  Majorana and pseudo-Dirac heavy neutrinos are introduced into the type-I and
inverse seesaw models, respectively, in explaining the naturally small neutrino
mass. TeV scale heavy neutrinos can also be accommodated to have a sizable
mixing with the Standard Model light neutrinos, through which they can be
produced and detected at the high energy colliders. In this paper we consider
the Next-to-Leading Order QCD corrections to the heavy neutrino production, and
study the scale variation in cross-sections as well as the kinematic
distributions with different final states at $14$ TeV LHC and also in the
context of $100$ TeV hadron collider. The repertoire of the Majorana neutrino
is realized through the characteristic signature of the same-sign dilepton
pair, whereas, due to a small lepton number violation, the pseudo-Dirac heavy
neutrino can manifest the trileptons associated with missing energy in the
final state. Using the $\sqrt{s}=8$ TeV, $20.3$ fb$^{-1}$ and $19.7$ fb$^{-1}$
data at the ATLAS and CMS respectively, we obtain prospective scale dependent
upper bounds of the light-heavy neutrino mixing angles for the Majorana heavy
neutrinos at the $14$ TeV LHC and $100$ TeV collider. Further exploiting a
recent study on the anomalous multilepton search by CMS at $\sqrt{s}=8$ TeV
with $19.5$ fb$^{-1}$ data, we also obtain the prospective scale dependent
upper bounds on the mixing angles for the pseudo-Dirac neutrinos. We thus
project a scale dependent prospective reach using the NLO processes at the $14$
TeV LHC.
