Introduction
Disaster hit Japan Fukushima Daiichi nuclear power station on March 11, 2011,
Due to the wide release of radioactivity from the Chernobyl accident in 1986 and is far worse than the 1979 Three Mile Island accident in the United States. Unlike at Chernobyl and Three Mile Island, Fukushima destruction was initiated by natural disasters massive earthquake and tsunami rather than equipment failure and human error. The tsunami knocked out the backup power systems needed to cool the reactors at the plant, causing some of them to undergo melting fuel, hydrogen explosions and radioactive releases. Fukushima disaster studies have identified changes in the design, response actions, and other safety improvements that can be reduced or eliminated the amount of radioactivity released from the factory. As a result, Fukushima has prompted a re-examination of nuclear safety requirements around the world, including the United States.
Radioactive contamination from the Fukushima plant forced the evacuation of communities up to 25 miles away, which affects up to 100,000 people, many of them forever barred from their homes. Believed to have prevented the transfer of radiation exposure among residents of Japanese regulatory limits in most cases. Near-term mortality and morbidity resulting from radiation may not be believed; even cancer and other long-term health effects remain possible. Workers at the plant exposed to radiation levels far higher, with at least two suffered radiation burns on their feet after wading in contaminated water. Two other workers drown in the tsunami.
Disaster recovery has focused on restoring the cooling systems at three of the most badly damaged reactors at the plant six units and stop the radioactive emissions into air and water. The work has been affected by high radiation levels in the plant and the continuing severe structural damage. Japanese government announced December 16, 2011, that damaged the Fukushima reactors has reached "cold shutdown," a milestone in the reactor cooling water is below the boiling temperature at atmospheric pressure. In the winter closure, the threat of further releases of radioactive decline may allow some residents to begin returning to the least contaminated evacuation zone.
Japan's environment minister announced December 19, 2011 that about $ 15 billion was
Provided for the contamination of the plant Fukushima Daiichi, an undertaking that has ever occurred before. Complete decommissioning and dismantling the plant is expected to take 40 years, and the total cost of disasters recently estimated by the committee of the Japanese government exceeded $ 75 billion.
Institute of Nuclear Power Operations (INPO), a security organization established by the U.S. nuclear power industry after the Three Mile Island accident, issue a detailed description of the Fukushima accident in November 2011. INPO report provides a timeline of actions taken in response to each unit Fukushima Daiichi plant and the sequence of events leading to the main reactor core damage and radioactive release. It aims "to provide accurate, consolidated source of information" about the event. However, the report notes, "Because of the extensive damage at the site, some of the event details are not known or have not been confirmed.
The purpose of this CRS report is to highlight aspects of the Fukushima disaster that may bear on the safety of U.S. nuclear plants and nuclear energy policy in general. It gives a brief explanation of the Fukushima incident, including new details provided by INPO reports, public discourse by the disaster, and a description of U.S. aid given to Japan.
Summary
The huge earthquake and tsunami that struck Japan's Fukushima Daiichi nuclear power station on March 11, 2011, knocked out backup power systems that were needed to cool the reactors at the plant, causing three of them to undergo fuel melting, hydrogen explosions, and radioactive releases. Radioactive contamination from the Fukushima plant forced the evacuation of communities up to 25 miles away and affected up to 100,000 residents, although it did not cause any immediate deaths.
Tokyo Electric Power Company (TEPCO) operates the Fukushima nuclear power complex in the Futaba district of Fukushima prefecture in Northern Japan, consisting of six nuclear units at the Fukushima Daiichi station and four nuclear units at the Fukushima Daini station. All the units at the Fukushima complex are boiling water reactors, with reactors 1 to 5 at the Fukushima Daiichi site being the General Electric Mark I design, which is also used in the United States. The Fukushima Daiichi reactors entered commercial operation in the years from 1971 (reactor 1) to 1979 (reactor 6). The Fukushima Daini reactors shut down automatically after the earthquake and were able to maintain sufficient cooling.
When the earthquake struck, Fukushima Daiichi units 1, 2, and 3 were generating electricity and shut down automatically. The earthquake caused offsite power supplies to be lost, and backup diesel generators started up as designed to supply backup power. However, the subsequent tsunami flooded the electrical switchgear for the diesel generators, causing most AC power in units 1 to 4 to be lost. Because Unit 4 was undergoing a maintenance shutdown, all of its nuclear fuel had been removed and placed in the unit's spent fuel storage pool. One generator continued operating to cool units 5 and 6.
