The FUKUSHIMA DAIICHI NUCLEAR DISASTER (福島第一原子力発電所事故, Fukushima Dai-ichi ( pronunciation ) genshiryoku hatsudensho jiko) was an energy accident at the Fukushima Daiichi Nuclear Power Plant in Fukushima , initiated primarily by the tsunami following the Tōhoku earthquake on 11 March 2011. Immediately after the earthquake, the active reactors automatically shut down their sustained fission reactions . However, the tsunami disabled the emergency generators that would have provided power to control and operate the pumps necessary to cool the reactors. The insufficient cooling led to three nuclear meltdowns , hydrogen-air explosions , and the release of radioactive material in Units 1, 2, and 3 from 12 March to 15 March. Loss of cooling also caused the pool for storing spent fuel from Reactor 4 to overheat on 15 March due to the decay heat from the fuel rods .
On 5 July 2012, the Fukushima Nuclear Accident Independent Investigation Commission (NAIIC) found that the causes of the accident had been foreseeable, and that the plant operator, Tokyo Electric Power Company (TEPCO), had failed to meet basic safety requirements such as risk assessment, preparing for containing collateral damage, and developing evacuation plans . On 12 October 2012, TEPCO admitted for the first time that it had failed to take necessary measures for fear of inviting lawsuits or protests against its nuclear plants.
The Fukushima disaster was the most significant nuclear incident
since April 26, 1986 the
In February 2017, TEPCO released images taken inside Reactor 2 by a remote-controlled camera, that show there is a 2-meter hole in the metal grating under the pressure vessel in the reactor's primary containment vessel, which could have been caused by fuel escaping the pressure vessel. Radiation levels of about 210 Sv per hour were subsequently detected inside the Unit 2 containment vessel.
* 1 Overview
* 2 Plant description
* 2.1 Cooling
* 2.2 Backup generators
* 2.3 Central fuel storage areas
* 3 Prior safety concerns
* 3.1 1967: Layout of the emergency-cooling system
* 3.2 1991: Backup generator of Reactor 1 flooded
* 3.3 2008:
* 4 Events
* 4.1 Tōhoku earthquake
* 4.4 Units 1, 2, and 3
* 4.4.1 Core meltdowns
* 4.5 Units 4, 5, and 6
* 4.5.1 Unit 4 * 4.5.2 Units 5 and 6
* 4.6 Central fuel storage areas
* 4.7 Contamination
* 4.7.1 Contamination in the eastern Pacific
* 5 Response
* 5.1 Poor communication and delays
* 6 Event rating
* 7 Aftermath
* 7.1 Risks from radiation
* 7.2 Thyroid screening program
* 7.2.1 Chernobyl comparison
* 7.3 Effects on evacuees * 7.4 Radioactivity releases * 7.5 Insurance * 7.6 Compensation * 7.7 Energy policy implications * 7.8 Equipment, facility, and operational changes
* 8 Reactions
* 8.1 Japan * 8.2 International
* 8.3 Investigations
* 8.3.1 NAIIC * 8.3.2 Investigation Committee
* 9 See also
* 10 References
* 10.1 Notes * 10.2 Sources
* 11 External links
* 11.1 Investigation * 11.2 Video, drawings, and images * 11.3 Artwork * 11.4 Other
Fukushima Daiichi Nuclear Power Plant comprised six separate
boiling water reactors originally designed by
Immediately after the earthquake, the electricity-producing Reactors 1, 2, and 3 automatically shut down their sustained fission reactions by inserting control rods in a legally-mandated safety procedure referred to as SCRAM , which ceases the reactors' normal running conditions. As the reactors were unable to generate power to run their own coolant pumps, emergency diesel generators came online, as designed, to power electronics and coolant systems. These operated nominally until the tsunami destroyed the generators for Reactors 1–5. The two generators cooling Reactor 6 were undamaged and were sufficient to be pressed into service to cool the neighboring Reactor 5 along with their own reactor, averting the overheating issues that Reactor 4 suffered.
The largest tsunami wave was 13 meters high and hit 50 minutes after the initial earthquake, overwhelming the plant's seawall , which was 10 m high. The moment of impact was recorded by a camera. Water quickly flooded the low-lying rooms in which the emergency generators were housed. The flooded diesel generators failed soon afterwards, resulting in a loss of power to the critical coolant water pumps. These pumps needed to continuously circulate coolant water through a Generation II reactor for several days to keep the fuel rods from melting, as the fuel rods continued to generate decay heat after the SCRAM event. The fuel rods would become hot enough to melt during the fuel decay time period if an adequate heat sink was not available. After the secondary emergency pumps (run by back-up electrical batteries ) ran out, one day after the tsunami, 12 March, the water pumps stopped and the reactors began to overheat . The insufficient cooling eventually led to meltdowns in Reactors 1, 2, and 3, where the resulting corium is believed to have melted through the bottom of each reactor pressure vessel.
Meanwhile, as workers struggled to supply power to the reactors' coolant systems and restore power to their control rooms , a number of hydrogen-air chemical explosions occurred, the first in Unit 1, on 12 March and the last in Unit 4, on 15 March. It is estimated that the hot zirconium fuel cladding-water reaction in Reactors 1–3 produced 800 to 1000 kilograms of hydrogen gas each. The pressurized gas was vented out of the reactor pressure vessel where it mixed with the ambient air, and eventually reached explosive concentration limits in Units 1 and 3. Due to piping connections between Units 3 and 4, or alternatively from the same reaction occurring in the spent fuel pool in Unit 4 itself, Unit 4 also filled with hydrogen, resulting in an explosion. In each case, the hydrogen-air explosions occurred at the top of each unit, that was in their upper secondary containment buildings . Drone overflights on 20 March and afterwards captured clear images of the effects of each explosion on the outside structures, while the view inside was largely obscured by shadows and debris.
There have been no fatalities linked to short term overexposure to radiation reported due to the Fukushima accident, while approximately 18,500 people died due to the earthquake and tsunami. The maximum cancer mortality and morbidity estimate according to the linear no-threshold theory is 1,500 and 1,800 but with most estimates considerably lower, in the range of a few hundred. In addition, the rates of psychological distress among evacuated people rose fivefold compared to the Japanese average due to the experience of the disaster and evacuation.
In 2013, the
World Health Organization
A screening program a year later in 2012 found that more than a third
(36%) of children in
A survey by the newspaper Mainichi Shimbun computed that of some
300,000 people who evacuated the area, approximately 1,600 deaths
related to the evacuation conditions, such as living in temporary
housing and hospital closures, had occurred as of August 2013, a
number comparable to the 1,599 deaths directly caused by the
earthquake and tsunami in the
On 5 July 2012, the Japanese National Diet -appointed Fukushima Nuclear Accident Independent Investigation Commission (NAIIC) submitted its inquiry report to the Japanese Diet. The Commission found the nuclear disaster was "manmade", that the direct causes of the accident were all foreseeable prior to 11 March 2011. The report also found that the Fukushima Daiichi Nuclear Power Plant was incapable of withstanding the earthquake and tsunami. TEPCO, the regulatory bodies (NISA and NSC) and the government body promoting the nuclear power industry (METI), all failed to correctly develop the most basic safety requirements—such as assessing the probability of damage, preparing for containing collateral damage from such a disaster, and developing evacuation plans for the public in the case of a serious radiation release. Meanwhile, the government-appointed Investigation Committee on the Accident at the Fukushima Nuclear Power Stations of Tokyo Electric Power Company submitted its final report to the Japanese government on 23 July 2012. A separate study by Stanford researchers found that Japanese plants operated by the largest utility companies were particularly unprotected against potential tsunami.
TEPCO admitted for the first time on 12 October 2012 that it had failed to take stronger measures to prevent disasters for fear of inviting lawsuits or protests against its nuclear plants. There are no clear plans for decommissioning the plant, but the plant management estimate is thirty or forty years.
A frozen soil barrier was constructed in an attempt to prevent further contamination of seeping groundwater by melted-down nuclear fuel , but in July 2016 TEPCO revealed that the ice wall had failed to stop groundwater from flowing in and mixing with highly radioactive water inside the wrecked reactor buildings, adding that they are "technically incapable of blocking off groundwater with the frozen wall".
