The neutronic modelling of the VENUS-F critical core experiments with the ERANOS deterministic code (FREYA EU FP7 project)

The EURATOM FP7 project FREYA was launched in 2011 to support the design and licensing of leadcooled reactors, by choosing as reference the MYRRHA and ALFRED fast spectrum systems. During the five-year project, a number of critical experiments were conducted in the VENUS-F zero-power reactor with the main aim to validate the neutronic codes adopted for the core design. Five critical core configurations were assembled in VENUS-F: the start-up core, the mock-up dedicated to ALFRED and three layouts simulating the MYRRHA reactor conditions. The ERANOS code system, coupled with the JEFF-3.1 nuclear data library, was one of the tools adopted for the design and characterisation of the experiments. In this paper, the results obtained with the ERANOS deterministic code are compared with the experimental measurements of integral and local parameters, such as: the core reactivity and kinetic parameters, the lead void reactivity worth, the axial and radial distributions of fission rates for the nuclides of major interest, the spectral indexes of important actinides (e.g., U238, Pu239, Np237, Am241) respect to U235. The comparison between measurements and simulations shows a general good agreement, with some discrepancies for few local parameters that are here discussed.