Civil engineering: Basic concepts

The building housing MYRRHA should have various properties: it must house the MYRRHA facility, the remote handling mechanisms and possibly also "hot" laboratories. The building must be able to resist seismic activity that could occur in the region. And of course, the major constraint is protection of the neighbourhood of radioactive radiation and pollution in the unlikely case of an accident.

Two distinct building configurations have been investigated. Construction techniques (available and proven) in the working conditions at Mol (aquifer sands, watertight layers only available at 180 m depth) have been studied for both configurations. 

In the "reference" configuration, also called "shallow underground", the roof structure (about 10 m) of the building remains above ground. An engineered earth cover (also 10 m thick) can possibly be added to increase protection against a plane crash and also to better integrate the new building in its surroundings. The foundation invert lies at 30 m depth. References exist for this configuration. This building has a thin rectangular shape as its horizontal section is 105 m x 38 m. The current upgrade of the MYRRHA building is still based on this reference configuration. 

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In the "alternative" configuration, also called "deep underground", only the accesses remain visible and the whole structure is then covered with earth to re-establish the natural ground level. The foundation invert lies at 50 m depth, and such construction would be a "first of a kind". Therefore we tried to re-arrange the building components and reach a more feasible depth for the foundation invert. We obtain a building shape more quadratic (the horizontal section is 70 m x 47 m) while the foundation invert lies at 43 m depth. A "deep underground" alternative seems thus feasible.

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