الفهرس 
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Abstract
Monte Carlo (MCNP5) comparative study was accomplished to compare the neutronic behavior of nuclear reactors when controlled by Boron, Silver, or lutetium control rods. MCNP5 model of the WWER reactors benchmark experimental reactor LR-0 reactor was used in this present study. Many neutronic parameters were tallied, including neutron flux in fuel and moderator, neutron energy spectrum, radial distribution of neutron flux, fission rate, and power, neutron absorption density and spectrum in control rods, required amount of control rods needed to obtain criticality, and power peaking factor. In addition; burn up behavior of the different models. In one step, all control rods had equal atom density to that of natural Boron (but their inserted lengths were different) to compare their neutronic influence per atom. In a second step, the control rods were all fully inserted inside the core; with Silver at natural density while Boron at less than natural density. It was found that all the three materials could control the reactor reactivity, but Ag and Lu needed much greater density than natural. Boron provided continual power distribution in the reactor core. Epithermal and fast Neutron fluxes in fuel increased when Silver was used as the control material in reactor.