Njinga R.L., Ibrahim Y.V., Adeleye M.O and Jonah S.A.
The need to ascertain the neutron flux stability after the recent installation of permanent 1.0 mm cadmium lined in the larger outer irradiation channel A-3 was performed in this work. The specific activity ratios, inner-to-outer channel of Nigeria Research Reactor-1 (i.e. A-1/B-4, B- 2/B-4, and B-3/B4) were determined averagely to be 2.06 with a percentage deviation error of 4.63 %. The inner-to-outer with cadmium lined (i.e. A-1/A-3, B-2/A-3, B-3/A-3) was found on the average to be 22.66 with percentage deviation error of 1.58%. Also, the outer-to-outer with cadmium (i.e. A-2/A-3) was obtained to be 11.55 with percentage deviation error of -0.87%. The values of resonance-to-thermal cross section of the inner channels oscillate in a stable trend and for the outer channel B-4, it was observed to be good. These stable trends in the obtained nuclear data I0(α) and Q0(α) values and the specific activity ratios indicates that the neutron flux distributions after installation of a cadmium lined in one of the large outer irradiation channel have not been affected. Thus, a normal routine activation of samples in the channels will continue. The cadmium lined provides a good platform for implementation of epithermal and fast Neutron Activation Analysis in NIRR-1
