Work has started on the foundations for the Pallas research reactor at Petten, in the municipality of Schagen in the Netherlands.

In February, the Nuclear & Radiation Protection Authority (ANVS – Autoriteit Nucleaire Veiligheid en Stralingsbescherming) granted a construction licence for the reactor and Rijkswaterstaat issued the Water Act permit for the intake and discharge of cooling water.

The Pallas reactor is intended to replace the existing 45 MWt High Flux Reactor (HFR), operated by NRG on behalf of the European Union’s Joint Research Centre, which began operation in September 1960. The new 55MWt tank-in-pool type Pallas reactor will be able to deploy the neutron flux more efficiently and effectively than the HFR. The decision on funding for the overall Pallas programme is being debated by the government and is expected to be made this year. The Minister of Health, Welfare & Sport instructed Pallas to continue with project preparations to avoid unnecessary delays.

Using special excavation techniques, diaphragm walls were put in place placed into which the concrete will be poured. “Now that all the necessary permits are in place, we can proceed with the realisation of the construction pit in which the Pallas reactor will be built,” said Pallas Programme Director Peter Dijk. The work on the construction pit is expected to be completed by the end of 2024 ready for the construction of the reactor.

For the construction pit, a hole will be dug about 50 metres by 50 metres and 21 metres deep. First, one-and-a-half-metre-wide trenches are dug into which concrete is poured to form the diaphragm walls. The diaphragm walls will be anchored with 380 bored piles, after which the soil will be excavated and the concrete bottom of the construction pit will be poured to keep the empty pit in place, and later to support the reactor. This work will be carried out by BESIX.

Foundation Preparation Pallas-Reactor said preparations for the realisation of the construction pit will continue pending a final financing decision from the Dutch government and state aid approval from the European Commission.

Image: Work begins on the foundation for the Pallas research reactor (courtesy of Pallas)