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14 декабря, 2021
As specified in the Law of the People’s Republic of China on Prevention and Control of Radioactive Pollution [9], RAW is defined as material, which contains or is contaminated with radionuclides at concentrations or radioactivity levels greater than the clearance level as established by the regulatory body without foreseen further use. In China, RAW arises principally from NPP, research reactors, the nuclear fuel cycle, nuclear technology applications, the exploitation and utilization of uranium and thorium resources, as well as clean-up activities of contaminated sites and/or facilities such as that shown in Fig. 22.2: some nuclear facilities in the Gobi Desert in the west part of China (Qinghai Province), which were used during the 1950s and 1960s, need to be cleaned up.
To meet the needs for its nuclear power expansion, China has developed uranium enrichment and fuel element manufacture capability. At present, two uranium enrichment plants are in operation, with annual total centrifugal enrichment capacity of 1,100 tons of separation work. The first nuclear fuel assembly production line was established in 1988 in Sichuan province, supplying most of the nuclear fuel elements to the Qinshan NPP (Fig. 22.3). Subsequently, the technologies for designing and manufacturing nuclear fuel elements have been imported on a step-by-step basis, to which a technical adaptation was later made. This means that China’s PWR fuel element manufacture can meet the requirements of the international generic standards, so as to ensure that the supply of nuclear fuel elements meets the demands of the current PWR plants in China. Through introducing technology from Canada, a high pressure reactor fuel element production line, with
22.2 Nuclear facilities in the Gobi Desert in Qinghai Province in the west part of China, which were used in the 1950s and 1960s, need to be cleaned up. |
22.3 Qinshan nuclear power plant with five reactor units. |
a capacity of 200 tonnes per year, was built in Inner Mongolia, Northern China, where it provides HWR fuel elements for Qinshan NPP III.
China ’s RAW categorization system is based on pre-disposal management and disposal of RAW. In pre-disposal management, the RAW categorization system accounts for the nuclear facility operational experience in waste treatment and conditioning requirements, which includes a quantitative categorization system for radioactive gaseous, liquid and solid wastes. The disposal-based RAW categorization system focuses on the final disposal of RAW, in conjunction with the origin of the waste and the planned disposal approach.
The pre-disposal management-based waste categorization system is used to manage gaseous, liquid and solid RAW generated at nuclear facilities, with a detailed categorization for different forms of wastes according to their radioactive characteristics as shown in Table 22.3 . This is consistent with the basic requirements of waste treatment but puts more emphasis on
Table 22.3 Pre-disposal-based waste categorization system
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the cleaning index, shielding design, and other field protection requirements. These requirements are implemented in the waste treatment and conditioning processes for various systems. It is noticeable that most Chinese standards on nuclear or radioactive waste management are coherent with the current IAEA classification scheme. For example, both the IAEA and Chinese standards specify that management of decay heat should be considered if the thermal power of waste packages reaches several watts per cubic metre [10,11].
The disposal-based radioactive waste categorization system divides solid radioactive waste into solid LLW, solid ILW, solid HLW, solid alpha waste and the waste arising from mining and milling of uranium and thorium, and naturally occurring radioactive materials (NORM) waste. Disposal options considered include centralized deep geological disposal, regional nearsurface disposal, and centralized landfill, and others, as shown in Table 22.4. Solid LLW containing only short-lived radionuclides can be released from regulatory control when the radioactivity contained is below the regulatory clearance levels. However, management of cleared waste should be in compliance with other relevant environmental requirements.