  The majority of neutrino oscillation experiments have obtained evidence for
neutrino oscillations that are compatible with the three-flavor model.
Explaining anomalous results from short-baseline experiments, such as LSND and
MiniBooNE, in terms of neutrino oscillations requires the existence of sterile
neutrinos. The search for sterile neutrino mixing conducted in NOvA uses a long
baseline of 810 km between Near Detector (ND) at Fermilab and Far Detector (FD)
in Minnesota. The signal for sterile neutrino oscillations is a deficit of
neutral-current neutrino interactions at the FD with respect to the ND
prediction. In this document, We will present the analysis improvements that we
are implementing for future NC sterile neutrino searches with NOvA. These
include: improved modelling of our detector response; the inclusion of NC 2p2h
interaction modelling; implementing a better energy reconstruction techniques;
and including possible oscillation due to sterile neutrinos in the ND . This
improvements enable us to do a simultaneous ND-FD shape fit of the NC energy
spectrum covering a wider sterile mass range than previous analyses.
