Monju
Encyclopedia
is a Japan
ese sodium-cooled fast reactor
, located in Tsuruga, Fukui Prefecture
. Construction started in 1986 and the reactor achieved criticality
for the first time in April 1994. Its name is a reference to Manjusri
.
Monju is a sodium
cooled
, MOX
-fueled, loop-type reactor with three primary coolant loops, producing 280 MWe from 714 MWt.
An accident in December 1995, in which a sodium leak caused a major fire, forced a shutdown. A subsequent scandal involving a cover-up of the scope of the accident delayed its restart until May 6, 2010, with renewed criticality reached on May 8, 2010. In August 2010 another accident, involving dropped machinery, shut down the reactor again. As of June 2011, the reactor has only generated electricity for one hour since its first testing two decades prior.
The plant is located on a site that spans 1.08 km2 (267 acres), the buildings occupy 28,678 m2 (7 acres), and it has 104,680 m2 of floor space. It employs 368 workers.
inside a pipe carrying sodium coolant to break, possibly at a defective weld
point, allowing several hundred kilograms of sodium to leak out onto the floor below the pipe. Upon coming into contact with the air, the liquid sodium reacted with oxygen and moisture in the air, filling the room with caustic fumes and producing temperatures of several hundred degrees Celsius
. The heat was so intense that it warped several steel
structures in the room. An alarm sounded around 7:30 p.m., switching the system over to manual operations, but a full operational shutdown was not ordered until around 9:00 p.m., after the fumes were spotted. When investigators located the source of the spill they found as much as three tons of solidified sodium.
Fortunately, the leak occurred in the plant's secondary cooling system, so the sodium was not radioactive. However, there was massive public outrage in Japan when it was revealed that Power Reactor and Nuclear Fuel Development Corporation
(PNC), the semigovernmental agency then in charge of Monju, had tried to cover up the extent of the accident and resulting damage. This coverup included falsifying reports and the editing of a videotape taken immediately after the accident, as well as the issuing of a gag order
to employees regarding the existence of the real tapes.
announced their intention to restart the Monju reactor. This decision was met with resistance by the public, resulting in a series of court battles. On January 27, 2003, the Nagoya High Court's Kanazawa
branch made a ruling reversing its earlier 1983 approval to build the reactor, but then on May 30, 2005, Japan's Supreme Court gave the green light to reopen the Monju reactor.
The restart was scheduled for October 2008, having been moved back five months. A restart date of February 2009 was again delayed due to the discovery of holes in the reactor's auxiliary building; in August 2009 it was announced that restart might be in February 2010.
In February 2010, JAEA obtained official approval to restart the reactor from the Japanese Government. The restart was definitely scheduled for the end of March. In late February, JAEA requested Fukui Prefecture and Tsuruga City for deliberations aimed at resuming test operation. Having obtained the go-ahead from both entities, JAEA started criticality testing, after which it took some months before commercial operation could resume - as for any new nuclear plant.
Operators started withdrawing control rods on May 6, 2010, marking the restart of the plant. The Fukui Prefecture
governor, Issei Nishikawa
asked the METI for additional stimulus to the prefecture including an expansion of the Shinkansen
in turn for the restart of the plant. Monju achieved criticality on May 8, at 10:36 AM JST. Test runs were to continue until 2013, at which point the reactor could have started to feed power into the electric grid, being "full fledged" operation.
In September 2011 the ministry of education, science and technology asked for the fiscal year of 2012 only 20 to 30 percent of the budget to maintain and manage the Monju reactor for the year 2011. The uncertainty about Japan's future energy policy caused the ministry to conclude, that the project could not proceeded.
The testrun of the reactor, in which the reactor's output would be raised to 40 percent of its capacity by the end of March 2012, was postponed on 29 September 2011, by the Japanese Government because the uncertainty over the future of nuclear energy.
After the disaster in Fukushima, the Atomic Energy Commission of Japan made a start with a review of Japan's long term energy policy. An outline of this policy would be published within 12 months. On 30 September officials of the Science and Technology ministry explained on meetings in the city of
Tsuruga and the prefecture Fukui
their decision not to start the test-run.
On 27 November nuclear disaster minister Goshi Hosono said that scrapping the Monju-fast-breeder reactor is an options, that is given a serious thought. The remark was made after a visit to the plant. Politicians and private-sector experts of the ruling Democratic Party of Japan made proposals for a thorough operational and budgetary review in the government's energy policy screening session earlier in the week before his visit.
Hosono said: "There are various opinions and (the government) should consider them including such a possibility. The long-running Monju program has come to a "crossroads."
