  We show that in a reactor disappearance oscillation experiment the
sensitivity to the mixing parameter can be substantially improved for $(1 -
5\cdot10^{-4}) eV^{2}$ mass parameter range which includes both the LSND and
the atmospheric neutrino oscillation regions. The objectives are: to search for
the sterile neutrinos and to get a better understanding of the atmospheric
neutrino oscillation mechanism. The parameters of the underground (600 m.w.e.)
Krasnoyarsk reactor and data from the CHOOZ reactor oscillation experiment are
used to estimate the effect and background rates.
