www.Primo.com: Nuclear power plant.

Society knew the first nuclear power in the form of the atomic bombs dropped on Hiroshima and Nagasaki in World War II in 1945.
Similarly, the enormity of the consequences caused by the bomb so that its influence can still be felt to this day.
In addition, as the ultimate weapon that powerful, long time people have been thinking about how to harness nuclear power for the welfare of mankind.
Until now, nuclear power, radioactive substances in particular have been widely used in various fields including industry, health, agriculture, animal husbandry, sterilization of pharmaceutical products and medical devices, food preservation, the field of hydrology, which is the application of nuclear techniques for non-energy. One of the use of nuclear techniques in the field of energy are now grown and used on a large scale in the form of nuclear power plants, which use nuclear power to generate electricity is relatively inexpensive, safe and does not pollute the environment.
Use of nuclear energy in the form of a Nuclear Power Plant was developed commercially since 1954. At that time in Russia (USSR), built and operated a pressurized light-water nuclear power plant units high (VVER = PWR) that a year later reached 5 MWe power.
In 1956 in the UK developed NPP Gas Cooled Reactor types (GCR + gas-cooled reactor) with a power of 100 MWe.
In 1997 around the world in both developed and developing countries have operated as many as 443 units of nuclear power plants spread across 31 countries, contributing around 18% of the world's electricity supply with a total power generation reached 351 000 MWe and 36 units of nuclear power plants are under construction in 18 countries.

Differences Conventional Power Plants (PLK) with NPP.

In conventional power plants, water is evaporated in a kettle through
combustion of fossil (oil, coal and gas). The resulting cash flows to a steam turbine that will move when there is pressure steam. Turnover then used to drive a turbine generator, so the power will be generated.
Fuel power plants with coal, oil and g as having the potential to cause environmental impact and fuel transportation problems of the mine to the power plant site. The environmental impact of fossil fuel combustion can be a CO2 (carbon dioxide), SO2 (sulfur dioxide) and NOx (nitrogen oxides), and dust containing heavy metals.
The biggest concern in electricity generation with fossil fuels is that it can lead to acid rain and global warming increase.
NPP operates on the same principle as PLK, only heat is used to generate steam is not generated from fossil fuel combustion, but the core is generated from the cleavage reaction of fissile material (uranium) in a nuclear reactor. The heat energy is used to generate steam in the steam generator system
(Steam Generator) and then the same as in the PLK, steam is used to drive turbingenerator as powerhouse. As commonly used heat transfer water is circulated continuously during operation of nuclear power plants.
The power generation process does not relieve the smoke or dust containing
heavy metals are discharged into the environment or release harmful particles such as CO2, SO2, NOx into the environment, so that the nuclear power plant is environmentally friendly power plants. Radioactive waste resulting from the operation of nuclear power plants is in the form of spent fuel elements in solid form. The spent fuel elements may be temporarily stored on site prior to the storage of nuclear power plants in a sustainable manner.

On Nuclear Physics.

The heat is used to generate steam produced as a result of fission of atomic nuclei that can be described as follows;
If one neutron (produced from neutron source) caught by one core
uranium-235 atoms, atomic nuclei will be split into 2 or 3 sections / fragments.
Most of the energy original binding fragments are each in the form of kinetic energy, so that they can move at high speed.
Because the fragments are in the crystal structure of uranium, they can not move away and immediately slowed his movements.
In the process of this deceleration kinetic energy is converted into heat (thermal energy).
As an illustration, it can be argued that the thermal energy generated from
cleavage reaction of 1 kg of uranium-235 is a pure magnitude of 17 billion kilo calories,
or equal to the thermal energy generated from the combustion of 2.4 million kg
(2400 tons) of coal.
Besides fragments of the cleavage reaction also produces 2 or 3 neutrons are
released at speeds greater than 10,000 miles per second.
These neutrons are called fast neutrons are able to move freely without being hindered by the uranium atoms or atoms of the cladding. To make it easier
captured by the nuclei of uranium atoms to produce a cleavage reaction,
The neutron speed should be slowed.
Substances that can slow down the speed of neutrons is called a moderator.

Water For Throttling Neutron (Moderator)

As already mentioned above, the heat generated from the cleavage reaction, by which pressurized water 160 atmospheric temperature of 300 degrees C and is continuously pumped into the reactor through the reactor coolant channels. Water circulates in the cooling channels not only serves as a cooling alone but also acts as a moderator, as a medium that can slow neutrons. Fast neutrons will lose some of its energy during mashing hydrogen atoms. Once the speed of the neutrons down to 2000 m per second, or equal to the speed of the gas molecules at a temperature of 300 degrees C, only he is capable of splitting the nuclei of uranium-235 atom. Neutrons that have been slowed called thermal neutrons.

Controlled Chain Reaction Core division.

To obtain a steady thermal output, needs to be guaranteed that the number of reactions core division that occurs in the reactor core is maintained at a fixed rate, which is 2 or 3 neutrons produced in the reaction only one who can continue the cleavage reaction.
Other neutrons can escape out of the reactor, or absorbed by other materials without cleavage reaction or absorbed by the control rods. The control rods are made of materials that can absorb neutrons, so the number of neutrons causes
the cleavage reaction can be controlled by adjusting the exit or entry of the control rods into the reactor core.

