What is nuclear radiation.doc

What is nuclear radiation?Now lets examine what nuclear radiation is, and what we can do to protect ourselves from it.Radiation can damage cells and their DNA through its ionizing effect. This effect happens when a high-energy carrying particle or photon removes an electron within an atoms nucleus from its orbit, thereby changing the properties of the atom. If there is enough ionization, DNA, cell, and tissue damage will occur.Damage to ones health largely depends on the time and density of exposure to radiation. Some simple measures can help to prevent oneself from being affected by radiation. Be careful to protect facial features and the body, by wearing masks and gloves.Do not eat or drink contaminated food or water. When exposed to radiation outdoors, take a shower immediately. And finally, some experts say taking iodic pills can help, but it must be done under the guidance of a doctor.Countries seeing minimal radiation effectsMany countries have enhanced monitoring for possible nuclear fallout, after several explosions at Japans Fukushima nuclear power plant. So far, there has been no evidence of any negative effect from the blasts in other nations.South Korea says radioactive substances will not reach the nation. 70 monitoring sites across the country have reported normal radiation levels.Meanwhile, Russia says radiation levels are within legal limits at its 32 monitoring sites on the far east coast.Far across the Pacific Ocean, the state of California in the US says there is little possibility that the western coast of the US will be affected by the blasts. Even in the worst case scenario, with melting rods, nuclear pollution in Japan would not pose any threat to the US.Tele interview: Will radiation leaks become worse?For more on this issue, were now joined on phone by Mr. Teng Jianqun, Director of the Center for Arms Control, at the China Institute of International Studies. Thanks for joining us, Mr. Teng .Q1: Based on the current situation, will the radiation leaks at the Fukushima Nuclear Plant become worse?Q2: Many people in China are quite anxious about the situation, and officials are sending out messages to reassure them. Please tell us why the country is unlikely to be affected?Q3: But in the end, we all share the same water. So what are the chances of sea products becoming contaminated?China showing no sign of radiationFears over radioactive material leakage are growing among cities in China after reports of a spike in nuclear leakage at the Fukushima nuclear plant. China has since strengthened its monitoring of nuclear radiation. Basic radiation knowledge is also being provided to educate the public on the worrying situation. China begun around the clock inspection of nuclear radiation on Sunday. Monitoring stations in Shanghai as well as those in the eastern provinces of Heilongjiang, Liaoning, Shandong, Jiangsu, Zhejiang and Fujian were ordered to conduct around-the-clock surveillance of radioactive substances in the air and sea water.In Shanghai, special monitoring facilities have been employed. So far, all data show that meteorological conditions in Shanghai are within safe limits. Detection work in six other coastal provinces have also revealed no change in radiation levels.China Meteorological Administration says winds were expected to carry any radiation from Japan out over the Pacific Ocean and away from China for at least the next three days.However, due to the seriousness of the accident at the Fukushima nuclear plant, China will continue its monitoring work at entry ports for any sign of radiation. Authorities promise to inform the public of the dangers of radioactive substances and precautionary measures to take in case of contamination.Meanwhile, the Ministry of Health released instructions on radiation prevention and treatment to ease the panic among the public.Yang Guoshan, research fellow of Academy of Military Medical Science, said, There are medicines for contamination of different nuclear elements. But before taking the medicine, we need to first make sure how much radiation we have been exposed to. If its a tiny amount, no treatment is needed.Experts say radiation detection and treatment should only be carried out by doctors. The government is also urging its people not to buy or take iodine for fear of nuclear contamination. Japanese goods undergo radiation checksAs quake-stricken Japan attempts to cool overheating reactors at damaged nuclear power plants, Other Asian countries have begun checking food products for radiation.Amid all the fear and panic over the nuclear leak, the UN health body said there was no evidence of contamination outside of Japan. The World Health Organization is also warning against rumors falsely saying a radiation cloud was spreading across Asia.In South Korea both vendors and consumers of Japanese food are concerned. In this Japanese restaurant in Seoul the owner is worried that she will not be able to stock up on food, since food imports from Japan are now being strictly checked by the local government.Mathumoto Hitomi, CEO of Japanese Restaurant, said, Our food stuffs are all imported from Japan, so its likely I need to replace them with Korean goods in the near future.Consumers are nervous about eating food imported from Japan, fearing it might now be contaminated by radiation and lead to cancers and abnormalities to unborn babies.Lee Hyun-Hee, S. Korean Consumer, said, We use Japanese ingredients a lot here. It will be better not to consume the food that is imported from Japan for a while.In South Korea, the import rate of Japanese goods is expected to decrease sharply after recent events.Elsewhere in Asia, many countries have also begun monitoring radiation levels to detect for isotopes.In Thailand, samples of Japanese seafood are collected at the International Airport.The merchandise will be