【Discussion Thread 54】Should media with low radioactivity be considered highly hazardous and not allow for any trace leaks?

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This post was last edited by kareale88 on 2019-4-29 08:53 [Discussion Thread 54] Should media with low radioactivity be considered highly hazardous and not allow any trace leaks? At the same time, what is the limit that is harmful to the human body? ............................................................................................................................................ The millisievert is one of the basic units of radiation dose. The main unit of radiation dose is the sievert (Sv), but since this is a very large unit, millisieverts (mSv) are usually used, with 1 mSv equal to 0.001 Sv. There is also the microsievert (μSv), with 1 μSv = 0.001 mSv. For the average person, such as those who are not exposed to radioactive substances in their daily work, the normal annual exposure due to environmental background radiation (mainly radon in the air) is 1–2 millisieverts per year. High levels of radiation are harmful to the human body, but it is still uncertain whether low doses of radiation are beneficial or not. With the development of human civilization and advances in science, the issue of radiation is receiving increasing attention. What about cosmic rays, radiation from nuclear power plants, radiation from electrical appliances, radiation from mobile phones? There’s also radioactive substances in soil, water, and food; even potassium in the human body can emit radiation, and so on. Radiation from various sources seems to form an invisible \"radiation web\" that tightly encircles humanity. But people can’t avoid eating, drinking, using things, or enjoying life just because they are afraid of radiation. Therefore, determining the dose of radiation at which it becomes harmful to human health is a question that people are eager to know, as well as a challenge that scientists around the world strive to solve. When it comes to radiation, what people might think of first is nuclear radiation; the atomic bombings of Hiroshima and Nagasaki caused hundreds of thousands of deaths ； The Chernobyl nuclear disaster also resulted in a tragedy that shocked the world. In daily life, what people are most concerned about is the radiation from electrical appliances – such as computers, copiers, telephones, televisions, and mobile phones – and whether they can cause harm to users 　　In fact, the greatest radiation hazards faced by humans come from nature, that is, from the sky, the ground, and the environment surrounding people’s daily lives. According to research by American scientists, the average person in the United States is exposed to 350 millirems of radiation from natural sources per year; of this amount, 40 millirems come from cosmic rays alone. 　　John Pois, director of the Maryland Institute of International Epidemiology, said, “What we eat, drink, and breathe is all low in radiation.” Fred Mantler, head of the Department of Radiology at the University of New Mexico School of Medicine, also said that when examining people affected by radiation, it is found that about 2/3 of them are affected by natural background radiation, while 15% are affected by medical equipment used by doctors. The impact caused by other factors is very small; the proportion of radiation from nuclear reactors and research institutions is less than a few percent. The hazards of electromagnetic radiation do exist. I remember reading a report once about a British study that followed people for 10 years, and it found that households that used microwave ovens more frequently had a higher incidence of cancer. The safe radiation distance for a microwave oven is 6 meters, and it’s impossible for ordinary households to maintain such a distance. It is a fact that electromagnetic radiation is difficult to protect against. There are also risks associated with mobile phone radiation. Television sets emit more electronic radiation. Microwave radiation is not equivalent to “cooking”. Infrared radiation is not harmful, but excessive exposure to ultraviolet rays has many dangers. Science is rigorous; it is not a simple equivalence.