Onagawa Nuclear Power Plant
Encyclopedia
The is a nuclear power plant
located on a 1,730,000 m2 (432 acres) site in Onagawa
in the Oshika District
and Ishinomaki
city, Miyagi Prefecture
, Japan. It is managed by the Tohoku Electric Power Company
. It was the most quickly constructed nuclear power plant in the world.
The Onagawa-3 unit was used as a prototype for the Higashidori Nuclear Power Plant
.
The plant conforms fully to ISO 14001, a set of international environmental management standards. The plant's waste heat water leaves 7 degrees Celsius higher than it came in and is released 10 meters under the surface of the water, in order to reduce adverse effects on the environment
All the reactors were constructed by Toshiba
.
was satisfied that the countermeasures taken by the plant operator to prevent a reoccurrence were adequate.
and recorded vibrations above what the plant was designed for. Analysis after the event, however, found no damage to the reactor systems. Some people reported seeing smoke come from the plant after the earthquake and reported it, thinking that it indicated an accident, but the smoke was actually produced by the backup diesel generators.
, the nuclear safety agency said, was reported by Kyodo News http://english.kyodonews.jp/news/2011/04/84063.html
A fire from the turbine section of the plant following the 2011 Tōhoku earthquake
was reported by Kyodo News
.
On March 13, 2011, levels of radiation on site reached 21μSv
/hour, a level at which Tohoku Electric Power Company
were mandated to declare state of emergency, and they did so at 12:50, declaring the lowest-level such state. Within 10 minutes the level had dropped to 10μSv/hour. The Japanese authorities assume the temporarily heightened values were due to radiation from the Fukushima I nuclear accidents and not from the plant itself. On March 13 20:45 UTC, the IAEA announced that radiation levels at the Onagawa plant had returned to normal background levels.
The three units remain in cold shutdown since the earthquake of 11 March. Two hundred people who lost their homes to the tsunami took refuge in the plant. The April 7th aftershock damaged 2 of the 3 external power lines to the plant but cooling was maintained through the third line.
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 1,730,000 m2 (432 acres) site in Onagawa
Onagawa, Miyagi
is a town located in Oshika District, Miyagi, Japan. The town was formed in 1926. The town takes pride in the fact that it still has beaches with "squeaking sand", which has apparently become rare in Japan due to human induced environmental changes. Onagawa is a port town, and right at the...
in the Oshika District
Oshika District, Miyagi
is a district located in Miyagi Prefecture, Japan.As of 2003, the district has an estimated population of 16,069 and a population density of 115.80 persons per km²...
and Ishinomaki
Ishinomaki, Miyagi
is a city located in Miyagi Prefecture, Japan.As of January 1, 2010, the city had an estimated population of 164,294 and a population density of 295.83 persons per km²...
city, Miyagi Prefecture
Miyagi Prefecture
is a prefecture of Japan in the Tōhoku Region on Honshu island. The capital is Sendai.- History :Miyagi Prefecture was formerly part of the province of Mutsu. Mutsu Province, on northern Honshu, was one of the last provinces to be formed as land was taken from the indigenous Emishi, and became the...
, Japan. It is managed by the Tohoku Electric Power Company
Tohoku Electric Power Company
is electric utility, servicing 7.6 million individual & corporate customers in 6 prefectures in Tōhoku region plus Niigata Prefecture. It provides electricity at 100 V, 50 Hz, though some area use 60 Hz....
. It was the most quickly constructed nuclear power plant in the world.
The Onagawa-3 unit was used as a prototype for the Higashidori Nuclear Power Plant
Higashidori Nuclear Power Plant
The is a nuclear power plant located in the town of Higashidōri in eastern Aomori Prefecture, on the Shimokita Peninsula, facing the Pacific Ocean. It is unique in Japan in that at this four-unit site, two units are run by one company, the Tōhoku Electric Power Company and two units are run by the...
.
The plant conforms fully to ISO 14001, a set of international environmental management standards. The plant's waste heat water leaves 7 degrees Celsius higher than it came in and is released 10 meters under the surface of the water, in order to reduce adverse effects on the environment
All the reactors were constructed 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...
