1. What is a “nuclear accident”? A nuclear accident is a serious deviation from operational conditions that occurs in a nuclear facility or activity. In such a situation, if the relevant specialized safety facilities fail to function as designed, the release of radioactive material may reach unacceptable levels. 2. How far is it safe to evacuate? Under normal circumstances, the first priority is to limit the occurrence of radiation exposure. The effects of radioactive smoke cloud deposition are minimized primarily by evacuating or concealing the affected population. Depending on the amount of radioactive material released into the atmosphere and the prevailing meteorological conditions (e.g., wind and precipitation), and based on the center of the explosion, the state will determine within what radius emergency sheltering measures should be taken. 3. How to protect yourself? First of all, avoid panic, listen to the radio or watch TV in time, and act according to the instructions of the government. Stay indoors in situations where radioactive contamination may be present. Take iodine tablets according to the government’s instructions. Only the government can decide whether iodine tablets are needed after assessing the status of the accident. They should not be taken solely on the basis of personal subjectivity or out of fear. 4. After a nuclear accident, even if I have not been exposed to radiation, I still feel scared. In any accident, whether or not there has been or has not been actual radiation exposure, there will be mental fatigue and anxiety. This is attributable to people’s self-perception of health risks, and it depends in part on whether people believe that the authorities are competent and trustworthy, and that prompt and effective action has been taken to control the radiation dose. At the same time medical practitioners should provide the necessary psychological counseling for their work to relieve the state of psychological panic. 5. How should the public control their emotions and maintain a good state of mind during and after an emergency? Emergencies involving nuclear and radiation are prone to cause people’s fear. In this regard, the principle of prevention should be implemented first. Victims who have been psychologically shocked can be relieved of their stress by means of methods that have a calming effect on the heart. Some of the affected persons may exhibit certain undesirable behaviors, others may show inhibition, withdrawal, passivity and negative characteristics, and there may be others who show signs of disorientation. These situations require that the psychologist must adopt a psychotherapeutic approach that is tailored to the specific situation of the patient. The patient’s family members and relevant personnel should promptly arrange psychotherapy for those with these manifestations. 6. Which personnel should receive assistance in mental health? After a disaster, mental health assistance should be given to those who have developed psychological disorders. Generally, survivors who are directly involved in a large-scale disaster or bereaved, or who have lost property, are potential disaster victims who need timely psychological assistance; followed by individuals and families with whom they have close ties; personnel engaged in rescue or search, or members and volunteers assisting in reconstruction or rehabilitation should also be taken into consideration; and individuals who have a high level of vulnerability to disaster scenarios may also show signs of psychopathology and need help. The “hidden” should also be taken into account. 7. What does “concealment” mean? The term “sheltering” refers to people staying in or going indoors with windows, doors, and ventilation systems closed to minimize inhalation and external exposure to radioactive material in the plume (fallout) and to minimize external exposure from radioactive deposits. 8. What does “evacuation” mean? It refers to the emergency relocation of people from the affected area to avoid or minimize large-dose exposures from the plume or high levels of radioactive deposits. It is a short-term measure and people are expected to return to their original residence within a limited period of time. 9. How far can the smoke cloud float after a nuclear accident? This is very difficult to predict. It depends on wind speed and other meteorological conditions. 10. How much radiation dose will be caused by the released radioactive material and what are its adverse health effects? Depending on the total amount of radioactive material released, the dose to the public may be in the range of low or even very low levels. The world background dose of natural radiation per capita is 2.4mSv/year, with regional differences resulting in values that can vary from one region to another, for example, up to 200mSv in some parts of Iran and India. Health effects such as acute radiation sickness occur when the whole body exposure dose is greater than 1Gy. However, for the radioactive fallout released in nuclear power plant accidents, it is unlikely that such a high dose of irradiation will occur after a large amount of radioactive smoke cloud has been transported over long distances. 