Classification of building fire risk: Flash point A (℃): Disposal scheme
1, protective measures (1) provide secondary protection for emergency personnel entering the combustion zone, and cover them with fire water guns; (2) The minimum protection for the personnel involved in the disposal on site shall be no less than level 3.
2. Eliminating Danger (1) Peripheral Fire Extinguishing Before attacking the leakage point and the main fire point, the peripheral fire point must be completely extinguished.
(2) plugging 1) According to the leakage situation on site, study and formulate a plugging scheme, and implement it strictly according to the plugging scheme; 2) Explosion-proof measures must be taken for all plugging actions to ensure safety; 3) Close the front valve and cut off the leakage source.
(3) Turn to 1) Dump or empty the storage tank through process measures; 2) transfer dangerous bottles.
(4) Ignition When the air pressure in the tank is reduced, the flame is automatically extinguished, or the flame is extinguished by the cooling water flow, but there is still gas diffusion, which can not be blocked and still cause harm, decisive measures should be taken to ignite.
3. Fire extinguishing (1) Fire extinguishing conditions 1) The surrounding fire has been completely extinguished; 2) Danger sources such as surrounding kindling have been completely controlled; 3) The ignition box has been completely cooled; 4) Rescuers, equipment and fire extinguishing agents are ready; 5) The material source has been cut off and the internal pressure has dropped significantly; 6) The plugging is ready and can be completed in a short time.
(2) Fire extinguishing method 1) Valve closing and gas cutting method: close the valve, cut off the gas source, and extinguish the fire by yourself. 2) Dry powder fire extinguishing method: according to the combustion situation, use dry powder gun on vehicle, dry powder gun with hose, cart type and portable dry powder fire extinguisher to extinguish the fire. 3) Water flow cutting and sealing method: multiple water guns are used side by side or crosswise to form a dense water flow surface, which concentrates on unburned hydrogen below the root of the flame and gradually moves to the head of the flame to cut off the contact between the flame and the air and extinguish the fire.
4) Bypass injection method: fire extinguishing agents such as haloalkane and inert gas are injected into the bypass of the pipeline in front of the nozzle to extinguish the fire.
related news
The Atomic Energy Safety and Security Agency of Japan's Ministry of Economy, Trade and Industry announced on June 4, 20 1/that a hydrogen explosion occurred in Unit 3 of Fukushima Daiichi Nuclear Power Plant at local time 1 1 (Beijing time 01), and the building where the reactor was located was damaged. Tokyo Electric Power Company subsequently announced that after the explosion, seven people were missing nearby. After the earthquake, four nuclear power plants in Japan were affected to varying degrees, and 1 1 nuclear reactors stopped running.
The Japanese government reported to the International Atomic Energy Agency that excessive nuclear radiation was detected outside the Nukawa nuclear power plant, and the readings of radioactive materials around the nuclear power plant facilities exceeded the allowable level. The government is investigating radioactive sources. While notifying the International Atomic Energy Agency, the Japanese government stressed that all three reactors of the Nuchuan nuclear power plant are in a "controlled state" at this stage. According to the International Atomic Energy Agency, on June 3, the internal pressure of an affected reactor at the Nagawa nuclear power plant was released "by releasing steam", and "the Japanese authorities announced the possibility of hydrogen accumulation".
1. Location of Fukushima Daiichi Nuclear Power Plant: Hydrogen explosion in Unit 3 about 200 kilometers northeast of Tokyo. Gong Shenglong, spokesman of the Atomic Energy Safety and Security Agency, confirmed that a hydrogen explosion occurred in Unit 3 of the Fukushima Daiichi Nuclear Power Plant on the morning of 14. The NHK screen shows that white smoke emerged from the explosion site, and the protective cover of the concrete structure outside the reactor of Unit 3 was damaged, exposing the metal frame. The operator of the nuclear power plant, Tokyo Electric Power Company, said that the reactor pressure vessel and the metal shield directly protecting the reactor were not damaged. The wall thickness of the metal protective cover is about 15 cm, and there is a concrete protective cover outside. Yukio Edano, Chief Cabinet Secretary of Japan, said on June 4th that the explosion of Unit 3 could be regarded as a hydrogen explosion, just like the explosion of Unit 1 before, that is, the hydrogen generated inside the reactor overflowed and came into contact with external oxygen, and it was not a nuclear explosion. He pointed out that according to the person in charge of the nuclear power plant, the container where the reactor was placed was not damaged, and it was unlikely that a large amount of radioactive materials would fly away. After confirming that many people were exposed to nuclear radiation explosion, seven people were missing nearby. Tokyo Electric Power Company announced that the whereabouts of an employee from the cooperative company and six