The loss of all AC power in units 1 to 3 prevented valves and pumps from operating that were
needed to remove heat and pressure that was being generated by the radioactive decay of the
nuclear fuel in the reactor cores. As the fuel rods in the reactor cores overheated, they reacted
with steam to produce large amounts of hydrogen, which escaped into the unit 1, 3, and 4 reactor buildings and exploded (the hydrogen that exploded in Unit 4 is believed to have come from Unit 3). The explosions interfered with efforts by plant workers to restore cooling and helped spread radioactivity. Cooling was also lost in the reactors' spent fuel pools, although recent analysis has found that no significant overheating took place.
Radioactive material released into the atmosphere produced extremely high radiation dose rates near the plant and left large areas of land uninhabitable, especially to the northwest of the plant.
Picture 1. Japan Earthquake Epicentre and Nuclear Plant Locations
The earthquake on March 11, 2011, off the east coast of Honshu, Japan's largest island, reportedly caused an automatic shutdown of 11 of Japan's 55 operating nuclear power plants.5 Most of the shutdowns proceeded without incident. However, the plants closest to the epicentre, Fukushima and Onagawa (Refer picture 1), were damaged by the earthquake and resulting tsunami. The Fukushima Daiichi plant subsequently suffered hydrogen explosions and severe nuclear fuel damage, releasing significant amounts of radioactive material into the environment.
Picture 2.General Electric Mark I Boiling Water Reactor and Containment Building
Tokyo Electric Power Company (TEPCO) operates the Fukushima nuclear power complex in the Futaba district of Fukushima prefecture in Northern Japan, consisting of six nuclear units at the Fukushima Daiichi station and four nuclear units at the Fukushima Daini station. All the units at the Fukushima complex are boiling water reactors (BWRs), with reactors 1 to 5 at the Fukushima Daiichi site being the General Electric Mark I design (Refer Picture 2). The Fukushima Daiichi reactors entered commercial operation in the years from 1971 (reactor 1) to 1979
(Reactor 6).
Identifies whether the Fukushima nuclear disaster is natural or man-made. Clearly explain your justification.
Fukushima Daiichi nuclear power plant is located in the towns of Okuma and Futaba Japan. Commissioned in 1971, this plant consists of six boiling water reactors which drove the electrical generators with a combined power of 4.7 GW, making Fukushima Daiichi one of the 15 largest nuclear power stations in the world. Fukushima was the first nuclear plant to be designed, constructed and run in conjunction with General Electric, Boise, and Tokyo Electric Power Company (TEPCO).The plant suffered major damage from the 9.0 earthquakes and subsequent tsunami that hit Japan on March 11, 2011 and, as of today, is not expected to reopen. The earthquake and tsunami disabled the reactor cooling systems, leading to nuclear radiation leaks and triggering a 30 km evacuation zone surrounding the plant. On April 20, 2011, the Japanese authorities declared the 20 km evacuation zone a no-go area which may only be entered under government supervision.
Although triggered by these cataclysmic events, the subsequent accident at the Fukushima Daiichi Nuclear Power Plant cannot be regarded as a natural disaster. Damage by the earthquake and the consequent tsunami could not be ruled out as direct causes of the disaster, however. This finding may have serious implications for Japan's intact nuclear reactors, which were shut down following the Fukushima accident. An independent investigation commission accused TEPCO and regulators at the nuclear and industrial safety agency of failing to take adequate safety measures, despite evidence that the area was susceptible to powerful earthquakes and tsunamis, Fukushima nuclear power plant accident was the result of collusion between the government, the regulators and TEPCO, and the lack of governance. It also said that, "They effectively betrayed the nation's right to be safe from nuclear accidents. It is believed that the root causes were the organisational and regulatory systems that supported faulty rationales for decisions and actions, rather than issues relating to the competency of any specific individual. Therefore, the independent investigation commission concluded that the accident was clearly 'man-made' that could and should have been foreseen and prevented.
Carefully observed the industrial process and operation of the Fukushima nuclear plant.
Any typical nuclear reactor set aside Fukushima power plant is only part of the life-cycle for nuclear power. The process starts with uranium mines situated underground, open-pit, or in-situ leach mines. Atoms of uranium are the largest and also the heaviest known to occur on earth. Being heavy they are also very unstable. The nucleus of a uranium atom can easily break up into two smaller pieces. This process is called fission. The two fragments so produced fly apart with tremendous speed. As they collide with other atoms in a lump of uranium they come to a stop. In the process they heat up the uranium lump. This is how energy is released from the atom and converted to heat. The energy produced in fission is described as atomic energy by some and nuclear energy by others.
