Fukushima I Nuclear Power Plant
Encyclopedia
The , also known as Fukushima Dai-ichi (dai-ichi means "number one"), is a disabled nuclear power plant
located on a 3.5 square kilometres (864.9 acre) site in the towns of Okuma
and Futaba
in the Futaba District
of Fukushima Prefecture
, Japan
. First commissioned in 1971, the plant consists of six boiling water reactor
s (BWR). These light water reactor
s drove electrical generators with a combined power of 4.7 GWe, making Fukushima Daiichi one of the 15 largest nuclear power stations in the world. Fukushima I was the first nuclear plant to be constructed and run entirely by the Tokyo Electric Power Company (TEPCO). The plant suffered major damage from the 9.0 earthquake
and subsequent tsunami
that hit Japan on March 11, 2011 and 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.
The Fukushima II Nuclear Power Plant
, or Fukushima Dai-ni, is located to the south and also run by TEPCO.
, those for Units 3 and 5 by Toshiba
, and Unit 4 by Hitachi
. All six reactors were designed by General Electric. Architectural design for General Electric's units was done by Ebasco
. All construction was done by Kajima. Since September 2010, Unit 3 has been fueled by a small fraction (6%) of mixed-oxide (MOX) fuel
, rather than the low enriched uranium (LEU) used in the other reactors. Units 1–5 were built with Mark I type (light bulb torus) containment structures
. The Mark I containment structure was slightly increased in volume by Japanese engineers. Unit 6 has a Mark II type (over/under) containment structure.
Unit 1 is a 460 MW boiling water reactor
(BWR-3) constructed in July 1967. It commenced commercial electrical production on March 26, 1971, and was initially scheduled for shutdown in early 2011. In February 2011, Japanese regulators granted an extension of ten years for the continued operation of the reactor. It was damaged during the 2011 Tōhoku earthquake and tsunami
.
Unit 1 was designed for a peak ground acceleration
of 0.18 g
(1.74 m/s2) and a response spectrum
based on the 1952 Kern County earthquake
, but rated for 0.498 g. The design basis for Units 3 and 6 were 0.45 g (4.41 m/s2) and 0.46 g (4.48 m/s2) respectively. All units were inspected after the 1978 Miyagi earthquake
when the ground acceleration was 0.125 g (1.22 m/s2) for 30 seconds, but no damage to the critical parts of the reactor was discovered. The design basis for tsunamis was 5.7 meters.
The reactor's emergency diesel generators and DC batteries, crucial components in helping keep the reactors cool in the event of a power loss, were located in the basements of the reactor turbine buildings. The reactor design plans provided by General Electric specified placing the generators and batteries in that location, but mid-level engineers working on the construction of the plant were concerned that this made the back up power systems vulnerable to flooding. TEPCO elected to strictly follow General Electric's design in the construction of the reactors.
.
The Fukushima Daiichi site is divided into two reactor groups, the leftmost group when viewing from the ocean contains units 4,3,2 and 1 going from left to right. The rightmost group when viewing from the ocean contains the newer units 5 and 6, respectively the positions from left to right. A set of seawalls protrude into the ocean, with the water intake in the middle and water discharge outlets on either side.
The Shin-Fukushima substation also connects to the Fukushima Daini plant by the Tomioka Line (富岡線). Its major connection to the north is the Iwaki Line (いわき幹線), which is owned by Tohoku Electric Power. It has two connections to the south-west that connect it to the Shin-Iwaki substation (新いわき).
admitting that the company had previously submitted fake inspection and repair reports. The report revealed that TEPCO failed to inspect more than 30 technical components of the six reactors, including power boards for the reactor's temperature control valves, as well as components of cooling systems such as water pump motors and emergency power diesel generators. In 2008, the IAEA warned Japan that the Fukushima was built using outdated safety guidelines, and could be a "serious problem" during a large earthquake. The warning led to the building of an emergency response center in 2010, used during the response to the 2011 nuclear accident.
