Question

Discuss in detail, one way in which atomic nuclear decay takes place. What is the significance of atomic nuclear decay? Analyze the societal implications of using this process.
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Answer 1

There are three types of nuclear decay: alpha, beta, and gamma. Alpha decay would involve removal of a helium nucleus (2 protons & 2 neutrons). Beta decay would involve removal of a high-speed electron. Gamma decay would not involve a material change, but rather a loss of electromagnetic radiation.

As for societal implications, nuclear reactions such as these can take as long as several billion years to complete. During that time, the released radiation poses a danger to living organisms. For a specific example, spent radioactive fuel (or waste) from nuclear power plants must be sealed off from the environment until the radiation release is complete, or below a minimum threshold considered dangerous.

Answer 2

A useful addendum to what adastra has said is that the radioactive activity (i.e. dangerousness) and half-life of radioactive substances are inversely related. That is, the shorter the half-life, the more radioactive a substance is, and the more radioactive (dangerous) it is, the quicker it decays. Substances with very long half-lifes, like uranium, are radioactive at such low levels that they pose no serious health risk at all, and nothing special needs to be done to protect people from them.

On the other hand, very short-lived radioisotopes, such as those created in a nuclear explosion or nuclear reactor, are intensely radioactive and very dangerous -- but fortunately decay to harmlessness very quickly, in days or weeks.

Answer 3

You also asked about the uses of radioactive decay. There are three, in decreasing order of importance:

1. Nuclear medicine. Radioactive substances can be used to "map out" portions of the body that aren't easily imaged with X-rays or MRI. For example, the structure of tiny blood vessels in the heart or brain, or the presence of small fractures in bones. The radioactivity allows extremely small amounts of the "tracer" substance to be detected, because it is such unusual and energetic emission. Additionally, substance can be made radioactive which have a chemical affinity for certain organ systems, for example radioactive iodine for the thyroid. Radioactive substances can also be used in therapy, to destroy cancer cells for example, when external radiation is too awkward. For example, if a cancerous tumor is located deep inside vital tissue, an external radiation source might damage too much surrounding tissue to be used. But radioactive substances can be implanted directly in the affected region, and confine the radiation to the important area.

2. Archaeology and geoscience. The decay of naturally-occuring radioactive substances provides an internal "clock" for many objects and substances that allows you to reliably date how long it has been since they were alive, if we're talking about materials like wood, or since they were formed from volcanic or other geological action, if we are talking about substances like gases in the atmosphere. This "radio-dating" is a valuable resource for scientists studying the distant past of human history, or the history of the climate.

3. Power. There are a few cases where a very compact source of power is needed and where refueling is out of the question. For example, deep-space or deep ocean research probes or implanted medical devices. In cases like these it is possible to use the heat produced by decay of a radioactive substance to provide a tiny and very long-lived source of power. (The heat is usually used with a thermoelectric cell to produce electrical power.)