  Determination of the neutrino mass hierarchy using a reactor neutrino
experiment at $\sim$60 km is analyzed. Such a measurement is challenging due to
the finite detector resolution, the absolute energy scale calibration, as well
as the degeneracies caused by current experimental uncertainty of $|\Delta
m^2_{32}|$. The standard $\chi^2$ method is compared with a proposed Fourier
transformation method. In addition, we show that for such a measurement to
succeed, one must understand the non-linearity of the detector energy scale at
the level of a few tenths of percent.
