Browsing by Author "Jonah, S.A."

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    Investigative studies on effect of reflector thickness on the performance of low enriched uranium-fueled miniature neutron source reactors.
    (2011) Odoi, H.C.; Akaho, E.H.K.; Anim-Sarpong, S.; Jonah, S.A.; Nyarko, B.J.B.; Abrefah, R.G.; Lawson, I.; Ibrahim, Y.V.; Birinkorang, S.A.; Boffie, J.
    Neutronics analyses were performed on the 30 kW(th) GHARR-1 facility to investigate the effects on increased beryllium annular reflector thickness on nuclear criticality safety and on the neutron flux levels in the experimental channels. The investigative study was carried out using the Monte Carlo code MCNP on a hypothetical LEU UO 2 core theoretically enriched to 12.6% and having the same core configuration as the present 90.2% enriched HEU U-Al core. The analyses were performed on four models consisting of a reference model with 10.2 cm annular reflector thickness and three new design modification models with increased reflector thickness of 10.3, 10.4 and 10.5 cm respectively. The simulations indicated average thermal neutron fluxes of (9.80 ± 0.0017)E+11 n/cm 2 s in the inner irradiation channels for the reference model, indicating a 2% decrease with respect to the nominal flux of 1.00E+12 n/cm 2 s. Relatively lower neutron fluxes were obtained for the modification models with an average of (9.79 ± 0.0017)E+11 n/cm 2 s, representing losses of 2.01% and 0.01% with respect to the HEU core and reference LEU model. © 2011 Elsevier B.V. All rights reserved.
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    Monte Carlo simulation of additional safety control rod for commercial MNSR to enhance safety
    (Annals of Nuclear Energy, 2012-06) Ibrahim, Y.V.; Odoi, H.C.; Njinga, R.L.; Adeleye, M.O.; Jonah, S.A.
    A Monte Carlo simulation of additional safety rods for NIRR-1 HEU and LEU cores was carried out using the MCNP5 version 1.6 code. Two additional safety control rods having the same material composition as the main central control rod except for the surface area were studied. The following reactor core physics parameters were determined; neutron flux distribution within the core with safety rods withdrawn, control rod (CR) worth for each rod, core excess reactivity, shutdown margin and some kinetic parameters. Results obtained indicate that it would be feasible to include two additional safety control rods to improve safety level of the MNSR with little or no modification to the existing core configuration. © 2012 Elsevier Ltd. All rights reserved.
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    Thermal neutron reflection method for measurement of total hydrogen contents in Ghanaian petroleum products.
    (2001-11-01) Akaho, E.H.K.; Jonah, S.A.; Dagadu, C.P.K.; Maakuu, B.T.; Adu, P.S.; Anim-Sarpong, S.; Kyere, A.W.K.
    A fast and non-destructive technique based on thermal neutron reflection was used to determine total hydrogen contents in petroleum products available in Ghana. A source holder consisting of an 241Am-Be neutron source and 3He neutron probe designed for detection of liquid levels was used to measure reflection parameter as a function of hydrogen contents in liquid hydrocarbons which served as standards. The measured data were fitted to two linear equations for two different geometrical arrangements. The trend of data was found to be consistent with theoretical analysis based on neutron moderation. The calibration lines were used to determine hydrogen contents in 10 petroleum products. The results agree favourably with those obtained using different experimental set-ups with other neutron sources and probes. The technique was also used to determine the quality of diluted petrol with aviation fuel.