Explosion After Chernobyl Disaster Of 1986 Engineering Essay

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This research report is about Japan Fukushima Nuclear Power Plant disaster on 11th March 2011 which was the worst nuclear explosion after Chernobyl disaster of 1986. After gone through this case of studies, the awareness in safety factors are the main priority in industrial management and manufacturing. It will also improving a knowledge in handling, managing, preventive, maintaining the safety factors and handling any crisis on a industrial management.

INTRODUCTION

March 11, 2011, this earthquake was the largest earthquake to hit Japan in 140 years period. Continue recalled memory of the tsunami that struck 11 Asian countries in 2004. At that time, it was reported over 226,000 people in 11 countries were killed.

Japan's nuclear crisis described as the world's most serious since the Chernobyl disaster in Ukraine in 1986, deepened on March 15, 2011, when the radiation level was found to increase to harmful levels around a nuclear plant after some reactors exploded.

Prime Minister Naoto Kan urged people living within 30 kilometers of the Fukushima nuclear plant, 240 kilometers north of Tokyo, so do not leave home and save electricity. When talking about the radiation levels in reactor No.. 4 which exploded on March 15, 2011, Chief Cabinet Secretary Yukio Edano admitted that there were obvious possibilities population health can be affected.

French Embassy in the statement warned, low level radioactive wind could reach Tokyo in about 10 hours, but authorities detect radiation levels above normal earlier than that in the Japanese capital.

Radiation levels in the city of Maebashi, 100 kilometers north of Tokyo at up to 10 times the normal level, while only low levels of radiation detected in the mother country of the rising sun, the 'no problem', said city officials according to Kyodo news agency.

Regional countries are also increasingly concerned about the risk of radiation, including China. Air China airlines cancel flights to Tokyo while the Japanese government announced a no-fly zone as far as 30 kilometers around the reactor at Fukushima.

Japanese media started criticizing Kan on disaster mitigation actions and criticized the government and nuclear plant operator, TEPCO for failing to deliver full information about the incident, especially health risk.

However, the explosion in the reactor could cause civilian long-term exposure to radiation, which increases the risk of thyroid and bone cancers and leukemia, particularly to children and the unborn child.

A total of four explosions at the Fukushima plant since the complex was damaged in the earthquake and tsunami on March 11, the latest explosion at reactor No. 2.and 4, on March 15 2011.

The Fukushima nuclear disaster is natural or man-made.?

Tokyo: The nuclear accident in Fukushima last year constituted a "man-made disaster 'and not simply due to the tsunami, according to a Japanese parliamentary panel, in a final report on the disaster.

"Fukushima Nuclear Power Plant Accident TEPCO is collaborative decision by secret government, regulators and TEPCO and the lack of governance and participation.

"It affects the rights of the country to be safe from a nuclear accident. Therefore we concluded that the accident was clearly man-made, "said the chairman of the Independent Inquiry Commission Fukushima Nuclear Accident, Kiyoshi Kurokawa.

"We believe that the real cause is the regulatory and supervisory system that supports the rationale for decisions and actions damage over issues related to the inability of certain individuals."

An earlier report by the plant operator Tokyo Electric Power (TEPCO) to explain all major utility says that the consequence of the earthquake and tsunami that are out of the expectations.

But an independent group of journalists who report their results in February said that TEPCO can and should do more.

It also says that, if the company involved for the solution, the employee shall be transferred from the crippled plant and the disaster could spread far beyond all expectations.

Results published recently urged further investigation of the impact an earthquake measuring 9.0 contrary to the tsunami affected reactors at Fukushima.

The industrial process and operation of the Fukushima nuclear plant.

Nuclear Power Plant Fukushima I, also known as Fukushima Dai-ichi ,is a nuclear power plant located at a parcel of land with an area of 3,500,000-square-meter (860-acre) in the town of Okuma and Futaba in the Futaba District, Fukushima Province, Japan. Plant that was first used in 1971 consisted of six boiling water reactors (boiling water reactor, BWR). Light-water reactors are driving electrical generators with a total power of 4.7 GWe, making Fukushima I as one of the 15 largest nuclear power stations in the world. Fukushima I was the first nuclear plant built and operated entirely by the Tokyo Electric Power Company (TEPCO). The plant suffered severe damage from the earthquake and the subsequent 9.0 tsunami that hit Japan on March 11, 2011, thus disabling the reactor cooling system stoking widespread move order in surrounding plants, so they have no hope to reopen.