self-defense members are unknown and are currently being confirmed. TEPCO also said that 1 1 the injured were hospitalized. On the same day, several nuclear power plant workers and members of the Self-Defense Force were confirmed to have suffered from nuclear radiation, including six employees from Tokyo Electric Power Company and partner companies, and a male member of the Self-Defense Force who injected seawater into the reactor of Unit 3. Unit 3 is likely to have a core meltdown due to the decrease of reactor water level. It has been pointed out that there is a danger of hydrogen explosion before. Cooling Failure of Unit 2 Japan News Agency reported that the cooling system of Unit 2 of Fukushima Daiichi Nuclear Power Plant failed on June 14. According to the Atomic Energy Safety and Security Agency, the Unit 2 reactor "completely lost its cooling function". The cooling system failure occurred in 1 unit and unit 3 before the external hydrogen explosion. The Associated Press reported on June 5438+04 that the seawater "can't be filled". Alvarez said that whether seawater and boric acid can cool the reactor depends on the amount and speed of perfusion, which needs to last for several days without interruption. Japanese experts say that injecting seawater is the best way to cool the reactor at present, but boron in seawater will inevitably corrode the reactor, and this expensive equipment will be completely scrapped. 14 local time 16: 34, the water level in the reactor of unit 2 dropped rapidly, resulting in the fuel rods completely exposed to the water for a period of time. If the accumulated heat cannot be discharged smoothly, the reactor will also face the danger of core melting. 265438+100000 emergency transfer The Atomic Energy Safety and Security Agency said that before the hydrogen explosion of Unit 3, the nuclear radiation in two places of the Fukushima Daiichi nuclear power plant exceeded the standard. At 2: 20 on June 4, 65438, the nuclear radiation at one location was 75 1 microsievert per hour, and 20 minutes later, the nuclear radiation at another location was 650 microsievert per hour. The acceptable amount of radiation is 500 microsieverts per hour. The maximum amount of nuclear radiation that the human body can bear every year is about 1000 microsieverts. After the hydrogen explosion, the nuclear radiation measured at the regional monitoring points of the nuclear power plant was 20 microsieverts per hour, which did not rise rapidly. The Atomic Energy Safety and Security Agency said that around the Fukushima Daiichi nuclear power plant, the current wind speed is about 1 m per second, and the wind direction is from south to north. The Institute of Atomic Energy Safety and Security appealed to people within 20 kilometers of Fiona Fang, which is centered on nuclear power plants, to take shelter indoors. Steam was released from the nuclear power plant 1 unit due to the increase of internal pressure, and the leaked hydrogen mixed with oxygen and exploded. Japan's * * news agency learned from the Fire Department of Japan's Ministry of Internal Affairs and Communications that three people were previously contaminated by radioactive materials from the Fukushima Daiichi nuclear power plant, but after radiation removal, they still measured high pollution values and entered secondary radiation medical institutions for treatment. According to the figures released by the United Nations, by the evening of 13, the Japanese government had transferred and resettled 590,000 people in the disaster area, including 2 10/00,000 people due to the leakage of the Fukushima Daiichi nuclear power plant.
2. Location of Fukushima No.2 Nuclear Power Plant: About 200 kilometers northeast of Tokyo, in Fukushima No.2 Nuclear Power Plant, disaster prevention robots sent by the government, 1, Units 2 and 4 are all waiting for exhaust and decompression, and Unit 3 has been successfully cooled. The Ministry of Education, Culture, Sports, Science and Technology of Japan announced on June 38+03 that it is transporting disaster prevention robots near the first and second nuclear power plants in Fukushima Prefecture, and will engage in disaster relief work in high-radiation places where people are not allowed to get close. Location of Donghai No.2 Nuclear Power Plant: 20 km away from Tokyo/KLOC-0.
Restoring external power supply, Japan Atomic Energy Power Generation Company announced on June 4 that the East China Sea No.2 Nuclear Power Plant, which stopped running automatically, will resume external power supply and replace the emergency diesel generator to cool its reactor temperature. Japan Atomic Energy Power Company revealed that after the earthquake, the reactor stopped running immediately, and at the same time, the water pump continued to be started to supply cooling water to reduce the reactor temperature. It is expected that the reactor will enter a stable "low temperature shutdown state" in the near future. /kloc-On the evening of 0/3, Donghai No.2 Nuclear Power Plant announced that one of its two cooling systems had failed. A spokesman for Japan Atomic Energy and Electric Power Company said: "Due to the tsunami, the seawater pump powered by a diesel generator in our cooling system failed, and then we stopped the cooling system manually." Usually, after the reactor is shut down, the nuclear fuel needs to be cooled for several days to return to normal temperature.
