In the universe, energy is available in different forms for our use. We can feel the presence of energy through warmth, light, sound, movement, growth and power. In nature, energy exists in forms of mechanical energy, chemical energy, radiant energy, thermal energy and nuclear energy that can be derived from naturally occurring resources such as the sun, the earth’s heat, the wind, water (rivers, lakes, tides, and oceans), fossil fuels (coal, oil, and natural gas), biomass, and radioactive minerals.
The advent of civilization started only after the discovery of fire and using the thermal energy for various purposes. Initially energy demand was very low and that used to be met mostly by renewable resources only. With industrial growth and the science & technological advancement it became possible to produce electricity that made our life lives more comfortable and convenient. Production of electricity requires the primary energy resources hence comes under the category of secondary energy. Today, largest amount of primary energy is used for electricity generation. When nuclear energy, residing in radioactive elements is used as primary source in harnessing electricity, it is known as Nuclear Energy or Nuclear Power. Today there are about 450 nuclear power reactors that are used to generate electricity in about 30 countries around the world
What is nuclear energy?
Nuclear energy, as the name says, is released from the nucleus of an atom during nuclear reactions, i.e., nuclear fusion and nuclear fission. In nuclear fusion, nuclei of light atoms are fused together to create heavier atom while in case of fission heavy atom splits up to lighter nuclei releasing vast amount of free energy. Fusion process has several advantages over fission, since it requires vastly available hydrogen as fuel and generates nonradioactive waste. But fusion based Nuclear reactor has not yet been commercially developed because it requires very high temperature, upto several million Kelvin as in the stars including Sun. Therefore, at present, we are only using nuclear fission reaction for power generation. Uranium metal, which is present in earth crust and mined all over the world, is commonly used as fuel in fission reactors. In a Nuclear power plant, a controlled chain reaction of uranium is achieved to produce heat energy, which is used for boiling the water to make steam. This steam finally drives turbines to produce electricity.
How it is clean?
From an environment perspective, nuclear plants offer clean energy. In an operational nuclear plant almost no harmful green house gases produce and also the water discharged from a nuclear power plant contains no harmful pollutants and meets regulatory standards for temperature designed to protect aquatic life. Many may argue that carbon dioxide, a strong green house gas, is produced during operations like mining or construction. But statistics indicate that the CO2 produced during all the process of nuclear power generation is about 50 times less that of the coal-based plants and at least 25 times less than natural gas plants. We know that the our energy demand is increasing day by day and we cannot afford to use conventional thermal power plants since they consume fossil fuels and emit green house gases which in turn results in creating environmental imbalance. Nuclear energy is certainly providing a solution in reducing the emission of green house gases to save our precious environment. The nuclear power does not produce significant amount of waste, and moreover one third of the total nuclear waste is reprocessed to recover useful fuel. Rest of the waste is contained and disposed off at the suitable underground geological sites without affecting the ecology.
Reliability and sustainability are the areas where nuclear energy takes over the renewable alternative source of energies like solar, wind, biomass etc. It is independent of unreliable weather or climate conditions, unpredictable cost fluctuation and has extensive fuel resources. Uranium- the nuclear fuel is fairly abundant about 4 parts per million in the earths’ crust. Besides, thorium, which is 4 times more abundant than that of uranium in earth crust, can also be used as fuel in nuclear reactor. The essence of nuclear power is that it requires very little fuel to produce large amount of energy- 1000 MWe capacity nuclear reactor requiring annually only 27 tonnes of uranium, on the other hand 3.2 million tonnes of coal is consumed per year in the same capacity of Thermal power plant. Further, though theoretically uranium is finite and nonrenewable but in nuclear reactor plutonium is recovered and recycled as new fuel element to produce more energy. All these factors make nuclear resources almost inexhaustible and capable of fulfilling future energy demand.
Is Nuclear Energy is Safe?
