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Generating Nuclear Power
Radioactive elements are used to generate nuclear power in a scientifically controlled atmosphere. Uranium and Thorium metal for generating nuclear power are mined deep in the earth. Uranium is a silvery white metallic element of atomic number 92. It consists of 92 protons and 92 electrons and has 6 valence electrons. The nucleus is bound between 141 and 146 neutrons with 6 isotopes. Isotope U 238 has 146 neutrons and Isotope U 235 has 143 neutrons. All the six isotopes are unstable and have weak radioactivity. Its density is 70% more than Lead.
Uranium 238 (99.284%) is found in nature and is commercially extracted from uranium-bearing minerals. It decays slowly emitting alpha particles. Its half-life is 4.5 billion years. With adequate concentration, the isotopes sustain a nuclear chain reaction that generates intense heat in nuclear reactors. Its byproduct is fissile material used for nuclear weapons. Uranium metal reacts with nonmetallic elements with its reactivity increasing with temperature. Uranium also dissolves in hydrochloric and nitric acid.
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System Analysis of a Nuclear Power Plant
- Intense heat is generated by nuclear fission.
- Carbon dioxide gas is injected into the fission zone.
- Hot gas converts water into superheated steam.
- Steam drives the turbines.
- Turbines drive the electrical generators.
- Electricity is connected to supply grid.
The output is free from carbon dioxide and smoke. It produces large amounts of energy from a small quantity of nuclear fuel. A small amount of nuclear waste, which is dangerous, is generated . The discarded waste must be carefully sealed and buried deep in the earth to allow slow decay to reduce radioactivity. The decay process takes many years.
Nuclear Meltdown is an informal designation. Nuclear meltdown causes severe nuclear reactor problems due to overheating of the reactor. This happens when a fission reaction exceeds its limits, and the uranium fuel rods begin to liquefy. The reactor becomes overheated beyond its safety limit. Water cooling of the reactor is auto-controlled. The reactor will leak when the cooling system fails, and it can explode if immediate corrective action is not taken. Shut down action should immediately follow.
Overheating of the reactor increases superheated steam pressure, causing the steel body to develop a crack. A tremendous nuclear explosion is the end result. Failure of the water cooling system is the prime reason for this dangerous hazard.
The Chernobyl plant in the USSR had several such nuclear meltdowns. The shutdown system was of improper design. A major explosion caused many deaths and inflicted cancer in many people who died later. There was a flaw in the reactor plant: it was not contained within a massive building to minimize explosion intensity. (Please see attached photo of a German nuclear plant below.) The reactor system is protected within strong, high, massive buildings.
Major disasters happen if reliable and guaranteed safety precautions and norms are not adhered to. Maintaining and enforcing the stringent safety norms costs lots of money.
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Nuclear critics are relentlessly vociferous on the possible risks of nuclear reactor accidents, the vexing problems of disposing nuclear waste, and the imminent dangers of nuclear fuel transportation. These are facts which cannot be taken lightly.
The trend in the increase of nuclear plants is growing in the world. Add to that the ever increasing number of dangerous nuclear weapons. The world has not considered natural calamities like volcanoes, massive destructive floods, and earth quakes. In such situations destruction of a nuclear plant is practically unavoidable. World debate on nuclear issues must ponder inevitable dangerous catastrophes.
Considering all these facts, it is definitely sensible to use harmless solar energy, wind power, geothermal energy, rice husk fuel, ocean energy, and hydraulic power. These are economical, free, and natural renewable resources.
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Japan - A Wake Up Call?
In March 2011, Japan experienced one of the greatest earthquakes in the history of humankind. Japan, a county known for pioneering nuclear technology and setting up numerous nuclear power plants could not handle the pressure of earthquake tremors that shook its nuclear energy program badly. Two major nuclear power plants were destroyed by the earthquake aftershocks and the surrounding area was instantaneously vacated. Japan is a great country and it is known for fighting back. It will definitely fight back and rebuild itself but this is certainly a wakeup call for those developing countries which are amassing nuclear weapons and building nuclear power plants without having any sound disaster-control technology.
It is high time that lessons are learned and sound disaster control technologies are put into place because if right steps are not taken in the right time, things will definitely get worse than Japan.