From quantum physics to engineering: polonium-containing molecules in MYRRHA

The main message of this talk will be: ab initio simulations for molecules and crystals can help forward large engineering projects in nuclear physics, in particular when direct experiments are too expensive or too dangerous. I will sketch – from an outsider point of view – the case of MYRRHA, the world’s first subcritical nuclear fission reactor driven by a particle accelerator. MYRRHA is going to be built at SCK-CEN in Belgium. As a subcritical reactor, it is safe by design (no meltdown possible). As a fast reactor, it uses fissile material more efficiently. Furthermore, it will be used to develop and produce new medical radioisotopes, as test facility for materials to be used in future fission and fusion reactors, and as a transmutator to transform long-lived nuclear waste of current fission reactors into shorter-lived isotopes. Among the many engineering challenges in designing this reactor, there is the question how to deal with short-lived yet radiotoxic 210Po that is inevitably produced in the liquid metal coolant of the reactor. Examining the chemistry of Po is difficult, exactly due to this radiotoxicity. Ab initio calculations are a safe alternative, provided sufficient accuracy is achieved. But how will one assess accuracy if there are hardly experiments to compare with? I will discuss our take on this “catch 22”.