Nuclear power plants are used to generate electricity but an accident at a nuclear power plant could release dangerous radiation throughout the surrounding area. So, nuclear power plants are harmful to human beings and animals if it is not properly maintained. More than 150,000 people have evacuated from their living area in Fukushima due to the leakage of radiation from the nuclear power plant. In this article, let us see how nuclear power plants are dangerous to human beings and animals.
Nuclear power plants are used to generate electricity by nuclear chain reaction. The nuclear chain reaction is a fission reaction, where the neutrons from the previous step continue to propagate and repeat the reaction. When a U235 nucleus is hit by a neutron, it produces Ba139, Kr92, and three other neutrons. These neutrons hit another U235 nucleus and it continues as a chain reaction.
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| Pressurized Water Reactor | Image by U.S.NRC., Public domain, via Wikimedia Commons |
The main part of the nuclear power plant is the nuclear reactor. Nuclear chain reactions take place inside the nuclear reactor. In a nuclear reactor, there is a fuel rod enriched with U235 it reacts with the water (acts as a coolant or moderator ) and the presence of the neutron in the water hits the U235 nucleus and starts the nuclear chain reaction in the fuel rod. Through a nuclear chain reaction, nuclear energy ( heat energy ) is obtained. Here, the water which is act as a coolant absorbs the heat extracted from the nuclear fission reaction.
Now, the hot coolant moves to the heat exchanger and transfers the heat to the water present in the heat exchanger. The water in the heat exchanger absorbs the heat from the coolant and transfers it into the hot stream. The hot stream drives the turbine and produces electricity.
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| Two CANDU ( CANada Deuterium Uranium ) fuel bundles, each about 50 cm long, 10 cm in diameter | Image by Atomic Energy of Canada Limited, Attribution, via Wikimedia Commons |
When the lifetime of the fuel rods exists, it is removed from the reactor and stored safely because the elements Ba139 and Kr92 present in the fuel rods are radioactive elements that emit dangerous radiation for several years.
These radiations are harmful to human beings and animals. It causes cancer and other dangerous diseases. So, these fuel rods are packed in concrete barrels and buried under the deep see because salt water doesn't allow the radioactive rays to come out.
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| Radiation hotspot in Kashiwa, February 2012 | Image by English: Abasaa日本語: あばさー, Public domain, via Wikimedia Commons |
If the maintenance of the fuel rods failed, the radiation may spread all over the surrounding area. The establishment of the nuclear power plant should be made outside of the urban areas then it will be safe for the surrounding people. The important problem in nuclear power plants is maintaining the radioactive waste ( used fuel rods ) if it fails, there will be a nuclear explosion. Then, the surrounding environment will be affected by the radiation for several years.
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