Fukushima II Nuclear Power Plant, or Fukushima Dai-ni, located 11.5 kilometers (7.1 mi) south of Fukushima I and also run by TEPCO.

Reactors for Units 1, 2, and 6 supplied by General Electric, those for Units 3 and 5 by Toshiba, and Unit 4 by Hitachi. All six reactors designed by General Electric. The design of the units is made by General Electric Ebasco. All construction work done by Kajima. Since September 2010, Unit 3 generated by a small proportion (6%) oxide fuel blend (mixed oxide, MOX), in contrast to low enriched uranium (low Enriched uranium, LEU) used in the other reactors. Units 1-5 are used to structure the Mark I containment type (light bulb torus). Mark I containment structure plus a little volume by Japanese engineers. Unit 6 has a Mark II type containment structure (up / down).

Unit 1 is a 460 MW boiling water reactor (BWR-3) constructed in July 1967. It commenced commercial electrical production on 26 March 1971, and the first is scheduled to close in early 2011. In February 2011, the authorities allowed the reactor operation is extended for another 10 years. Unfortunately, the damaged Unit 1 result Tohoku earthquake and tsunami of 2011.

Unit 1 is designed for a peak ground acceleration of 0:18 g (1.74 m/s2) and a response spectrum based on the 1952 Kern County earthquake. Basic design of Unit 3 and 6 respectively are 0:45 g (4.41 m/s2) and 0.46 g (4:48 m/s2). All units undergo checks after the 1978 Miyagi earthquake when the ground acceleration of 0125 g (1.22 m/s2) for 30 seconds, but was found not to damage the parts most important reactor. The design basis for tsunamis was 5.7 meters.

The impact of the Fukushima nuclear disaster to the society, ecology, sociology and health.

4.1 Impact to the Society

The nuclear disaster caused the people who stayed at the Fukushima to move out from their residence. After the declaration of the nuclear emergency, the Government ordered an evacuation for the residents. Around 170, 000 - 200, 000 people was officially evacuated on 13 March 2011.

Due to the evacuation, the daily life of the residents was not the same as before anymore. The residents lost their houses, daily needs and lots of their properties. This was because these residents that were evacuate, were asked to stay inside, close doors and windows and turn off their air conditioning by the NHK on the 12 March 2011, and reported by The Guardian. They were also advised to cover their mouths for own safety with masks, towels and not to drink the tap water.

4.2 Impact to the Ecology

The nuclear power caused mutations in some insects and animals . The discovery raised concerns that local residents due to leakage of nuclear radiation will have an impact on other species

Some scientists say about 12 percent of moth larvae pale blue grass exposed to nuclear radiation after a tsunami hit northeastern Japan on March 2011 are found to have such peculiarities have small wings and a damaged eye

Joji Otaki is a scientists who is associate professor at the University of Ryukyu, Okinawa tell, all the insects bred in a laboratory outside the radioactive zone with 18 percent of the children of butterflies have the same problem

However, this figure rose to 34 percent when it comes to the third generation species

The research team also gathers 240 tail butterfly in Fukushima in September last year, six months after the tsunami occurred

Otaki, said that 52 percent of insects have thus abnormal nature is a very high proportion

4.3 Impact to the Sociology

The greatest impact in terms of sociology in Japan is Japanese government has said will help to increase the assets of Fukushima by providing a fund of $ 13 billion to $ 27 billion. Funds will also be raised from local banks and private companies in Japan to help the power plant to get going again. TEPCO's infrastructure will be able to rise again with the intervention of local investors. This is one of the strategies undertaken by the government to save a giant company which is essential for energy production and the national economy.

"Future discussions about sustainability and 'eco-friendly' community planning need to take into consideration natural disasters, such as tsunami and earthquakes. He added, what happened in Japan was not simply some freak accident triggered by a natural disaster." - Hoichi Hasegawa.

After what happened, clearly indicates that this is a problem of the natural sciences. Sociologists and social scientists also help to reduce the profound impact of what has happened. They are now trying to get up to rebuild communities destroyed by the earthquake, tsunami and the Fukushima tragedy through a national approach. They are said to be able to contribute significantly to the sustainable planning.The values ​​that can be learned by the sociologist is in terms of the weather forecast, resilient techniques during disasters, how people react during a disaster, how quickly and effectively in dealing with social stigma, isolation of those who survived, how to heal their trauma and rebuilding communities after disasters.

Social policies in Fukushima, Japan rebuild energy which will be carried out by sociologists. It is very complicated as it is hard to predict the next disaster will hit (if any). It will be dealt with more or less good if the magnitude of what had happened. In terms of social cost will also be improved only by collective efforts and discipline by sociologists who work in environmental planning and disaster.This disaster is said to have resulted in the capacity of electricity produced has decreased by about 45% than before.

