SPM SCIENCE NUCLEAR ENERGY
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Radioactive substances have many uses including thickness control of materials like paper and foil, food preservation through irradiation, medical diagnosis using radioactive tracers, leak detection of underground pipes, radioactive dating of ancient materials, cancer treatment through radiotherapy, sterilization of medical equipment, and agricultural applications like using tracers to determine plant nutrient needs and inducing mutations to develop hardier seed varieties.
SPM SCIENCE NUCLEAR ENERGY
- 1. CHAPTER 6: NUCLEAR ENERGY 6.3. USES OF RADIOACTIVE SUBSTANCES
- 2. 5 main categories of the uses radioactive substances In industry In food technology In archaeology In medicine In agriculture
- 3. 6.3.1 Controlling the thickness of substances To control the thickness of paper, aluminium foil and other sheets during the manufacturing process. The amount of radioactivity which passes through a material can be detected and used to control the thickness of the material.
- 5. In paper mills, the thickness of the paper can be controlled by measuring how much beta radiation passes through the paper to a Geiger counter. The radioactive source is a b emitter (beta emitter). This has the right amount of penetration to be useful for thickness control of aluminium foil. The counter controls the pressure of the rollers to give the correct thickness. With paper, or plastic, or aluminium foil, beta rays are used, because it will not go through the paper.
- 6. 6.3.2 Food preservation Ready made food must be preserved from deterioration due to bacteria and so on before being shipped to consumers. Irradiate the food with gamma radiation
- 7. Even after it has been packaged, gamma rays can be used to kill bacteria, mould and insects in food. This process prolongs the shelf-life of the food, but sometimes changes the taste.
- 8. As tracers in medical diagnosis 6.3.3 Radioactive tracer Tracers: bone scans, kidney scans, and others. Radioactive isotopes and radioactively labeled molecules are used as tracers to identify abnormal bodily processes. This is possible because some natural elements tend to concentrate in certain parts of the body: iodine in the thyroid, phosphorus in the bones, potassium in the muscles. When a patient is injected with a radioactive element, a special camera can take pictures of the internal workings of the organ.
- 10. To detect leakage of liquids, such as water and oil, from underground pipes A little radioactive substance is added to the liquid at the source Using a radiation detector , the level of radiation at the surface is monitored The radiation rate will be high at the point where there is leakage
- 11. 6.3.4 Radioactive dating Animals and plants have a known proportion of Carbon-14 (a radioisotope of Carbon) in their tissues. When they die they stop taking Carbon in, then the amount of Carbon-14 goes down at a known rate (Carbon-14 has a half-life of 5700 years). The age of the ancient organic materials can be found by measuring the amount of Carbon- 14 that is left.
- 12. The radioactive source would be a g emitter (gamma emitter). g radiation can penetrate through the ground (and metal pipe) and be detected at the surface. Alpha and beta radiation would not penetrate through to the surface. The g emitter would have a short half-life to minimize the possible danger to living organisms near to the pipe. A short half-life means that the amount of radioactivity being emitted from the pipe would decrease quickly.
- 13. Radiations can also be used to kill cancerous cells in patient’s body Called as (Radiotheraphy) Usually beta ray are used Gamma rays are also used to irradiate the affected region of a patient from the outside 6.3.5 Destroying cancer cells (Medicine)
- 14. As sterilisers: Gamma rays are also used to sterilise hospital equipment, especially plastic syringes, surgical gloves and so on that would be damaged if heated.
- 15. 6.3.6 Agriculture ASTRACERS: phosphorus-32 is a radioisotope that emits beta particles This is used partially in the production of fertilisers The fertiliser will be absorbed by the plants and then transported to various parts of the plants By detecting the radiation from this radioactive phophorus from outside the plant, agriculturists can determine how much phosphorus is needed by various parts of the plant
- 16. For genetic modification: Gamma radiation can cause modifications to the gene of cells. This is known as mutation To produce better quality seeds which are more resistant to pests, changes in weather and so on