  $\underline{\textbf{MO}}$nte-carlo $\underline{\textbf{N}}$ucleon transport
$\underline{\textbf{C}}$ode (MONC) for nucleon transport is being developed for
several years. Constructive Solid Geometry concept is applied with the help of
solid bodies. Union, subtraction and intersection Boolean operations are used
to construct heterogeneous zones. Scaling, rotation, and translation operation
of the basic bodies are allowed to construct more complex zones. Module of
repetitive structure for lattice, core calculations in reactor and detector
simulation is developed. Graphical User Interface along with visualization
tools is developed to make input, construction and display of geometry, and
analysis of output data. Low energy neutron transport module is developed using
continuous linearly interpolable point neutron cross section data below 20MeV
neutron energy. The code is benchmarked for simulation of accelerator driven
sub-critical system, neutron shielding, heat and neutron flux distribution and
keff of the critical assemblies. It is observed that results of keff are in
agreement within $\sim$ 3mk with experimental results of critical assemblies as
well as the values obtained from MCNP.