Main article: Fukushima Daiichi Nuclear Power Plant
Fukushima Daiichi Nuclear Power Plant site close-up *
Map of Japan\'s electricity distribution network , showing incompatible systems between regions. Fukushima is in the 50 hertz Tohoku region. *
Simplified cross-section sketch of a typical BWR Mark I containment as used in units 1 to 5 Key: RPV: reactor pressure vessel DW: dry well enclosing reactor pressure vessel. WW: wet well - torus-shaped all around the base enclosing steam suppression pool. Excess steam from the dry well enters the wet well water pool via downcomer pipes. SFP: spent fuel pool area SCSW: secondary concrete shield wall
The Fukushima Daiichi Nuclear Power Plant consisted of six GE light water boiling water reactors (BWRs) with a combined power of 4.7 gigawatts, making it one of the world's 25 largest nuclear power stations . It was the first GE-designed nuclear plant to be constructed and run entirely by the Tokyo Electric Power Company (TEPCO). Reactor 1 was a 439 MWe type (BWR-3) reactor constructed in July 1967, and commenced operation on 26 March 1971. It was designed to withstand an earthquake with a peak ground acceleration of 0.18 g (1.74 m/s2) and a response spectrum based on the 1952 Kern County earthquake . Reactors 2 and 3 were both 784 MWe type BWR-4s. Reactor 2 commenced operation in July 1974, and Reactor 3 in March 1976. The earthquake design basis for all units ranged from 0.42 g (4.12 m/s2) to 0.46 g (4.52 m/s2). After the 1978 Miyagi earthquake , when the ground acceleration reached 0.125 g (1.22 m/s2) for 30 seconds, no damage to the critical parts of the reactor was found. Units 1–5 have a Mark-1 type (light bulb torus ) containment structure ; unit 6 has Mark 2-type (over/under) containment structure. In September 2010, Reactor 3 was partially fueled by mixed-oxides (MOX) .
At the time of the accident, the units and central storage facility contained the following numbers of fuel assemblies:
LOCATION UNIT 1 UNIT 2 UNIT 3 UNIT 4 UNIT 5 UNIT 6 CENTRAL STORAGE
REACTOR FUEL ASSEMBLIES 400 548 548 0 548 764 N/A
SPENT FUEL ASSEMBLIES 292 587 514 1331 946 876 6375
FUEL TYPE UO 2 UO 2 UO 2/MOX UO 2 UO 2 UO 2 UO 2
NEW FUEL ASSEMBLIES 100 28 52 204 48 64 N/A
Diagram of the cooling systems of a BWR See also: Decay heat § Power reactors in shutdown , and Nuclear reactor safety system
Nuclear reactors generate electricity by using the heat of the fission reaction to create steam. When the reactor stops operating, the radioactive decay of unstable isotopes in the fuel continues to generate heat (decay heat ) for a time, and so require continued cooling. Initially this decay heat amounts to approximately 6.5% of the amount produced by fission, decreasing over several days before reaching shutdown levels. Afterwards, spent fuel rods typically require several years in a spent fuel pool before they can be safely transferred to dry cask storage vessels. The decay heat in the Unit 4 spent fuel pool had the capacity to boil about 70 metric tons of water per day (12 gallons per minute).
In the reactor core, high-pressure systems cycle water between the reactor pressure vessel and heat exchangers . These systems transfer heat to a secondary heat exchanger via the essential service water system , using water pumped out to sea or an onsite cooling tower . Units 2 and 3 were equipped with steam turbine-driven emergency core cooling systems that could be directly operated by steam produced by decay heat, and which could inject water directly into the reactor. Some electrical power was needed to operate valves and monitoring systems.
Unit 1 was equipped with a different, entirely passive cooling system, the Isolation Condenser (IC). It consisted of a series of pipes run from the reactor core to the inside of a large tank of water. When the valves are opened, steam flows upward to the IC where the cool water in the tank condenses the steam back to water, and it runs under gravity back to the reactor core. For unknown reasons, Unit 1's IC was operated only intermittently during the emergency. However, during a 25 March 2014 presentation to the TVA, Dr Takeyuki Inagaki explained that the IC was being operated intermittently to maintain reactor vessel level and to prevent the core from cooling too quickly which can increase reactor power. Unfortunately, as the tsunami engulfed the station, the IC valves were closed and could not be reopened automatically due to the loss of electrical power, but could have been opened manually. On 16 April 2011, TEPCO declared that cooling systems for Units 1–4 were beyond repair.
When a reactor is not producing electricity, its cooling pumps can be powered by other reactor units, the grid, diesel generators, or batteries.
Two emergency diesel generators were available for each of Units 1–5 and three for Unit 6.
In the late 1990s, three additional backup generators for Units 2 and 4 were placed in new buildings located higher on the hillside, to comply with new regulatory requirements. All six units 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. The switching station for Unit 6 was protected inside the only GE Mark II reactor building and continued to function. 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.
The reactor's emergency diesel generators and DC batteries, crucial components in powering cooling systems after a power loss, were located in the basements of the reactor turbine buildings, in accordance with GE's specifications. Mid-level engineers expressed concerns that this left them vulnerable to flooding.
Fukushima I was not designed for such a large tsunami, nor had the reactors been modified when concerns were raised in Japan and by the IAEA.
Fukushima II was also struck by the tsunami. However, it had incorporated design changes that improved its resistance to flooding, reducing flood damage. Generators and related electrical distribution equipment were located in the watertight reactor building, so that power from the electricity grid was being used by midnight. Seawater pumps for cooling were protected from flooding, and although 3 of 4 initially failed, they were restored to operation.
CENTRAL FUEL STORAGE AREAS
Used fuel assemblies taken from reactors are initially stored for at least 18 months in the pools adjacent to their reactors. They can then be transferred to the central fuel storage pond. Fukushima I's storage area contains 6375 fuel assemblies. After further cooling, fuel can be transferred to dry cask storage, which has shown no signs of abnormalities.
Many of the internal components and fuel assembly cladding are made from zircaloy because it is relatively transparent to neutrons. At normal operating temperatures of approximately 300 °C (572 °F), zircaloy is inert. However, above 1200 degrees Celsius, zirconium metal can react exothermically with water to form free hydrogen gas. The reaction between zirconium and the coolant produces more heat, accelerating the reaction. In addition, zircaloy can react with uranium dioxide to form zirconium dioxide and uranium metal. This exothermic reaction together with the reaction of boron carbide with stainless steel can release additional heat energy, thus contributing to the overheating of a reactor.
PRIOR SAFETY CONCERNS
1967: LAYOUT OF THE EMERGENCY-COOLING SYSTEM
The Fukushima reactor control room in 1999
On 27 February 2012, the Nuclear and Industrial Safety Agency ordered TEPCO to report its reasoning for changing the piping layout for the emergency cooling system.
The original plans separated the piping systems for two reactors in the isolation condenser from each other. However, the application for approval of the construction plan showed the two piping systems connected outside the reactor. The changes were not noted, in violation of regulations.
After the tsunami, the isolation condenser should have taken over the function of the cooling pumps, by condensing the steam from the pressure vessel into water to be used for cooling the reactor. However, the condenser did not function properly and TEPCO could not confirm whether a valve was opened.
1991: BACKUP GENERATOR OF REACTOR 1 FLOODED
On 30 October 1991, one of two backup generators of Reactor 1 failed, after flooding in the reactor's basement. Seawater used for cooling leaked into the turbine building from a corroded pipe at 20 cubic meters per hour, as reported by former employees in December 2011. An engineer was quoted as saying that he informed his superiors of the possibility that a tsunami could damage the generators. TEPCO installed doors to prevent water from leaking into the generator rooms.
The Japanese Nuclear Safety Commission stated that it would revise its safety guidelines and would require the installation of additional power sources. On 29 December 2011, TEPCO admitted all these facts: its report mentioned that the room was flooded through a door and some holes for cables, but the power supply was not cut off by the flooding, and the reactor was stopped for one day. One of the two power sources was completely submerged, but its drive mechanism had remained unaffected.
