In most ores, rocks and soils the radioactive isotopes of the three natural decay series (238U, 232Th and 235U) and 40K are present in small concentrations. But in some naturally occurring radioactive material (NORM), such as zircon sands, the radioactivity concentrations are significantly higher than the world average noticed in soils and rocks. The typical activity concentrations of 238U and 232Th in zircon sands are 3000 and 600 Bq per kg, respectively. Ceramic industry is one of the major consumer of zircon sands. Therefore the ceramic factories and ceramic materials are receiving increased attention from regulatory agencies. This work deals with the occupational exposure to natural ionising radiation in workplaces of ceramic factories. During 2004 samples were collected at several ceramic factories from the Emilia-Romagna Region (Italy); factories were sampled to provide representative productions. The total effective dose to workers has been calculated by summing the effective dose from external sources and the committed effective dose for internal exposure. Radiation dose rate measurements were made using a portable survey meter (Automess 6150 AD2). Radon levels were monitored by performing radon concentration measurements of the working areas by either passive and active devices. Short-term radon screening measurements were performed using an ionisation chamber radon monitor (AlphaGUARD PQ2000). For long-term measurements, electret ionisation chambers were used (E-PERM System). An air sampling pump was used to determine worker exposure to total dust concentration. The radioactivity concentrations of dusts were estimated indirectly by determining the radioactivity concentrations of raw materials employed in the ceramic production. Activity concentrations were measured by a HPGe gamma-spectrometer connected to a multi-channel analyser. The estimated effective doses received by the workers, generally, are lower than 1 mSv per year. Radiation exposure is higher for workers employed in the zircon sands milling and in the ceramic glaze preparation areas.
Occupational exposure to ionising radiation in ceramic industry
RIGHI, SERENA;ROSSI, PIER LUCA;BRUZZI, LUIGI
2005
Abstract
In most ores, rocks and soils the radioactive isotopes of the three natural decay series (238U, 232Th and 235U) and 40K are present in small concentrations. But in some naturally occurring radioactive material (NORM), such as zircon sands, the radioactivity concentrations are significantly higher than the world average noticed in soils and rocks. The typical activity concentrations of 238U and 232Th in zircon sands are 3000 and 600 Bq per kg, respectively. Ceramic industry is one of the major consumer of zircon sands. Therefore the ceramic factories and ceramic materials are receiving increased attention from regulatory agencies. This work deals with the occupational exposure to natural ionising radiation in workplaces of ceramic factories. During 2004 samples were collected at several ceramic factories from the Emilia-Romagna Region (Italy); factories were sampled to provide representative productions. The total effective dose to workers has been calculated by summing the effective dose from external sources and the committed effective dose for internal exposure. Radiation dose rate measurements were made using a portable survey meter (Automess 6150 AD2). Radon levels were monitored by performing radon concentration measurements of the working areas by either passive and active devices. Short-term radon screening measurements were performed using an ionisation chamber radon monitor (AlphaGUARD PQ2000). For long-term measurements, electret ionisation chambers were used (E-PERM System). An air sampling pump was used to determine worker exposure to total dust concentration. The radioactivity concentrations of dusts were estimated indirectly by determining the radioactivity concentrations of raw materials employed in the ceramic production. Activity concentrations were measured by a HPGe gamma-spectrometer connected to a multi-channel analyser. The estimated effective doses received by the workers, generally, are lower than 1 mSv per year. Radiation exposure is higher for workers employed in the zircon sands milling and in the ceramic glaze preparation areas.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
