and permit requirements; this is why power plants are built on the coast and have their own jetty.

Is a new reactor pressure vessel radioactive?

No. A vessel leaving the factory has never operated with fuel, so it is not radioactive and is not subject to the rules for transporting radioactive material. What makes the transport difficult is not radiation but weight, dimensions, surface sensitivity and the documentation and protection requirements arising from the vessel's nuclear safety class. The vessel is therefore transported under general heavy-cargo rules and in line with the project quality plan.

Sources

Published: 18.10.2026 · Voltim Global