To assess internal exposure due to inhalation of radioactive aerosols and gases generated in high-energy accelerator facilities, physicochemical properties such as particle size of aerosols and chemical form of gases are important information. We measured the particle size distribution and concentration of aerosols to coexist with radionuclide formed by high-energy radiation emission in the target room of LINAC and estimated the long term variation of particle size and concentration of radioactive aerosols in high-energy acceleration facilities by a simple model. The estimated concentration and size distribution of aerosols were relatively consistent with the experimental results. We also calculated the time variation of the particle size distribution of radioactive chlorine aerosols from the measured particle size of non-radioactive aerosols. These results suggest that the diameter of aerosols generated at accelerator facilities grow to about 500 nanometers under conditions of continuous operation.
Cosmetics claiming hormesis effects are available through Internet. Although the hormesis effect is explained in each product of cosmetics, there is no explanation about the radiation source. The existence of the progeny nuclides of Th and U series (RI) was comfirmed by the γ-ray spectroscopy using a HPGe detector. The highest radioactivity densities were 68Bq/g of the Th-series included in the hormesis powder. Because the particles containing RI were of the size of 1-10 micrometer by observing and analyzing SEM-EDX, there is a risk of inhaling the powder to the deep into the lungs. Furthermore, as about 1% RI was dissolved in water, the uptake of the RI to the body would be possible. The highest value of the evaluation of uniform radiation exposure to some organs by the continuous usage for 10 years was 5.5mSv/y of the hormesis powder inhalation to the lung. Furthermore, the calculated quantity of the radioactivity of progeny of 222Rn deposited in the body after continuous use of the hormesis cream every day for one year becomes 24Bq. The possibility of accumulation of the radioactivity in the body from the hormesis cosmetics cannot be denied. The addition of the radioisotope to cosmetics is prohibited in some EU countries by the regulation. It's proposed in this paper that the legitimacy of the addition of the radioisotope should be seriously re-examined.
We examined the effects of a diuretic, isotonic saline, and chelating agent, catechol-3, 6-bis (methyleiminodiacetic acid) (CBMIDA), on the excretion and prevention of renal damage of depleted uranium (DU). Male Wistar rats (8 weeks old) divided into seven groups were preinjected intraperitoneally with 4mg/kg DU and then the six groups were injected intraperitoneally with a diuretic, a diuretic plus isotonic saline, 480mg/kg or 720mg/kg CBMIDA alone, or 480mg/kg or 720mg/kg CBMIDA plus a diuretic and saline for three days, and the one group was as the control (no treatment). The rats were killed 6 days after DU injection. The results indicated that the diuretic alone and the diuretic with isotonic saline were not effective in removing uranium from the body and protecting the renal function, and also did not help to increase significantly the effects of CBMIDA.
Vietnam was one of the earliest countries, who applied ionizing radiation in medicine, since 1923, Dr. Marie Curie had supplied radium sources to Hanoi cancer hospital for radiotherapy. However, we did not give sufficient attention to radiation protection involving, e. g. technology, legislation, until 1980s. Recently with the strong support from International Atomic Energy Agency (IAEA) and Vietnam government nuclear technology has been strongly and widely developed in different branches and radiation protection situation in Vietnam has been improved step by step. Strategy for Peaceful Utilization of Atomic Energy up to 2020 approved by the prime minister on January 3th, 2006 confirms that nuclear power plant will be put in operation by 2020. To ensure the implementation of the strategy, the first priority should be given to radiation protection and nuclear safety. This paper presents shortly some activities of radiation safety in Vietnam. The requirements for developing this field in Vietnam are also discussed.
A sampling system was designed to rapidly detect an unexpected release of 129I during a weekly batch-sampling of a stack gas. The system consisted mainly of a sampling unit and an iodine monitor with an NaI(T1) scintillation detector. A relationship between in situ count rate of the monitor and 129I activity collected in the sampling unit was derived from several sets of data obtained with the system at the Tokai reprocessing plant. The system and relationship allowed us to estimate the amount of 129I release at an arbitrary time during the batch-sampling. A different iodine monitor with a Ge detector was also tested to overcome a difficulty in selective measurement of 129I with the NaI(T1) scintillation detector in the presence of 85Kr in the target gas. The test demonstrated a feasibility of the real-time, 85Kr-interference-free monitoring of atmospheric 129I release.