  One of the most abundant man-made sources of low energy (few~MeVs) neutrinos,
reactor neutrino, is not only useful for studying neutrino properties, but it
is also used in practical applications. In this study, we investigate the
practical use of reactor neutrino detectors for nuclear safeguard in Vietnam,
specifically at the Dalat Nuclear Reactor, a future research facility, and
presumably commercial reactors with 500~kW, 10~MW, and 1000~MW thermal powers,
respectively. We compute the rate of observed inverted beta decay events, as
well as the statistical significance of extracting isotope composition under
the practical assumptions of detector mass, detection efficiency, and
background level. We find that a 1-ton detector mass can allow us to detect the
reactor's on-off transition state from a few hours to a few days, depending on
the standoff distance and reactor thermal power. We investigate how background
and energy resolution affect the precision of the extracted weapon-usable
${}^{239}\text{Pu}$ isotope. We conclude that in order to distinguish the 10\%
variation of the ${}^{239}\text{Pu}$ in the 10~MW thermal power reactor, a
1-ton detector placed 50~m away must achieve 1\% background level. Increasing
the statistics by using a 10x larger detector or placing it $\sqrt{10}$ times
closer to the reactor alleviates the requirement of the background level to
10\%.
