Ye Qi Zhen: nuclear power plant design, when the environment there are three elementary requirements for security, the first reactor when the event of a failure of the reactor to stop. Second, the reactor heat to export. The merely distinction with the nuclear power plant where the pot is the pot stops flaming to no energy,
nike sb 2011 广东肇庆拆除巨型关公塑像 官方称确保良好生态, and up to red peppery merely, nuclear power plants continued to issue some heat, about 6.6% of the original power, but also to adviser them out of the energy to continue cooling. Third, the inclusion in the containment of radioactive material. If you emulate these three principles, even in the event of any accident,
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Reporter: Where is reflected in the benefits of nuclear stamina? The 4 nuclear reactors in China is how to set the security barrier? The so-called nuclear power plant defense in depth tactics is how is it?
Second, the flood control requirements. Design will take into list hurricanes, tsunamis, sea class mushroom, storm, upstream barrier bursts, and the wave clash, further the probability of one-thousandth to decide. Factory layer height is higher than Jizhun Hong level.
to the three:
However, the first nuclear power plant design elevation of the seawall was 5.7 meters, when the earthquake triggered a tsunami in the Fukushima nuclear power plant zone is 14 meters, which makes emergency engine chamber flooded,
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Third, the crisis power supply, 500 kV cardinal web, yet also has a 220,000-volt devoted export power afford. The design of each unit has two emergency diesel engines, one can certify the emergency power supply, and also consider setting up a dedicated backup outer power supply.
of whether the appropriate measures?
Reporter: Fukushima nuclear power plant problems for those links, the design of nuclear power plants have appropriate security measures? Please annotate.
of the construction of the PWR nuclear power plant, which all of the material and the incidence of nuclear fission in contact with water, are secluded inside the containment, with the steam turbine generator is isolated, which with Japan BWR occurrence is different.
Editor's note
13 hours later, mobile generators arrive, but because the power distribution appliance at the base, was flooded, and can not be interlocked until March 12 turned 15 had not been made, a current power cord grafting to the pump power, but this period it was too late. Super-elevation design of the tsunami led to the plant power, no external power supply, no internal emergency power supply, full-time director of power, resulting in long-term core cooling manner is not obtainable. The second safety requirements, namely is, heat export,
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defense in depth how to set up the system?
China has four nuclear reactors to ensure the safety barrier, the first barrier for the fuel pellet and cladding. Nuclear fission produces more than 98% of radioactive material remain in the ceramic pellets of uranium dioxide is not released. The second barrier for the fuel cladding. Fuel pellets sealed in zirconium alloy shell archive to discourage fuel and radioactive fission products into a loop in the water, which is completely closed, even if the gas is also confined here, there is some space left, and the zirconium tube fuel wands can handle the pressure, the maximum number of closed gas emissions is insufficient to make it crack. The third barrier, and a circulate for the pressure vessel pressure boundary. Posed by the nuclear fuel kernel enclosed in a steel pressure vessel, pressure vessel and the whole circuit is a high pressure, the radioactive material will not drip into the reactor building. The fourth barrier is the containment, is the cement framework. The safety of shell diameter is 37 meters thick and virtually 1 measure containment and tight iron Souza, a certain interior pressure, it does not abuse the containment to discourage radioactive substances into the context.
to defense in depth strategy of nuclear power plants, while scampering a set of control system, once the accident stopped to put the heap, and then there are other security systems to defend it. For sample, the pressure vessel out of water, to supplement it with the safety injection system, tall pressure inside the containment, resulting in a lot of steam, and a safety shower systems, spray water into the pressure down. Evaporator is no water, and boiled away, and with the assistant water supply system to increase. (Reporter Hu Qifeng)
issue a:
question two:
Ye Qi Zhen: the problems for the Fukushima nuclear power plants, nuclear power plant design in a great number of security measures: First, anti-seismic design. The safety of all contained in nuclear power plants, ought be designed according to secure shutdown earthquake, this is the averaging of words, even the earthquake position, I would also favor to preserve the function of the system, the pile can stop. Therefore, the plant should be placed on the foundation of bedrock honesty, must be away from the fault, principally in the surface cracks or dislocation of the spirited fault, must not construct nuclear power plants.
