1.1 BACKGROUND OF THE STUDY
The central characteristics of a nuclear reactor are its controllable, self-sustaining fission chain reaction which releases useful neutrons and energy (CNSC, 2003). This controllability was shown to be greatly achieved via control rod motion and as such the knowledge of a reactor‟s response to specific control rod motions is essential for the safety, efficiency, operation and durability of a nuclear research reactor (Souza and Mesquita, 2010).
Research reactors are nuclear reactors that are majorly neutron source. Also called non-power reactors, the major contrasts between them and power reactors are that power reactors are utilized for electricity production, heat generation, or maritime propulsion while the neutrons produced by a research reactor are used for several purpose which include scattering, non-destructive testing, analysis and testing of materials, production of radioisotopes, research and public outreach and education. Research reactors comprise a wide range of civil and commercial nuclear reactors which are generally not used for power generation (Ahmed et al, 2006). Over 270 research reactors are currently operating in more than 50 countries (Parrish and Nicholas, 2007). Research reactors are separated into various classes of which one of such is the Miniature Neutron Source Reactor (MNSR) which the Nigeria Research Reactor-1 (NIRR-1) fall under.
The Nigeria Research Reactor-1 (NIRR-1), is the 8th commercial Miniature Neutron Source Reactor (MNSR) designed by China Institute of Atomic Energy (CIAE). First criticality was achieved on 03 February 2004. It is particularly designed for use in neutron activation analysis (NAA) and limited radioisotope production.