  The fast neutron rate is measured at the site of NEOS experiment, a short
baseline neutrino experiment located in a tendon gallery of a commercial
nuclear power plant, using a 0.78-liter liquid scintillator detector. A pulse
shape discrimination technique is used to identify neutron signals. The
measurements are performed during the nuclear reactor-on and off periods and
found to be ~20 per day for both periods. The fast neutron rate is also
measured at an overground site with a negligible overburden and is found to be
~100 times higher than that at the NEOS experiment site.
