M. Calviani

Advanced nuclear energy systems and the need of accurate nuclear data: the n_TOF project at CERN

To satisfy the worlds constantly increasing demand for energy, a suitable mix of different energy sources has to be devised. In this scenario, an important role could be played by nuclear energy, provided that major safety, waste and proliferation issues affecting current nuclear reactors are satisfactorily addressed. To this purpose, a large effort has been under way for a few years towards the development of advanced nuclear systems with the aim of closing the fuel cycle. Generation IV reactors, with full or partial waste recycling capability, accelerator driven systems, as well as new fuel cycles are the main options being investigated. The design of advanced systems requires improvements in basic nuclear data, such as cross-sections for neutron-induced reactions on actinides. In this paper, the main concepts of advanced reactor systems are described, together with the related needs of new and accurate nuclear data. The present activity in this field at the neutron facility n_TOF at CERN is discussed.

Neutron beam imaging with an XY-micromegas detector at n_TOF at CERN

A micromegas detector with a segmented anode in two orthogonal directions, equipped with a neutron/charged particle converter, was developed by a joint effort at CEA and CERN. This XY-micromegas allows the determination of a neutron beam image on an area of 6×6 cm2 with a spatial resolution of 0.5 mm as a function of neutron time of flight (n_TOF). The experimental results collected in three years of operation at the n_TOF facility are summarized together with a comparison with simulations performed by means of the FLUKA code.