  An experiment to search for light sterile neutrinos was conducted at a
reactor with a thermal power of 2.8 GW located at the Hanbit nuclear power
complex. The search was done with a detector consisting of a ton of Gd-loaded
liquid scintillator in a tendon gallery approximately 24 m from the reactor
core. The measured antineutrino event rate is 1976 per day with a signal to
background ratio of about 22. The shape of the antineutrino energy spectrum
obtained from eight-month data-taking period is compared with a hypothesis of
oscillations due to active-sterile antineutrino mixing. It is found to be
consistent with no oscillation. An excess around 5 MeV prompt energy range is
observed as seen in existing longer baseline experiments. The parameter space
of $\sin^{2}2\theta_{14}$ down below 0.1 for $\Delta m^{2}_{41}$ ranging from
0.2 eV$^{2}$ to 2.3 eV$^{2}$ and the optimum point for the previously reported
reactor antineutrino anomaly are excluded with a confidence level higher than
90%.
