Evaluation of the annual effective dose due to the external irradiation induced by using NORM added consumer products

Abstract

This study aims to evaluate the annual effective dose from a sleeping mattress containing naturally occurring radioactive material (NORM). In this study, the dose rate was measured using two different portable radiation detectors, namely the Geiger Müller (GM) tube and portable high-purity germanium (HPGe) detector; the annual effective dose was calculated using annualized usage of the products, and the equivalent does was evaluated via Monte Carlo (MC) simulation and using the model of the human body, which is known as a computational human phantom. The dose rate of the product, excluding background radiation at the shielded room, was measured as 0.22 and 0.13 μSv/h in the GM-tube and portable HPGe, respectively. Assuming that the sleeping mattress was used for an average sleeping of 8 h/day, the annual effective dose was calculated as 0.64 and 0.38 mSv/y using the GM-tube and portable HPGe detectors, respectively. Also, the annual effective dose calculated using MC simulation and radioactivity values from the nuclides analysis was 0.13 mSv/y. The annual effective dose calculated using the two different portable detectors and MC simulation is less than the annual effective dose limit for the general public, which is set at 1 mSv/y. This technique could be used not only for the safety regulation for products containing NORM but also for the accurate evaluation of the effective dose for radiation workers in the diverse radiation field.