Determination of long-lived activation products in Triga Mark II research reactor concrete shield - Abs20

To determine neutron activation inside the TRIGA research reactor concrete body a special sample-holder for irradiation inside the horizontal channel penetrating the reactor body was developed and tested. In this paper the description of the sample-holder, experiment conditions and results of long-lived activation measurements are given. Long-lived neutron-induced gamma-ray-emitting radioactive nuclides in the samples of actual reactor concrete were measured with HPGe detector. The most active long-lived radioactive nuclides in barytes concrete samples were found to be ⁶⁰Co, ¹⁵²Eu and ¹³³Ba and in ordinary concrete samples ⁶⁰Co and ¹⁵²Eu. Measured activity density of all nuclides was found to decrease almost linearly with depth in logarithmic scale. (authors)