What is radioactive iodine?
radioisotope of iodine, iodine and iodine -125 -131 is relatively large noxious radionuclides. Radioactive iodine into the blood, about 70% present in plasma, 30% presently transferred to the tissues and apparatuses within the body and selectively concentrated in the thyroid. Therefore, the health perils of radioactive iodine on thyroid damage chiefly. Radioactive iodine is warmhearted accustom in nuclear medication diagnosis.
us to see by the entire episode process. Fukushima nuclear power vegetation has 6 units first. Unit 1 is in consensus with 0.18g (g refers to floor acceleration of gravity) design (now nuclear power plant devise is based ashore the intensity of ground acceleration measured with the conventional seismic intensity namely differ, according to ground acceleration tin be compared to the strict principles of technicians, to think the erections, equipment, piping, etc. can not afford a seismic intensity), and the remaining units by 0.45g alternatively 0.46g design. March 11, Japan, earthquake triggered a tsunami. The 9 earthquake is equivalent to 0.52g, extra than a design criterion.
cooling failure to export the waste heat, causing the reactor temperature, pressure increases, the continued loss of coolant, fuel exposed, the original is the inclusion of water and steam. Exposed to the fuel temperature is high, and commonly the temperature of water vapor around 200 degrees, there is no cool down on to the thousands of degrees. 1000-2000 degrees circumstances, and partly beneath water, from a chemical repercussion with the zirconium to generate hydrogen. A plant outside the containment, hydrogen plant to go to the altitude of concentration,
paige jeans, a concentration of 10% of the time (usually at 4% or fewer), met oxygen in the atmosphere, a hydrogen burst occurred. 12, No. 1 unit of hydrogen explosion, 14, explosion of hydrogen Unit 3, 15, 2 units of hydrogen explosion, which ripped through the plant to make plant bare.
Fukushima nuclear accident in Japan caused the topic is still subject to public consideration. Today, we invited our nuclear power administration of the specialists, the Chinese Academy of Engineering, Nuclear Group, CST, agent manager of the Ye Qi Zhen, to respond reader friends concerned about three issues: First, there are so many pre-built security measures, why Fukushima nuclear power plant end still facing a Second, Fukushima problems because the links, the design of nuclear power whether there are suitable measures? Third, rely on China to assure the safety of nuclear reactors?
What is radioactive cesium?
environment cesium -137 easily sponged into the body, evenly dispensed in the body; deserving to the release of cesium--137 γ-ray, it is simple to detect in vitro. Into the main body retention of radioactive cesium in the soft tissue in the body, particularly brawn, bone and portly in cheap concentrations; relatively high levels of radioactive cesium, when ingested can cause astute and chronic harm. Cesium -137 for γ radiation,
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fourth serious accident hindrance and mitigation. There are mobile plant explosion prevention measures hydrogen, a complete measurement system, once the high concentration of hydrogen to hydrogen elimination, and now the new design of the non-active hydrogen compound device. Emissions of radioactive gas through the percolate, the radioactive bathe. While quickly relieving the steam discharged into the containment, because China is a pressurized water reactor, the pressure is high if the second loop, we then secondary emissions of steam, the steam is not radioactive at this time, but also can cool the main circuit, the main circuit emissions are emissions in the security shell.
was said to have been shutdown, and how could it work wrong? Because fair shutdown, the heap of spent oil dismissed into the tarn, and waste heat, just to pump a few percentage of the heat. 1 hour behind the earthquake, the water and there is no cooling, the water is open, at one atmosphere pressure, more than one degree of water to evaporation caused the water level immediately dropped. A few days later,
puma womens, each reactor has approximately 1 million kilowatts of heat. Ten thousand kilowatts of heat without cooling, then you can boil 3 hundred tons of water a day, so they use helicopters to spray water cooling plant oil, but the effect is small.
- Further reading
Fukushima why the
Reporter: Many readers have a question, that is, since so many pre-built security measures,
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after the earthquake, the first nuclear power plant safety systems Fukushima start correctly. First of all safe shutdown, safety injection system and the emergency core cooling system started now, in the circumstance of wastage of offsite power, the emergency diesel engines are normally started. That is, before the tsunami, the operation of nuclear power plants is regular. The first is shutdown, the second cooling system starts up, the heat export to.
, for instance, around the boundary of the radiation Nuclear Power Station, the state limit of 0.25 mSv, the tangible dimension is 0.005 mSv. Cigarette smoked the equivalent of 0.001 mSv in 2005, measured 0.0047 mSv, equivalent to 5 smokes smoked.
early merged radioactive iodine is the main makeup of fission products in one of the explosions and reactor accidents, it is the main radionuclide pollution of the environment early.
a total of 38 isotopes of cesium, in appending to a stable isotope of cesium -133, the repose are radioactive. Broke the newspaper of radioactive cesium nuclear reactor action and the main fission productions produced.
Ye Qi Zhen: Nuclear power is clean energy, nuclear fission energy is controllable. One kilogram of uranium -235 fission energy released is equivalent to 2,400 tons of standard coal combustion energy. We are a million kilowatts of nuclear power as long as the appended 30 tons of fuel each year, the same power, thermal power plant burning 3.3 million tons of coal per year. A large number of nuclear power in reducing greenhouse gas emissions, a meaningful cutback in the pollution of the environment of carbon dioxide, sulfur dioxide and other gas emissions, also depress the cinder, reducing the transport, so the conveniences of nuclear energy is quite prominent, is the strategic choice of China's energy development.
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Linear Mode
