The safe installation of the reactor pressure vessel (RPV) and steam generators at the Hinkley Point C nuclear power plant has highlighted the importance of careful planning, clear communication and precision engineering on a complex, multi‑contractor construction site. With numerous organisations operating heavy machinery across limited space, every movement must be scheduled and executed with exacting accuracy to maintain safety and ensure the programme remains on track.
At the Somerset site,
EDF and its contract partners are constructing the first in a new generation of UK nuclear stations.
Framatome, responsible for manufacturing the RPV and steam generators, engaged
Mammoet to handle and install these highly sensitive components. Weighing up to 520 tonnes, these units form the core of the plant and will ultimately supply electricity to three million homes per unit.
Framatome required a lifting and handling solution independent of all pre‑existing site cranes and equipment, ensuring the operation could proceed safely and without disruption to surrounding construction work. Mammoet’s long experience in engineering bespoke solutions for nuclear construction, maintenance and decommissioning projects made it a natural fit for the task. The most significant challenge was manoeuvring the enormous components through a relatively small opening in the reactor building.
Darren Watson, sales director, Mammoet, explained: “The congestion around the unit, and the spatial limitations within which we were required to perform our activities gave Mammoet an interesting challenge. We engineered a solution, including a gantry system, which spanned from the identified pickup location and would bring the components to the required height for relocation into the building. This system also had to lift and manoeuvre these large sensitive components.”
Controlled transportationTo meet these requirements, Mammoet’s engineers designed and built the Outside Lifting System (OLS). Using a combination of winches and strand jacks, the OLS lifted the components directly from SPMTs before lowering them onto a specially engineered skid system. This allowed controlled transportation into the building. Because the geometry of the reactor building prevented a straight‑line approach, the skid system incorporated a 30deg curve. A tailor‑made turntable, designed to accommodate the transport saddles, enabled the components to rotate as they followed the curved path.
Once inside the structure, the units had to be carefully transitioned from horizontal to vertical orientation before being placed into their final positions. This was carried out using two Mammoet temporary lifting devices (TLDs) attached to the existing polar crane.
The main lift was performed by a 600‑tonne‑capacity TLD equipped with a containerised winch, while a second TLD rated to 320 tonnes used strand jacks to complete the rotation. The entire lifting system was electrically powered, reducing emissions and noise on site while improving environmental and operational safety conditions.
Mr Watson added: “The ability of our engineers to develop bespoke solutions to perform these highly complex operations is one of many areas where we add value to nuclear power projects. Our experienced teams, extensive toolbox, and track record for operational excellence and safety is what sets Mammoet apart. Few companies can even dream of delivering the types of projects Mammoet can perform.”
Mammoet’s nuclear expertise is well established. The company previously supplied a gantry system for component installation at Flamanville in France, while its PTC35 ring crane is currently supporting the extension of the Bruce Power facility in Ontario, Canada. The work at Hinkley Point C further demonstrates its capability to engineer precise, site‑specific heavy‑lift solutions for the most demanding nuclear environments.