Quantitative analysis of gamma-ray emitting radionuclide in reactor pool water of HANARO

The species and concentrations of the radionuclide in the primary coolant of HANARO were analyzed by using the gamma-ray spectroscopy. The full-energy peak efficiency for the volume source was calibrated as a function of the photon energy for an HPGe detector. The primary coolant of HANARO was picked at the primary coolant purification system, and the water at the upper part of the reactor pool was taken at about 20 cm under the pool surface. In the primary coolant, the concentrations of Na-24, Mg-27 and Al-28 were much higher than those of other nuclide, and they were in 1-6 x 106 Bq/liter. Their origins were radiative reactions of aluminium used as the structure material and cladding of the nuclear fuel. The concentrations of Xe-138 and Xe-133 were relatively higher than those of other fission fragments. The source of the fission fragments in the coolant was the surface contamination of the nuclear fuel by uranium. Ar-41, Ce-141, Na-24 and Xe-133 were detected in the water at the upper part of the reactor pool. Na-24 was the main source of the pool top radiation level, and Xe-133 and Ar-41 were the main gaseous radionuclide released through the reactor pool surface