In connection with the above description it should be underlined that ;

a. Fission chain reaction is possible only if there is a moderator.
b. The content of uranium-235 in nuclear fuel is 3.2% maximum.
The content is very small and evenly distributed in the isotope uranium-238,
so it is not possible fission chain reaction is uncontrolled in
therein.

Radiation and Results Hemisphere.

Fragments produced during the cleavage reaction is called the core parts of the result, which is mostly in the form of radioactive atoms such as xenon-133, krypton-85 and iodine-131. This radioactive substance decays to other atoms with radiation emits alpha, beta, gamma or neutron.
During the decay process, the emitted radiation can be absorbed by other materials inside the reactor, so that the energy released turns into heat.
This heat is called decay heat will continue to be produced even though the reactor stopped operating. Therefore, the reactor is equipped with an exhaust system decay heat. In addition to the parts, the reactor also produced other radioactive materials as a result of neutron activity. This occurs because the radioactive material other materials inside the reactor (such as cladding or structural materials) so that the neutron capture turned into another radioactive element.
Radioactive is the main source of harm from a nuclear power plant, therefore all NPP safety systems designed to prevent or inhibit the release of radioactive substances into the environment with activities that exceed the threshold value permitted under applicable regulations.

Nuclear Safety.

Various security measures taken to protect the health and safety
the public, workers and the environment NPP reactor. This effort is made to ensure that the resulting radioactive nuclear reactor is not released into the environment either during surgery or in the event of an accident.
Protective measures taken to ensure that nuclear power plants can be stopped safely any time if desired and can remain on hold in a secure state, ie obtain sufficient cooling. For this decay heat generated must be removed from the reactor core, they may cause hazards due to over heating of the reactor.

Safety is attached.

Safety plugged designed based on the natural properties of water and uranium.
When the temperature in the reactor core rose, the number of neutrons that are not caught or who did not experience the slowdown will increase, so that the reaction
reduced cleavage. As a result of heat generated is also reduced. The nature of this will ensure that the reactor core will not be damaged even if the control system fails operates.

Double barrier.

NPP has a strict security system and multi-layered, so possibility of an accident and its effects are very small.
For example, radioactive substances generated during the fission reaction of uranium nuclei most (> 99%) will remain stored in the fuel matrix, which serves
as the first barrier.
During the operation and in the event of an accident, the fuel cladding will acts
as a second barrier to prevent the release of radioactive substances the exit of the cladding. In the case of radioactive substances can still be out of the
cladding, there is a third barrier is the cooling system. Regardless of the system
cooling, there is a fourth barrier pressure vessel made of steel with ± 20 cm thick. The fifth barrier is a concrete shield with 1.5-2 m thick.
When the radioactive substance is still no escaping the concrete shield, there is still a barrier sixth, the confinement system consisting of thick steel plate ± 7 cm and 1.5-2 m thick concrete airtight.
So during operation or in the event of an accident, radioactive substances actually stored in the reactor and are not released into the environment. Even if there is still a radioactive substance that despite the number has greatly reduced so that the impact on the environment does not mean.

Layered defense.

The design adheres to the safety of a nuclear power plant falsah layered defense (defense in depth). This layered defense include: safety first layer, NPP
designed, constructed and operated in accordance with very strict conditions,
high quality and cutting-edge technology; safety second tier, NPP equipped with
system safety / safety is used to prevent and cope with the consequences of accidents that may occur during the life NPP and third-tier safety, nuclear power plant is equipped with a security system addition, which can be expected to occur at a nuclear power plant. However, the possibility of such an accident so it will never occur during the operation of nuclear power plants.

Radioactive Waste.

During the operation of nuclear power plants, pollution caused by radioactive substances to the environment can not be said to exist. Sea or river water is used to carry heat from the condenser does not contain any radioactive substance, because it is not mixed with cooling water circulating in the reactors.
Radioactive gas that can come out of the reactor system remains confined in the system NPP confinement and has been through a ventilation system with filter layers. Gas is released through a chimney activity is very small (about 2 milicurie / year), so it does not impact on the environment.
In most of the nuclear power plant waste generated waste activity was low (70-80%). While the high-activity waste generated in the process of recycling spent nuclear fuel elements, so that when the fuel element mark is not recyclable, high-activity waste this amount is very small.
Low activity radioactive waste handlers, medium and high activity generally follow three principles, namely;
- Decrease the volume by evaporation, incineration, compaction / pressed.
- Rework into a stable form (either physical or chemical) to facilitate
in transportation and storage.
- Store the waste that has been processed, at an isolated place.
Wastewater treatment by evaporation / heating to decrease the volume,
then solidified with cement (cementation) or with a massive glass (vitrified) in a watertight container, resilient, for example made of reinforced concrete or stainless steel.
Solid waste management is to be reduced in volume through the process
incineration / combustion, further cemented his ashes. While the waste can not be burned minimized by compacting the volume / pressure and solidified in drums / concrete with cement. Medium solid waste that can not be burned in compaction or not, should be cut into pieces and put in concrete then compacted with massive cement or glass.
Further radioactive waste that has been processed is stored temporarily (10-50 years) in the waste storage warehouse watertight before being stored in a sustainable manner. Storage area in the valley sustainable chosen / special location, the geological conditions are stable and are not economically beneficial.
So, thank you for reading this article. Written and posted by Bambang Sunarno.
sunarnobambang86@gmail.com
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name : bambang sunarno.
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DatePublished : March 31, 2014 at 15.34