The reactivity worth measurement system for control rods of the TRIGA MARK-II research reactor of Bangladesh has been design and developed. The theory of the kinetic technique of measuring reactivity has been used by ...The reactivity worth measurement system for control rods of the TRIGA MARK-II research reactor of Bangladesh has been design and developed. The theory of the kinetic technique of measuring reactivity has been used by this measurement system. The system comprises of indigenous hardware and software for online acquisition of neutron flux signals from reactor console and then computes the reactivity worth accordingly. Here for the TRIGA MARK-II research reactor, the reactivity measurement system was implemented with a dedicated circuit assembly and a conventional personal computer. A high-level Visual Basic real-time programming has been developed for data acquisition, reactivity calculation, online display (numerically as well as graphically), saving data, etc. To measure reactivity worth of TRIGA reactor control rods the rod drop experimental technique has been adopted. The results of tests experiments, carried out with the rod drop method for measuring various reactivity worth of control rods have been presented in the paper. A comparison between this results with the results using period method and that of computation method, demonstrated that the response of this reactivity measurement system is fast enough to monitor and measure the safety-related reactivity and power excursions in the reactor.展开更多
Spinel-type Mg0.35Cu0.20Zn0.45Fe1.94O4 ferrites were synthesized by using the solid-state reaction technique. The XRD patterns of the sintered samples indicated the formation of single-phase cubic spinel structure. Th...Spinel-type Mg0.35Cu0.20Zn0.45Fe1.94O4 ferrites were synthesized by using the solid-state reaction technique. The XRD patterns of the sintered samples indicated the formation of single-phase cubic spinel structure. The apparent density of the sample is found to increase whereas porosity decreases with the increase in sintering time. The grain growth of the samples is enhanced with the increase in sintering time which is attributed to the liquid phase due to CuO during sintering. The initial permeability of the ferrite is found to increase with the increase in sintering time but the resonance frequency shifts towards the lower frequency. This increase in permeability is correlated to the increase of density and the grain size of the sample. The resistivity of the samples decreases with 103/T ensuring the semiconducting nature of the samples. Room temperature DC resistivity and activation energy of the samples decrease what is attributed to the increased Fe2+ ions content with the increase in sintering time. The dielectric constant (e￠) of the samples decreases with increasing frequency whereas e￠ increases as the temperature increases exhibiting normal dielectric behaviour of the magnetic semiconductor ferrite. The observed variation of electrical and dielectric properties is explained on the basis of Fe2+/Fe3+ ionic concentration as well as the electronic hopping frequency between Fe3+ and Fe2+ ions in the present ferrite sample.展开更多
文摘The reactivity worth measurement system for control rods of the TRIGA MARK-II research reactor of Bangladesh has been design and developed. The theory of the kinetic technique of measuring reactivity has been used by this measurement system. The system comprises of indigenous hardware and software for online acquisition of neutron flux signals from reactor console and then computes the reactivity worth accordingly. Here for the TRIGA MARK-II research reactor, the reactivity measurement system was implemented with a dedicated circuit assembly and a conventional personal computer. A high-level Visual Basic real-time programming has been developed for data acquisition, reactivity calculation, online display (numerically as well as graphically), saving data, etc. To measure reactivity worth of TRIGA reactor control rods the rod drop experimental technique has been adopted. The results of tests experiments, carried out with the rod drop method for measuring various reactivity worth of control rods have been presented in the paper. A comparison between this results with the results using period method and that of computation method, demonstrated that the response of this reactivity measurement system is fast enough to monitor and measure the safety-related reactivity and power excursions in the reactor.
文摘Spinel-type Mg0.35Cu0.20Zn0.45Fe1.94O4 ferrites were synthesized by using the solid-state reaction technique. The XRD patterns of the sintered samples indicated the formation of single-phase cubic spinel structure. The apparent density of the sample is found to increase whereas porosity decreases with the increase in sintering time. The grain growth of the samples is enhanced with the increase in sintering time which is attributed to the liquid phase due to CuO during sintering. The initial permeability of the ferrite is found to increase with the increase in sintering time but the resonance frequency shifts towards the lower frequency. This increase in permeability is correlated to the increase of density and the grain size of the sample. The resistivity of the samples decreases with 103/T ensuring the semiconducting nature of the samples. Room temperature DC resistivity and activation energy of the samples decrease what is attributed to the increased Fe2+ ions content with the increase in sintering time. The dielectric constant (e￠) of the samples decreases with increasing frequency whereas e￠ increases as the temperature increases exhibiting normal dielectric behaviour of the magnetic semiconductor ferrite. The observed variation of electrical and dielectric properties is explained on the basis of Fe2+/Fe3+ ionic concentration as well as the electronic hopping frequency between Fe3+ and Fe2+ ions in the present ferrite sample.
