This thesis shows the theory for determining the prompt neutron generation time of a nuclear reactor using perturbation theory and a 1/v absorber. Three methods are discussed as experimental procedures based on the reactor design and measurement techniques. This thesis uses the reactivity oscillator in the Idaho State University AGN℗Ơ201 reactor along with boron-10 samples to conduct the experiments. Asymptotic period measurements determine the reactivity worth of the boron-10 samples and are compared to DISNEL simulations. The DISNEL simulations produced generation times varying from 35-56 u.sec depending on the mass of boron added to the reactor. Experimental results were much lower than expected ranging from 6-15 pec. Possible reasons that can be corrected with future research are offered in the results and conclusion section.

The prompt neutron generation time for the Annular Core Research Reactor was experimentally determined using a prompt-period technique. The resultant value of 25.5 [mu]s agreed well with the analytically determined value of 24 [mu]s. The three different methods of reactivity insertion determination yielded ±5% agreement in the experimental values of the prompt neutron generation time. Discrepancies observed in reactivity insertion values determined by the three methods used (transient rod position, relative delayed critical control rod positions, and relative transient rod and control rod positions) were investigated to a limited extent. Rod-shadowing and low power fuel/coolant heat-up were addressed as possible causes of the discrepancies.

The purpose of this experiment was to determine the neutron spectrum of the ISU AGN201 reactor using both computer calculations and physical measurements and then to make comparisons between the results provided by the different methods. The regions of interest in the reactor for neutron spectral measurements were the core center region and the reflector region. Computer simulations performed using MCNP5 and DISNEL were both used to obtain neutron spectra. For the experimental portions, several foils were irradiated in the regions of interest. Each foil had a unique response function and could thus provide independent information that could then be used to obtain a neutron spectrum. Since there were fewer foil activation responses than the desired number of energy groups, the problem was under-determined; therefore, unfolding methods had to be utilized. The modified least-squares method and the maximum entropy method were both used. The MAXED software package was used for the maximum entropy method. MAXED indicated spectra with higher thermal neutron contributions and lower fast neutron contributions than the default MCNP spectra indicated for both the center and reflector regions. The modified least-squares method was very consistent with default MCNP spectra and provided significant uncertainty reduction. DISNEL and MCNP agreed very well for the center spectrum and fairly well for the reflector spectrum. This consistency illustrates that MCNP, with the most current set of cross-sections, and spectral measurement methods using the analysis tools described herein, are equally reliable methods of determining neutron spectra in a reactor of the relative simplicity of the AGN reactor.