2008: TSUNAMI STUDY IGNORED
In 2007, TEPCO set up a department to supervise its nuclear facilities. Until June 2011, its chairman was Masao Yoshida , the Fukushima Daiichi chief. A 2008 in-house study identified an immediate need to better protect the facility from flooding by seawater. This study mentioned the possibility of tsunami-waves up to 10.2 metres (33 ft). Headquarters officials insisted that such a risk was unrealistic and did not take the prediction seriously.
A Mr. Okamura of the Active Fault and Earthquake Research Center
(replaced in 2014 by Research Institute of Earthquake and Volcano
Geology (IEVG), Geological Survey of Japan (GSJ), AIST ) urged TEPCO
and NISA to review their assumption of possible tsunami heights based
on a tenth century earthquake , but it was not seriously considered at
that time. The U.S.
Nuclear Regulatory Commission
VULNERABILITY TO EARTHQUAKES
Japan, like the rest of the Pacific Rim , is in an active seismic
zone, prone to earthquakes. The International Atomic Energy Agency
(IAEA) had expressed concern about the ability of Japan's nuclear
plants to withstand earthquakes. At a 2008 meeting of the G8\'s
Nuclear Safety and Security Group in Tokyo, an
Further information: Timeline of the Fukushima Daiichi nuclear
2011 Tōhoku earthquake and tsunami
The 9.0 MW Tōhoku earthquake occurred at 14:46 on Friday, 11 March
2011, with the epicenter near
When the earthquake struck, units 1, 2, and 3 were operating, but units 4, 5, and 6 had been shut down for a scheduled inspection. Reactors 1, 2, and 3 immediately shut down automatically; this meant the plant stopped generating electricity and could no longer use its own power. One of the two connections to off-site power for units 1–3 also failed, so 13 on-site emergency diesel generators began providing power.
TSUNAMI AND FLOODING
The height of the tsunami that struck the station approximately 50 minutes after the earthquake. A: Power station buildings B: Peak height of tsunami C: Ground level of site D: Average sea level E: Seawall to block waves
The earthquake triggered a 13-to-15-metre (43 to 49 ft)-high tsunami that arrived approximately 50 minutes later. The waves overtopped the plant's 5.7 metres (19 ft) seawall , flooding the basements of the power plant's turbine buildings and disabling the emergency diesel generators at approximately 15:41. TEPCO then notified authorities of a "first-level emergency". The switching stations that provided power from the three backup generators located higher on the hillside failed when the building that housed them flooded. Power for the plant's control systems switched to batteries designed to provide power for about eight hours. Further batteries and mobile generators were dispatched to the site, but were delayed by poor road conditions; the first arrived at 21:00 11 March, almost six hours after the tsunami struck.
Unsuccessful attempts were made to connect portable generating equipment to power water pumps. The failure was attributed to flooding at the connection point in the Turbine Hall basement and the absence of suitable cables. TEPCO switched its efforts to installing new lines from the grid. One generator at unit 6 resumed operation on 17 March, while external power returned to units 5 and 6 only on 20 March.
The government initially set in place a four-stage evacuation process: a prohibited access area out to 3 km, an on-alert area 3–20 km and an evacuation prepared area 20–30 km. On day one, an estimated 170,000 people were evacuated from the prohibited access and on-alert areas. Prime Minister Kan instructed people within the on-alert area to leave and urged those in the prepared area to stay indoors. The latter groups were urged to evacuate on 25 March. The 20 kilometer exclusion zone was guarded by roadblocks to ensure that fewer people would be affected by the radiation.
The earthquake and tsunami damaged or destroyed more than one million buildings leading to a total of 470,000 people needing evacuation. Of the 470,000, the nuclear accident was responsible for 154,000 being evacuated.
As of March 2016, of the original 470,000 evacuees, 174,000 remain.
UNITS 1, 2, AND 3
THIS SECTION NEEDS EXPANSION. You can help by adding to it . (August 2013)
See also: Fukushima Daiichi nuclear disaster (Unit 1 Reactor) , Fukushima Daiichi nuclear disaster (Unit 2 Reactor) , and Fukushima Daiichi nuclear disaster (Unit 3 Reactor)
In Reactors 1, 2, and 3, overheating caused a reaction between the water and the zircaloy , creating hydrogen gas. On 12 March, an explosion in Unit 1 was caused by the ignition of the hydrogen, destroying the upper part of the building. On 14 March, a similar explosion occurred in the Reactor 3 building, blowing off the roof and injuring eleven people. On the 15th, there was an explosion in the Reactor 2 building due to a shared vent pipe with Reactor 3.
The amount of damage sustained by the reactor cores during the accident, and the location of molten nuclear fuel ("corium ") within the containment buildings , is unknown; TEPCO has revised its estimates several times. On 16 March 2011, TEPCO estimated that 70% of the fuel in Unit 1 had melted and 33% in Unit 2, and that Unit 3's core might also be damaged. As of 2015 it can be assumed that most fuel melted through the reactor pressure vessel (RPV), commonly known as the "reactor core") and is resting on the bottom of the primary containment vessel (PCV), having been stopped by the PCV concrete. In July 2017 a remotely controlled robot filmed for the first time apparently melted fuel, just below the pressure vessel of Unit 3.
TEPCO released further estimates of the state and location of the fuel in a November 2011 report. The report concluded that the Unit 1 RPV was damaged during the disaster and that "significant amounts" of molten fuel had fallen into the bottom of the PCV. The erosion of the concrete of the PCV by the molten fuel after the core meltdown was estimated to stop at approx. 0.7 metres (2 ft 4 in) in depth, while the thickness of the containment is 7.6 metres (25 ft) thick. Gas sampling carried out before the report detected no signs of an ongoing reaction of the fuel with the concrete of the PCV and all the fuel in Unit 1 was estimated to be "well cooled down, including the fuel dropped on the bottom of the reactor". Fuel in Units 2 and 3 had melted, however less than in Unit 1, and fuel was presumed to be still in the RPV, with no significant amounts of fuel fallen to the bottom of the PCV. The report further suggested that "there is a range in the evaluation results" from "all fuel in the RPV (none fuel fallen to the PCV)" in Unit 2 and Unit 3, to "most fuel in the RPV (some fuel in PCV)". For Unit 2 and Unit 3 it was estimated that the "fuel is cooled sufficiently". According to the report, the greater damage in Unit 1 (when compared to the other two units) was due to the longer time that no cooling water was injected in Unit 1. This resulted in much more decay heat accumulating, as for about 1 day there was no water injection for Unit 1, while Unit 2 and Unit 3 had only a quarter of a day without water injection.
In November 2013, Mari Yamaguchi reported for
According to a December 2013 report, TEPCO estimated for Unit 1 that "the decay heat must have decreased enough, the molten fuel can be assumed to remain in PCV (primary container vessel)".
In August 2014, TEPCO released a new revised estimate that Reactor 3 had a complete melt through in the initial phase of the accident. According to this new estimate within the first three days of the accident the entire core content of Reactor 3 had melted through the RPV and fallen to the bottom of the PCV. These estimates were based on a simulation, which indicated that Reactor 3's melted core penetrated through 1.2 metres (3 ft 11 in) of the PCV's concrete base, and came close to 26–68 centimetres (10–27 in) of the PCV's steel wall.
In February 2015, TEPCO started the muon scanning process for Units 1, 2, and 3. With this scanning setup it will be possible to determine the approximate amount and location of the remaining nuclear fuel within the RPV, but not the amount and resting place of the corium in the PCV. In March 2015 TEPCO released the result of the muon scan for Unit 1 which showed that no fuel was visible in the RPV, which would suggest that most if not all of the molten fuel had dropped onto the bottom of the PCV – this will change the plan for the removal of the fuel from Unit 1.
In February 2017, six years after the disaster, radiation levels inside the Unit 2 containment building were crudely estimated to be about 650 Sv/h. The estimation was revised later to 80 Sv/h. These readings were the highest recorded since the disaster occurred in 2011 and the first recorded in that area of the reactor since the meltdowns. Images showed a hole in metal grating beneath the reactor pressure vessel, suggesting that melted nuclear fuel had escaped the vessel in that area.