On 4 April 2011, TEPCO vice president Takashi Fujimoto announced that the company was canceling plans to build Reactors No. 7 and 8. On May 20 TEPCO's board of directors' officially voted to decommission Units 1 through 4 of the Fukushima Daiichi nuclear power plant and to cancel plans to build units 7 and 8. It refused however to make a decision regarding units 5 and 6 of the station or units 1 to 4 of the Fukushima Daini nuclear power station until a detailed investigation is made. It said in the interim it will work to preserve these reactors in the state of cold shutdown.
(NRC) ranked the failure of the emergency electricity generators and subsequent failure of the cooling systems of plants in seismically very active regions one of the most likely risks. The Japanese Nuclear and Industrial Safety Agency
(NISA) cited this report in 2004. According to Jun Tateno, a former NISA scientist, TEPCO did not react to these warnings and did not respond with any measures.
Film maker Adam Curtis
mentioned the risks of the type of boiling water reactor
s cooling systems such as those in Fukushima I, and claimed the risks were known since 1971 in a series of documentaries in the BBC in 1992 and advised that PWR type
reactors should have been used.
on the moment magnitude scale
occurred at 14:46 Japan Standard Time
(JST) off the northeast coast of Japan
. Units 4, 5 and 6 had been shut down prior to the earthquake for planned maintenance. The remaining reactors were shut down automatically after the earthquake
, and the remaining decay heat of the fuel was being cooled with power from emergency generators. The subsequent destructive tsunami
with waves of up to 14 meters (the reactors were designed to handle up to 5,7 meters) disabled emergency generators required to cool the reactors. Over the following three weeks there was evidence of partial nuclear meltdown
s in units 1, 2 and 3: visible explosions, suspected to be caused by hydrogen gas, in units 1 and 3; a suspected explosion in unit 2, that may have damaged the primary containment vessel; and a possible uncovering of the units 1, 3 and 4 spent fuel pool
s. Radiation releases caused large evacuations, concern about food and water supplies, and treatment of nuclear workers.
The events at units 1, 2 and 3 have been rated at Level 7 (major release of radioactive material with widespread health and environmental effects requiring implementation of planned and extended countermeasures) on the International Nuclear Event Scale
, and those at unit 4 as Level 3 (Serious Incident) events.
On 3 April 2011, two bodies were discovered in the basement turbine room most likely because the workers ran there during the tsunami.
2011 Earthquake-Tsunami accident
Nuclear power plant
A nuclear power plant is a thermal power station in which the heat source is one or more nuclear reactors. As in a conventional thermal power station the heat is used to generate steam which drives a steam turbine connected to a generator which produces electricity.Nuclear power plants are usually...
located on a 3.5 square kilometres (864.9 acre) site in the towns of Okuma
Okuma, Fukushima
is a town located in Futaba District, Fukushima, Japan.As of 2010, the town has an estimated population of 11,511 and a density of 146.26 persons per km². The total area is 78.70 km². In March 2011 the town was evacuated by government order due to the Fukushima I nuclear accident.-External ...
and Futaba
Futaba, Fukushima
is a town located in Futaba District, Fukushima, Japan.As of 2003, the town had an estimated population of 7,406 and a density of 144.09 persons per km². The total area is 51.40 km².-2011 disaster:...
in the Futaba District
Futaba District, Fukushima
is a district located in Fukushima, Japan.As of 2003, the district has an estimated population of 75,220 and a density of 86.95 persons per km². The total area is 865.12 km².-Towns and villages:*Futaba*Hirono*Katsurao*Kawauchi*Namie*Naraha*Ōkuma...
of Fukushima Prefecture
Fukushima Prefecture
is a prefecture of Japan located in the Tōhoku region on the island of Honshu. The capital is the city of Fukushima.-History:Until the Meiji Restoration, the area of Fukushima prefecture was known as Mutsu Province....
, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
. First commissioned in 1971, the plant consists of six boiling water reactor
Boiling water reactor
The boiling water reactor is a type of light water nuclear reactor used for the generation of electrical power. It is the second most common type of electricity-generating nuclear reactor after the pressurized water reactor , also a type of light water nuclear reactor...
s (BWR). These light water reactor
Light water reactor
The light water reactor is a type of thermal reactor that uses normal water as its coolant and neutron moderator. Thermal reactors are the most common type of nuclear reactor, and light water reactors are the most common type of thermal reactor...
s drove electrical generators with a combined power of 4.7 GWe, making Fukushima Daiichi one of the 15 largest nuclear power stations in the world. Fukushima I was the first nuclear plant to be constructed and run entirely by the Tokyo Electric Power Company (TEPCO). The plant suffered major damage from the 9.0 earthquake
2011 Tōhoku earthquake and tsunami
The 2011 earthquake off the Pacific coast of Tohoku, also known as the 2011 Tohoku earthquake, or the Great East Japan Earthquake, was a magnitude 9.0 undersea megathrust earthquake off the coast of Japan that occurred at 14:46 JST on Friday, 11 March 2011, with the epicenter approximately east...
and subsequent tsunami
Tsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...
that hit Japan on March 11, 2011 and 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.
The Fukushima II Nuclear Power Plant
Fukushima II Nuclear Power Plant
The , or Fukushima Dai-ni , is a nuclear power plant located on a site in the town of Naraha and Tomioka in the Futaba District of Fukushima Prefecture, Japan...
, or Fukushima Dai-ni, is located to the south and also run by TEPCO.
Power plant information
The reactors for Units 1, 2, and 6 were supplied by General ElectricGeneral Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...
, those for Units 3 and 5 by Toshiba
Toshiba
is a multinational electronics and electrical equipment corporation headquartered in Tokyo, Japan. It is a diversified manufacturer and marketer of electrical products, spanning information & communications equipment and systems, Internet-based solutions and services, electronic components and...
, and Unit 4 by Hitachi
Hitachi
Hitachi is a multinational corporation specializing in high-technology.Hitachi may also refer to:*Hitachi, Ibaraki, Japan*Hitachi province, former province of Japan*Prince Hitachi and Princess Hitachi, members of the Japanese imperial family...
. All six reactors were designed by General Electric. Architectural design for General Electric's units was done by Ebasco
Electric Bond and Share Company
The Electric Bond and Share Company was originally a holding company that sold securities of electric utilities. It was created by General Electric in 1905. The company was restructured after the Public Utility Holding Company Act of 1935. Later known as EBASCO Services, it provided engineering...
. All construction was done by Kajima. Since September 2010, Unit 3 has been fueled by a small fraction (6%) of mixed-oxide (MOX) fuel
MOX fuel
Mixed oxide fuel, commonly referred to as MOX fuel, is nuclear fuel that contains more than one oxide of fissile material. MOX fuel contains plutonium blended with natural uranium, reprocessed uranium, or depleted uranium. MOX fuel is an alternative to the low-enriched uranium fuel used in the...
, rather than the low enriched uranium (LEU) used in the other reactors. Units 1–5 were built with Mark I type (light bulb torus) containment structures
Containment building
A containment building, in its most common usage, is a steel or reinforced concrete structure enclosing a nuclear reactor. It is designed, in any emergency, to contain the escape of radiation to a maximum pressure in the range of 60 to 200 psi...
. The Mark I containment structure was slightly increased in volume by Japanese engineers. Unit 6 has a Mark II type (over/under) containment structure.
Unit 1 is a 460 MW boiling water reactor
Boiling water reactor
The boiling water reactor is a type of light water nuclear reactor used for the generation of electrical power. It is the second most common type of electricity-generating nuclear reactor after the pressurized water reactor , also a type of light water nuclear reactor...
(BWR-3) constructed in July 1967. It commenced commercial electrical production on March 26, 1971, and was initially scheduled for shutdown in early 2011. In February 2011, Japanese regulators granted an extension of ten years for the continued operation of the reactor. It was damaged during the 2011 Tōhoku earthquake and tsunami
2011 Tōhoku earthquake and tsunami
The 2011 earthquake off the Pacific coast of Tohoku, also known as the 2011 Tohoku earthquake, or the Great East Japan Earthquake, was a magnitude 9.0 undersea megathrust earthquake off the coast of Japan that occurred at 14:46 JST on Friday, 11 March 2011, with the epicenter approximately east...
.
