  The possibility of searching for right-handed neutrinos at the MoEDAL's
Apparatus for Penetrating Particles (MAPP) detector is investigated in this
work. In particular, pair-production of right-handed (RH) neutrinos $N$ from
either a $B-L$ gauge boson $Z'$, as well as Standard Model (SM) $Z$ boson are
considered. Under a no-background assumption, we show that the MAPP detector
can be sensitive to active-sterile neutrino mixing strengths as low as $V_{\mu
N}^2 \approx 10^{-12}$ for multiple choices of $m_N / m_{Z'}$ values, when
taking the $B-L$ gauge coupling $g_{B-L} = 10^{-3}$ near its current limit. The
SM $Z$ boson portal can reach a similar sensitivity, when the effective mixing
between the $B-L$ and SM gauge boson is $\alpha \approx 0.01$.