UNITS 4, 5, AND 6
Main article: Fukushima Daiichi units 4, 5 and 6 Aerial view of the station in 1975, showing separation between units 5 and 6, and 1–4. Unit 6, not completed until 1979, is seen under construction.
Reactor 4 was not operating when the earthquake struck. All fuel rods from Unit 4 had been transferred to the spent fuel pool on an upper floor of the reactor building prior to the tsunami. On 15 March, an explosion damaged the fourth floor rooftop area of Unit 4, creating two large holes in a wall of the outer building. It was reported that water in the spent fuel pool might be boiling. Radiation inside the Unit 4 control room prevented workers from staying there for long periods. Visual inspection of the spent fuel pool on 30 April revealed no significant damage to the rods. A radiochemical examination of the pond water confirmed that little of the fuel had been damaged.
In October 2012, the former Japanese Ambassador to Switzerland and Senegal, Mitsuhei Murata, said that the ground under Fukushima Unit 4 was sinking, and the structure may collapse.
In November 2013, TEPCO started the process of moving the 1533 fuel rods in the Unit 4 cooling pool to the central pool. This process was completed on 22 December 2014.
Units 5 And 6
Reactors 5 and 6 were also not operating when the earthquake struck. Unlike Reactor 4, their fuel rods remained in the reactor. The reactors had been closely monitored, as cooling processes were not functioning well. Both Unit 5 and Unit 6 shared a working generator and switchgear during the emergency and achieved a successful cold shutdown nine days later on 20 March.
CENTRAL FUEL STORAGE AREAS
On 21 March, temperatures in the fuel pond had risen slightly, to 61 °C and water was sprayed over the pool. Power was restored to cooling systems on 24 March and by 28 March, temperatures were reported down to 35 °C.
Main article: Radiation effects from the Fukushima Daiichi nuclear disaster Sub article: Comparison of Fukushima and Chernobyl nuclear accidents with detailed tables inside Map of contaminated areas around the plant (22 March – 3 April 2011) Fukushima dose rate comparison to other incidents and standards, with graph of recorded radiation levels and specific accident events from 11 to 30 March Radiation measurements from Fukushima Prefecture, March 2011 Seawater-contamination along coast with Caesium-137, from 21 March until 5 May 2011 (Source: GRS ) Radiation hotspot in Kashiwa, February 2012
Radioactive material was released from the containment vessels for several reasons: deliberate venting to reduce gas pressure, deliberate discharge of coolant water into the sea, and uncontrolled events. Concerns about the possibility of a large scale release led to a 20-kilometre (12 mi) exclusion zone around the power plant and recommendations that people within the surrounding 20–30 km zone stay indoors. Later, the UK, France, and some other countries told their nationals to consider leaving Tokyo, in response to fears of spreading contamination. In 2015, the tap water contamination was still higher in Tokyo compared to other cities in Japan. Trace amounts of radioactivity, including iodine-131 , caesium-134 , and caesium-137 , were widely observed.
Between 21 March and mid-July, around 27 PBq of caesium-137 (about
8.4 kg) entered the ocean, with about 82 percent having flowed into
the sea before 8 April. However, the Fukushima coast has some of the
world's strongest currents and these transported the contaminated
waters far into the
A monitoring system operated by the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) tracked the spread of radioactivity on a global scale. Radioactive isotopes were picked up by over 40 monitoring stations.
On 12 March, radioactive releases first reached a CTBTO monitoring station in Takasaki, Japan, around 200 km away. The radioactive isotopes appeared in eastern Russia on 14 March and the west coast of the United States two days later. By day 15, traces of radioactivity were detectable all across the northern hemisphere. Within one month, radioactive particles were noted by CTBTO stations in the southern hemisphere.
Estimates of radioactivity released ranged from 10–40% of that of Chernobyl. The significantly contaminated area was 10 -12% of that of Chernobyl.
In March 2011, Japanese officials announced that "radioactive iodine-131 exceeding safety limits for infants had been detected at 18 water-purification plants in Tokyo and five other prefectures". On 21 March, the first restrictions were placed on the distribution and consumption of contaminated items. As of July 2011 , the Japanese government was unable to control the spread of radioactive material into the nation's food supply. Radioactive material was detected in food produced in 2011, including spinach, tea leaves, milk, fish, and beef, up to 320 kilometres from the plant. 2012 crops did not show signs of radioactivity contamination. Cabbage, rice and beef showed insignificant levels of radioactivity. A Fukushima-produced rice market in Tokyo was accepted by consumers as safe.
On 24 August 2011, the Nuclear Safety Commission (NSC) of Japan published the results of the recalculation of the total amount of radioactive materials released into the air during the accident at the Fukushima Daiichi Nuclear Power Station. The total amounts released between 11 March and 5 April were revised downwards to 130 PBq (petabecquerels , 3.5 megacuries ) for iodine-131 and 11 PBq for caesium-137, which is about 11% of Chernobyl emissions. Earlier estimations were 150 PBq and 12 PBq.
In 2011, scientists working for the Japan Atomic Energy Agency, Kyoto University and other institutes, recalculated the amount of radioactive material released into the ocean: between late March through April they found a total of 15 PBq for the combined amount of iodine-131 and caesium-137, more than triple the 4.72 PBq estimated by TEPCO. The company had calculated only the direct releases into the sea. The new calculations incorporated the portion of airborne radioactive substances that entered the ocean as rain.
In the first half of September 2011, TEPCO estimated the radioactivity release at some 200 MBq (megabecquerels, 5.4 millicuries ) per hour. This was approximately one four-millionth that of March. Traces of iodine-131 were detected in several Japanese prefectures in November and December 2011.
According to the French Institute for Radiological Protection and
Nuclear Safety , between 21 March and mid-July around 27 PBq of
caesium-137 entered the ocean, about 82 percent before 8 April. This
emission represents the most important individual oceanic emissions of
artificial radioactivity ever observed. The Fukushima coast has one of
the world's strongest currents (
As of March 2012, no cases of radiation-related ailments had been reported. Experts cautioned that data was insufficient to allow conclusions on health impacts. Michiaki Kai, professor of radiation protection at Oita University of Nursing and Health Sciences , stated, "If the current radiation dose estimates are correct, (cancer-related deaths) likely won't increase."
In May 2012, TEPCO released their estimate of cumulative radioactivity releases. An estimated 538.1 PBq of iodine-131, caesium-134 and caesium-137 was released. 520 PBq was released into the atmosphere between 12–31 March 2011 and 18.1 PBq into the ocean from 26 March – 30 September 2011. A total of 511 PBq of iodine-131 was released into both the atmosphere and the ocean, 13.5 PBq of caesium-134 and 13.6 PBq of caesium-137. TEPCO reported that at least 900 PBq had been released "into the atmosphere in March last year alone".
In 2012 researchers from the Institute of Problems in the Safe Development of Nuclear Energy, Russian Academy of Sciences, and the Hydrometeorological Center of Russia concluded that "on March 15, 2011, ~400 PBq iodine, ~100 PBq cesium, and ~400 PBq inert gases entered the atmosphere" on that day alone.
In August 2012, researchers found that 10,000 nearby residents had been exposed to less than 1 millisievert of radiation, significantly less than Chernobyl residents.
As of October 2012, radioactivity was still leaking into the ocean. Fishing in the waters around the site was still prohibited, and the levels of radioactive 134Cs and 137Cs in the fish caught were not lower than immediately after the disaster.
On 26 October 2012, TEPCO admitted that it could not stop radioactive material entering the ocean, although emission rates had stabilized. Undetected leaks could not be ruled out, because the reactor basements remained flooded. The company was building a 2,400-foot-long steel and concrete wall between the site and the ocean, reaching 100 feet below ground, but it would not be finished before mid-2014. Around August 2012 two greenling were caught close to shore. They contained more than 25,000 becquerels (0.67 millicuries ) of caesium-137 per kilogram, the highest measured since the disaster and 250 times the government's safety limit.
