The Reactor Experiment for Neutrino Oscillation (RENO) has been taking data near the Hanbit
nuclear power plant in South Korea, using two identical detectors since August 2011.
The experiment made a definitive measurement of the smallest neutrino mixing angle $\theta_{13}$ in
2012, based on the disappearance of reactor electron antineutrinos. The RENO experiment
has obtained more precise values of the mixing angle and the neutrino squared-mass-difference
$|\Delta m_{ee}^2|$ from an energy and baseline dependent reactor neutrino disappearance using $\sim$1500 live days of data.
Based on the ratio of inverse-beta-decay (IBD) prompt spectra measured in two identical far and near detectors, we obtain $\sin^2(2\theta_{13}) = 0.086 \pm 0.006(stat.) \pm 0.005(syst.)$ and
$|\Delta m_{ee}^2| = [2.61^{+0.15}_{-0.16}(stat.) ^{+0.09}_{-0.09}(syst.)] \times 10^{-3}~eV^2$.
An excess of reactor antineutrinos near 5 MeV is observed in the measured prompt spectrum with respect to the most commonly used models. The excess is found to be consistent with coming from reactors and show a weak correlation with the $^{235}$U fuel fraction. A precise value of $\theta_{13}$ would provide important information on determination of the leptonic CP phase if combined with a result of an accelerator neutrino beam experiment.