Unit 1 was designed for a peak ground acceleration
Peak ground acceleration
Peak ground acceleration is a measure of earthquake acceleration on the ground and an important input parameter for earthquake engineering, also known as the design basis earthquake ground motion...
of 0.18 g
G-force
The g-force associated with an object is its acceleration relative to free-fall. This acceleration experienced by an object is due to the vector sum of non-gravitational forces acting on an object free to move. The accelerations that are not produced by gravity are termed proper accelerations, and...
(1.74 m/s2) and a response spectrum
Response spectrum
A response spectrum is simply a plot of the peak or steady-state response of a series of oscillators of varying natural frequency, that are forced into motion by the same base vibration or shock. The resulting plot can then be used to pick off the response of any linear system, given its natural...
based on the 1952 Kern County earthquake
1952 Kern County earthquake
The 1952 Kern County earthquake occurred on July 21, 1952, in Kern County, California, with a magnitude of 7.5Mw. It was the largest earthquake to strike Southern California since the Fort Tejon earthquake of 1857 and the 1872 Lone Pine earthquake, causing immense and widespread damage. The main...
, but rated for 0.498 g. The design basis for Units 3 and 6 were 0.45 g (4.41 m/s2) and 0.46 g (4.48 m/s2) respectively. All units were inspected after the 1978 Miyagi earthquake
1978 Miyagi earthquake
The occurred at 17:14 local time on 12 June. It had a magnitude of 7.7, JMA magnitude 7.4, and triggered a small tsunami. The earthquake reached a maximum intensity of Shindo 5 in Sendai and caused 28 deaths and 1,325 injuries.-Geology:...
when the ground acceleration was 0.125 g (1.22 m/s2) for 30 seconds, but no damage to the critical parts of the reactor was discovered. The design basis for tsunamis was 5.7 meters.
The reactor's emergency diesel generators and DC batteries, crucial components in helping keep the reactors cool in the event of a power loss, were located in the basements of the reactor turbine buildings. The reactor design plans provided by General Electric specified placing the generators and batteries in that location, but mid-level engineers working on the construction of the plant were concerned that this made the back up power systems vulnerable to flooding. TEPCO elected to strictly follow General Electric's design in the construction of the reactors.
Site layout
The location of the plant was on a bluff which was originally 35-meters above sea level. During construction, however, TEPCO lowered the height of the bluff by 25-meters. One reason the bluff was lowered was so that the base of the reactors could be constructed on solid bedrock to mitigate the threat posed by earthquakes. Another reason was the lowered height would keep the running costs of the seawater pumps low. TEPCO did not factor in the tsunami risk when planning the site's construction. Therefore, the lowered height would result in the plant being more vulnerable to tsunamiTsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...
.
The Fukushima Daiichi site is divided into two reactor groups, the leftmost group when viewing from the ocean contains units 4,3,2 and 1 going from left to right. The rightmost group when viewing from the ocean contains the newer units 5 and 6, respectively the positions from left to right. A set of seawalls protrude into the ocean, with the water intake in the middle and water discharge outlets on either side.
