Press Release

PALLAS-reactor preparatory works progress

17 June 2024

Preparatory works on the construction pit of the PALLAS-reactor have been underway. To realise the construction pit, in which the PALLAS-reactor will be placed, a hole about 50 meters by 50 meters and 21 meters deep is being dug. Since May 2023, when first concrete was poured, preparatory works have been conducted is several steps.

30 pieces of one-and-a-half-meter-wide trenches were dug, into which concrete was poured to realise the diaphragm walls.  The ring beam was placed around the top part of the walls to connect the walls. Further, series of works inside of the pit itself started by drilling 162 bored steel tubes with 15 anchor strings. The anchors are between 48 and 64 metres long and tensed to the ground by a mixture of grout. In order to reach the depth of 21 meters, the pit was excavated – first by dry excavation, in the second phase in the wet way.

Sand was extracted, clay and peat have been disposed of at the sand depot. The pit is still filled with water up to the groundwater level to balance groundwater pressure.

Today, on 17 June, installing 380 foundation piles to a depth of -47.0 NAP was completed. The 33-metre-long piles were drilled from the pontoon, using the pile cleaning device (PCD) to accurately position the drilling pile on the bottom. Five rounds of quality tests had been conducted prior to the start of the drilling to verify pre-determined parameters of drilling of the piles such as speed, torque, and flow speed of the grout.

In the next step, the layer of gravel will be applied at the bottom of the excavated pit to allow for a good quality concrete pour. In a final step, 48,000 m3 of water  will be pumped out of the construction pit.

So far, the works have progressed smoothly thanks to successful collaboration of NRG PALLAS, ICHOS (main designer) and BESIX (contractor for Pit & Foundation phase).

Every day, 30,000 patients depend on the production of medical radioisotopes from Petten in North Holland. This number is expected to increase due to the introduction of new treatments with medical isotopes from reactors and the growth in the number of patients with cancer and cardiovascular diseases worldwide. NRG PALLAS has therefore taken the initiative to realise the PALLAS-reactor in Petten. This initiative is fully supported by the Dutch Cabinet.  


For more information please contact

Cora Blankendaal 1

Cora Blankendaal
Press Officer