Estimation of the activation of local reactor shielding concretes

Abstract

Many elements in reactor shielding concrete become radioactive due to interaction with neutrons during the operation of a nuclear reactor. These radioactive elements will build up over the time due to ( n, γ) reaction and contribute to the radioactive waste during decommissioning of the reactor, they will increase the dose from the inner part of the biological shielding (concrete) surrounding a nuclear reactor during maintenance works within reactor containment, and their effect should be taken in the calculations of the dose behind the concrete shield. Six mixtures of local ordinary and special shielding concretes have been investigated in this study. Their compositions were determined using X-ray diffraction and neutron activation analysis using the Syrian Miniature Neutron Source Reactor (MNSR) and consequently the dose rates. Based on the results of the analyses and comparing to the published limits in the references, it has been found that 60Co, 152Eu, 154Eu and 134Cs will be the most effective radioactive nuclides existing in the local concrete, but Dolomite aggregates contain the minimum limits of them and it has been found that Fe, Mg, and Ti the major elements existing in the local concrete.