In any case, the uranium ore is extracted, usually converted into a stable and compact form such as yellowcake, and then transported to a processing facility. Here, the yellowcake is converted to uranium hexafluoride, which is then enriched using various techniques. At this point, the enriched uranium, containing more than the natural 0.7% U-235, is used to make rods of the proper composition and geometry for the particular reactor that the fuel is destined for. The fuel rods will spend about 3 operational cycles (typically 6 years total now) inside the reactor, generally until about 3% of their uranium has been fissioned, then they will be moved to a spent fuel pool where the short lived isotopes generated by fission can decay away. After about 5 years in a spent fuel pool the spent fuel is radioactively and thermally cool enough to handle and it can be moved to dry storage casks or reprocessed.
Control of operation of the nuclear power station involves two things. Regulation of power generation to maintain it at a safe and steady level and secondly total shutdown of the reactor very quickly if needed. The power is kept constant by the use of what are known as adjuster rods. These are stainless steel rods. When these rods are introduced into the reactor vessel, the chain reaction slows down and heat generation drops. If the control rods are slightly pulled out of the reactor vessel, the chain reaction picks up and power level rises. In another word if the reactor gets too hot, the control rods are lowered in and it cools down. If that doesn't work, there are sets of emergency control rods that automatically drop in and shut the reactor down completely. To shutdown the reactor completely, the heavy water is drained out of the reactor vessel in a fraction of a second. In the absence of heavy water in the vessel, the chain reaction ceases totally. Below shows the simple process for easy understanding of Fukushima nuclear Power Plant and many others.
Advantages of nuclear power plant
Nuclear power costs about the same as coal
Does not produce smoke or carbon dioxide, so it does not contribute to the greenhouse effect
Produces small amounts of waste.
Produces huge amounts of energy from small amounts of fuel.
Nuclear power is reliable.
Disadvantages of nuclear power plant
Nuclear power is reliable, but a lot of money has to be spent on safety - if it does go wrong, a nuclear accident can be a major disaster.
Although not much waste is produced, it is very dangerous.
It must be sealed up and buried for many thousands of years to allow the radioactivity to die away.
For all that time it must be kept safe from earthquakes, flooding, terrorists and everything else.
Evaluate the impact of the Fukushima nuclear disaster to the society, ecology, sociology and health.
The collapse of the Fukushima Dai-ichi Nuclear Power Plant caused a massive release of radioactive materials to the environment. A prompt and reliable system for evaluating the biological impacts of this accident on animals has not been available. The massive release of radioactive caused physiological and genetic damage to the pale grass blue Zizeeria maha, a common lycaenid butterfly in Japan. Samples were collected in the Fukushima area in May 2011, some of which showed relatively mild abnormalities. The 1st generation offspring from the first-voltine females showed more severe abnormalities, which were inherited by the newer generation. Adult butterflies collected in September 2011 showed more severe abnormalities than those collected in May. Similar abnormalities were experimentally reproduced in individuals from a non-contaminated area by external and internal low-dose exposures. It is evident that artificial radionuclides from the Fukushima Nuclear Power Plant caused physiological and genetic damage to this species. The triple disaster has highlighted and compounded such pre-existing underlying issues as falling birth rates, the fragmenting of the family unit, and the shrinking of local communities. During the five years before the disaster, birth rates had been steadily falling in Japan. The now daily concerns about radiation levels, safe food and water have left many young couples unwilling to take on the perceived risky task of raising children in a dangerous environment. The prevalent trend during the pre-quake years, brought about primarily by lack of economic development in local communities, had been for young people to leave their villages to seek higher-paid jobs in the larger towns and cities, only returning home for holidays and other celebrations. The immediate consequence of this has been the decline of village communities. The longer-term consequence will be the erosion of regional identity, at a time when, more than ever, communities affected by the earthquake need their younger generation. Predicted future cancer deaths due to accumulated radiation exposures in the population living near Fukushima have ranged from none to 100 to a non-peer-reviewed "guesstimate" of 1,000. On 16 December 2011, Japanese authorities declared the plant to be stable, although it would take decades to decontaminate the surrounding areas and to decommission the plant altogether.
Outline the actions taken by Tokyo Electric Power Company (TEPCO), government and the regulatory body during the occurrence of the Fukushima nuclear disaster.
