title: Neutron fluctuations: The importance of being delayed.
abstract: The neutron population in a nuclear reactor is subject to fluctuations in time and in space due to the competition of diffusion by scattering, births by fission events, and deaths by absorptions. As such, fission chains provide a prototype model for the study of spatial clustering phenomena. In order for the reactor to be operated in stationary conditions at the critical point, the population of prompt neutrons instantaneously emitted at fission must be in equilibrium with the much smaller population of delayed neutrons, emitted after a Poissonian time by nuclear decay of the fissioned nuclei. In this work, we will show that the delayed neutrons, although representing a tiny fraction of the total number of neutrons in the reactor, actually have a key impact on the fluctuations, and their contribution is very effective in quenching the spatial clustering.
authors.affiliation: CNRS, LIPHY, F-38000 Grenoble, France.|Université Grenoble Alpes, LIPHY, F-38000 Grenoble, France.
authors.forename: B
authors.initials: B
authors.lastname: Houchmandzadeh
authors.affiliation: CEA/Saclay, DEN/DANS/DM2S/SERMA/LTSD, 91191 Gif-sur-Yvette, France.
authors.forename: E
authors.initials: E
authors.lastname: Dumonteil
authors.affiliation: CEA/Saclay, DEN/DANS/DM2S/SERMA/LTSD, 91191 Gif-sur-Yvette, France.
authors.forename: A
authors.initials: A
authors.lastname: Mazzolo
authors.affiliation: CEA/Saclay, DEN/DANS/DM2S/SERMA/LTSD, 91191 Gif-sur-Yvette, France.
authors.forename: A
authors.initials: A
authors.lastname: Zoia