Dr. Wang Ju said that in China's past nuclear military industry, the construction of atomic bombs and hydrogen bombs produced some high-level radioactive wastes, which are now liquid and will become solid in the future and finally be disposed of. At present, China vigorously develops nuclear power plants, which will also produce spent fuel, which needs post-treatment. The whole process of treatment is that after the spent fuel is taken out of the reactor, it must be post-treated to take out uranium and plutonium. The rest is high-level radioactive waste liquid, which will become glass solidified body and eventually be buried underground.
It is understood that 99% of the waste generated by the nuclear industry belongs to low-level radioactive waste, which is relatively easy to handle. The remaining 1% contains a variety of high-concentration radionuclides that are extremely harmful to human body, one of which is called plutonium, which can cause death as long as 10 mg is ingested. Its toxicity can not be used by ordinary physical, chemical or
Biological methods can degrade or eliminate it, and only through its own radioactive decay can the harm be gradually reduced. It will take thousands of years, tens of thousands of years or even longer for high-level radioactive waste to be harmless. At present, deep geological disposal is the most realistic disposal method of high-level radioactive waste: that is, building a repository underground. In order to ensure that nuclides will not migrate outward, layers of barriers must be set up. Firstly, the high-level radioactive waste liquid is glass solidified, and then the glass solidified body is put into a metal can. Backfill materials are filled around these waste cans in the repository. At the same time, we need to find a huge natural rock as the shell of the repository. Because stable and complete rock mass is the most powerful guarantee to ensure that nuclides do not migrate outward.
Dr. Wang Ju said that the so-called geological disposal is simply to dig a pit and bury it, but where to dig a pit, how to dig a pit and how to build multiple barriers to prevent nuclides from migrating outward are all important research topics. The third and most crucial question is how to convince everyone that you are safe to be buried here. The first two are relatively easy, and the most difficult thing is to convince everyone that your approach is safe.
He said that China's military nuclear waste liquid is about 1000 to 2,000 cubic meters. According to the medium and long-term nuclear power development plan for 2020, China will build 32 nuclear reactors to supply 4% of the country's electricity. At present, China's nuclear power plants produce more than 400 tons of spent fuel every year, and the storage capacity is expected to reach tens of thousands of tons by 2020. It is estimated that China will produce 83,000 tons of spent fuel within 60 years. This is equivalent to the current amount of spent fuel in the United States.
China began to study and explore the geological disposal of nuclear waste from 1986. In 2003, China promulgated the Law on the Prevention and Control of Radioactive Pollution, which stipulated centralized disposal of high-level radioactive waste. In 2006, the Ministry of Science and Technology, the Commission of Science, Technology and Industry for National Defense and the Ministry of Environmental Protection jointly formulated the Guidelines for Research and Development Planning of Geological Disposal of High Level Radioactive Waste. A three-stage strategy was formulated. From now until 2020, choose the location of the repository and build an underground laboratory; In 2020-2040, field experiments were carried out relying on underground laboratories; The construction of knowledge base began in 2040 and will be completed in 2050. By then, nuclear waste can be received and put into operation.
Wang Ju said that China is now doing more site selection work, and six places have been selected in China, namely South China, East China, Inner Mongolia, Xinjiang, Southwest China and Northwest China. At present, the work is concentrated in Beishan, Gansu Province, and a systematic long-term evaluation has been carried out. 14 boreholes have been drilled, and their geological and socio-economic conditions have been evaluated. He said that Beishan is a very suitable place. First of all, the climate is dry, it doesn't rain much all the year round, and the land is vast and sparsely populated. The county area of 60,000 square kilometers is equivalent to the area of Zhejiang Province, but there are only 1.2 million people, mainly living in two towns, and the rest are scattered nomadic people. Geological stability, less earthquakes. There is also good granite there, which is very complete. We hope to choose a site there. Now the country requires comparison, and choose a place in East China or South China for comparison. But other places are densely populated.
Wang Ju said that China is facing social and technological challenges. At present, the state has invested heavily in how to build nuclear power plants, not how to manage nuclear waste. There are no regulations and technical standards for high-level radioactive waste. The implementation unit of geological disposal is still under discussion.
According to the medium and long-term development plan of nuclear power, a spent fuel reprocessing fund will be established.