Roadmap towards the decommissioning of Units 1-4 of TEPCO Fukushima Daiichi Nuclear Power Station
Cold Shutdown Condition is maintained at Unit 1-3. Measures to complement status monitoring are being implemented.
Investigation of the inside of Unit 1 PCV and installation of PCV thermometer and water gauge
Installation of Unit 2 RPV alternative thermometer
Countermeasures against accumulated water increased by groundwater intrusion
Groundwater intrusion prevention (Groundwater bypass)
Removal of radioactive materials (Multi-nuclide removal equipment installation)
Storage of contaminated water/treated water (Additional tanks)
Continue implementation of measures to minimize the impact of radiation on the area outside the power station
Effective radiation dose reduction at the site boundaries
Reduction of densities of radioactive materials included in the seawater in the port
Preparation for fuel removal from the spent fuel pool is in progress
Debris removal from the upper part of Units 3-4 Reactor Building and cover installation for fuel removal at Unit 4
Soundness investigation of the unused (unirradiated) fuel in Unit 4 spent fuel pool
Securing a sufficient number of workers and work safety
Ensuring the APD usage and collaboration with cooperative companies
Heat stroke prevention
Research and development for fuel debris removal and radioactive waste processing and disposal
Decontamination of the inside of buildings and development of the comprehensive radiation dose reduction plan
Investigation and repair of the leakage on the bottom of the PCV
Understanding and analyzing the condition of the inside of the reactor
Characterization of fuel debris and preparation for fuel debris processing
Radioactive waste processing and disposal
Strengthening of Research and Development management
Future plan for research centres
Research and Development Management Headquarters
Securing and fostering human resources from a long- and-midterm perspective
Apart from all those mentioned above, Japan have also taken lots more step as per below during the occurrence of the nuclear power plant disaster
Investigations of the Japanese Lower House
New legal restrictions for exposure to radiation proposed
Request for decommissioning the Tokai Daini Power plant
Fukushima wants all 10 nuclear reactors scrapped
TEPCO request for government compensation
At least 1 trillion yen needed for decontamination
Majority of Japanese nuclear reactors taken off line
Extra staff members for Kiev embassy
Energy debate changed in Japan
40 year limit for life span of nuclear reactors
Food-aid used to lower fears for contaminated food abroad
Okuma asked to be declared as no-go-zone
Postponement of analogue shutdown in Fukushima
No return-zone
Evacuation zone partial lifted
Monitoring the impact of radiation-exposure at the health of residents
Testing School lunches
Stress-tests
Debris disposal
Interim Storage facility
Criminal charges against NISA, NSA and TEPCO
Compensation criteria for former residents of the evacuation zones
Propose effective preventive action to be strengthen by Tokyo Electric Power Company (TEPCO) in re-examine the nuclear plant safety.
Before the Fukushima Dai-ichi nuclear disaster, TEPCO did not put in place tsunami protection measures as part of its accident management program. The TEPCO's measures against a situation, in which reactor cores are seriously damaged by a natural disaster other than a tsunami, were also quite deficient. This came to light from the testimony of several TEPCO officials during hearings conducted by this Investigation Committee. At the Fukushima Dai-ichi , three of its nuclear reactors got severe simultaneous damage. After flooding cut off all power supply, there was no defense at all to deal with this, making it extremely difficult to cope with the situation. One can only conclude that TEPCO's lack of prior accident management measures to deal with a tsunami was an extremely serious problem. Nevertheless below are the guidelines TEPCO should consider in re-examining the plant safety
The need for independence and transparency
Organizational preparedness for swift and effective emergency response
Recognition of its role as a provider of disaster-related information to Japan and the world
Retention of first-rate human resources such as greater specialized expertise
Efforts to collect information and acquire scientific knowledge
Recapitulation
Lack of severe accident preparedness for tsunamis
Lack of awareness of the ramifications of a multidimensional disaster
Lack of an all-encompassing perspective
Conclusion
Tepco Fukushima Nuclear Power Plant accident was the result of collusion between the government, regulators and the [private plant operators] Tepco, and the lack of governance by the said party. They effectively betrayed its right to be safe from a nuclear accident. Therefore, we concluded that the accident was clearly "man-made".
We believe that the cause of the organization and regulation rather than issues related to the competence of any particular individual.
All the right failed to develop the most basic safety requirements - such as assessing the probability of damage, ready to contain the collateral damage from any disaster, and develop evacuation plans for the public in case of a serious release of radiation.