4.4 Impact to the Health

In terms of health, many felt around the disaster impact. Estimated death shortly earthquake and tsunami stood at 20,000 people. However, no deaths were recorded during radiation warning issued in Fukushima. What is disturbing, said Fukushima leak will produce 1,000 types of cancer-related deaths in the future.

From the angle of radiation, what happened, Fukushima radiation release critically polluted "dead zone" of several hundred square kilometers around the plant, and low levels of radioactive material have been found around North America and Europe. The radiation exposure to the surrounding population is small, 19 percent of released radiation deposited on land and most of it dumped in the Pacific.

A month after the disaster, the head of the United Nations Committee of Science Effects of Atomic Radiation, predicted that there would be no serious health consequences of radiation-induced public.The United States has predicted experience between 0 and 12 and 0 and 30 deaths morbidities cancer, however the method is less specific in areas that only low concentrations of radionuclides.

Steps have been taken by the Japanese government is to transfer the Japanese government agencies 20 kilometer radius around the plant and distribute iodine tablets to prevent the intake of radioiodine. The government also prohibits the planting on the verge of radiation. Research to be about 600 deaths was reported during the migration process. Most of the cases are due to exhaustion and exposure among the elderly and chronically ill.

(Jacobson, 2012) stated that "You still have an obligation to transfer the people who according to the worst case scenario."

The actions taken by Tokyo Electric Power Company (TEPCO), government and the regulatory body during the occurrence of the Fukushima nuclear disaster.

Instruction issued that people within a 20 km (12 mi) zone around the Fukushima Daiichi nuclear plant must leave, and urged that those living between 20 km and 30 km from the site to stay indoors by Prime Minister Naoto Kan. The latter groups were also instructed to evacuate. Morethan 50,000 people were evacuated during 12 March. The figure increased to 170,000-200,000 people on 13 March, after officials voiced the possibility of a meltdown.

Anti-nuclear stance in the months following the Fukushima disaster. The is order from Japanese government the aging Hamaoka Nuclear Power Plant be closed over earthquake and tsunami fears, and also would freeze plans to build new reactors. In July 2011, Mr. Kan said that "Japan should reduce and eventually eliminate its dependence on nuclear energy saying that the Fukushima accident had demonstrated the dangers of the technology". In August 2011, the Japanese Government passed a bill to subsidize electricity from renewable energy sources. An energy white paper, approved by the Japanese Cabinet in October 2011, says "public confidence in safety of nuclear power was greatly damaged" by the Fukushima disaster, and calls for a reduction in the nation's reliance on nuclear power.

TEPCO notified authorities, as required by law, of a "First level emergency".The Fukushima II plant, which was also struck by the tsunami, incorporated design changes which improved its resistance to flooding and it sustained less damage. Generators and related electrical distribution equipment were located in the watertight reactor building, so that power from the grid was being used by midnight.Seawater pumps for cooling were given protection from flooding, and although 3 of 4 failed in the tsunami, they were able to be restored to operation.In the late 1990s, three additional backup generators for reactors Nos. 2 and 4 were placed in new buildings located higher on the hillside, to comply with new regulatory requirements. All six reactors were given access to these generators, but the switching stations that sent power from these backup generators to the reactors' cooling systems for Units 1 through 5 were still in the poorly protected turbine buildings. All three of the generators added in the late 1990s were operational after the tsunami. If the switching stations had been moved to inside the reactor buildings or to other flood-proof locations, power would have been provided by these generators to the reactors' cooling systems.

After the diesel generators located in the turbine buildings failed, emergency power for control systems was supplied by batteries that were designed to last about eight hours. Further batteries and mobile generators were dispatched to the site, delayed by poor road conditions with the first not arrivingalmost six hours after the tsunami struck.

Attempts to connect portable generating equipment to power water pumps were eventually discontinued after numerous attempts, as the connection point in the Turbine Hall basement was flooded and because of difficulties finding suitable cables.TEPCO switched its efforts to installing new lines from the grid to the cooling systems.One plant generator at Unit 6 was restored to operation on 17 March, and external power returned to Units 5 and 6, on 20 March, allowing cooling equipment to be restarted.

Responders include International Atomic Energy Agency, World Meteorological Organization and the Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization, which has radiation detection equipment deployed around the world.