11. What are the early protective measures? Early refers to the occurrence of nuclear and radiation emergencies within 1 to 2 days after the occurrence of protective measures that can be used for personnel are: concealment, respiratory protection, taking stable iodine, evacuation, control of import and export access and so on. Respiratory protection is the action of covering the nose with a dry or wet towel, which prevents or reduces inhalation of radionuclides. Taking stable iodine can prevent or reduce the deposition of radioactive iodine in the smoke plume in the thyroid gland after it enters the body. 12. What are the protective measures in the mid-phase? At the mid-incident stage, a considerable amount of radioactive material has been deposited on the ground. At this point, early protective measures may continue for individuals, except that discontinuation of respiratory protection may be considered. In order to avoid excessive cumulative doses from prolonged stays, the competent authorities may take the form of controlled and planned relocation of the population from the contaminated area to the outside. Restrictions on the sale and consumption of locally produced or stored food and drinking water should also be considered. According to the characteristics of the irradiation pathway for personnel in this period, protective measures can also be taken: the use of stored fodder in animal husbandry, decontamination of personnel’s body surface, and treatment of the sick and wounded. 13. What are the protective measures for the period? In the late phase of the incident (recovery phase) the question is: whether and when normal life in society can be resumed; or whether further protective measures are needed. In the late phase of an incident, the main exposure pathways are internal exposure due to ingestion of contaminated food and inhalation of resuspended material. Therefore, protective measures that can be taken include control of import and export access routes, avoidance of relocation, control of food and water, use of stored feed and decontamination of the area. 14. What should the public do in the event of a nuclear and radiation emergency? In the event of a nuclear and radiological emergency, the first thing the public must do is to obtain as much credible information as possible about the emergency and to understand the decisions and notifications of governmental departments. Communication with local authorities should be maintained through various means, and it is important not to believe rumors or gossip. The second thing to do is to quickly take the necessary protective measures to protect yourself. For example, you can choose the nearest building for concealment, you should close the doors and windows and turn off the ventilation equipment. Evacuate in an organized and orderly manner according to the arrangements of the local government. When a radioactive dispersal event is judged to have occurred, it is important not to face the wind or run with the wind, but to try to hide to the side of the wind and quickly enter a building to take cover. Take respiratory protection, including covering the mouth and nose with a wet towel or piece of cloth to filter out radioactive particles. If radioactive contamination of body surfaces is suspected, use bathing and changing clothes to minimize radioactive contamination. Prevent ingestion of contaminated food or water. In the event of a nuclear and radiological terrorist incident, the public should pay special attention to maintaining a stable state of mind and should never be in a state of panic. 15. Under what circumstances should concealment measures be taken? What should the public be aware of? Concealment is one of the main protective measures in the early and middle stages of an emergency that involves the release of a relatively large amount of radioactive material into the atmosphere. Most buildings can reduce the inhalation dose to people inside the building by about half. After a period of sheltering and the passage of the plume, airborne radionuclide concentrations within the shelter will increase, and ventilation is necessary to reduce airborne radioactivity to levels equivalent to cleaner outdoor levels. Consequently, sheltering is less effective protection against a sustained release. The duration of concealment is generally considered to be no more than 2 days. 16. Under what circumstances are personal protective measures required? What should the public be aware of? Some personal protective measures are required when the air is contaminated with radioactive material. Covering the mouth and nose with handkerchiefs, towels, fabrics, etc. can reduce the dose due to inhalation of radioactive material by about 90%. Surface protection can be provided by a variety of everyday clothing, including hats, bandanas, raincoats, gloves and boots. Decontamination of personnel who have been or are suspected to have been contaminated by radioactive contamination of body surfaces is as simple as telling the personnel concerned to shower with water and to remove and store contaminated clothing, shoes, hats, etc., until there is time to monitor or treat them at a later date. It is important to prevent the spread of radioactive contamination to uncontaminated areas. 17. What is meant by “iodine protection”? When an accident has caused or may cause the release of radioactive isotopes of iodine, compounds containing non-radioactive iodine are distributed to residents as a protective medicine to reduce the dose to the thyroid gland. 