kept away from the Thai market until the test has proven the goods are safe to consume.China, Japans largest trading partner, has also issued an order to monitor the radiation levels of Japanese goods to see if there is any possible contamination.Latest supervision: China unaffected by radiation leaksChina has begun monitoring radiation across the country after the leak of radioactive material at the crippled Fukushima nuclear power plant in Japan. The latest results show that China is so far unaffected. In northeast Chinas Liaoning Province, the provincial Nuclear Safety Administration immediately ordered its radiation monitoring stations in Dandong, Dalian and Shenyang to make a complete check for any radioactivity in the atmosphere. New tests have been carried out including site sampling and lab analysis since Sunday.Zhao Changfu, Dep. Director-General of Liaoning Environment Protection Dept, said, Nothing unusual has been discovered for five days.In the coastal city of Yantai in Shandong Province, the citys environment monitoring station has also carried out all-day tests since Saturday.Meanwhile, seven radiation monitoring stations in Southeast Chinas Jiangsu Province have been put to work and the figures can be updated as quickly as every five seconds. The Province is also collecting air samples.Kuang Heng, Suzhou Nuclear & Radiation Safety Monitoring Stn, said, The figures are within the normal range and nothing unusual has been discovered.Ningbos monitoring station in Zhejiang Province has enacted its emergency plan since the quake and radiation levels are also normal there.WHO: Potassium iodide pills are not radiation antidotesThe World Health Organization says, on its website, that potassium iodide pills are not radiation antidotes.It says, they dont protect against external radiation or against any other radioactive substances, apart from radioactive iodine.They may also cause medical complications, for some individuals such as people, with poorly functioning kidneys.Therefore, taking potassium iodide, should be started only when there is a CLEAR public health recommendation to do so.NuclearRadiationNuclear powers danger to health ,safety ,and evey life itself can be summed up in one word:radiation. Nuclear radiation has a certain mystery about it ,partly because it cannot be detected by human senses.It cant be seen or heard ,or touched or started ,even though it may be all aruond us.These are other things like that.For example ,radio waves are all around us but we cant detect them or sense them without a radio reeiver.Similarly ,we cant sense radioactivity without a radiation detector.But unlike common radio waves ,nuclear radiation is not harmless to human beings and other living things. At very high levels ,radiation can kill an animal or human being outright by killing off cells in vital organs .But even the lowest levels can do serious damage.There is no levels of radiation that is completely safe.If the radiation does not hit anything important ,the damage amy not be significant.This is the case when only a few cells are hit,and if they are killed outright ,your body will replace the dead cells with health ones.But if the few cells are only damaged ,and if they reproduce themselves ,you may be in trouble.They reproduce themselves in a deformaed way.They may grow into cancer.Sometimes this does not show up for many years.Nuclear and radiation accidentsA nuclear and radiation accident is defined by the International Atomic Energy Agency as an event that has led to significant consequences to people, the environment or the facility. Examples include lethal effects to individuals, large radioactivity release to the environment, or reactor core melt.2 The prime example of a major nuclear accident is one in which a reactor core is damaged and significant amounts of radiation are released, such as in the Chernobyl Disaster in 1986.The impact of nuclear accidents has been a topic of debate practically since the first nuclear reactors were constructed. It has also been a key factor in public concern about nuclear facilities.3 Some technical measures to reduce the risk of accidents or to minimize the amount of radioactivity released to the environment have been adopted. Despite the use of such measures, there have been many accidents with varying impacts as well near misses and incidents.34Benjamin K. Sovacool has reported that worldwide there have been 99 accidents at nuclear power plants.5 Fifty-seven accidents have occurred since the Chernobyl disaster, and 57% (56 out of 99) of all nuclear-related accidents have occurred in the USA.5 Serious nuclear power plant accidents include the Fukushima Daiichi nuclear disaster (2011), Chernobyl disaster (1986), Three Mile Island accident (1979), and the SL-1 accident (1961).6 Stuart Arm states, apart from Chernobyl, no nuclear workers or members of the public have ever died as a result of exposure to radiation due to a commercial nuclear reactor incident.7Nuclear-powered submarine mishaps include the K-19 reactor accident (1961),8 the K-27 reactor accident (1968),9 and the K-431 reactor accident (1985).6 Serious radiation accidents include the Kyshtym disaster, Windscale fire, radiotherapy accident in Costa Rica,10 radiotherapy accident in Zaragoza,11 radiation accident in Morocco,12 Goiania accident,13 radiation accident in Mexico City, radiotherapy unit accident in Thailand,14 and the Mayapuri radiological accident in India.14The International Atomic Energy Agency maintains a website reporting recent accidentsNuclear power plant accidentsOne of the worst nuclear accidents to date was the Chernobyl disaster which occurred in 1986 in Ukraine. That accident killed 30 people directly, as well as damaging approximately $7 billion of property. A study published in 2005 estimates that there will eventually be up to 4,000 additional cancer deaths related