Reactor data
Units 7 and 8 were planned to start construction in April 2012 and 2013 and to come into operation in October 2016 and 2017 respectively. The project was formally canceled by TEPCO in April 2011 after local authorities questioned the fact that they were still included in the supply plan for 2011, released in March 2011, after the accidents. The company stated that the plan had been drafted before the earthquake.| Unit | Type | Containment | Start construction | First criticality | Commercial operation | Electric power | Reactor supplier | Architecture | Construction | Fuel |
|---|---|---|---|---|---|---|---|---|---|---|
| Fukushima I – 1 | BWR Boiling water reactor The boiling water reactor is a type of light water nuclear reactor used for the generation of electrical power. It is the second most common type of electricity-generating nuclear reactor after the pressurized water reactor , also a type of light water nuclear reactor... -3 |
Mark I | July 25, 1967 | October 10, 1970 | March 26, 1971 | 460 MW | General Electric General Electric General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States... |
Ebasco | Kajima | LEU |
| Fukushima I – 2 | BWR-4 | Mark I | June 9, 1969 | May 10, 1973 | July 18, 1974 | 784 MW | General Electric | Ebasco | Kajima | LEU |
| Fukushima I – 3 | BWR-4 | Mark I | December 28, 1970 | September 6, 1974 | March 27, 1976 | 784 MW | Toshiba Toshiba is a multinational electronics and electrical equipment corporation headquartered in Tokyo, Japan. It is a diversified manufacturer and marketer of electrical products, spanning information & communications equipment and systems, Internet-based solutions and services, electronic components and... |
Toshiba | Kajima | LEU/MOX MOX fuel Mixed oxide fuel, commonly referred to as MOX fuel, is nuclear fuel that contains more than one oxide of fissile material. MOX fuel contains plutonium blended with natural uranium, reprocessed uranium, or depleted uranium. MOX fuel is an alternative to the low-enriched uranium fuel used in the... |
| Fukushima I – 4 | BWR-4 | Mark I | February 12, 1973 | January 28, 1978 | October 12, 1978 | 784 MW | Hitachi Hitachi Hitachi is a multinational corporation specializing in high-technology.Hitachi may also refer to:*Hitachi, Ibaraki, Japan*Hitachi province, former province of Japan*Prince Hitachi and Princess Hitachi, members of the Japanese imperial family... |
Hitachi | Kajima | |
| Fukushima I – 5 | BWR-4 | Mark I | May 22, 1972 | August 26, 1977 | April 18, 1978 | 784 MW | Toshiba | Toshiba | Kajima | |
| Fukushima I – 6 | BWR-5 | Mark II | October 26, 1973 | March 9, 1979 | October 24, 1979 | 1,100 MW | General Electric | Ebasco | Kajima | |
| Fukushima I – 7 (planned) | ABWR Advanced Boiling Water Reactor The Advanced Boiling Water Reactor is a Generation III boiling water reactor. The ABWR is currently offered by GE Hitachi Nuclear Energy and Toshiba... |
Canceled 04/2011 | (As originally planned) October 2016 | 1,380 MW | Canceled 04/2011 | |||||
| Fukushima I – 8 (planned) | ABWR | Canceled 04/2011 | (As originally planned) October 2017 | 1,380 MW | Canceled 04/2011 |
Electrical connections
The Fukushima Daiichi plant is connected to the power grid by four lines, the 500 kV Futaba Line (双葉線), the two 275 kV Ōkuma Lines (大熊線) and the 66 kV Yonomori line (夜の森線) to the Shin-Fukushima (New Fukushima) substation.The Shin-Fukushima substation also connects to the Fukushima Daini plant by the Tomioka Line (富岡線). Its major connection to the north is the Iwaki Line (いわき幹線), which is owned by Tohoku Electric Power. It has two connections to the south-west that connect it to the Shin-Iwaki substation (新いわき).
Operating history
The plant reactors came online from 1970 through 1979. From the end of 2002 through 2005, the reactors were among those shut down for a time for safety checks due to the TEPCO data falsification scandal. On Feb 28, 2011 TEPCO submitted a report to the Japanese Nuclear and Industrial Safety AgencyNuclear and Industrial Safety Agency
The is a Japanese nuclear regulatory and oversight branch of the Agency for Natural Resources and Energy under the Ministry of Economy, Trade and Industry. It was created in 2001 during the 2001 Central Government Reform. It has a main office in Kasumigaseki, Chiyoda, Tokyo that works with the...
admitting that the company had previously submitted fake inspection and repair reports. The report revealed that TEPCO failed to inspect more than 30 technical components of the six reactors, including power boards for the reactor's temperature control valves, as well as components of cooling systems such as water pump motors and emergency power diesel generators. In 2008, the IAEA warned Japan that the Fukushima was built using outdated safety guidelines, and could be a "serious problem" during a large earthquake. The warning led to the building of an emergency response center in 2010, used during the response to the 2011 nuclear accident.