Many countries have advised their nationals to leave Tokyo, citing the risk associated with the nuclear plants' on going accident. International experts have said that a workforce in the hundreds or even thousands would take years or decades to clean up the area. Stock prices of many energy companies reliant on nuclear sources have dropped, while renewable energy companies have increased dramatically in value.

There has been a significant re-evaluation of existing nuclear power programs in many countries. What had been growing acceptance of nuclear power in the United States was eroded sharply following the 2011 Japanese nuclear accidents. World-wide, a study by UBS, reported on 12 April 2011, suggests that around 30 nuclear plants may be closed as a result Increased anti-nuclear sentiment has been evident in India, Italy, Germany, Spain, Switzerland, Taiwan, and the United States.

Every company that operates a nuclear power plant has committed to order new backup emergency equipment. More than 300 pieces of safety equipment already have been installed or ordered. Operators of nuclear energy facilities have taken steps to make safe plants even safer.

Effective preventive action to be strengthen by Tokyo Electric Power Company (TEPCO) in re-examine the nuclear plant safety.

Tsunami has caused unimagined disaster to Fukushima power plant. It cause lot of problems and damaged. Many parties concerned to participate to help solve the problems faced at the time.

The power had failed at 3:42 pm and even then, the reactor core will still produce about 1.5% of their nominal power of heat, about one hour after the close of the fission reaction, based on the decay of fission products - the reactor core produces about 22 MW in 1 unit and 33 MW in unit 2 & 3.Many steams were generated in the reactor pressure vessel housing the core because no removal by blood flows to the external heat exchanger. It is released into the main dry containment (PCV), through a safety valve. The hydrogen produced by the interaction of the fuel cladding very hot zirconium with steam after the water level dropped will join the steam release.

When the pressure started to rise here, the steam is directed into a chamber below the reactor oppression (in containment), but what is worrying is that the internal temperature and pressure increased dramatically.Therefore, water injection had started. Where, various systems available to this and eventually Emergency Core Cooling System (ECCS) is used. More alarming, the system gradually failed for three days. Therefore, water injection began to reactor pressure vessel (RPV) through the fire pump.But this will require internal pressure to be released initially by venting to the suppression chamber/wetwell.

In unit 1, as all know, the water level falls on fuel about three hours after the scram at 6 pm and the fuel coincide 1.5 hours later at 07:30. The temperature of the exposed fuel has risen to some 2800°C. Therefore, what is happening, the center began to melt after a few hours, and 16 hours after the scram at 7am on Saturday (12th March 2011), most of it had fallen into the water at the bottom of the RPV. Since then, the RPV temperature has dropped continuously without control.

At about 2:30 pm on Saturday (12th March 2011), when the pressure is increased, several attempts have been made to release the containment, and when the external power and compressed air source utilized successfully. Venting was designed to be through a heap outside, but in the absence of a lot of power has been caused to flow back to the top of the reactor building, which cause serious system failure. Hydrogen was vented steam escort, noble gases and aerosols. At 15:36 on Saturday (12th March 2011), a hydrogen explosion has occurred at the level of building services in the unit 1 reactor containment. The explosion caused the roof blew off and the cladding at the top of the building. Worse fuel decay heat problems, hydrogen has been mixed with air and ignited. As we know, Zirconium cladding oxidation at high temperatures in the presence of steam will produce hydrogen exothermic.

What happens in the unit 1 is in most of the core, as the corium consisting of liquid fuel and control rods, it was assumed to be at the bottom of the RPV, but then it appeared that it was mostly through the bottom of the RPV and erode some about 65cm below the concrete drywell which is 2.6m thick. This has reduced the intensity of the heat and allows the mass to solidify.

What happens in units 2 &unit 3 also seems most liquid fuel to a certain level, but to a lesser degree than what is happening in unit 1, in one or two days later. In mid-May, the core at unit 1 still will produce 1.8 MW of heat while unit 2 & 3 will produce about 3.0 MW each. Meanwhile, in unit 2, the injection of water using steam-driven back-up water injection system has failed on Monday (14th March 2011). It is about six hours before the injection of seawater using fire pumps to the RPV. Delays occur because the pressure is released through the RPV had wetwell, which requires power and nitrogen, before the fire pump can be used. After cooling back-up has been lost, the reactor water level decreased dramatically.

