The effect of air ventilation system operation on radon concentrations in transfer channel-interim storage for spent fuel (TC-ISSF)

Most people spend their time indoors at work, where levels of harmful pollutants are often much higher than when staying at home. Radon (222Rn) is a major source of ionizing radiation. The purpose of this study was to determine the impact of the air ventilation system on the level of Radon concentration that contributes to the effective dose for workers. Long-term exposure to radon and radioactive materials can increase the risk of lung cancer. Radon concentrations are a complex function of different parameters and can change significantly over certain time intervals. Therefore, the mean value of the long-term (1 year) test is usually used in radon assessment studies. However, the short-term (1 day) test results can be used for initial screening or to perform follow-up tests when the long-term test results exceed the threshold value. Measurements were conducted on May 11 - 13, 2022, in this case representing the indoor measurements. Radon measurements were carried out with indoor air ventilation parameters using two ventilation system operating modes (VAC) when OFF and VAC when ON. From the results of Radon measurements, the effect of VAC when not operated on Radon concentrations is very large, with a graph that tends to increase to 152 Bq/m3, while VAC air ventilation has a very minor effect on Radon concentrations when it is operating and tends to drop to about 3 Bq/m3. The results of the estimated effective dose to workers due to the influence of radon concentrations ranged from 0.02 to 1.09 mSv/year. These results indicate that the concentration of radon in the pool room at the Transfer Channel Interim Storage for Spent Fuel (TC-ISSF) is below 300 Bq/m3, so it is still safe to work. To reduce the risk of lung cancer due to radon concentrations, the most likely effort is to regulate the ventilation system.