On 22 July 2013, it was revealed by TEPCO that the plant continued to
leak radioactive water into the Pacific Ocean, something long
suspected by local fishermen and independent investigators. TEPCO had
previously denied that this was happening. Japanese Prime Minister
On 20 August, in a further incident, it was announced that 300 metric
tons of heavily contaminated water had leaked from a storage tank,
approximately the same amount of water as one eighth (1/8) of that
found in an
Olympic-size swimming pool
On 26 August, the government took charge of emergency measures to prevent further radioactive water leaks, reflecting their lack of confidence in TEPCO.
As of 2013, about 400 metric tons per day of cooling water was being pumped into the reactors. Another 400 metric tons of groundwater was seeping into the structure. Some 800 metric tons of water per day was removed for treatment, half of which was reused for cooling and half diverted to storage tanks. Ultimately the contaminated water, after treatment to remove radionuclides other than tritium , may have to be dumped into the Pacific. TEPCO intend to create an underground ice wall to reduce the rate contaminated groundwater reaches the sea.
In February 2014,
On 10 September 2015, floodwaters driven by Typhoon Etau prompted mass evacuations in Japan and overwhelmed the drainage pumps at the stricken Fukushima nuclear plant. A TEPCO spokesperson said that hundreds of metric tons of radioactive water had entered the ocean as a result. Plastic bags filled with contaminated soil and grass were also swept away by the flood waters.
Contamination In The Eastern Pacific
In March 2014, numerous news sources, including
Government agencies and TEPCO were unprepared for the "cascading nuclear disaster". The tsunami that "began the nuclear disaster could and should have been anticipated and that ambiguity about the roles of public and private institutions in such a crisis was a factor in the poor response at Fukushima". In March 2012, Prime Minister Yoshihiko Noda said that the government shared the blame for the Fukushima disaster, saying that officials had been blinded by a false belief in the country's "technological infallibility", and were taken in by a "safety myth". Noda said "Everybody must share the pain of responsibility."
Physicist and environmentalist
POOR COMMUNICATION AND DELAYS
The Japanese government did not keep records of key meetings during the crisis. Data from the SPEEDI network were emailed to the prefectural government, but not shared with others. Emails from NISA to Fukushima, covering 12 March 11:54 PM to 16 March 9 AM and holding vital information for evacuation and health advisories, went unread and were deleted. The data was not used because the disaster countermeasure office regarded the data as "useless because the predicted amount of released radiation is unrealistic." On 14 March 2011 TEPCO officials were instructed not to use the phrase "core meltdown" at press conferences.
On the evening of March 15, Prime Minister Kan called Seiki Soramoto, who used to design nuclear plants for Toshiba, to ask for his help in managing the escalating crisis. Soramoto formed an impromptu advisory group, which included his former professor at the University of Tokyo, Toshiso Kosako, a top Japanese expert on radiation measurement. Mr. Kosako, who studied the Soviet response to the Chernobyl crisis, said he was stunned at how little the leaders in the prime minister’s office knew about the resources available to them. He quickly advised the chief cabinet secretary, Yukio Edano, to use SPEEDI, which used measurements of radioactive releases, as well as weather and topographical data, to predict where radioactive materials could travel after being released into the atmosphere.
The Investigation Committee on the Accident at the Fukushima Nuclear Power Stations of Tokyo Electric Power Company 's interim report stated that Japan's response was flawed by "poor communication and delays in releasing data on dangerous radiation leaks at the facility". The report blamed Japan's central government as well as TEPCO, "depicting a scene of harried officials incapable of making decisions to stem radiation leaks as the situation at the coastal plant worsened in the days and weeks following the disaster". The report said poor planning worsened the disaster response, noting that authorities had "grossly underestimated tsunami risks" that followed the magnitude 9.0 earthquake. The 12.1 metre (40 ft) high tsunami that struck the plant was double the height of the highest wave predicted by officials. The erroneous assumption that the plant's cooling system would function after the tsunami worsened the disaster. "Plant workers had no clear instructions on how to respond to such a disaster, causing miscommunication, especially when the disaster destroyed backup generators."
In February 2012, the Rebuild Japan Initiative Foundation described how Japan's response was hindered by a loss of trust between the major actors: Prime Minister Kan, TEPCO's Tokyo headquarters and the plant manager. The report said that these conflicts "produced confused flows of sometimes contradictory information". According to the report, Kan delayed the cooling of the reactors by questioning the choice of seawater instead of fresh water, accusing him of micromanaging response efforts and appointing a small, closed, decision-making staff. The report stated that the Japanese government was slow to accept assistance from U.S. nuclear experts.
A 2012 report in
From 17 to 19 March 2011, US military aircraft measured radiation within a 45-km radius of the site. The data recorded 125 microsieverts per hour of radiation as far as 25 km (15.5 mi) northwest of the plant. The US provided detailed maps to the Japanese Ministry of Economy, Trade and Industry (METI) on 18 March and to the Ministry of Education, Culture, Sports, Science and Technology (MEXT) two days later, but officials did not act on the information.
The data were not forwarded to the prime minister's office or the Nuclear Safety Commission (NSC), nor were they used to direct the evacuation. Because a substantial portion of radioactive materials reached ground to the northwest, residents evacuated in this direction were unnecessarily exposed to radiation. According to NSC chief Tetsuya Yamamoto, "It was very regrettable that we didn't share and utilize the information." Itaru Watanabe, from the Science and Technology Policy Bureau, blamed the US for not releasing the data.
Data on the dispersal of radioactive materials were provided to the U.S. forces by the Japanese Ministry for Science a few days after March 11; however, the data was not shared publicly until the Americans published their map on March 23, at which point Japan published fallout maps compiled from ground measurements and SPEEDI the same day. According to Watanabe's testimony before the Diet, the US military was given access to the data "to seek support from them" on how to deal with the nuclear disaster. Although SPEEDI's effectiveness was limited by not knowing the amounts released in the disaster, and thus was considered "unreliable", it was still able to forecast dispersal routes and could have been used to help local governments designate more appropriate evacuation routes.
On 19 June 2012, science minister Hirofumi Hirano stated that his "job was only to measure radiation levels on land" and that the government would study whether disclosure could have helped in the evacuation efforts.
On 28 June 2012 Nuclear and Industrial Safety Agency officials apologized to mayor Yuko Endo of Kawauchi Village for NISA having failed to release the American-produced radiation maps in the first days after the meltdowns. All residents of this village were evacuated after the government designated it a no-entry zone. According to a Japanese government panel, authorities had shown no respect for the lives and dignity of village people. One NISA official apologized for the failure and added that the panel had stressed the importance of disclosure; however, the mayor said that the information would have prevented the evacuation into highly polluted areas, and that apologies a year too late had no meaning.
In June 2016, it was revealed that TEPCO officials had been instructed on 14 March 2011 not to describe the reactor damage using the word "meltdown". Officials at that time were aware that 25–55% of the fuel had been damaged, and the threshold for which the term "meltdown" became appropriate (5%) had been greatly exceeded. TEPCO President Naomi Hirose told the media: "I would say it was a cover-up... It’s extremely regrettable.”
Main article: Accident rating of the Fukushima Daiichi nuclear disaster Comparison of radiation levels for different nuclear events
The incident was rated 7 on the International Nuclear Event Scale
(INES). This scale runs from 0, indicating an abnormal situation with
no safety consequences, to 7, indicating an accident causing
widespread contamination with serious health and environmental
effects. Prior to Fukushima, the
A 2012 analysis of the intermediate and long-lived radioactivity released found about 10–20% of that released from the Chernobyl disaster. Approximately 15 PBq of caesium-137 was released, compared with approximately 85 PBq of caesium-137 at Chernobyl, indicating the release of 26.5 kilograms (58 lb) of caesium-137.
Unlike Chernobyl, all Japanese reactors were in concrete containment vessels, which limited the release of strontium-90 , americium-241 , and plutonium , which were among the radioisotopes released by the earlier incident.
Some 500 PBq of iodine-131 were released, compared to approximately 1,760 PBq at Chernobyl. Iodine-131 has a half life of 8.02 days, decaying into a stable nuclide. After ten half lives (80.2 days), 99.9% has decayed to xenon-131 , a stable isotope.