Core damage began about 8 pm, and it is now understood that while a lot of fuel then melted and might fall into the water at the bottom of the RPV about 100 hours after the scram. Pressure was released at 13 and again at 15, to avoid a repetition of the unit 1 hydrogen explosion, while the blowout panel, near the top of the building opened. In the early Tuesday (15th March 2011), the pressure suppression chamber under actual reactor seems to be broken, probably due to hydrogen explosion there and containment drywell pressure in the fall. Subsequent inspection suppression chamber does not support the interpretation that is due to state it breaks. Later analysis suggested that PCV leak developed on Tuesday (15th March 2011).

In unit 3, at 11am on the Saturday (12th March 2011) and early in the Sunday (13th March 2011), the main back-up water injection system failed water injection using high pressure system fail and the water level drops dramatically. Injection of seawater using fire pumps have been done shortly before noon and RPV pressure was reduced by venting steam into the wetwell. What happened next, early on Sunday venting chamber oppression and control has been successfully implemented. The result is now understood that the core damage started about 9 am and many or all of the liquid fuel in the morning of Sunday (13th March 2011) and may fall into the water below the RPV, or maintained at the core shroud support plate.

Early on the Monday (14th March 2011), PCV venting recurrence, and this turned out to backflow to level of building services at 11 am, a very large hydrogen explosion occurred here at the unit 3 reactor which has caused much blew off the roof and walls and pulled down the top of the building. Worse case, this explosion created a lot of debris, and some on the ground near the 3 units is highly radioactive.

In defueled unit 4, on Tuesday (14th March 2011) at about 6 am, there was an explosion has occurred again. This time the building was destroyed and another damaged unit 3 superstructure. This is apparently of hydrogen arising in unit 3 and unit 4 as a result of backflow in a shared channel when released from unit 3.For that, the water had to and was injected into each of three reactor units more or less continuously. External heat exchanger water had to be used to boil off for a few months in the absence of normal heat removal.

More worried, there radioactive emission peak at 15, but the source is still uncertain. It is constantly changing due to volatile fission products and easy-airborne being carried by hydrogen and steam, hydrogen explosion venting and releasing a lot of radioactive material into the atmosphere, especially iodine and cesium. In June, that it is estimated that 800kg -1000 kg of hydrogen was produced in each unit.

Nitrogen is injected into all three reactor containment vessel in an attempt to remove concerns about further hydrogen explosions, and in December has also been initiated for pressure vessels. Gas control system has been done. This system is used to extract and purify the gas from the PCV to prevent leakage of cesium occurred was assigned to unit 1, unit 2 and unit 3. Using a technique of injection into the RPVs, water is circulated through a new water treatment plant to achieve cooling is quite effective, and the temperature is below a RPVs stable in the range 60-76 ° C at end-October, and 27-54 ° C in mid-January.

RPV pressure is slightly above the atmosphere (102-109 kPa) in January, due to water and nitrogen injection. However, because they leak, common definitions of "cold shutdown" does not apply, and Tepco wait to bring under the control of radioactive releases before declaring "a state of cold shutdown" in mid-December, with the approval of NISA. This, with the Prime Minister's announcement, officially brought to a close phase of the 'accident' events.The AC electricity supply from external source was connected to all units by 22 March.  Power was restored to instrumentation in all units except unit 3 by 25 March. However, radiation levels inside the plant were so high that normal access was impossible until June.

CONCLUSION

Based on these reports of collusion between corporate power and the nuclear regulator, causing a lack of security measures in reducing disaster..Nuclear disaster at Fukushima as a result of great earthquake and devastating tsunami March 11, 2011, could not be categorized as a natural disaster. Similarly, the commission concluded investigator in parliaments Japanese.

Atomic disaster at Fukushima Daiichi NPP is the result of human error. Because frankly it is predictable and can be prevented. But effective action to respond to disasters, adverse impacts could be reduced to light. So final conclusions commission investigator in parliaments Japanese.

In three of four Fukushima Daiichi NPP reactor core melting occurred atoms. Also the volume of radioactive substances leaking into the atmosphere large enough,

Meanwhile, the president of TEPCO Fukushima NPP operator, Naomi Hirose said, will rehabilitate four atomic reactors in Fukusima-Daini NPP which also suffered damage, but lighter than Fukushima Daiichi. The atomic experts warn danger if the reactor is activated again.

Pictures.

C:\Users\Wayne\Desktop\fukushima-before-1.jpg

Picture taken before Fukushima disaster

C:\Users\Wayne\Desktop\JapanNuclearPlantDamage.jpg

Before and after picture of Fukushima Plant

C:\Users\Wayne\Desktop\fukushima-butterflies-3.jpgC:\Users\Wayne\Desktop\Fukushima Rabbit.jpg

Animals and insects that effected in Fukushima disaster

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