On 4 April 2011, TEPCO vice president Takashi Fujimoto announced that the company was canceling plans to build Reactors No. 7 and 8. On May 20 TEPCO's board of directors' officially voted to decommission Units 1 through 4 of the Fukushima Daiichi nuclear power plant and to cancel plans to build units 7 and 8. It refused however to make a decision regarding units 5 and 6 of the station or units 1 to 4 of the Fukushima Daini nuclear power station until a detailed investigation is made. It said in the interim it will work to preserve these reactors in the state of cold shutdown.
| Year | Unit 1 | Unit 2 | Unit 3 | Unit 4 | Unit 5 | Unit 6 |
|---|---|---|---|---|---|---|
| 1970 | 60.482 | |||||
| 1971 | 2024.3 | |||||
| 1972 | 2589.1 | |||||
| 1973 | 2216.8 | 5.949 | ||||
| 1974 | 1629.7 | 3670.1 | 284.7 | |||
| 1975 | 0 | 622.1 | 2961.8 | |||
| 1976 | 1563.9 | 4191.4 | 4807.1 | |||
| 1977 | 0 | 49.7 | 2171.1 | 875.1 | ||
| 1978 | 1497.6 | 3876.3 | 2753.7 | 3163.2 | 4806.7 | |
| 1979 | 2504.4 | 2976 | 4916.3 | 3917.4 | 3898.6 | 3235.6 |
| 1980 | 1249.5 | 2889 | 4287 | 4317 | 4282.6 | 6441.1 |
| 1981 | 1084.8 | 3841.8 | 3722.8 | 4667.5 | 4553.9 | 7418.6 |
| 1982 | 2355 | 5290.2 | 2886.8 | 5734.7 | 4061.3 | 6666.5 |
| 1983 | 3019.5 | 3422.7 | 4034 | 4818.2 | 5338.8 | 5387.8 |
| 1984 | 2669.761 | 3698.718 | 4497.326 | 4433.166 | 4691.482 | 5933.242 |
| 1985 | 1699.287 | 4266.285 | 5798.641 | 4409.031 | 4112.429 | 5384.802 |
| 1986 | 2524.683 | 5541.101 | 4234.196 | 4315.241 | 4157.361 | 7783.537 |
| 1987 | 3308.888 | 3851.078 | 3748.839 | 5964.048 | 3995.012 | 7789.201 |
| 1988 | 2794.464 | 4101.251 | 5122.991 | 5309.892 | 5952.712 | 5593.058 |
| 1989 | 1440.778 | 6516.393 | 5706.694 | 4232.648 | 4766.535 | 5128.362 |
| 1990 | 2352.405 | 3122.761 | 2919.548 | 4273.767 | 3956.549 | 7727.073 |
| 1991 | 1279.986 | 3853.054 | 4491.022 | 6483.384 | 6575.818 | 6948.662 |
| 1992 | 1794.061 | 4568.531 | 6098.742 | 4082.747 | 4841.234 | 5213.607 |
| 1993 | 2500.668 | 4186.704 | 4204.301 | 4206.577 | 4059.685 | 6530.932 |
| 1994 | 3337.532 | 2265.961 | 4202.304 | 6323.277 | 4246.206 | 8079.391 |
| 1995 | 3030.829 | 6396.469 | 5966.533 | 5485.662 | 5878.681 | 6850.839 |
| 1996 | 2298.589 | 5192.318 | 4909.655 | 4949.891 | 5666.866 | 6157.765 |
| 1997 | 3258.913 | 4618.869 | 2516.651 | 4556.81 | 4609.382 | 9307.735 |
| 1998 | 3287.231 | 3976.16 | 2632.682 | 5441.398 | 5369.912 | 6328.985 |
| 1999 | 2556.93 | 3158.382 | 5116.09 | 5890.548 | 6154.135 | 7960.491 |
| 2000 | 3706.281 | 5167.247 | 5932.485 | 4415.901 | 1647.027 | 7495.577 |
| 2001 | 487.504 | 5996.521 | 5637.317 | 5858.452 | 5905.13 | 7778.874 |
| 2002 | 3120.2 | 5101.018 | 3567.314 | 4687.718 | 6590.488 | 6270.918 |
| 2003 | 0 | 1601.108 | 2483.557 | 0 | 2723.76 | 4623.905 |
| 2004 | 0 | 3671.49 | 3969.674 | 4728.987 | 5471.325 | 1088.787 |
| 2005 | 851.328 | 3424.939 | 5103.85 | 1515.596 | 2792.561 | 7986.451 |
| 2006 | 3714.606 | 3219.494 | 4081.932 | 4811.409 | 4656.9 | 5321.767 |
| 2007 | 610.761 | 5879.862 | 4312.845 | 5050.607 | 5389.565 | 6833.522 |
| 2008 | 3036.562 | 5289.599 | 6668.839 | 4410.285 | 3930.677 | 8424.526 |
| 2009 | 2637.414 | 4903.293 | 4037.601 | 5462.108 | 5720.079 | 7130.99 |
| 2010 | 2089.015 | 6040.782 |
Warnings and design critique
In 1990 the US Nuclear Regulatory CommissionNuclear Regulatory Commission
The Nuclear Regulatory Commission is an independent agency of the United States government that was established by the Energy Reorganization Act of 1974 from the United States Atomic Energy Commission, and was first opened January 19, 1975...