Venue: The Nagawa Nuclear Power Station, 250km northeast of Tokyo, declared a state of emergency, and the Japanese government declared the Nagawa Nuclear Power Station in Miyagi Prefecture to enter an "atomic emergency" on 13. Three. According to the latest news released by the Vienna-based International Atomic Energy Agency on June 5438+03, according to the notification from the Japanese Atomic Energy Department, the radiation in the surrounding area of the Nukawa nuclear power plant has dropped to the normal standard. Earlier, Japan had informed the International Atomic Energy Agency that the Nukawa nuclear power plant under the Tohoku Electric Power Company had entered the lowest level of emergency due to the detection of radioactive materials. After investigation, the radiation source is not from the three reactors of the Nukawa Nuclear Power Plant. Japan speculates that the cause of abnormal radiation readings may be related to the Fukushima Daiichi nuclear power plant that exploded. Reuters quoted Japanese nuclear safety experts as saying that the radiation intensity outside the Nukawa nuclear power plant was about 700 times higher than normal, but the absolute value of nuclear radiation was not high. The above-normal level of nuclear radiation intensity may be due to the fact that after the leakage of Fukushima Daiichi nuclear power plant, radioactive materials "drifted with the wind to the area where the Nagawa nuclear power plant is located". The Nukawa Nuclear Power Plant is located at the junction of Nukawa-CHO and Ishinomaki, Muru Prefecture, Miyagi Prefecture. When the earthquake occurred on June 5438+0 1 day, a fire broke out in the basement of the turbine room of Nuchuan Nuclear Power Station 1 unit, which was later extinguished, without causing radioactive pollution to the outside.
American media reported that the crew of the aircraft carrier Ronald Reagan who went to Japan to participate in disaster relief was exposed to radiation. On June 3rd, 65438, The New York Times quoted government officials as saying that the crew of Ronald Reagan was exposed to radiation equivalent to 1 month in about 1 hour due to the radioactive cloud generated when the damaged nuclear power plant approached Japan.
According to these officials, the outside of the American helicopter carrying out its mission about 97 kilometers north of the damaged nuclear power plant is polluted by radioactive dust and needs to be cleaned. According to the report, there is no indication that American soldiers are unwell due to nuclear exposure. However, for the sake of safety, the US military decided to temporarily withdraw the aircraft carrier to the sea. Ronald Reagan and George Washington aircraft carriers 1 1 set out for Japan to participate in disaster relief.
The U.S. Nuclear Regulatory Commission said on 13 that due to the weather, a small amount of radioactive material leaked from Fukushima nuclear power plant has been far away from people. "Considering that the two countries are thousands of miles apart, Hawaii, Alaska, overseas territories of the United States and the west coast of the United States will not suffer from any harmful radiation."
The threshold of nuclear power plants in China is higher than the world average. According to Xu Yun, chief expert of fast reactor of China National Nuclear Corporation and chief engineer of fast reactor engineering department of China Academy of Atomic Energy, he told Xinhua News Agency on June 14 that China's nuclear safety regulations and standards have adopted the latest research results of the International Atomic Energy Agency, and the construction and operation of nuclear power plants are safe and controllable. However, we should learn from this incident in Japan, improve our understanding of nature and make a more comprehensive plan. Wei Xu said that the Japanese Fukushima nuclear power plant 1 unit was the first batch of commercial nuclear power plants built in the late 1960s. Most of the nuclear power plants in operation and construction in China are improved or innovative nuclear power plants since 1980s and 1990s, and their safety performance is better than that of the first batch of commercial nuclear power plants put into operation. He said: "The threshold of nuclear power plants in China is higher than the world average, and the site selection of nuclear power plants is more conservative and safe." 2. Natural disasters are considered in the site selection of Daya Bay Nuclear Power Station. According to Xinhua News Agency, the relevant person in charge of Daya Bay Nuclear Power Station said on June 38+03 that the data of the power station monitoring system of the company's earthquake office showed that the threshold values of the seismic instrument system (KIS) of Daya Bay Nuclear Power Station and Ling 'ao Nuclear Power Station were normal and no alarm was triggered. The earthquake will not have any destructive impact on Daya Bay Nuclear Power Station and Ling 'ao Nuclear Power Station. The person in charge said that the site of Daya Bay Nuclear Power Station was selected from more than ten alternative sites in the coastal areas of Guangdong Province. There has never been an earthquake of magnitude 6 or above in the history of the factory area and its surrounding areas, and there is no seismic active layer of magnitude 6 or above within 20 kilometers. The crust is safe and stable, and the probability of strong earthquakes is very low. According to reports, at present, natural disasters such as earthquakes are fully considered in the site selection of nuclear power plants in China, and coastal areas with stable geological structures are selected, so there is a lot of room for site selection of nuclear power plants. 3. No abnormality was found in monitoring all over the country. According to the evening news of Xinhua News Agency, Ministry of Environmental Protection (National Nuclear Safety Administration) 14, at present, no abnormalities have been found in radiation environmental monitoring in various parts of China, and all nuclear power units operating in China are in normal state. /kloc-on the evening of 0/4, the relevant person in charge of the Ministry of Environmental Protection (National Nuclear Safety Administration) answered a reporter's question on the radioactive release of the Fukushima Daiichi nuclear power plant in Japan. He said that since March 12, the Ministry of Environmental Protection has launched a national radiation environmental monitoring network, and the monitoring results have been published on the website of the Ministry of Environmental Protection. At present, no abnormalities have been found in radiation environmental monitoring in various parts of China, and all nuclear power units in operation in China are in a normal state.
4. Will this Japanese accident affect China? Chen Jianxin: At present, I don't think so. The scope of the accident is relatively small and will not pose a threat to China. However, this nuclear accident should be a wake-up call for all countries.