Application of CR-39 for the characterization of the neutron distribution in the neutron radiography channel of the Algerian reactor NUR is reported. The neutron detection assembly, consisting of a boron neutron-charged particle converter in contact with CR-39, was used to map the neutron flux over a 10.5×21cm2 area. The relationship between the CR-39 track density and the neutron flux has been established by a mathematical development of the detection and revelation conditions for the charged particles emitted in the neutron-induced reactions in the converter. The degree of homogeneity of the neutron field has been determined and the higher and lower neutron fluxes have been situated.