Main article: Fukushima Daiichi nuclear disaster casualties
No deaths followed short-term radiation exposure, though there were a number of deaths in the evacuation of the nearby population, while 15,884 died (as of 10 February 2014 ) due to the earthquake and tsunami.
RISKS FROM RADIATION
Very few cancers would be expected as a result of accumulated radiation exposures, even though people in the area worst affected by Japan's Fukushima nuclear accident have a slightly higher risk of developing certain cancers such as leukemia , solid cancers , thyroid cancer , and breast cancer .
Estimated effective doses from the accident outside Japan are considered to be below (or far below) the dose levels regarded as very small by the international radiological protection community.
In 2013, WHO reported that area residents who were evacuated were
exposed to so little radiation that radiation-induced health effects
were likely to be below detectable levels. The health risks were
calculated by applying conservative assumptions, including the
conservative linear no-threshold model of radiation exposure, a model
that assumes even the smallest amount of radiation exposure will cause
a negative health effect. The report indicated that for those
infants in the most affected areas, lifetime cancer risk would
increase by about 1%. It predicted that populations in the most
contaminated areas faced a 70% higher relative risk of developing
thyroid cancer for females exposed as infants, and a 7% higher
relative risk of leukemia in males exposed as infants and a 6% higher
relative risk of breast cancer in females exposed as infants.
One-third of involved emergency workers would have increased cancer
These percentages represent estimated relative increases over the
baseline rates and are not absolute risks for developing such cancers.
Due to the low baseline rates of thyroid cancer, even a large relative
increase represents a small absolute increase in risks. For example,
the baseline lifetime risk of thyroid cancer for females is just
three-quarters of one percent and the additional lifetime risk
estimated in this assessment for a female infant exposed in the most
affected location is one-half of one percent. — World Health
Organization. "Health Risk Assessment from the nuclear accident after
the 2011 Great East Japan Earthquake and
According to a linear no-threshold model (LNT model), the accident would most likely cause 130 cancer deaths. However, radiation epidemiologist Roy Shore countered that estimating health effects from the LNT model "is not wise because of the uncertainties." Darshak Sanghavi noted that to obtain reliable evidence of the effect of low-level radiation would require an impractically large number of patients, Luckey reported that the body's own repair mechanisms can cope with small doses of radiation and Aurengo stated that “The LNT model cannot be used to estimate the effect of very low doses…”
In April 2014, studies confirmed the presence of radioactive tuna off the coasts of the pacific U.S. Researchers carried out tests on 26 albacore tuna caught prior to the 2011 power plant disaster and those caught after. However, the amount of radioactivity is less than that found naturally in a single banana. Caesium-137 and caesium-134 have been noted in Japanese whiting in Tokyo Bay as of 2016. "Concentration of radiocesium in the Japanese whiting was one or two orders of magnitude higher than that in the sea water, and an order of magnitude lower than that in the sediment." They were still within food safety limits.
As of June 2016, dispersed nuclear fallout and associated radiation
contamination continue to pollute the environment.
Tilman Ruff , a
professor at the
University of Melbourne
Five years after the event, the Department of Agriculture from the University of Tokyo (which holds many experimental agricultural research fields around the affected area) has noted that "the fallout was found at the surface of anything exposed to air at the time of the accident. The main radioactive nuclides are now caesium-137 and caesium-134 ", but these radioactive compounds have not dispersed much from the point where they landed at the time of the explosion, "which was very difficult to estimate from our understanding of the chemical behavior of cesium".
THYROID SCREENING PROGRAM
World Health Organization
According to the Tenth Report of the
In October 2015, 137 children from the
However, despite his paper being widely reported by the media, an undermining error, according to teams of other epidemiologists who point out Tsuda's remarks are fatally wrong, is that Tsuda did an apples and oranges comparison by comparing the Fukushima surveys, which uses advanced ultrasound devices that detect otherwise unnoticeable thyroid growths, with data from traditional non-advanced clinical examinations, to arrive at his "20 to 50 times what would be expected" conclusion. In the critical words of epidemiologist Richard Wakeford, “It is inappropriate to compare the data from the Fukushima screening program with cancer registry data from the rest of Japan where there is, in general, no such large-scale screening,”. Wakeford's criticism was one of seven other author's letters that were published criticizing Tsuda's paper. According to Takamura, another epidemiologist, who examined the results of small scale advanced ultrasound tests on Japanese children not near Fukushima, "The prevalence of thyroid cancer does not differ meaningfully from that in Fukushima Prefecture,”.
Thyroid cancer is one of the most survivable cancers, with an approximate 94% survival rate after first diagnosis. That rate increases to a nearly 100% survival rate if caught early.
Main article: Comparison of Fukushima and Chernobyl nuclear accidents
Radiation deaths at Chernobyl were also statistically undetectable. Only 0.1% of the 110,645 Ukraninian cleanup workers, included in a 20-year study out of over 500,000 former Soviet clean up workers, had as of 2012 developed leukemia, although not all cases resulted from the accident.
Data from Chernobyl showed that there was a steady then sharp increase in thyroid cancer rates following the disaster in 1986, but whether this data can be directly compared to Fukushima is yet to be determined.
Chernobyl thyroid cancer incidence rates did not begin to increase above the prior baseline value of about 0.7 cases per 100,000 people per year until 1989 to 1991, 3–5 years after the incident in both adolescent and child age groups. The rate reached its highest point so far, of about 11 cases per 100,000 in the decade of the 2000s, approximately 14 years after the accident. From 1989 to 2005, an excess of 4,000 children and adolescent cases of thyroid cancer were observed. Nine of these had died as of 2005, a 99% survival rate.
EFFECTS ON EVACUEES
In the former
We know from Chernobyl that the psychological consequences are enormous. Life expectancy of the evacuees dropped from 65 to 58 years – not because of cancer, but because of depression , alcoholism, and suicide . Relocation is not easy, the stress is very big. We must not only track those problems, but also treat them. Otherwise people will feel they are just guinea pigs in our research.
A survey by the Iitate local government obtained responses from approximately 1,743 evacuees within the evacuation zone. The survey showed that many residents are experiencing growing frustration, instability, and an inability to return to their earlier lives. Sixty percent of respondents stated that their health and the health of their families had deteriorated after evacuating, while 39.9% reported feeling more irritated compared to before the disaster.
Summarizing all responses to questions related to evacuees' current family status, one-third of all surveyed families live apart from their children, while 50.1% live away from other family members (including elderly parents) with whom they lived before the disaster. The survey also showed that 34.7% of the evacuees have suffered salary cuts of 50% or more since the outbreak of the nuclear disaster. A total of 36.8% reported a lack of sleep, while 17.9% reported smoking or drinking more than before they evacuated.
Stress often manifests in physical ailments, including behavioral changes such as poor dietary choices, lack of exercise, and sleep deprivation. Survivors, including some who lost homes, villages, and family members, were found likely to face mental health and physical challenges. Much of the stress came from lack of information and from relocation.
A survey computed that of some 300,000 evacuees, approximately 1,600 deaths related to the evacuation conditions, such as living in temporary housing and hospital closures that had occurred as of August 2013, a number comparable to the 1,599 deaths directly caused by the earthquake and tsunami in the Prefecture. The exact causes of these evacuation related deaths were not specified, because according to the municipalities, that would hinder relatives applying for compensation.
In June 2011, TEPCO stated the amount of contaminated water in the complex had increased due to substantial rainfall. On 13 February 2014, TEPCO reported 37 kBq (1.0 microcurie ) of cesium-134 and 93 kBq (2.5 microcuries ) of cesium-137 were detected per liter of groundwater sampled from a monitoring well.
According to reinsurer Munich Re , the private insurance industry will not be significantly affected by the disaster. Swiss Re similarly stated, "Coverage for nuclear facilities in Japan excludes earthquake shock, fire following earthquake and tsunami, for both physical damage and liability. Swiss Re believes that the incident at the Fukushima nuclear power plant is unlikely to result in a significant direct loss for the property ">
The amount of compensation to be paid by TEPCO is expected to reach 7 trillion yen.