.
Reactors on Site
| Unit | Type | Start of Operation | Electric Power |
|---|---|---|---|
| Onagawa - 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... |
June 1, 1984 | 524 MW |
| Onagawa - 2 | 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... |
July 28, 1995 | 825 MW |
| Onagawa - 3 | 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... |
January 30, 2002 | 825 MW |
Unit 1
Shut down manually on 25 February 2005 because it was determined that the reactor containment leaked small amounts of nitrogen. The unit was restarted once Nuclear and Industrial Safety AgencyNISA
NISA may refer to:*Nuclear and Industrial Safety Agency, part of the Japanese Ministry of Economy, Trade and Industry*NIS America, the US subsidiary of Nippon Ichi Software...
was satisfied that the countermeasures taken by the plant operator to prevent a reoccurrence were adequate.
Unit 2
- May 2006 it was confirmed that a pipe was leaking due to debris damage.
- June 7, 2006 Difficulties with pressure control prompted further inspections.
- July 7, 2006 METI and the Nuclear and Industrial Safety AgencyNuclear and Industrial Safety AgencyThe 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...
determined that the plant's performance was not satisfactory.
Unit 3
- July 7, 2006 Due to pipe integrity concerns the reactor was shut down.
- November 25, 2006 Following repairs the reactor was restarted.
- March 11, 2011 2011 Tōhoku earthquake damaged the turbines after a fire broke out and was shut down.
2005
The Onagawa Nuclear Power Plant was affected by the 2005 Miyagi earthquake2005 Miyagi earthquake
The 2005 Miyagi earthquake was a powerful earthquake that struck the east coast of the Japanese island of Honshū at 11.46am on August 16, causing casualties, building collapses and power outages.-Earthquake characteristics:...
and recorded vibrations above what the plant was designed for. Analysis after the event, however, found no damage to the reactor systems. Some people reported seeing smoke come from the plant after the earthquake and reported it, thinking that it indicated an accident, but the smoke was actually produced by the backup diesel generators.
2011
On April 8, 2011, a leak of radioactive water spilled from pools holding spent nuclear fuel rods following the 2011 Tōhoku earthquake2011 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...
, the nuclear safety agency said, was reported by Kyodo News http://english.kyodonews.jp/news/2011/04/84063.html
A fire from the turbine section of the plant following the 2011 Tōhoku 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...
was reported by Kyodo News
Kyodo News
is a nonprofit cooperative news agency based in Minato, Tokyo. It was established in November 1945 and it distributes news to almost all newspapers, and radio and television networks in Japan. The newspapers using its news have about 50 million subscribers. K. K. Kyodo News is Kyodo News' business...
.
On March 13, 2011, levels of radiation on site reached 21μSv
Sievert
The sievert is the International System of Units SI derived unit of dose equivalent radiation. It attempts to quantitatively evaluate the biological effects of ionizing radiation as opposed to just the absorbed dose of radiation energy, which is measured in gray...
/hour, a level at which Tohoku Electric Power Company
Tohoku Electric Power Company
is electric utility, servicing 7.6 million individual & corporate customers in 6 prefectures in Tōhoku region plus Niigata Prefecture. It provides electricity at 100 V, 50 Hz, though some area use 60 Hz....
were mandated to declare state of emergency, and they did so at 12:50, declaring the lowest-level such state. Within 10 minutes the level had dropped to 10μSv/hour. The Japanese authorities assume the temporarily heightened values were due to radiation from the Fukushima I nuclear accidents and not from the plant itself. On March 13 20:45 UTC, the IAEA announced that radiation levels at the Onagawa plant had returned to normal background levels.
The three units remain in cold shutdown since the earthquake of 11 March. Two hundred people who lost their homes to the tsunami took refuge in the plant. The April 7th aftershock damaged 2 of the 3 external power lines to the plant but cooling was maintained through the third line.
See also
- 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...
- List of boiling water reactors
- Lists of nuclear disasters and radioactive incidents