Abstract:
As discussed elsewhere, the measurement of a non-zero value for $\theta_{13}$ would open up a wide range of possibilities to explore CP-violation and the mass hierarchy. Experimental methods to measure currently the unknown mixing angle $\theta_{13}$ include accelerator searches for the $\nu_{e}$ appearance and precise measurements of reactor antineutrino disappearance. The reactor antineutrino experiments are designed to search for a non-vanishing mixing angle $\theta_{13}$ with unprecedented sensitivity. This document describes current reactor antineutrino experiments and synergy between accelerator searches for the $\nu_{e}$ appearance and precise measurements of reactor antineutrino disappearance.

Abstract:
After the neutrino mixing angle $\theta_{13}$ has been precisely measured by the reactor antineutrino experiments, one of the most important open questions left in neutrino physics is the neutrino mass hierarchy. Jiangmen Underground Neutrino Observatory (JUNO) is designed to determine the neutrino mass hierarchy (MH) without exploring the matter effect. The JUNO site location is optimized to have the best sensitivity for the mass hierarchy determination. JUNO will employ a 20 kton liquid scintillator detector located in a laboratory 700 meters underground. The excellent energy resolution and PMT coverage will give us an unprecedented opportunity to reach a 3-4 $\sigma$ precision. In this paper, the JUNO detector design and simulation work will be presented. Also, RENO-50, another medium distance reactor antineutrino experiment, will do a similar measurement. With the efforts of these experiments, it is very likely that the neutrino mass hierarchy will be determined in the next 10 years.

Abstract:
Neutrinos are elementary particles in the standard model of particle physics. There are 3 flavors of neutrinos that oscillate among themselves. Their oscillation can be described by a 3$\times$3 unitary matrix, containing three mixing angles $\theta_{12}$, $\theta_{23}$, $\theta_{13}$, and one CP phase. Both $\theta_{12}$ and $\theta_{23}$ are known from previous experiments. $\theta_{13}$ was unknown just two years ago. The Daya Bay experiment gave the first definitive non-zero value in 2012. An improved measurement of the oscillation amplitude $\sin^{2}2(\theta_{13})$ = $0.090^{+0.008}_{-0.009}$ and the first direct measurement of the $\bar\nu_{e}$ mass-squared difference $\mid$$\Delta m^2_{ee}$$\mid$ = $(2.59^{+0.19}_{-0.20})\times10^{-3} \rm eV^{2}$ were obtained recently. The large value of $\theta_{13}$ boosts the next generation of reactor antineutrino experiments designed to determine the neutrino mass hierarchy, such as JUNO and RENO-50 .

Abstract:
Rising interest in nuclear reactors as a source of antineutrinos for experiments motivates validated, fast, and accessible simulations to predict reactor fission rates. Here we present results from the DRAGON and MURE simulation codes and compare them to other industry standards for reactor core modeling. We use published data from the Takahama-3 reactor to evaluate the quality of these simulations against the independently measured fuel isotopic composition. The propagation of the uncertainty in the reactor operating parameters to the resulting antineutrino flux predictions is also discussed.

Abstract:
We discuss the size of the electron-antineutrino electron into electron-antineutrino electron cross section reduction due to the rejection of the events with a vertex bremsstrahlung photon above a certain energy in the final state. In particular we analyze the effect in experiments designed to detect the low energy electron-antineutrino and electron-neutrino from a nuclear reactor and from the Sun. We find that such reduction has to be considered in a relatively high statistic reactor experiment, while it is negligible for pp and 7Be solar neutrino detection.

Abstract:
The calculations of the time-dependent reactor antineutrino energy spectrum are presented. Some problems associated with sensitive searches for neutrino magnetic moment and neutrino oscillations in reactor antineutrino flux are considered.

Abstract:
We discuss reactor antineutrino oscillations with non-standard interactions (NSIs) at the neutrino production and detection processes. The neutrino oscillation probability is calculated with a parametrization of the NSI parameters by splitting them into the averages and differences of the production and detection processes respectively. The average parts induce constant shifts of the neutrino mixing angles from their true values, and the difference parts can generate the energy (and baseline) dependent corrections to the initial mass-squared differences. We stress that only the shifts of mass-squared differences are measurable in reactor antineutrino experiments. Taking Jiangmen Underground Neutrino Observatory (JUNO) as an example, we analyze how NSIs influence the standard neutrino measurements and to what extent we can constrain the NSI parameters.

Abstract:
Reactor antineutrino experiment are used to study neutrino oscillation, search for signatures of nonstandard neutrino interaction, and monitor reactor operation for safeguard application. Reactor simulation is an important source of uncertainties for a reactor neutrino experiment. Commercial code is used for reactor simulation to evaluate fission fraction in Daya Bay neutrino experiment, but the source code doesn't open to our researcher results from commercial secret. In this study, The open source code DRAGON was improved to calculate the fission rates of the four most important isotopes in fissions, $^{235}$U,$^{238}$U,$^{239}$Pu and $^{241}$Pu, and then was validated for PWRs using the Takahama-3 benchmark. The fission fraction results are consistent with those of MIT's results. Then, fission fraction of Daya Bay reactor core was calculated by using improved DRAGON code, and the fission fraction calculated by DRAGON agreed well with these calculated by SCIENCE. The average deviation less than 5\% for all the four isotopes. The correlation coefficient matrix between $^{235}$U,$^{238}$U,$^{239}$Pu and $^{241}$Pu were also studied using DRAGON, and then the uncertainty of the antineutrino flux by the fission fraction was calculated by using the correlation coefficient matrix. The uncertainty of the antineutrino flux by the fission fraction simulation is 0.6\% per core for Daya Bay antineutrino experiment. The uncertainties source of fission fraction calculation need further to be studied in the future.

Abstract:
According to different effects on neutrino oscillations, the unitarity violation in the MNSP matrix can be classified into the direct unitarity violation and the indirect unitarity violation which are induced by the existence of the light and the heavy sterile neutrinos respectively. Of which sub-eV sterile neutrinos are of most interesting. We study in this paper the possibility of searching for sub-eV sterile neutrinos in the precision reactor antineutrino oscillation experiments with three different baselines at around 500 m, 2 km and 60 km. We find that the antineutrino survival probabilities obtained in the reactor experiments are sensitive only to the direct unitarity violation and offer very concentrated sensitivity to the two parameters $\theta^{}_{14}$ and $\Delta m^{2}_{41}$. If such light sterile neutrinos do exist, the active-sterile mixing angle $\theta^{}_{14}$ could be acquired by the combined rate analysis at all the three baselines and the mass-squared difference $\Delta m^{2}_{41}$ could be obtained by taking the Fourier transformation to the L / E spectrum. Of course, for such measurements to succeed, both high energy resolution and large statistics are essentially important.

Abstract:
The spectral shape of reactor antineutrinos measured in recent experiments shows anomalies in the neutrino flux predictions. New precision measurements of the reactor neutrino spectra as well as more complete input in nuclear data bases are needed to resolve the observed discrepancies between flux models and experimental results. We combine experiments at reactors which are highly enriched in ${}^{235}$U with commercial reactors with typically lower enrichment to gain new insights into the origin of the anomalous neutrino spectrum. As an example, we discuss the option of a direct comparison of the measured shape in the currently running Double Chooz near detector and the upcoming Stereo experiment.