Nuclear Radioactivity: May 2011

Saturday 7 May 2011

Nuclear fission and fusion and radioactivity

Done by: Joshua Ong (11) 2P2

Nuclear fission and fusion

—Nuclear fission: the splitting of uranium or plutonium atom to release energy.

—Nuclear fusion: A nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy.

Nuclear radioactivity

—Particulate and electromagnetic radiation emitted from atomic nuclei in various nuclear processes.

—Nuclear power generation does emit relatively low amounts of carbon dioxide (CO2). The emissions of green house gases and therefore the contribution of nuclear power plants to global warming is therefore relatively little.

—This technology is readily available, it does not have to be developed first.

—It is possible to generate a high amount of electrical energy in one single plant.

Disadvantages of Nuclear plants

—The waste from nuclear energy is extremely dangerous and it has to be carefully looked after for several thousand years.

—The consequences of an accident would be absolutely devastating both for human being as for the nature.

—The energy source for nuclear energy is Uranium. Uranium is a scarce resource, its supply is estimated to last only for the next 30 to 60 years depending on the actual demand.

—The time frame needed for formalities, planning and building of a new nuclear power generation plant is in the range of 20 to 30 years

How does radiation transmit?

—Energetic particles or energy or waves travel through a medium or space.

How is radiation harmful to humans?

—Radiation consists of several types of subatomic particles, principally those called gamma rays, neutrons, electrons, and alpha particles, that shoot through space at very high speeds, something like 100,000 miles per second. They can easily penetrate deep inside the human body, damaging some of the biological cells of which the body is composed. This damage can cause a fatal cancer to develop, or if it occurs in reproductive cells, it can cause genetic defects in later generations of offspring.

How does radiation affect the environment?

—Positive: Natural radiation showers down from the distant reaches of the cosmos and continuously radiates from the rocks, soil, and water on the Earth itself.

—Negative: can result in pollution to the environment, killing plants and nature.

—In conclusion: Most radiation originates from earthly sources, and the real effects of radiation pollution depend on the type of radiation and the amount of energy emitted. High doses of radiation can kill, but low doses can actually benefit both plants and animals.

Half- life

—Half-life is the period of time it takes for a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms (radioactive decay), but it may apply to any quantity which follows a set-rate decay.

Biological half- life

—Biological half- life or elimination half-life is the time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiological activity. In a medical context, half-life may also describe the time it takes for the blood plasma concentration of a substance to halve ("plasma half-life") its steady-state. The relationship between the biological and plasma half-lives of a substance can be complex, due to factors including accumulation in tissues, active metabolites, and receptor interactions.

Example of half- life

—For example, the biological half-life of water in a human is about 7 to 14 days, though this can be altered by behaviour. The biological half-life of cesium in humans is between one and four months. This can be shortened by feeding the person Prussian blue, which acts as a solid ion exchanger which absorbs the cesium while releasing potassium ions.