Radioenvironmental survey of the Megalopolis power plants fly ash deposits

Publisher Summary The Megalopolis lignite field basin is located in the centre of the Peloponnesus peninsula in southern Greece. The lignite fired power plants in operation in this region have a total capacity of 850 MW and produce over 2 million metric tons of fly ash annually; this is primarily disposed of in deposits located mainly at exhausted lignite mines. The disposed fly ash has a 226Ra content of about 1000 Bq kg −1 . It is concluded that, from the natural radioactivity point of view, the exhausted lignite mines at Megalopolis, in the way that they are restored by fly ash deposition, do not significantly differ from the rest of the Megalopolis lignite field basin, despite the fact that most of the underground soil layers consist of fly ash with high 226 Ra content. A possible explanation for this might be that the radon emanation power from the fly ash layer is as low as the radon emanation power from natural soil due to a fly ash crystallization process in the power plant furnace.