Measurement of neutron flux distribution in the irradiation channel in the Ghana Research Reactor-1 using Monte Carlo method

Abstract

The Monte Carlo method was used to determine the neutron fluxes in the irradiation channels of the Ghana Research Reactor-1. The MCNP5 code was used for this purpose to simulate the radial and axial distribution of the neutron fluxes within all the 10 irradiation channels. After the MCNP simulation, it was observed that axially, the fluxes rise to a peak before falling and then finally leveling out. It was also observed that the fluxes were higher in the center of the irradiation channels; the fluxes got higher as it moved toward the center of the core. The multiplication factor ( k eff) was observed as 1.000397 ± 0.0007. Radially, the thermal, epithermal and fast neutron flux in the inner irradiation channel range from 1.15 × 10 12 n/cm 2.s ± 0.1018 × 10 11 − 1.19 × 10 12 n/cm 2.s ± 0.1172 × 10 11, 1.21 × 10 12 n/cm 2.s ± 0.1014 × 10 11 − 1.36 × 10 12 n/cm 2.s ± 0.1038 × 10 11 and 2.47 × 10 11 n/cm 2.s ± 0.1120 × 10 10 − 2.97 × 10 11 n/cm 2.s ± 0.1255 × 10 10 respectively. For the outer channel, the flux range from 7.14 × 10 11 n/cm 2.s ± 0.1381 × 10 10 − 7.38 × 10 11 n/cm 2.s ± 0.208 × 10 10 for thermal, 1.94 × 10 11 n/cm 2.s ± 0.1014 × 10 10 − 2.51 × 10 11 n/cm 2.s ± 0.1281 × 10 10 for epithermal and 3.69 × 10 10 n/cm 2.s ± 0.8912 × 10 8 − 5.14 × 10 10 n/cm 2.s ± 0.1009 × 10 9 for fast. The results have shown that there are flux variations within the irradiation channels both axially and radially.