This report presents results from the application of the Monte Carlo N-Particle (MCNP) computer code to the252Cf neutron activation analysis (NAA) Device in the Technical Physics Institute of the Heilongjiang Science Academy of the
People's Republic of China. The thermal and epithermal neutron flux at the sample positions and the neutron and photon fluxes
on the surfaces of the device were calculated. A comparison between the calculated and experimental thermal and epithermal
neutron fluxes at sample positions yield relative errors of less than 10% for the thermal neutron flux.