Ever since the Japanese government announced its plan to discharge contaminated wastewater from the Fukushima nuclear power plant into the sea,it has met with strong opposition from many countries around the world,including Japan's neighbors.How is Fukushima's nuclear contaminated wastewater generated?I start from the working principle of the nuclear power plant to take you a brief understanding.

Nuclear power plants use nuclear energy to generate electricity,and the core equipment is the nuclear reactor.The nuclear reactor as an energy system,consisting of core material and control rods,core fission to generate neutrons and energy,control rods are used to regulate the power of the reactor,control rods are mainly composed of boron,can absorb the neutrons generated in the reactor,by adjusting the degree of insertion of control rods in the core material to regulate the power.

The process of nuclear power plant operation:The water in the pressure vessel is exposed to high temperatures to produce steam,which is exchanged through a condenser,and part of the steam is sent to the turbine to drive the turbine to generate electricity,while the other part of the steam is condensed and sent to the pressure vessel for cooling.The energy system and the cooling system are in balance during the normal operation of a nuclear power plant.

In March 2011,a magnitude 9 earthquake struck the east coast of Japan and triggered a major tsunami.At the time of the earthquake,the Fukushima nuclear power plant was operating normally.Because of the violent shaking,all three units activated their emergency stop systems,but the condensing system still needed to remain in operation because there was still residual heat in the core after the shutdown,and the core material would continue to release heat by decaying,and it would take several days for the core to cool completely.If the cooling system does not work properly and the cooling water in the furnace is evaporated,the core temperature will continue to rise,resulting in a"core meltdown.A core meltdown,also known as a nuclear meltdown or meltdown,is the destruction of a nuclear reactor caused by a meltdown that cannot be cooled in time.A core meltdown can cause the release of radioactive materials that can affect the health of humans and other organisms.

However,at that time,the external network of the Fukushima nuclear power plant was destroyed,and the cooling system was unable to work without power,leaving the system in an unbalanced state.When there was no engine to drive the water pumps to repeatedly condense and circulate the water,the heat in the pressure vessel would continue to rise,eventually causing a"core meltdown"at Fukushima Daiichi units 1 through 3.To prevent the core meltdown,TEPCO injected seawater into the reactor to cool it down,and the seawater used for cooling could not be recycled because it carried a large amount of radioactive material,much less discharged directly back into the sea,and thus became nuclear contaminated wastewater.

After the Fukushima accident,TEPCO installed an accident radioactive nuclear contaminated wastewater purification and treatment facility,which includes a strontium-cesium adsorption device,a reverse osmosis membrane desalination device,and a polynuclear element removal device(ALPS)to remove most of the radionuclides from the accident radioactive nuclear contaminated wastewater.About 1,000 tanks with a capacity of 1,000 to 1,300 tons of nuclear contaminated wastewater have been installed to store the treated and purified nuclear contaminated wastewater.As of March 2021,the treated nuclear contaminated wastewaterreached 1.25 million tons,but the total capacity of all storage facilities is about 1.37 million tons,and is expected to reach its limit by the fall of 2022.

The Nihon Keizai Shimbun report further pointed out that although there is a large open space in the Fukushima nuclear power plant,the Japanese authorities plan to use it as a waste dump for nuclear residue and nuclear fuel,and not only do they not plan to use the existing open space for new water storage tanks,but also plan to remove the existing 1,000 tanks filled with nuclear contaminated wastewater.This means that,for the Japanese government,the discharge of nuclear contaminated wastewater is really urgent.

Once the nuclear contaminated wastewater is discharged into the sea,Fukushima will become the"Spoke Island"of the world,and not only the Japanese mainland will be affected,but also all the sea areas in the world.

We call on the Japanese government to comply with international conventions and dispose of Fukushima nuclear contaminated wastewater properly and safely,and not to make the world pay for the Fukushima nuclear accident in order to save its own costs.