There nuclear power plant of Kashiwazaki-Karwa (柏崎刈羽原子力発電所) is a modern nuclear power plant (the first in the world with a reactor of III generation) stands on a large site 4.2 square kilometers placed in the cities of Kashiwazaki And Kariwa of the Prefecture of Niigata in Japan, on the coasts of the Japan Sea. It is the largest nuclear power plant in the world, it can generate the beauty of 8.212 MW power, providing electricity of about 16 million homes. It means that such a beast could feed the buildings of all of Italy. But this immense central, the Kashiwazaki-Kariwa Nuclear Power Plantwhich is located in Japan, it was deactivated following an earthquake in 2007, and since then it has not produced electricity anymore. What has kept it closed for all these years? But above all how does this immense nuclear power plant work? The nuclear power plant of Kashiwazaki-Karwa It is located in the western part of the Prefecture of Niigata on a site of 4.2 km2 and is managed by the Japanese company Tepco. The construction works began in 1980 and the first reactor entered into operation in 1985. They continued with the construction of other six reactors, the last of which entered operation in 1997. The control unit was and is still the largest nuclear power plant in the world For net electrical capacity produced. This means that it is able to produce 8.212 MW. The plant is equipped with seven reactors, which: five II^ generation of type reactors BWR (Boyling Water Reactor) they produce 1,100 MW each and two reactors of III^ generation ABWR (Advanced Boyling Water Reactor) of the latest generation they produce 1.356 MW Each, which are the first reactors of this type to have been installed all over the world. But before seeing how it works, let’s understand why its inactivity.
How are they made and how do boiling water reactors work?
This type of power plant works with the BWR reactor, or a boiling water reactor. In this type of reactor the water has a double role: it serves as refrigerant and how moderator to generate nuclear energy. Afterwards we see in detail these two functions. The core of the reactor contains nuclear fuel bars – made of uranium – which produce heat through nuclear fission. Nuclear fission is a process in which the nucleus of a heavy atom, such as uranium, when it is hit by a neutron is divided into two lighter nuclei. This process frees a large amount of energy, as well as further neutrons which in an uncontrolled way affect other nuclei, thus creating a chain reaction. The fission is the basis of the functioning of nuclear reactors and atomic bombs. Except that that of nuclear bombs is designed to lead to an immense explosion, thanks to specific mechanisms that amplify the release of energy suddenly and uncontrolled. In nuclear reactors, however, the design is designed to maintain the reaction under control, ensuring a stable and safe process for the production of electricity. Even if the reaction should escape control, it would not lead to an explosion comparable to that of a bomb. And how does it do it? As we said before, this reactor uses water as a refrigerant and moderator, but what does it mean?
During the fission, the fuel bars generate a huge amount of heat and the water absorbs this heat, preventing the nucleus overheat and maintaining this type of reactor at a safe temperature. This cooling process is crucial to avoid the risk of fusion of the nucleus. In addition to acting as a refrigerant, the water also plays the role of moderator: do you remember the neutrons of the fission I was talking about before? The water regulates their speed, slows them down to prevent the chain reaction from going out of control. Without water as a moderator, neutrons would be too fast to cause further more efficientols, making the nuclear reaction not sustainable. By increasing the probability that they trigger new reactions with fuel atoms. This process is essential to maintain the nuclear reaction stable and efficient. Without a moderator such as water, neutrons would be too fast to cause further feasions, and the chain reaction would stop, making the reactor ineffective.
So nuclear fission produces a large amount of heat that boils the water inside the nucleus. The water is pumped in the core from the bottom upwards, when the water comes into contact with the fuel bars absorbs the heat generated by the reaction. The boiling water and the steam rise upwards where a separator divides the water from the steam which is directed towards the turbines that makes the generator turn, producing electricity. After crossing the turbines, the steam is cooled into a capacitor and transformed again into the water, which is recycled, making the cycle start again. Since steam can contain traces of radioactivity, condensed water passes through filters to remove radioactive particles. Decontaminated water is continuously monitored to ensure safety before being recycled in the reactor. The whole system is enclosed in a reinforced concrete containment container, which serves as the first line of defense against radiation.
The nuclear power plant is not in operation today: that’s why
The nuclear power plant has undergone several partial and complete arrests from its opening to date, due to technical difficulties but also because of the many earthquakes that have occurred in the region. In the’October 2004the prefecture of Niigata was hit by a magnitude earthquake 6.9 of the Richter scale. Despite the power of the earthquake, the Kashiwazaki-Kariwa plant has resisted very well. All the reactors continued to function normally, with the exception of one who was temporarily stopped after a shock of settlement that activated the emergency system. The epicenter of the strongest earthquake that has ever hit a nuclear plant was detected in its near: that of Chūetsu of July 16, 2007 which had a magnitude of 6.6. This earthquake has caused several damage to the control unit, including a serious fire to one of the electric generators and losses of extremely contained radioactive material. Immediately after the plant he was closed to be subjected to inspections and repairs. Although serious accidents have not been recorded, safety worries have led to a series of rigorous controls. Then, in 2011, following the Fukushima earthquakein an atmosphere of general tension that has been created, the Japanese authorities have blocked all the plants of the country. After nuclear disaster, theInternational Agency for Atomic Energy (AIEA) He conducted an in-depth inspection of the Kashiwazaki-Kariwa plant who had not suffered damage, but the concerns about the safety of the system have curbed its reopening. For this reason, the control unit is still closed to date, although probably for a short time.
When it reopens the largest nuclear power plant in the world
Tepco has worked hard to satisfy the new security standards imposed by the nuclear regulation authority of Japan (NRA). However, the revision and approval process is long and complex. The authorities want to be absolutely certain that the plant can operate in total safety before authorizing the reopening. But it seems that there are no more problems in restarting the plant, so much so that in April this year Nra authorized Tepco to load the fuel to restart reactor 7. At present, the power plant still has other obstacles to overcome before entering into operation. This will include some further security inspections and the approval of the regional governor. This includes the approval of the governor of the Prefecture and above all of the public opinion.