Costs to Japanese taxpayers are likely to exceed 12 trillion yen ($100 billion). In December 2016 the government estimated decontamination, compensation, decommissioning, and radioactive waste storage costs at 21.5 trillion yen ($187 billion), nearly double the 2013 estimate.
In March 2017, a Japanese court ruled that negligence by the Japanese government had led to the Fukushima disaster by failing to use its regulatory powers to force TEPCO to take preventive measures. The Maebashi district court near Tokyo awarded ¥39 million (US$345,000) to 137 people who were forced to flee their homes following the accident.
ENERGY POLICY IMPLICATIONS
The number of nuclear power plant constructions started each
year worldwide, from 1954 to 2013. Following an increase in new
constructions from 2007 to 2010, there was a decline after the
Fukushima nuclear disaster. Electricity generation by source in
Japan (month-level data). Nuclear energy's contribution declined
steadily throughout 2011 due to shutdowns and has been mainly replaced
with thermal power stations such as fossil gas and coal power plants .
Komekurayama Solar Power Plant owned and operated by TEPCO in
Yamanashi Prefecture Part of the Seto Hill Windfarm in
Japan, one of several windfarms that continued generating without
interruption after the 2011 earthquake and tsunami and the Fukushima
nuclear disaster Price of PV modules (yen/Wp) in Japan
By March 2012, one year after the disaster, all but two of Japan's
nuclear reactors had been shut down; some had been damaged by the
quake and tsunami. Authority to restart the others after scheduled
maintenance throughout the year was given to local governments, who in
all cases decided against. According to
The Japan Times
Michael Banach, the current Vatican representative to the IAEA, told
a conference in Vienna in September 2011 that the disaster created new
concerns about the safety of nuclear plants globally. Auxiliary Bishop
of Osaka Michael Goro Matsuura said this incident should cause Japan
and other countries to abandon nuclear projects. He called on the
worldwide Christian community to support this anti-nuclear campaign.
Statements from Bishops' conferences in Korea and the Philippines
called on their governments to abandon atomic power. Author Kenzaburō
Ōe , who received a
The nuclear plant closest to the epicenter of the earthquake, the
Onagawa Nuclear Power Plant , successfully withstood the cataclysm.
The loss of 30% of the country's generating capacity led to much greater reliance on liquified natural gas and coal . Unusual conservation measures were undertaken. In the immediate aftermath, nine prefectures served by TEPCO experienced power rationing. The government asked major companies to reduce power consumption by 15%, and some shifted their weekends to weekdays to smooth power demand. Converting to a nuclear-free gas and oil energy economy would cost tens of billions of dollars in annual fees. One estimate is that even including the disaster, more lives would have been lost if Japan had used coal or gas plants instead of nuclear.
Many political activists have begun calling for a phase-out of
nuclear power in Japan, including
In contrast, others have said that the zero mortality rate from the Fukushima incident confirms their opinion that nuclear fission is the only viable option available to replace fossil fuels . Journalist George Monbiot wrote "Why Fukushima made me stop worrying and love nuclear power." In it he said, "As a result of the disaster at Fukushima, I am no longer nuclear-neutral. I now support the technology." He continued, "A crappy old plant with inadequate safety features was hit by a monster earthquake and a vast tsunami. The electricity supply failed, knocking out the cooling system. The reactors began to explode and melt down. The disaster exposed a familiar legacy of poor design and corner-cutting. Yet, as far as we know, no one has yet received a lethal dose of radiation."
In September 2011, Mycle Schneider said that the disaster can be understood as a unique chance "to get it right" on energy policy . "Germany – with its nuclear phase-out decision based on a renewable energy program – and Japan – having suffered a painful shock but possessing unique technical capacities and societal discipline – can be at the forefront of an authentic paradigm shift toward a truly sustainable, low-carbon and nuclear-free energy policy."
On the other hand, climate and energy scientists
As of September 2011 , Japan planned to build a pilot offshore floating wind farm , with six 2 MW turbines, off the Fukushima coast . The first became operational in November 2013. After the evaluation phase is complete in 2016, "Japan plans to build as many as 80 floating wind turbines off Fukushima by 2020." In 2012, Prime Minister Kan said the disaster made it clear to him that "Japan needs to dramatically reduce its dependence on nuclear power, which supplied 30% of its electricity before the crisis, and has turned him into a believer of renewable energy". Sales of solar panels in Japan rose 30.7% to 1,296 MW in 2011, helped by a government scheme to promote renewable energy. Canadian Solar received financing for its plans to build a factory in Japan with capacity of 150 MW, scheduled to begin production in 2014.
As of September 2012, the
Los Angeles Times
On 16 December 2012, Japan held its general election . The Liberal
Democratic Party (LDP) had a clear victory, with
In October 2013, it was reported that TEPCO and eight other Japanese power companies were paying approximately 3.6 trillion yen (37 billion dollars ) more in combined imported fossil fuel costs compared to 2010, before the accident, to make up for the missing power.
EQUIPMENT, FACILITY, AND OPERATIONAL CHANGES
As the crisis unfolded, the Japanese government sent a request for
robots developed by the U.S. military. The robots went into the plants
and took pictures to help assess the situation, but they couldn't
perform the full range of tasks usually carried out by human workers.
The Fukushima disaster illustrated that robots lacked sufficient
dexterity and robustness to perform critical tasks. In response to
this shortcoming, a series of competitions were hosted by
A number of nuclear reactor safety system lessons emerged from the incident. The most obvious was that in tsunami-prone areas, a power station's sea wall must be adequately tall and robust. At the Onagawa Nuclear Power Plant , closer to the epicenter of 11 March earthquake and tsunami, the sea wall was 14 meters tall and successfully withstood the tsunami, preventing serious damage and radioactivity releases.
Nuclear power station operators around the world began to install Passive Auto-catalytic hydrogen Recombiners ("PARs"), which do not require electricity to operate. PARs work much like the catalytic converter on the exhaust of a car to turn potentially explosive gases such as hydrogen into water. Had such devices been positioned at the top of Fukushima I's reactor and containment buildings, where hydrogen gas collected, the explosions would not have occurred and the releases of radioactive isotopes would arguably have been much less.
Unpowered filtering systems on containment building vent lines, known as Filtered Containment Venting Systems (FCVS), can safely catch radioactive materials and thereby allow reactor core de-pressurization, with steam and hydrogen venting with minimal radioactivity emissions. Filtration using an external water tank system is the most common established system in European countries, with the water tank positioned outside the containment building . In October 2013, the owners of Kashiwazaki-Kariwa nuclear power station began installing wet filters and other safety systems, with completion anticipated in 2014.
For generation II reactors located in flood or tsunami prone areas, a 3+ day supply of back-up batteries has become an informal industry standard. Another change is to harden the location of back-up diesel generator rooms with water-tight, blast-resistant doors and heat sinks , similar to those used by nuclear submarines . The oldest operating nuclear power station in the world, Beznau , which has been operating since 1969, has a 'Notstand' hardened building designed to support all of its systems independently for 72 hours in the event of an earthquake or severe flooding. This system was built prior to Fukushima Daiichi.
Upon a station blackout , similar to the one that occurred after Fukushima's back-up battery supply was exhausted, many that had constructed Generation III reactors adopt the principle of passive nuclear safety . They take advantage of convection (hot water tends to rise) and gravity (water tends to fall) to ensure an adequate supply of cooling water to handle the decay heat , without the use of pumps.
Main article: Japanese reaction to Fukushima Daiichi nuclear disaster Japan towns, villages, and cities in and around the Daiichi nuclear plant exclusion zone. The 20 km and 30 km areas had evacuation and shelter in place orders, and additional administrative districts that had an evacuation order are highlighted. However, the above map's factual accuracy is called into question as only the southern portion of Kawamata district had evacuation orders. More accurate maps are available.
Japanese authorities later admitted to lax standards and poor oversight. They took fire for their handling of the emergency and engaged in a pattern of withholding and denying damaging information. Authorities allegedly wanted to "limit the size of costly and disruptive evacuations in land-scarce Japan and to avoid public questioning of the politically powerful nuclear industry". Public anger emerged over an "official campaign to play down the scope of the accident and the potential health risks".