(NRC) ranked the failure of the emergency electricity generators and subsequent failure of the cooling systems of plants in seismically very active regions one of the most likely risks. The Japanese Nuclear and Industrial Safety Agency
Nuclear and Industrial Safety Agency
The is a Japanese nuclear regulatory and oversight branch of the Agency for Natural Resources and Energy under the Ministry of Economy, Trade and Industry. It was created in 2001 during the 2001 Central Government Reform. It has a main office in Kasumigaseki, Chiyoda, Tokyo that works with the...
(NISA) cited this report in 2004. According to Jun Tateno, a former NISA scientist, TEPCO did not react to these warnings and did not respond with any measures.
Film maker Adam Curtis
Adam Curtis
Adam Curtis is a British BAFTA winning documentarian and a writer, television producer, director and narrator. He works for BBC Current Affairs.-Early life and education:Curtis was born in 1955...
mentioned the risks of the type of boiling water reactor
Boiling water reactor
The boiling water reactor is a type of light water nuclear reactor used for the generation of electrical power. It is the second most common type of electricity-generating nuclear reactor after the pressurized water reactor , also a type of light water nuclear reactor...
s cooling systems such as those in Fukushima I, and claimed the risks were known since 1971 in a series of documentaries in the BBC in 1992 and advised that PWR type
Pressurized water reactor
Pressurized water reactors constitute a large majority of all western nuclear power plants and are one of three types of light water reactor , the other types being boiling water reactors and supercritical water reactors...
reactors should have been used.
Incidents and accident
- In 1978, fuel rods fell in reactor No. 3, causing a nuclear reaction. It took about seven and a half hours to place the rods back into proper positions.
- On February 25, 2009 a manual shutdown was initiated during the middle of a startup operation. The cause was a high pressure alarm that was caused by the shutting of a turbine bypass valve. The reactor was at 12% of full power when the alarm occurred at 4:03am due to a pressure increase to 1029.8 psi (7,100,221.1 Pa), exceeding the regulatory limit of 1002.2 psi (6,909,925.8 Pa) The reactor was reduced to 0% power, which exceeded the 5% threshold that requires event reporting, and pressure dropped back under the regulatory limit at 4:25am. Later, at 8:49am the control blades were completely inserted, constituting a manual reactor shutdown. An inspection then confirmed that one of the 8 bypass valves had closed and that the valve had a bad driving fluid connection. The reactor had been starting up following its 25th regular inspection which began on October 18, 2008.
- On March 26, 2009 unit 3 had problems with over-insertion of control blades during outage. Repair work was being done on equipment that regulates the driving pressure for the control blades, and when a valve was opened at 2:23pm a control blade drift alarm went off. On later inspection it was found that several of the rods had been unintentionally inserted.
- On November 2, 2010 unit 5 had an automatic SCRAM while an operator was conducting an adjustment to the control blade insertion pattern. The SCRAMScramA scram or SCRAM is an emergency shutdown of a nuclear reactor – though the term has been extended to cover shutdowns of other complex operations, such as server farms and even large model railroads...
was caused by a reactor low water level alarm. The turbine tripped along with the reactor and there was no radiation injury to workers.