18. Under what circumstances should I take stabilized iodine? After a nuclear and radiation emergency, it is possible for a person to ingest radioactive iodine and concentrate it in the thyroid gland, exposing this organ to a larger dose of irradiation; taking stable iodine at this time will reduce the absorption of radioactive iodine by the thyroid gland. If stable iodine is taken at the same time as radioactive iodine inhalation, 90% of the radioactive iodine deposition in the thyroid gland can be blocked. Taking stabilized iodine within a few hours of inhaling radioactive iodine can still reduce the amount of radioactive iodine absorbed by the thyroid by about half. The recommended dosage for adults is 100 mg of iodine, for pregnant women and children between 3 and 12 years old, the dosage is 50 mg, and for children under 3 years old, the dosage is 25 mg. 19. What should I pay attention to when taking stabilized iodine? For newborns within the first month of life, the amount of stabilized iodine taken should be kept to the lowest effective level. Stabilized iodine should be used with caution or not used in some people, e.g., people with nodules in the thyroid gland, people who have been cured of goiter, people who have been treated with radioactive iodine, people with chronic inflammatory diseases of the thyroid gland, people who have unilateral resection of the thyroid gland, people with subclinical hypothyroidism, people who are allergic to iodine, and people with certain skin disorders (acne, eczema, psoriasis). 20.Can iodine tablets (KI) prevent radiation? How does it prevent radiation? How much should I take? Physiologically, the main source of iodine in the human body is the absorption by the thyroid gland, which relies on iodine to produce thyroid hormones. ki is stable iodine, which saturates the thyroid gland with iodine and thus prevents radioactive iodine from being ingested. The Chernobyl experience has shown that radioactive iodine was a major factor in the impact of the Chernobyl accident, which resulted in over 5,000 cases of thyroid cancer in children, all of whom were between the ages of 0-18 years old in the irradiated population. Therefore, the primary targets for potassium iodide distribution are young children and pregnant women. Iodine tablets do not protect against radioactivity from outside the body and radioactivity other than iodine that is absorbed by the body. This is why iodine thyroid blockade will be used in most settings in combination with other protective measures (e.g., staying concealed indoors, closing doors and windows, etc.). Exposure to radioactive iodine can lead to a significant increase in thyroid cancer, especially in young children. Inhaled and ingested radioactive iodine accumulates in the thyroid gland. Prophylactic administration of potassium iodide prior to exposure prevents the uptake of radioactive iodine by the thyroid gland and reduces the long-term risk of thyroid cancer. In order to take full advantage of the iodine thyroid blocking effect of stabilized iodine, it is necessary to take stabilized iodine tablets before or as soon as possible after exposure. Even a few hours after the accident, the uptake of 50% iodine by the thyroid gland can still be blocked by taking them. To prevent inhalation of radioiodine isotopes, a single tablet dose of stabilized iodine is usually sufficient, which provides continuous protection for 24 hours and provides adequate protection to the thyroid gland in the event of an incoming smoke cloud containing radioiodine isotopes. However, in a prolonged sustained release situation, there is a risk of repeated exposure. Again, it is emphasized that potassium iodide provides the best protection only if it is taken before exposure to radioactive iodine. 21. Under what circumstances should food and drinking water be controlled? Consumption or drinking of food and drinking water contaminated with radionuclides should be prohibited or restricted when the concentration of these radionuclides in food and drinking water exceeds the levels specified in national standards. The national standards categorize food into two groups, one for general consumption and one for milk, baby food and drinking water; the concentration levels at which intervention is required are specified for each of the different nuclides. 22. What is radioactivity? Radioactivity has been discovered for more than a hundred years. The earliest discovery of radioactivity was made by the French scientist Becquerel, who in 1896, while studying the fluorescence phenomenon of uranium ore, discovered that uranium salts emitted penetrating radiation similar to X-rays. Two years later, the French physicist Madame Curie discovered polonium, another new element capable of emitting rays, from uranium ore, and four years later she discovered radium. Madame Curie suggested that the property of a substance to be able to emit rays spontaneously be called radioactivity. Nuclides that are radioactive are called radionuclides. Radionuclides emit radiation will become new isotopes, new isotopes may be radioactive isotopes, may also be stable isotopes, and this process is called radioactive decay. 23. Under normal circumstances, what kind of radiation exposure are people generally exposed to? The global average annual effective dose of individuals from natural radiation is about 2.4mSv, of which 0.4mSv is from cosmic rays, 0.5mSv from terrestrial γ-rays, 1.2mSv from inhalation (mainly indoor radon), and 0.3mSv from ingestion. it can be seen that radon is the most important source of irradiation. 24. What activities of people are also radioactive? Many activities of human beings are inseparable from radioactivity. For example, the radiation exposure dose from air, food and water ingested by people is about 0.25mSv/year. Wearing a luminous watch is 0.02mSv per year; traveling 2000km by plane is about 0.01mSv; smoking 20 cigarettes a day is 0.5-1mSv per year; an X-ray examination is 0.1mSv, and so on. People in the long-term practice and application found that a small amount of radiation exposure will not jeopardize human health, excessive exposure to radioactive rays on the human body will produce harm, make people sick, death. The larger the dose, the greater the harm.