Nuclear Waste Management

Nuclear Waste Management

Nuclear energy harnesses the energy released during the splitting or fusing of atomic nuclei. This heat energy is most often used to convert water to steam, turning turbines, and generating electricity.

However, nuclear energy also has many disadvantages. An event that demonstrated this was the terrible incident at Chernobyl'. Here on April 26,

1986, one of the reactors of a nuclear power plant went out of control and caused the world's worst known reactor disaster to date. An experiment that was not properly supervised was conducted with the water-cooling system turned off.

This led to the uncontrolled reaction, which in turn caused a steam explosion.

The reactor's protective covering was blown off, and approximately 100 million curies of radionuclides were released into the atmosphere. Some of the radiation spread across northern Europe and into Great Britain. Soviet statements indicated that 31 people died because of the accident, but the number of radiation-caused deaths is still unknown.

The same deadly radiation that was present in this explosion is also present in spent fuels. This presents special problems in the handling, storage, and disposal of the depleted uranium. When nuclear fuel is first loaded into a reactor, 238U and 235U are present. When in the reactor, the 235U is gradually depleted and gives rise to fission products, generally, cesium (137Cs) and strontium (90Sr). These waste materials are very unstable and have to undergo radioactive disintegration before they can be transformed into stable isotopes.

Each radioactive isotope in this waste material decays at its characteristic rate. A half-life can be less than a second or can be thousands of years long.

The isotopes also emit characteristic radiation: it can be electromagnetic (X- ray or gamma radiation) or it can consist of particles (alpha, beta, or neutron radiation). Exposure to large doses of ionizing radiation causes characteristic patterns of injury. Doses are measured in rads (1 rad is equal to an amount of radiation that releases 100 ergs of energy per gram of matter). Doses of more than 4000 rads severely damage the human vascular system, causing cerebral edema

(excess fluid), which leads to extreme shock and neurological disturba...

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...relatively low in cost compared to storage in a pool of water and can be moved around if necessary. Another way to dispose of radioactive wastes is through geologic isolation. This is the disposal of wastes deep within the crust of the earth. This form of disposal is attractive because it appears that wastes can be safely isolated from the biosphere for thousands of years or longer. Disposal in mined vaults does not require the use of advanced technologies, rather the application of what we know today. It is possible to locate mineral, rock, or other bodies beneath the surface of the earth that will not be subject to groundwater intrusion. A preferred place would be at least

1,500 feet below the earth's crust, so that it may avoid erosion for the specified period of time. None of the preceding methods offers a complete solution to the problem of nuclear waste. They only bury it, temporarily shoving it out of our current view for a latter generation to solve. Maybe the future inhabitants of this world will find a solution to this problem, for as we chose to continue the use of nuclear power, more and more waste will be accumulated, emitting deadly radiation long after we pass away.