The basic principle is basically the same as that of the water purifier that everyone usually uses. The key is to install raw materials that can absorb radioactive elements in the parts where radioactive wastewater flows, digest and absorb radioactive elements in water reasonably, and absorb radioactive elements stored in raw materials. After a period of time, the radioactive elements in the raw materials are saturated, and new adsorption raw materials can be replaced. The replaced raw materials filled with radioactive elements 2 and 2 are treated in a dry-solid sealing manner.
The waste water treatment system collects low-level radioactivity and high-level radioactivity respectively, and classifies waste water into storage boxes matching the radioactivity according to their sources, so that radioactive elements with short service life can decay rapidly. In Qinshan No.3 Nuclear Power Station, two storage tanks store medium and high level radioactive wastewater, and three storage tanks store low level radioactive wastewater.
If the wastewater level in the storage tank reaches a certain height-width ratio, the radioactive elements with short life will completely decay. At this time, turn on the circulating water pump of the waste liquid storage tank, and make it run continuously for more than 1 hour, so that the waste water in the storage tank can be fully mixed. Sample and analyze the wastewater in the box. If all the indicators detected in the box meet the environmental protection standards, the wastewater in the box can be directly discharged.
If the wastewater with moderate radioactive level does not meet the direct discharge standard after treatment, it must be purified and decontaminated again. See 1 for the production process of radioactive wastewater purification control loop. If the pressure difference at the filter outlet of the system is abnormal during the operation of machinery and equipment, it means that the filter is blocked and the filter element of the system needs to be replaced immediately. If the digested and absorbed raw materials are invalid, they must be replaced. Sampling analysis is a direct reference to determine the frequency of purification treatment cycle system and the actual effect of purification treatment.
3. Adsorption method.
20 1 1 urban roads, bridges and flood control there is an inconspicuous message in the fifth issue of May. China has developed a new technology for quickly and efficiently adsorbing waste water worried about nuclear environmental pollution, which can be used to prevent the external diffusion of radioactive iodine radionuclides such as iodine-13 1, and can be widely used in nuclear safety accidents and nuclear waste water. This new scientific research achievement will be quickly transformed into the main productive forces and economic benefits of Luohe City, Henan Province. Surprisingly, this kind of raw material has high adsorption efficiency for iodine-13 1 A new material made by this new process-20g of microbial ceramic particles for catalytic reaction was soaked in nuclear wastewater containing 12640Bq/L radioactive iodine-13 1 for 20 minutes, and the radioactive element iodine-13l could be adsorbed and fixed to 99.97%. The test shows that this new material is used to filter iodine-125 wastewater with radioactivity of 1.85 million Bq/L, and the load of radioactive iodine-125 sludge reaches 2% with only 5 rains. This new material is called catalytic reaction microbial ceramics, but it is not porcelain in general practical sense, and it is also different from traditional adsorption raw materials. The particle made by this new technology is a kind of high-efficiency adsorption raw material with directional male separation function, which can quickly, simply and efficiently adsorb immobile radioactive elements such as iodine-13 1 and iodine-125. The core of this technology is the determination, selective adsorption and immobilization of raw materials.
4. Multi-nuclide removal device (ALPS):
20 15 "Multi-nuclide Removal Device (ALPS)" mechanical equipment delivered by Tokyo Electric Power Company, Japan. According to the relevant person in charge of the company, ALPS can remove radioactive elements below Japanese national industry standards in addition to tritium that cannot be eliminated. The remaining practical problems depend on how to remove tritium. The person in charge said that with the current technology, tritium can not be completely eliminated on a global scale, and only after its concentration is diluted to a certain extent can it be discharged into the air or ocean. A small amount of tritium is considered to be less harmful to people's physical and mental health, and it is an international practice for nuclear power plants around the world to release tritium into the sea. The International Atomic Energy Agency (IAEA) also believes that the estuary after nuclear wastewater treatment is technically feasible, but separate radiation monitoring is needed during discharge to ensure that the discharge may meet the national standards. In view of the sewage entering the sea, Tokyo Electric Power Company of Japan thinks that this will not harm the health of local residents, nor will it endanger the quality of fish species.
By August 2020, 73% of the nuclear wastewater treated by ALPS still contains radioactive substances, so it must be treated again. "Science" magazine emphasizes that radioactive substances such as strontium 90 must decay for a long time, which is likely to have a longer delay and the potential risks to the natural environment and the body are more complicated.
6. evaporation.
If the nuclear waste water is sent to the heating furnace for combustion, the water polluted by nuclear radiation sources will not evaporate and be discharged into the gas. But according to this plan, nuclear waste water will pollute the air. In February, 2020, the Federation of relevant departments of the Japanese government, which is responsible for dealing with nuclear wastewater, published an analysis report, saying that releasing steam is also a feasible scheme besides being discharged into the ocean. Previously, after the nuclear safety accident at Three Mile Island in the United States, nuclear wastewater was evaporated and discharged into the air.
7. Send the nuclear bomb to the ground.
Dig a hole from the soil layer, and then build a pipeline with a depth of 2500 meters underground to discharge all the nuclear wastewater to the deepest depth of 2500 meters underground. But according to this plan, nuclear waste water will pollute surface water.
8. Electrolysis.
Nuclear waste water is converted into radon and co2 by electrolysis, and then discharged into the air.
9, mixed with cement, buried in the soil.
Mixing nuclear waste with cement will produce concrete blocks, which will then be buried underground.