Study of the Chernobyl fallout in 30-km zone after construction of the Confinement

Abstract

Radionuclides behavior on strongly contaminated territories of 30-km Chernobyl zone was studied. Samples in two layers for determination of the possible impact of works on construction of the "Shelter" object were collected. As a result, abnormal A(241Am)/A(137Cs) ratio was observed on a number of samples. The value varies between 0.004 to 0.30. Activity of 94Nb and 60Co was observed on the number of samples. Problems with spectrometer calibration appeared, when samples from Chernobyl zone with low activity were used. Calibration on efficiency of γ-rays registration become complicated in low energy interval because of different density of the investigated samples. To solve this problem methodological researches were performed, taking into account efficiency variation of γ-rays registration in samples with big volume. For this purpose, activities of 137Cs and γ-rays with 661 keV energy were compared. 137Cs activity was defined from appearance of Kx-emission of Ba (36 keV).

Keywords

• radionuclides
• migration
• americium
• niobium
• cobalt.