Assessing deposition levels of 55Fe, 60Co and 63Ni in the Ignalina NPP environment.

Abstract Two RBMK-1500 reactor units operated in Lithuania in the 1987–2004 period (one of them was stopped for decommissioning in 2004). This study presents a preliminary investigation of surface deposition density levels of 55 Fe and 63 Ni in moss samples collected in the close vicinity of the Ignalina NPP. Non-destructive analysis by the HPGe gamma-spectrometry was followed by radiochemical separation. Radiochemical analysis was based on anion-exchange and extraction chromatography. 55 Fe and 63 Ni activities were measured by liquid scintillation counting (LSC). The results indicate that the deposition values of 55 Fe are generally higher than those of 60 Co and 63 Ni.