At the same time a committee of the House of Representatives was planning to demand in December 2011 a review of the Monju-program.
In October 13, 2010, an unsuccessful attempt was made to retrieve the machine. The JAEA tried to recover the device used in fuel exchange but failed as it had become misshapen, preventing its retrieval through the upper lid.
The JAEA began preparatory engineering work on May 24, 2011 to set up equipment to be used to retrieve the IVTM that fell inside the vessel The fallen device was successfully retrieved from the reactor vessel on June 23, 2011.
is a test fast breeder reactor located in Ōarai, Ibaraki
. The reactor was built in the 1970s for the purpose of experimental tests and the development of FBR technologies. The reactor is still in operation today.
The successor to Monju is expected to be a larger demonstration plant that will be completed around 2025, built by the newly formed Mitsubishi FBR Systems
company.
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...
ese sodium-cooled fast reactor
Sodium-cooled fast reactor
The sodium-cooled fast reactor or SFR is a Generation IV reactor project to design an advanced fast neutron reactor.It builds on two closely related existing projects, the LMFBR and the Integral Fast Reactor, with the objective of producing a fast-spectrum, sodium-cooled reactor.The reactors are...
, located in Tsuruga, Fukui Prefecture
Fukui Prefecture
is a prefecture of Japan located in the Chūbu region on Honshū island. The capital is the city of Fukui.- Prehistory :The Kitadani Dinosaur Quarry, on the Sugiyama River within the city limits of Katsuyama, has yielded the Fukuiraptor kitadaniensis and Fukuisaurus tetoriensis as well as an unnamed...
. Construction started in 1986 and the reactor achieved criticality
Nuclear chain reaction
A nuclear chain reaction occurs when one nuclear reaction causes an average of one or more nuclear reactions, thus leading to a self-propagating number of these reactions. The specific nuclear reaction may be the fission of heavy isotopes or the fusion of light isotopes...
for the first time in April 1994. Its name is a reference to Manjusri
Manjusri
Mañjuśrī is a bodhisattva associated with transcendent wisdom in Mahāyāna Buddhism. In Esoteric Buddhism he is also taken as a meditational deity. The Sanskrit name Mañjuśrī can be translated as "Gentle Glory"...
.
Monju is a sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
cooled
Nuclear reactor coolant
A nuclear reactor coolant is a coolant in a nuclear reactor used to remove heat from the nuclear reactor core and transfer it to electrical generators and the environment....
, MOX
Mox
MOX might be a name or acronym for:*Malaysian Oxygen Berhad - A Malaysian company that is specializes in providing total gas solutions.*Mixed Oxide Fuel, from nuclear reprocessing*An alien race in the TimeSplitters 2 video game, the Mox...
-fueled, loop-type reactor with three primary coolant loops, producing 280 MWe from 714 MWt.
An accident in December 1995, in which a sodium leak caused a major fire, forced a shutdown. A subsequent scandal involving a cover-up of the scope of the accident delayed its restart until May 6, 2010, with renewed criticality reached on May 8, 2010. In August 2010 another accident, involving dropped machinery, shut down the reactor again. As of June 2011, the reactor has only generated electricity for one hour since its first testing two decades prior.
The plant is located on a site that spans 1.08 km2 (267 acres), the buildings occupy 28,678 m2 (7 acres), and it has 104,680 m2 of floor space. It employs 368 workers.
Monju sodium leak and fire
On December 8, 1995, the reactor suffered a serious accident. Intense vibration caused a thermowellThermowell
Thermowells are used to protect temperature sensors used to monitor industrial processes while permitting accurate measurement. They are typically installed in piping systems and subject to both hydrostatic and aerodynamic forces...
inside a pipe carrying sodium coolant to break, possibly at a defective weld
Welding
Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, with pressure sometimes...
point, allowing several hundred kilograms of sodium to leak out onto the floor below the pipe. Upon coming into contact with the air, the liquid sodium reacted with oxygen and moisture in the air, filling the room with caustic fumes and producing temperatures of several hundred degrees Celsius
Celsius
Celsius is a scale and unit of measurement for temperature. It is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death...
. The heat was so intense that it warped several steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
structures in the room. An alarm sounded around 7:30 p.m., switching the system over to manual operations, but a full operational shutdown was not ordered until around 9:00 p.m., after the fumes were spotted. When investigators located the source of the spill they found as much as three tons of solidified sodium.
