[en] The Double Chooz reactor oscillation experiment is designed to search for a non-vanishing value of the mixing angle θ_1_3. For the first phase of the experiment with only the far detector running, the reactor electron antineutrino flux is normalized via reactor simulation. For this first phase and from its last results, Double Chooz observed an evidence for a reactor electron antineutrino disappearance. In 227.93 days of far detector live time, we obtained sin"22θ_1_3=0.109±0.030(stat)±0.025(syst). This result excludes the no-oscillation hypothesis at 99.8% CL

[en] This paper presents a feasibility study of the use of the detection of reactor-antineutrinos (ν"¯_e) for non proliferation purpose. To proceed, we have started to study different reactor designs with our simulation tools. We use a package called MCNP Utility for Reactor Evolution (MURE), initially developed by CNRS/IN2P3 labs to study Generation IV reactors. The MURE package has been coupled to fission product beta decay nuclear databases for studying reactor antineutrino emission. This method is the only one able to predict the antineutrino emission from future reactor cores, which don't use the thermal fission of "2"3"5U, "2"3"9Pu and "2"4"1Pu. It is also the only way to include off-equilibrium effects, due to neutron captures and time evolution of the fission product concentrations during a reactor cycle. We will present here the first predictions of antineutrino energy spectra from innovative reactor designs (Generation IV reactors). We will then discuss a summary of our results of non-proliferation scenarios involving the latter reactor designs, taking into account reactor physics constraints

[en] Different Liquid Drop Model mass formulae have been studied. They include a Coulomb diffuseness correction Z²/A term and pairing and shell energies of the Thomas-Fermi model. The influence of the selected charge radius, the curvature energy and different forms of the Wigner term has been investigated. Their coefficients have been determined by a least square fitting procedure to 2027 experimental atomic masses. The different fits lead to a surface energy coefficient of 17-18 MeV. A large equivalent rms radius (r₀ = 1.22 - 1.24 fm) or a shorter central radius may be used. A rms deviation of 0.54 MeV can be reached between the experimental and theoretical masses. The remaining differences come from the determination of the shell and pairing energies. Mass predictions are given for exotic nuclei.

[en] Nuclear power plants produce large quantities of antineutrinos due to the beta decays of the fission products. Antineutrino measurements could comprise a unique means of providing information on the isotopic composition of the core, non-intrusively and in near real-time. To this aim we have started to study PBRs (Pebble Bed Reactors) with our simulation tools. We use a package called MCNP Utility for Reactor Evolution (MURE), initially developed by CNRS/IN2P3 labs to study Generation IV reactors. The MURE package has been coupled to fission product beta decay nuclear databases for studying reactor antineutrino emission. As a first step, the simulation of a pebble surrounded by He coolant which design is taken from an OECD/NEA benchmark has been performed. Simulations of the evolution of a single-cell for 3 kinds of prospect fuel: uranium, uranium/thorium or PuO_x, are compared with the results of the OECD/NEA benchmark. Various diversion scenarios assuming a 200 MWth reactor are discussed, deduced from our cell calculation, as a first estimate of the antineutrino emission characteristics. The emitted antineutrino characteristics depend on the fuel type, the mixing of regular fuel and proliferation-prone fuel, the pebble residency time. The first gross scenario presented in this paper prove that the usefulness of a neutrino detector is very sensitive to the power of the reactor and the reactor type itself. For the UO_x fuel, we have first focused on the reactor at steady state, which is the most relevant for a first sight, and found that an antineutrino detector of 2m³ placed at 25 m from a reactor of 200 MWth would be sensitive to the diversion of 1 SQ (Significant Quantity) within 3 months, even without taking into account the physics of detection which would enhance the discrepancy between the fissions of uranium and plutonium

[en] Different mass formulae derived from the liquid drop model and the pairing and shell energies of the Thomas-Fermi model have been studied and compared. They include or not the diffuseness correction to the Coulomb energy, the charge exchange correction term, the curvature energy, different forms of the Wigner term and powers of the relative neutron excess I=(N-Z)/A. Their coefficients have been determined by a least square fitting procedure to 2027 experimental atomic masses (G. Audi et al. (2003) ). The Coulomb diffuseness correction Z²/A term or the charge exchange correction Z^4/3/A^1/3 term plays the main role to improve the accuracy of the mass formula. The Wigner term and the curvature energy can also be used separately but their coefficients are very unstable. The different fits lead to a surface energy coefficient of around 17-18 MeV. A large equivalent rms radius (r₀=1.22-1.24 fm) or a shorter central radius may be used. An rms deviation of 0.54 MeV can be reached between the experimental and theoretical masses. The remaining differences come probably mainly from the determination of the shell and pairing energies. Mass predictions of selected expressions have been compared to 161 new experimental masses and the correct agreement allows to provide extrapolations to masses of 656 selected exotic nuclei.

[en] This paper attempts to summarize the actual problematic of reactor antineutrino energy spectra in the frame of fundamental and applied neutrino physics. Nuclear physics is an important ingredient of reactor antineutrino experiments. These experiments are motivated by neutrino oscillations, i.e. the measure of the θ₁₃ mixing angle. In 2011, after a new computation of the reactor antineutrino energy spectra, based on the conversion of integral data of the beta spectra from ²³⁵U, and ^239;241Pu, a deficit of reactor antineutrinos measured by short baseline experiments was pointed out. This is called the 'reactor anomaly', a new puzzle in the neutrino physics area. Since then, numerous new experimental neutrino projects have emerged. In parallel, computations of the antineutrino spectra independent from the ILL data would be desirable. One possibility is the use of the summation method, summing all the contributions of the fission product beta decay branches that can be found in nuclear databases. Studies have shown that in order to obtain reliable summation antineutrino energy spectra, new nuclear physics measurements of selected fission product beta decay properties are required. In these proceedings, we will present the computation methods of reactor antineutrino energy spectra and the impact of recent beta decay measurements on summation method spectra. The link of these nuclear physics studies with short baseline line oscillation search will be drawn and new neutrino physics projects at research reactors will be briefly presented. (authors)

[en] The aim of this work is to study the impact of the inclusion of the recently measured β decay properties of the "1"0"2","1"0"4","1"0"5","1"0"6","1"0"7Tc, "1"0"5Mo, and "1"0"1Nb nuclei in the calculation of the antineutrino (anti-ν) energy spectra arising after the fissions of the four main fissile isotopes "2"3"5","2"3"8U, and "2"3"9","2"4"1Pu in PWRs. These β feeding probabilities, measured using the Total Absorption Technique (TAS) at the JYFL facility of Jyväskylä, have been found to play a major role in the γ component of the decay heat for "2"3"9Pu in the 4-3000 s range. Following the fission product summation method, the calculation was performed using the MCNP Utility Reactor Evolution code (MURE) coupled to the experimental spectra built from β decay properties of the fission products taken from evaluated databases. These latest TAS data are found to have a significant effect on the Pu isotope energy spectra and on the spectrum of "2"3"8U showing the importance of their measurement for a better assessment of the reactor anti-ν energy spectrum, as well as importance for fundamental neutrino physics experiments and neutrino applied physics