\nNuclear power stations produce electricity, which of course is extremely useful. However, they also make radioactive waste. When items have no further use and have radioactivity above certain levels, they are known as radioactive waste....\nNuclear power stations produce electricity, which of course is extremely useful. However, they also make radioactive waste. When items have no further use and have radioactivity above certain levels, they are known as radioactive waste. Radioactive waste can come from a range of activities, including generating electricity from nuclear power stations, treating medical illnesses and conducting research. Did you know that radioactive waste can be harmful to us? Either by irradiation or contamination. We’re going to look at these two in this video. Irradiation is when a person or object is exposed to radiation without coming into direct contact with the radioactive source. The person doesn’t make direct contact with the radioactive barrel, but since irradiation can happen at a distance, the person is still at risk. The damage to the person only happens whilst the person is in the area of the radioactive waste. Therefore the person is only exposed to radiation for a short time, and so receives a low dose of radiation. Irradiation can sometimes be useful, particularly during cancer treatment. People are irradiated in an attempt to remove cancerous cells from their body. Irradiation is also used to sterilise surgical equipment, or to remove bacteria from fruit in supermarkets. The objects don’t become radioactive themselves, and so are safe for use or consumption. Contamination is when a person actually comes into contact with radioactive wastes. The person takes the radioactive source away with them, and so are exposed for a longer period of time and consequently have a higher dose which can lead to more damage. Contamination can happen in a variety of ways: from picking up a source, to breathing it, to ingesting it. Contamination is used in medicine, by injecting radioactive tracers into the body to see possible blockages. Radioactive tracers are also used to find leaks in water pipes. Radioactive waste can remain hazardous for a very short or a very long period of time, depending upon the different half lives. ‘Half lives’ mean the level of hazard of the radioactive waste reduces with time. If we start off with a kilogram of radioactive waste that has a half life of 100 years, after 100 years we will have 500g of radioactive waste. After another 100 years there will be 250g of it and so on. Eventually the amount of radiation will decrease until it reaches the same level as background radiation. For medical contamination that involves injecting radioactive sources, isotopes that have very short half-lives are selected. The half life is long enough that they stay active for detection to be done. But short enough that they reduce to low-risk levels as quickly as possible. Background radiation comes from artificial and natural sources around us, that we experience daily. It is low in magnitude so it isn’t harmful. However, for some radioactive wastes to reach this low background level it may take several thousand years. So just how harmful is radioactive waste? The answer depends on the half life of the waste and whether a person is irradiated or contaminated. It’s like asking, how long is a piece of string? We’ve now learned about the differences between irradiation and contamination.\n
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