[en] The article describes the key activities of the Institute for Advanced Nuclear Systems (ANS) of the Belgian Nuclear Research Centre SCK-CEN. The institute ANS shall increase the expertise and Belgian involvement, both technically and economically, in the field of fourth generation fission reactors and fusion reactors ITER-DEMO. Based on modelling, experimentation and numerical simulation, ANS shall produce the design for a fast spectrum facility with a European dimension at the Mol-site (the MYRRHA-project). Furthermore, ANS will develop and test technologies and instrumentation for innovative reactors, in collaboration with industry and other international research groups. The institute ANS shall provide services and support to industry and nuclear installations on a national and international level. These objectives will be accomplished in synergy with the institutes NMS (Nuclear Materials Science) and EHS (Environment, Health and Safety) by calling on their expertise and experimental techniques where appropriate, and by providing support and services to them