Comparison of the effects of cadmium-shielded irradiation channel and a boron carbide-shielded irradiation channel of the outer irradiation channel of the Ghana research reactor-1 using MNCP

The MCNP model for the Ghana Research Reactor-1 (GHARR-1) was redesigned to incorporate cadmium-shielded irradiation channel as well as boron carbide-shielded channel in one of the outer irradiation channels. Further investigations were made to consider the boron carbide-shielded channel and both results were compared to determine the best material for the shielded channel. Before arriving at the final design of only one shielded outer irradiation channel, extensive investigations were made into several other possible designs. The concept of redesigning a new MCNP model which has a shielded channel is to equip GHARR-1 with the means of performing efficient epithermal neutron activation analysis. After the simulation, a comparison of the results from the boron carbide-shielded channel model for GHARR-1 and the epicadmium shielded channel was made. The Keff of the boron carbide-shielded channel model was recorded as 1.00282±0.00008 while that or the epicadmium designed model was recorded as 1.00332±0.00008. A prompt neutron lifetime of 1.5237x10-4s was recorded for the cadmium designed model while a value of 1.5245x10-4s was recorded for the boron carbide-shielded design of GHARR-l. The neutron energy causing fission for the boron carbide-shielded design of GHARR-1 was 1.3533x10-2MeV while that of the cadmium designed model was 1.3513x10-2MeV.