In many cases, the Japanese government's reaction was judged to be less than adequate by many in Japan, especially those who were living in the region. Decontamination equipment was slow to be made available and then slow to be utilized. As late as June 2011, even rainfall continued to cause fear and uncertainty in eastern Japan because of its possibility of washing radioactivity from the sky back to earth.
To assuage fears, the government enacted an order to decontaminate over a hundred areas with a level contamination greater than or equivalent to one millisievert of radiation. This is a much lower threshold than is necessary for protecting health. The government also sought to address the lack of education on the effects of radiation and the extent to which the average person was exposed.
Previously a proponent of building more reactors, Kan took an increasingly anti-nuclear stance following the disaster. In May 2011, he ordered the aging Hamaoka Nuclear Power Plant closed over earthquake and tsunami concerns, and said he would freeze building plans. In July 2011, Kan said, "Japan should reduce and eventually eliminate its dependence on nuclear energy". In October 2013, he said that if the worst-case scenario had been realized, 50 million people within a 250-kilometer radius would have had to evacuate.
On 22 August 2011, a government spokesman mentioned the possibility that some areas around the plant "could stay for some decades a forbidden zone". According to Yomiuri Shimbun the Japanese government was planning to buy some properties from civilians to store waste and materials that had become radioactive after the accidents. Chiaki Takahashi, Japan's foreign minister, criticized foreign media reports as excessive. He added that he could "understand the concerns of foreign countries over recent developments at the nuclear plant, including the radioactive contamination of seawater".
Due to frustration with TEPCO and the Japanese government "providing
differing, confusing, and at times contradictory, information on
critical health issues" a citizen's group called "Safecast " recorded
detailed radiation level data in Japan. The Japanese government
"does not consider nongovernment readings to be authentic". The group
In 2014 Japan enacted the State Secrecy Law . The Fukushima incident falls under this law and, as a "state secret", independent investigations and reports are forbidden by law.
Main article: International reactions to the Fukushima Daiichi nuclear disaster Evacuation flight departs Misawa U.S. Navy humanitarian flight undergoes radioactive decontamination
The international reaction to the disaster was diverse and widespread. Many inter-governmental agencies immediately offered help, often on an ad hoc basis. Responders included IAEA, World Meteorological Organization and the Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization .
In May 2011, UK chief inspector of nuclear installations Mike
Weightman traveled to Japan as the lead of an International Atomic
Energy Agency (IAEA) expert mission. The main finding of this mission,
as reported to the
In September 2011,
In the aftermath, Germany accelerated plans to close its nuclear power reactors and decided to phase the rest out by 2022. Italy held a national referendum, in which 94 percent voted against the government's plan to build new nuclear power plants. In France, President Hollande announced the intention of the government to reduce nuclear usage by one third. So far, however, the government has only earmarked one power station for closure – the aging plant at Fessenheim on the German border – which prompted some to question the government's commitment to Hollande's promise. Industry Minister Arnaud Montebourg is on record as saying that Fessenheim will be the only nuclear power station to close.
On a visit to China in December 2014 he reassured his audience that nuclear energy was a "sector of the future" and would continue to contribute "at least 50%" of France's electricity output.
Another member of Hollande's Socialist Party, the MP Christian Bataille, says the plan to curb nuclear was hatched as a way of securing the backing of his Green coalition partners in parliament.
Nuclear power plans were not abandoned in Malaysia, the Philippines,
Kuwait, and Bahrain, or radically changed, as in Taiwan. China
suspended its nuclear development program briefly, but restarted it
shortly afterwards. The initial plan had been to increase the nuclear
contribution from 2 to 4 percent of electricity by 2020, with an
escalating program after that.
New nuclear projects were proceeding in some countries. KPMG reports 653 new nuclear facilities planned or proposed for completion by 2030. By 2050, China hopes to have 400–500 gigawatts of nuclear capacity – 100 times more than it has now. The Conservative Government of the United Kingdom is planning a major nuclear expansion despite widespread public objection. So is Russia. India are also pressing ahead with a large nuclear program, as is South Korea. Indian Vice President M Hamid Ansari said in 2012 that "nuclear energy is the only option" for expanding India's energy supplies, and Prime Minister Modi announced in 2014 that India intended to build 10 more nuclear reactors in a collaboration with Russia.
Three investigations into the Fukushima disaster showed the man-made nature of the catastrophe and its roots in regulatory capture associated with a "network of corruption, collusion, and nepotism." Regulatory capture refers to the "situation where regulators charged with promoting the public interest defer to the wishes and advance the agenda of the industry or sector they ostensibly regulate." Those with a vested interest in specific policy or regulatory outcomes lobby regulators and influence their choices and actions. Regulatory capture explains why some of the risks of operating nuclear power reactors in Japan were systematically downplayed and mismanaged so as to compromise operational safety.
Many reports say that the government shares blame with the regulatory agency for not heeding warnings and for not ensuring the independence of the oversight function. The New York Times said that the Japanese nuclear regulatory system sided with and promoted the nuclear industry because of amakudari ('descent from heaven') in which senior regulators accepted high paying jobs at companies they once oversaw. To protect their potential future position in the industry, regulators sought to avoid taking positions that upset or embarrass the companies. TEPCO's position as the largest electrical utility in Japan made it the most desirable position for retiring regulators. Typically the "most senior officials went to work at TEPCO, while those of lower ranks ended up at smaller utilities."
In August 2011, several top energy officials were fired by the Japanese government; affected positions included the Vice-minister for Economy, Trade and Industry ; the head of the Nuclear and Industrial Safety Agency, and the head of the Agency for Natural Resources and Energy.
In 2016 three former TEPCO executives, chairman Tsunehisa Katsumata and two vice presidents, were indicted for negligence resulting in death and injury. In June 2017 the first hearing took place, in which the three pleaded not guilty to professional negligence resulting in death and injury.
Main article: National Diet of Japan Fukushima Nuclear Accident Independent Investigation Commission
The Fukushima Nuclear Accident Independent Investigation Commission (NAIIC) was the first independent investigation commission by the National Diet in the 66-year history of Japan's constitutional government.
Fukushima "cannot be regarded as a natural disaster," the NAIIC panel's chairman, Tokyo University professor emeritus Kiyoshi Kurokawa , wrote in the inquiry report. "It was a profoundly man-made disaster – that could and should have been foreseen and prevented. And its effects could have been mitigated by a more effective human response." "Governments, regulatory authorities and Tokyo Electric Power lacked a sense of responsibility to protect people's lives and society," the Commission said. "They effectively betrayed the nation's right to be safe from nuclear accidents.
The Commission recognized that the affected residents were still struggling and facing grave concerns, including the "health effects of radiation exposure, displacement, the dissolution of families, disruption of their lives and lifestyles and the contamination of vast areas of the environment".
Main article: Investigation Committee on the Accident at the Fukushima Nuclear Power Stations of Tokyo Electric Power Company
The purpose of the Investigation Committee on the Accident at the Fukushima Nuclear Power Stations (ICANPS) was to identify the disaster's causes and propose policies designed to minimize the damage and prevent the recurrence of similar incidents. The 10 member, government-appointed panel included scholars, journalists, lawyers, and engineers. It was supported by public prosecutors and government experts. and released its final, 448-page investigation report on 23 July 2012.
The panel's report faulted an inadequate legal system for nuclear crisis management, a crisis-command disarray caused by the government and TEPCO, and possible excess meddling on the part of the Prime Minister's office in the crisis' early stage. The panel concluded that a culture of complacency about nuclear safety and poor crisis management led to the nuclear disaster.
Comparison of Fukushima and Chernobyl nuclear accidents
Environmental issues in Japan
Fukushima disaster cleanup
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Wikimedia Commons has media related to FUKUSHIMA DAICHI NUCLEAR DISASTER .
* The Fukushima Nuclear Accident Independent Investigation Commission Report website in English * Investigation Committee on the accidents at the Fukushima Nuclear Power Station of Tokyo Electric Power Company * The Radioactive Waters of Fukushima * Lessons Learned From Fukushima Dai-ichi – Report & Movie
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