According to statistics, between 1944 and 1999, including the Chernobyl nuclear accident, 405 radiological accidents occurred globally***, irradiating more than 3,000 people and resulting in 120 deaths.
The types of radiological accidents are categorized into the following nine main types. One is reactor accidents, such as the Chernobyl nuclear power plant accident in the former Soviet Union in 1986, in which the nuclear power plant's core melted down and exploded, causing radioactive material to disperse into the air and cause serious contamination. After the Chernobyl accident, it affected the level of iodine 131 in milk in various parts of China, with heavy contamination starting in Xinjiang and continuing eastward to Dalian and Shenyang. Under normal circumstances, there is no iodine 131 in milk; secondly, critical accidents; thirdly, loss of radioactive sources; fourthly, over-exposure to industrial sources; fifthly, over-exposure to medical irradiation; sixthly, accidents in transportation; seventhly, experimental accidents; eighthly, intentional acts involving radioactive substances; and ninthly, radioactive contamination of air, water and food.
According to the National Compendium of Radiation Accident Cases 1988-1998, written jointly by the Department of Health Law and Supervision of the Ministry of Health and the Three Bureaus of the Ministry of Public Security in 2001, 332 radiation accidents occurred on the Chinese mainland from 1988 to 1998***, with a total of 966 people irradiated. Accidents involving the loss of radioactive sources accounted for about 80 per cent of all accidents, and 258 occurred in ***, the vast majority of which were liability accidents, in which 584 radioactive sources were lost, 256 of which were not recovered. Among them, on June 25, 1990, the cobalt 60 source room staff of the Radiation Medicine Research Laboratory of the Second Military Medical University in Shanghai violated the regulations, resulting in seven staff members being exposed to large doses of irradiation, of which two died on the 25th and 90th days after irradiation, and the other five suffered from myeloid radiation sickness.
In 1992, when the Xinzhou Regional Science and Technology Commission in Shanxi Province relocated, the old site was transferred to the local environmental monitoring station. The Xinzhou Regional Science and Technology Commission had introduced five cobalt-60 radiation devices for breeding. When the environmental monitoring station was re-expanded, the Shanxi Provincial Environmental Protection Bureau was asked to dispose of the old radiation sources, but it failed to find out how many of them there were, resulting in one source being left down a well and taken home by a construction worker. He started having headaches and vomiting within an hour. His wife was pregnant at the time, and his father and brother were unfortunately irradiated as well. The hospital in Taiyuan did not know the cause of the illness, and the radioactive source fell out of his pocket, but no one was able to identify it. As a result, the source was thrown into the hospital's garbage. In the process, several people were irradiated. Fortunately, the radioactive source was eventually found. This incident ultimately resulted in 3 deaths and 10 injuries.
An earlier radiological accident in China, recorded by the International Atomic Energy Agency, occurred in 1963 in Sanliyan, Hefei, Anhui province. A cobalt 60 radioactive source for agricultural research that had not been used for years was placed near a river pond, and a child took it home to play with it, exposing his family and several villagers and eventually killing two people.
In recent years, the NNSA has also reported a number of radiological accidents. For example, on October 21, 2004, a private irradiation plant in Jining, Shandong Province, which was built in 1994, experienced a malfunction of its self-built static stacked cobalt 60 irradiator, and when the source of radiation did not fall back to a safe location down the shaft, two staff members entered the irradiation room without being monitored, and were exposed to irradiation for 10 minutes or so, at a distance of only 0.8 to 1.7 meters from the source, and both of them died in a resuscitation attempt. On April 11, 2008, five staff members of Shanxi Henze Irradiation Science and Technology Co., Ltd. entered the irradiation room without lowering the radioactive source to a safe position, carrying dosimeters that could not be used normally, and were irradiated with overdose, and one of them died and the other four suffered from radiation sickness.
In the 1990s, China was similar to the United States in terms of the number of accidents per year, and if you combine the number of accidents with the number of radioactive sources owned, China's accident rate was higher than that of the United States, about 40 times higher.
Radiation sources used in agriculture, medical care and other sectors are registered and under the control of the environmental protection department. The environmental protection department is very strict every year, and has set up a number of training centers across the country to provide rigorous training, but accidents still happen.
The public is very concerned about nuclear power plants, but for security reasons, they are heavily guarded and not accessible to the general public. It is recommended that nuclear power plants set up public reception centers to popularize knowledge about nuclear power and answer public concerns, which is necessary to relieve the public's psychological problems.
Normal operation of a nuclear power plant can result in the release of trace amounts of radionuclides, but these are within the permitted range. 2010's problem at Daya Bay's Unit 2 was a crack in the cladding of one of the fuel rods, which led to an increase in radioactivity in one circuit, and measures were taken to quickly restore it to normal. This cannot be described as an accident, and should be considered a very minor incident with no health effects.
As for the sewage problem involved in nuclear power plants, the nuclear power plants under construction attach great importance to environmental protection, and there are tests on shellfish and fish in the surrounding water bodies to detect whether the discharge of water from the nuclear power plants meets the discharge standards. Any large-scale industrial enterprises have sewage problems, nuclear power plants are no exception.