16 research outputs found
Antineutrino emission and gamma background characteristics from a thermal research reactor
The detailed understanding of the antineutrino emission from research
reactors is mandatory for any high sensitivity experiments either for
fundamental or applied neutrino physics, as well as a good control of the gamma
and neutron backgrounds induced by the reactor operation. In this article, the
antineutrino emission associated to a thermal research reactor: the OSIRIS
reactor located in Saclay, France, is computed in a first part. The calculation
is performed with the summation method, which sums all the contributions of the
beta decay branches of the fission products, coupled for the first time with a
complete core model of the OSIRIS reactor core. The MCNP Utility for Reactor
Evolution code was used, allowing to take into account the contributions of all
beta decayers in-core. This calculation is representative of the isotopic
contributions to the antineutrino flux which can be found at research reactors
with a standard 19.75\% enrichment in U. In addition, the required
off-equilibrium corrections to be applied to converted antineutrino energy
spectra of uranium and plutonium isotopes are provided. In a second part, the
gamma energy spectrum emitted at the core level is provided and could be used
as an input in the simulation of any reactor antineutrino detector installed at
such research facilities. Furthermore, a simulation of the core surrounded by
the pool and the concrete shielding of the reactor has been developed in order
to propagate the emitted gamma rays and neutrons from the core. The origin of
these gamma rays and neutrons is discussed and the associated energy spectrum
of the photons transported after the concrete walls is displayed.Comment: 14 pages, 11 figures, Data in Appendix A and B (13 pages
Online Monitoring of the Osiris Reactor with the Nucifer Neutrino Detector
Originally designed as a new nuclear reactor monitoring device, the Nucifer
detector has successfully detected its first neutrinos. We provide the second
shortest baseline measurement of the reactor neutrino flux. The detection of
electron antineutrinos emitted in the decay chains of the fission products,
combined with reactor core simulations, provides an new tool to assess both the
thermal power and the fissile content of the whole nuclear core and could be
used by the Inter- national Agency for Atomic Energy (IAEA) to enhance the
Safeguards of civil nuclear reactors. Deployed at only 7.2m away from the
compact Osiris research reactor core (70MW) operating at the Saclay research
centre of the French Alternative Energies and Atomic Energy Commission (CEA),
the experiment also exhibits a well-suited configuration to search for a new
short baseline oscillation. We report the first results of the Nucifer
experiment, describing the performances of the 0.85m3 detector remotely
operating at a shallow depth equivalent to 12m of water and under intense
background radiation conditions. Based on 145 (106) days of data with reactor
ON (OFF), leading to the detection of an estimated 40760 electron
antineutrinos, the mean number of detected antineutrinos is 281 +- 7(stat) +-
18(syst) electron antineutrinos/day, in agreement with the prediction 277(23)
electron antineutrinos/day. Due the the large background no conclusive results
on the existence of light sterile neutrinos could be derived, however. As a
first societal application we quantify how antineutrinos could be used for the
Plutonium Management and Disposition Agreement.Comment: 22 pages, 16 figures - Version
Antineutrino emission and gamma background characteristics from a thermal research reactor
14 pages, 11 figures, Data in Appendix A and B (13 pages)The detailed understanding of the antineutrino emission from research reactors is mandatory for any high sensitivity experiments either for fundamental or applied neutrino physics, as well as a good control of the gamma and neutron backgrounds induced by the reactor operation. In this article, the antineutrino emission associated to a thermal research reactor: the OSIRIS reactor located in Saclay, France, is computed in a first part. The calculation is performed with the summation method, which sums all the contributions of the beta decay branches of the fission products, coupled for the first time with a complete core model of the OSIRIS reactor core. The MCNP Utility for Reactor Evolution code was used, allowing to take into account the contributions of all beta decayers in-core. This calculation is representative of the isotopic contributions to the antineutrino flux which can be found at research reactors with a standard 19.75\% enrichment in U. In addition, the required off-equilibrium corrections to be applied to converted antineutrino energy spectra of uranium and plutonium isotopes are provided. In a second part, the gamma energy spectrum emitted at the core level is provided and could be used as an input in the simulation of any reactor antineutrino detector installed at such research facilities. Furthermore, a simulation of the core surrounded by the pool and the concrete shielding of the reactor has been developed in order to propagate the emitted gamma rays and neutrons from the core. The origin of these gamma rays and neutrons is discussed and the associated energy spectrum of the photons transported after the concrete walls is displayed