Scaling factors for activated corrosion products in low-level-wastes from power reactors

Abstract

Long-lived isotopes of corrosion products are very important for the disposal of low-level radioactive wastes. These nuclides serve for risk calculations of accidents. Their determination needs the radiochemical separation from high active main nuclides. Supervision of waste vessels is done by direct non-destructive γ-spectrometry of the key nuclide⁶⁰Co for corrosion products. The activity ratios of the long-lived nuclides to the key nuclides are called scaling factors. We have determined such factors radiochemically in evaporation residues of power water and cooling water. They are used for activity calculations of long-lived nuclides in the waste vessels. In case of⁵⁹Ni the obtained scaling factor was compared with a literature value and values calculated on the basis of nuclear data. Our value was in a good agreement with the calculated one. Due to the fact, that we have used low-level measurement techniques, we could perform the necessary chemical separations in a laboratory not exceeding the 10-fold free-level limit.