In general public there are several myths about nuclear energy. People have fear about radiation, radioactive waste, nuclear accidents and also the fear of nuclear weapons and consider nuclear energy to be unsafe. Contrastingly, nuclear energy is one the safest energy option and let us take a look how it is safe. Radiation through radioactive material may cause serious health risks. But people relate radiation only with nuclear reactors being unaware that the radiation is present everywhere in environment including our body. The fact is that the nuclear power plants account for less than 0.1% of average radiation exposure to the public, in contrast to 55% radon gas, 11% internal, i.e., from human body, 8% cosmic, 8% terrestrial, 11% medical x-rays and 4% nuclear medicines . The myth regarding the nuclear power plant is that they emit radiation which is harmful but nuclear power plants are designed in such a way that no radiation can be emitted. It may be interesting to know that the area near a nuclear power plant are so secure that a person living there for about 2000 years would get radiation exposure equivalent to an exposure from a medical x-rays.
Nuclear energy agencies strictly follow the waste management measures to isolate the radioactive waste from biosphere. To ensure that no significant environmental releases occur over a long period after disposal, a ‘multiple barrier’ disposal concept is used. The overall safety against migration of radioactive waste is achieved by proper selection of waste form, suitable engineered barriers, backfill materials and the characteristics of the geo environment of the repository site. The nuclear energy industry is the only energy industry which takes full responsibility of it all waste.
People concerned that the Nuclear energy can lead to the proliferation of nuclear weapons. The fact is that, nuclear power plants use the low-enriched uranium as nuclear reactor fuel that cannot be used as nuclear weapon material. Nuclear weapons require highly enriched uranium or plutonium and have completely independent technology of nuclear power plants. This is empathized by the fact that the initial development of nuclear technology was military and that time there were no nuclear power plants. If every commercial nuclear energy plant and all the supporting technology around the world were dismantled and none were ever built again, the proliferation of nuclear weapons would still be a threat. However, strict protocols administered by the International Atomic Energy Agency (IAEA) are used to control fuel enrichment, fabrication and reprocessing facilities to prevent the diversion of fissile material into weapons.
Fewer fatalities have occurred in the civilian nuclear power industry, they are but sporadic incidents when compared to the rate of accidents which occur in fossil fuel industries, coal mines and gas pipelines which have a history of eruption. Technologies are being develop to make nuclear power plants are more efficient and safer than ever before.
Our energy demand is expected to increase considerably in the coming years as the result of population growth and economic development. All of the various means of generating electricity have their role to play in meeting the rapidly increasing energy demands. But our growing energy demand cannot be fulfilled only by finite resources like fossil fuels, particularly coal and gas. Reports suggest that with the current reserve and rate of consumption will lead the coal to be exhausted in next 125 years. Green house gas emission and global warming are the other problems associated with our conventional energy production and consumption pattern. Renewable energy sources provide clean alternative of the fossil fuels but it is intermittent, costly and difficult to match the demand. Nuclear power plants do not pollute environment, their wastes end up as solids and, though requiring careful handling, are very much and are easily managed. No energy can beat nuclear energy when it comes to energy potentiality of fuel. In current scenario nuclear power provides 13.5% of world electricity (in India it shares only 2.5% of total electricity) which definitely need to increase if we want sustainable development. Nuclear energy is definitely the future energy choice particularly in concerns of clean, reliable, cost effective and large energy outputs. Besides electricity production nuclear energy has extensive uses in medical science ( medical diagnosis and radiotherapy), food and agriculture ( using the Sterile Insect Technique (SIT) which involves rearing large numbers of insects then irradiating them with gamma radiation before hatching, to sterilize them), food preservation, sterilization and radioisotope dating of rocks. This cannot be substituted by other means of energy. Hence if we use sensibly and carefully, nuclear energy can prove great gift for mankind and essential for the survival and growth of human civilization.
Author: Ms. Aastha Saxena,
Winner of National Scientific Write-up Contest-2012 held at NASI Allahabad.