Ricerc@Sapienza

Self-Powered Neutron Detectors (SPNDs) are currently used in reactors’ environmentto sense the magnitude of neutron-?uxes, usually for spatial-distribution mapping ofthe fuel region as to optimize burn-up strategies. During the development of tailoredinstrumentation for Lead-cooled Fast Reactors, the possibility to perform online spec-tral deconvolution of fast neutron-?uxes was recognized. Seven geometrically simi-lar SPNDs with di?erent neutron-sensitive materials, have been characterized by theMonte Carlo transport code MCNPX. ?anks to a database of spectral sensitivitiesvs.

In the framework of the HORIZON2020 SESAME European project (SESAME Project, EURATOM H2020, 2015), an experimental campaign has been carried out on the large LBE pool integral effect CIRCE facility at CR ENEA Brasimone (Tarantino et al., 2011). The experiments are based on the HERO Test Section installed into CIRCE (Rozzia et al., 2017), aiming at supporting the development of the ALFRED design (Frignani et al., 2017).

The Advanced Lead Fast Reactor European Demonstrator (ALFRED) was conceived in the framework of the LEADER (Lead-cooled European Advanced DEmonstration Reactor) project since 2010. Recently, a revised concept of the Reactor Coolant System (RCS) is ongoing to solve some identified issues such as thermal stratification and others. To verify the improvements of the ALFRED design the authors developed a detailed nodalization scheme of the reactor using RELAP5-3D© code.

Heat removal systems are of major importance for both present and future nuclear power plants as they belong to the set of systems devoted to ensure the integrity of the reactor core and to avoid core damage. The past experience and lessons learned on this topic suggest to adopt passive safety systems which can perform the safety function independently from operators' actions and external energy sources, ensuring long term reactor cooling.