Nuclear disaster of 2011
On 11 March 2011 an earthquake categorised as 9.0 MW2011 Tōhoku earthquake and tsunami
The 2011 earthquake off the Pacific coast of Tohoku, also known as the 2011 Tohoku earthquake, or the Great East Japan Earthquake, was a magnitude 9.0 undersea megathrust earthquake off the coast of Japan that occurred at 14:46 JST on Friday, 11 March 2011, with the epicenter approximately east...
on the moment magnitude scale
Moment magnitude scale
The moment magnitude scale is used by seismologists to measure the size of earthquakes in terms of the energy released. The magnitude is based on the seismic moment of the earthquake, which is equal to the rigidity of the Earth multiplied by the average amount of slip on the fault and the size of...
occurred at 14:46 Japan Standard Time
Japan Standard Time
Japan Standard Time or JST is the standard timezone of Japan, and is 9 hours ahead of UTC. For example, when it is midnight in UTC, it is 09:00 in Japan Standard Time. There is no daylight saving time, though its introduction has been debated several times. Japan Standard Time is the same as...
(JST) off the northeast coast of Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
. Units 4, 5 and 6 had been shut down prior to the earthquake for planned maintenance. The remaining reactors were shut down automatically after the earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
, and the remaining decay heat of the fuel was being cooled with power from emergency generators. The subsequent destructive tsunami
Tsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...
with waves of up to 14 meters (the reactors were designed to handle up to 5,7 meters) disabled emergency generators required to cool the reactors. Over the following three weeks there was evidence of partial nuclear meltdown
Nuclear meltdown
Nuclear meltdown is an informal term for a severe nuclear reactor accident that results in core damage from overheating. The term is not officially defined by the International Atomic Energy Agency or by the U.S. Nuclear Regulatory Commission...
s in units 1, 2 and 3: visible explosions, suspected to be caused by hydrogen gas, in units 1 and 3; a suspected explosion in unit 2, that may have damaged the primary containment vessel; and a possible uncovering of the units 1, 3 and 4 spent fuel pool
Spent fuel pool
Spent fuel pools are storage pools for spent fuel from nuclear reactors. They are typically 40 or more feet deep, with the bottom 14 feet equipped with storage racks designed to hold fuel assemblies removed from the reactor. A reactor's pool is specially designed for the reactor in which the...
s. Radiation releases caused large evacuations, concern about food and water supplies, and treatment of nuclear workers.
The events at units 1, 2 and 3 have been rated at Level 7 (major release of radioactive material with widespread health and environmental effects requiring implementation of planned and extended countermeasures) on the International Nuclear Event Scale
International Nuclear Event Scale
The International Nuclear and Radiological Event Scale was introduced in 1990 by the International Atomic Energy Agency in order to enable prompt communication of safety significance information in case of nuclear accidents....
, and those at unit 4 as Level 3 (Serious Incident) events.
On 3 April 2011, two bodies were discovered in the basement turbine room most likely because the workers ran there during the tsunami.
See also
- Nuclear power in JapanNuclear power in JapanNuclear energy was a national strategic priority in Japan, but there has been concern about the ability of Japan's nuclear plants to withstand seismic activity...
- List of boiling water reactors
- GE Three
2011 Earthquake-Tsunami accident
- 2011 Japanese nuclear accidents2011 Japanese nuclear accidentsThis is a list of articles describing aspects of the nuclear shut-downs, failures, and nuclear meltdowns triggered by the 2011 Tōhoku earthquake and tsunami.-Fukushima nuclear power plants:* Fukushima I Nuclear Power Plant...
- Radiation effects from Fukushima Daiichi nuclear disaster
- Japanese reaction to Fukushima Daiichi nuclear disaster
- International reaction to the Fukushima Daiichi nuclear disaster
External links
- Official site Tokyo Electric Company 東京電力・福島第一原子力発電所
- TEPCO News, Tokyo Electric Power Company
- TEPCO Webcam showing Fukushima I Nuclear Power Plant
- Archived photo. Units 1–4 can be seen from left to right.
- Radiation Dose Chart
- The Fukushima Daiichi Incident prepared by Dr. Matthias Braun - 01 April 2011, PEPA4-G, AREVA–NP GmbH (cryptome.org)
- 3D Google Earth view