to the accident among those exposed to significant radiation levels.16 Radioactive fallout from the accident was concentrated in areas of Belarus, Ukraine and Russia. Approximately 350,000 people were forcibly resettled away from these areas soon after the accident.16Benjamin K. Sovacool has reported that worldwide there have been 99 accidents at nuclear power plants from 1952 to 2009 (defined as incidents that either resulted in the loss of human life or more than US$50,000 of property damage, the amount the US federal government uses to define major energy accidents that must be reported), totaling US$20.5 billion in property damages.5 Fifty-seven accidents have occurred since the Chernobyl disaster, and almost two-thirds (56 out of 99) of all nuclear-related accidents have occurred in the USA. There have been comparatively few fatalities associated with nuclear power plant accidents.5Accident typesFor a list of many of the most important accidents see the International Atomic Energy Agency site.41edit Loss of coolant accidentMain article: Loss of coolantSee also: Nuclear meltdownand Design basis accidentedit Criticality accidentsA criticality accident (also sometimes referred to as an excursion or power excursion) occurs when a nuclear chain reaction is accidentally allowed to occur in fissile material, such as enriched uranium or plutonium. The Chernobyl accident is an example of a criticality accident. This accident destroyed a reactor at the plant and left a large geographic area uninhabitable. In a smaller scale accident at Sarov a technician working with highly enriched uranium was irradiated while preparing an experiment involving a sphere of fissile material. The Sarov accident is interesting because the system remained critical for many days before it could be stopped, though safely located in a shielded experimental hall.42 This is an example of a limited scope accident where only a few people can be harmed, while no release of radioactivity into the environment occurred. A criticality accident with limited off site release of both radiation (gamma and neutron) and a very small release of radioactivity occurred at Tokaimura in 1999 during the production of enriched uranium fuel.43 Two workers died, a third was permanently injured, and 350 citizens were exposed to radiation.edit Decay heatDecay heat accidents are where the heat generated by the radioactive decay causes harm. In a large nuclear reactor, a loss of coolant accident can damage the core: for example, at Three Mile Island a recently shutdown (SCRAMed) PWR reactor was left for a length of time without cooling water. As a result the nuclear fuel was damaged, and the core partially melted. The removal of the decay heat is a significant reactor safety concern, especially shortly after shutdown. Failure to remove decay heat may cause the reactor core temperature to rise to dangerous levels and has caused nuclear accidents. The heat removal is usually achieved through several redundant and diverse systems, and the heat is often dissipated to an ultimate heat sink which has a large capacity and requires no active power, though this method is typically used after decay heat has reduced to a very small value. However, the main cause of release of radioactivity in the Three Mile Island accident was a pilot-operated relief valve on the primary loop which stuck in the open position. This caused the overflow tank into which it drained to rupture and release large amounts of radioactive cooling water into the containment building.In 2011, an earthquake and tsunami caused a loss of power to two plants in Fukushima, Japan, crippling the reactor as decay heat caused 90% of the fuel rods in the core of the Daiichi Unit 3 reactor to become uncovered.44 As of May 30, 2011, the removal of decay heat is still a cause for concern.edit TransportTransport accidents can cause a release of radioactivity resulting in contamination or shielding to be damaged resulting in direct irradiation. In Cochabamba a defective gamma radiography set was transported in a passenger bus as cargo. The gamma source was outside the shielding, and it irradiated some bus passengers.In the United Kingdom, it was revealed in a court case that in March 2002 a radiotherapy source was transported from Leeds to Sellafield with defective shielding. The shielding had a gap on the underside. It is thought that no human has been seriously harmed by the escaping radiation.45edit Equipment failureEquipment failure is one possible type of accident, recently at Biaystok in Poland the electronics associated with a particle accelerator used for the treatment of cancer suffered a malfunction.46 This then led to the overexposure of at least one patient. While the initial failure was the simple failure of a semiconductor diode, it set in motion a series of events which led to a radiation injury.A related cause of accidents is failure of control software, as in the cases involving the Therac-25 medical radiotherapy equipment: the elimination of a hardware safety interlock in a new design model exposed a previously undetected bug in the control software, which could lead to patients receiving massive overdoses under a specific set of conditions.edit Human errorA sketch used by doctors to determine the amount of radiation to which each person had been exposed during the Slotin excursionMany of the major nuclear accidents have been directly attributable to operator or human error. This was obviously the case in the analysis of both the Chernobyl and TMI-2 accidents. At Chernobyl, a test procedure was being conducted prior to the accident. The leaders of the test permitted operators to disable and ignore key protection circuits and warnings that would have normally shut the reactor down. At TMI-2, operators permitted thousands of gallons of water to escape from the reactor plant before observing