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Fontenay-aux-Roses, France

International Congress on Advances in Nuclear Power Plants 2012, ICAPP 2012 | Year: 2012

The Institute of Radiological Protection and Nuclear Safety (IRSN) acts as technical support to French public authorities. As such, IRSN is in charge of safety assessment of operating and under construction reactors, as well as future projects. In this framework, one current objective of IRSN is to evaluate the ability and accuracy of numerical tools to foresee consequences of accidents. Neutronic studies step in the safety assessment from different points of view among which the core design and its protection system. They are necessary to evaluate the core behavior in case of accident in order to assess the integrity of the first barrier and the absence of a prompt criticality risk. To reach this objective one main physical quantity has to be evaluated accurately: the neutronic power distribution in core during whole reactor lifetime. Phénix end of life tests, carried out in 2009, aim at increasing the experience feedback on sodium cooled fast reactors. These experiments have been done in the framework of the development of the 4th generation of nuclear reactors. Ten tests have been carried out: 6 on neutronic and fuel aspects, 2 on thermal hydraulics and 2 for the emergency shutdown. Two of them have been chosen for an international exercise on thermal hydraulics and neutronics in the frame of an IAEA Coordinated Research Project. Concerning neutronics, the Control Rod Withdrawal test is relevant for safety because it allows evaluating the capability of calculation tools to compute the radial power distribution on fast reactors core configurations in which the flux field is very deformed. IRSN participated to this benchmark with the ERANOS code developed by CEA for fast reactors studies. This paper presents the results obtained in the framework of the benchmark activity. A relatively good agreement was found with available measures considering the approximations done in the modeling. The work underlines the importance of burn-up calculations in order to have afine core concentrations mesh for the calculation of the power distribution.

Ferran G.,PSN EXP SNC LNR | Haeck W.,PSN EXP SNC LNR | Gonin M.,Ecole Polytechnique - Palaiseau
Nuclear Data Sheets | Year: 2014

This paper provides a general status of the development of GAIA, a new nuclear data processing software. The first part mainly focuses on the concrete developments for resonance reconstruction in the general R-matrix formalism. Then the second part is about a new method for Doppler broadening using Fourier transform. © 2014.

Farhi E.,Laue Langevin Institute | Ferran G.,PSN EXP SNC LNR | Haeck W.,PSN EXP SNC LNR | Pellegrini E.,Laue Langevin Institute | Calzavara Y.,Laue Langevin Institute
Journal of Nuclear Science and Technology | Year: 2015

In this study, we report on recent neutron inelastic scattering experiments performed at the Institut Laue-Langevin (ILL) for H2O and D2O. The measured dynamic structure factors S(q, ω) have been reduced, normalised and transformed into the S(α, β) formalism, where α and β stand for the unit-less momentum and energy transfers, respectively. The measurements were complemented with molecular dynamics simulations. After processing with NJOY, new water neutron scattering cross-sections have been generated for use with e.g. the Monte Carlo N-Particle (MCNP) software in view to improve the accuracy of the nuclear facility models. As an example, we present improved accuracy calculations for the safety rod insertion impact on the criticality factor keff for the ILL high flux research reactor. © 2014 © 2014 Atomic Energy Society of Japan. All rights reserved.

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