Article

PALLAS Programme marks an important milestone in the realisation of the PALLAS-reactor. On the 7^th of May, works on the Pit & Foundation phase were completed, delivering a vital supporting structure for the construction on the PALLAS-reactor, and laying the foundation for the next phase of construction.

The completion of the Pit & Foundation finalises the construction works that precede the construction of the PALLAS-reactor itself. The Pit & Foundation phase completion results in the construction pit – a hole measuring 50 meters by 50 meters and 17.5 meters deep, into which the PALLAS-reactor building will later be placed. 

Some of the highlights of the construction phase include the realisation of 30 diaphragm walls, which are reinforced by 162 anchors. Following this, the pit was dug to a depth of 21 meters while filled with water. 380 piles were drilled to a depth of -47.0 NAP to balance groundwater pressure at the time. These piles were used in the construction phase to avoid underwater concrete to float to the surface and also functions foundation piles for the nuclear island.

The next step was the pouring of the 4000m3 of underwater concrete. After which 48,000 m³  of water were pumped out of the construction pit. In the final step, the foundation floor was realised by installing 790 tons of reinforcement bars, on top of which the 1.5-meter-thick concrete layer was poured.     

This series of construction works were carried out by BESIX, a contractor known for delivering technically demanding projects. Joint forces of NRG PALLAS, BESIX and ICHOS (the main designer) and combined expertise proved to be crucial for the streamlined execution of the foundation of the new reactor. We used specialist construction techniques and thorough preparation, which created room for innovative solutions that minimised waste materials and potential disturbances.

Special attention was paid to the security regime, which was developed in close cooperation with Croonwolter&dros. Additionally, collaboration with an ecologist has been underway to protect the surrounding dune landscape.

Preparation for the construction of the PALLAS-reactor and cooling system  

Currently, NRG PALLAS, together with FCC (the main contractor) and ICHOS, has been preparing for the start of construction. Preparatory works have been underway to restructure the construction site for the works on the lower floors of the PALLAS-reactor building and the construction pit of the secondary cooling system building. Further, preparations are underway for the installation of the cooling water pipeline, which will extract water from the great North Holland Canal and discharge it into the North Sea.

The new temporary office is being delivered shortly to provide 240 workspaces as the upcoming construction phase will bring more employees to work directly on the site in Petten.