Saturday, February 23, 2013

Radioactivity and Radioactive wastes

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               Radioactivity and Radioactive wastes                                Suhaib Khan

            With governments searching for effective sources of energy, nuclear energy has been touted for its effectiveness in comparison to other energy sources. The high building costs and dangerous wastes formed are countered by the relatively low fuel costs and low waste output. However even while being much more efficient than fossil fuels, which constitute about 70% of the energy used in the U.S., Nuclear energy makes up only about 20% due to concerns about safety and the environment. Behind these concerns are the volatile nature of the process and the production of radioactive waste.
            Nuclear power plants use a process called nuclear fission to generate heat and electricity. A commonly used isotope is Uranium-235 which is bombarded with Neutrons and gives off energy. This reaction is represented by the equation; as is shown, neutrons are given off, resulting in a chain reaction. The products of the fission reaction are very unstable and radioactive, as they release beta and gamma rays. Actinides are also left over giving off alpha particles. The radioactivity of these products paired with their extremely long half- lives makes them a problem to dispose, as doing so in the conventional means would prove disastrous for the environment.
            There are four main levels of radioactive wastes: very low (VLLW), low (LLW), intermediate (ILW), and high (HLW). VLLW and LLW are very easily disposable and do not require any shielding or excessive measures. ILW require a little bit more protection, but are still relatively easy to dispose of. HLW, which include the used fuels and fission products, are the ones that pose a serious threat to society. However, the 10,000 m3 annual world output of HLW is very small in comparison to the 200,000 m3 of all the other types of waste combined. These HLW are not disposed of traditionally but are kept at the nuclear reactor sites, mostly in storage ponds.
         Scientists have tried to develop more efficient and less dangerous ways to generate energy, one of which is nuclear fusion. Reflected by the equation
the absence of radioactive isotopes significantly reduces the waste output. Another solution that has been used is to combine the wastes into mixed oxide fuel, which can then be used again, reducing the radioactivity and volume drastically. Many strides have been achieved in making nuclear power a safe alternative energy, and it is quickly becoming the preferred fuel of the future.
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Aiman Moiz

There are about 20 million shipments of radioactive material each year. Radioactive material is used for many things other than the nuclear fuel cycle; in fact, about 5% of the shipments are related to the fuel cycle. Ever since 1961,the International Atomic Energy Agency has regulated all transport and storage of radioactive materials. These regulations in turn have been adopted by most nations as well. Despite the regulations on transportation, the IAEA does not regulate usage as strictly as it does transportation.
   Different fuel cycle labs are located in many areas of  the world and diverse types and sizes of materials must be sent back and forth. A large amount of these materials are similar to those used in corresponding endeavors. In the end, the fuel and waste produced by this industry is radioactive on varying levels.

    According to Ohio State University,The U.S. Department of Transportation specifies regulations for container safety, labeling, routing, and emergency response for the transportation of low-level radioactive waste. The regulations can be found in the "Hazardous Materials" section of Title 49 of the Code of Federal Regulations. These regulations state that radioactive waste must be stored and transported in a strong, tight container. There are different types of containers for different levels of radioactivity, type A for lower level waste and type B for anything that is highly unstable or giving of suffocating amounts of radiation. It must also be labeled either white or yellow and numbered according to how how unstable it is. It's stored similarly, so as to keep from releasing radiation or harming either humans or the environment.



3 comments:

  1. I agree with the first essay on its statement that nuclear energy is a future power source, because of its high energy output. the only problem, obviously, is a storage or reactor leak.

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  2. Radioactive wastes are created by humans as a by-product from nuclear power-generation, research projects, and bomb productions. Failure to correctly dispose nuclear waste can cause mutations, cancers, and loss of plant and animal life. The only means of permanent disposal of radioactive material is to allow it to decay. Because this may take hundreds of years, proper precautions would mean effective storage. Recently, Thorium Molten Salt Reactors were created; the reactors are capable of using less than one hundredth the amounts as the Light Water Reactors the USA uses to generate electricity.

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  3. highly radioactive wastes are extremely dangerous and must be properly disposed of to decrease the chances of diseases harmful to human life. They must be placed under water for shielding and cooled for several years before they can safely be placed for storage.The fuel still retains most of its energy potential and can be recycled and reused as new fuel.

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