Fortunately, the leak occurred in the plant's secondary cooling system, so the sodium was not radioactive. However, there was massive public outrage in Japan when it was revealed that Power Reactor and Nuclear Fuel Development Corporation
Power Reactor and Nuclear Fuel Development Corporation
The or for short, was a Japanese nuclear energy research organization established October 2, 1967 with the Atomic Fuel Corporation as its parent organization and disbanded 1998 to be restructured as Japan Nuclear Cycle Development Institute. The organization specialized in special Breeder...
(PNC), the semigovernmental agency then in charge of Monju, had tried to cover up the extent of the accident and resulting damage. This coverup included falsifying reports and the editing of a videotape taken immediately after the accident, as well as the issuing of a gag order
Gag order
A gag order is an order, sometimes a legal order by a court or government, other times a private order by an employer or other institution, restricting information or comment from being made public.Gag orders are often used against participants involved in a lawsuit or criminal trial...
to employees regarding the existence of the real tapes.
Restart
On November 24, 2000, Japan Atomic Energy AgencyJapan Atomic Energy Agency
The was formed October 1, 2005 by a merger of two previous semi-governmental organizations. While it inherited the activities of both PNC and JAERI, it also inherited the nickname of JAERI, "Genken" 原研, an abbreviated word for "nuclear research"....
announced their intention to restart the Monju reactor. This decision was met with resistance by the public, resulting in a series of court battles. On January 27, 2003, the Nagoya High Court's Kanazawa
Kanazawa, Ishikawa
is the capital city of Ishikawa Prefecture, Japan.-Geography, climate, and population:Kanazawa sits on the Sea of Japan, bordered by the Japan Alps, Hakusan National Park and Noto Peninsula National Park. The city sits between the Sai and Asano rivers. Its total area is 467.77 km².Kanazawa's...
branch made a ruling reversing its earlier 1983 approval to build the reactor, but then on May 30, 2005, Japan's Supreme Court gave the green light to reopen the Monju reactor.
The restart was scheduled for October 2008, having been moved back five months. A restart date of February 2009 was again delayed due to the discovery of holes in the reactor's auxiliary building; in August 2009 it was announced that restart might be in February 2010.
In February 2010, JAEA obtained official approval to restart the reactor from the Japanese Government. The restart was definitely scheduled for the end of March. In late February, JAEA requested Fukui Prefecture and Tsuruga City for deliberations aimed at resuming test operation. Having obtained the go-ahead from both entities, JAEA started criticality testing, after which it took some months before commercial operation could resume - as for any new nuclear plant.
Operators started withdrawing control rods on May 6, 2010, marking the restart of the plant. The Fukui Prefecture
Fukui Prefecture
is a prefecture of Japan located in the Chūbu region on Honshū island. The capital is the city of Fukui.- Prehistory :The Kitadani Dinosaur Quarry, on the Sugiyama River within the city limits of Katsuyama, has yielded the Fukuiraptor kitadaniensis and Fukuisaurus tetoriensis as well as an unnamed...
governor, Issei Nishikawa
Issei Nishikawa
is the governor of Fukui Prefecture in Japan. He was elected first in 2003. A native of Asahi, Fukui and graduate of Kyoto University, he joined the Ministry of Home Affairs in 1968.- External links :*...
asked the METI for additional stimulus to the prefecture including an expansion of the Shinkansen
Shinkansen
The , also known as THE BULLET TRAIN, is a network of high-speed railway lines in Japan operated by four Japan Railways Group companies. Starting with the Tōkaidō Shinkansen in 1964, the network has expanded to currently consist of of lines with maximum speeds of , of Mini-shinkansen with a...
in turn for the restart of the plant. Monju achieved criticality on May 8, at 10:36 AM JST. Test runs were to continue until 2013, at which point the reactor could have started to feed power into the electric grid, being "full fledged" operation.
In September 2011 the ministry of education, science and technology asked for the fiscal year of 2012 only 20 to 30 percent of the budget to maintain and manage the Monju reactor for the year 2011. The uncertainty about Japan's future energy policy caused the ministry to conclude, that the project could not proceeded.
The testrun of the reactor, in which the reactor's output would be raised to 40 percent of its capacity by the end of March 2012, was postponed on 29 September 2011, by the Japanese Government because the uncertainty over the future of nuclear energy.
After the disaster in Fukushima, the Atomic Energy Commission of Japan made a start with a review of Japan's long term energy policy. An outline of this policy would be published within 12 months. On 30 September officials of the Science and Technology ministry explained on meetings in the city of
Tsuruga and the prefecture Fukui
Fukui
Fukui is a Japanese name meaning "fortunate" or it can mean "one who is from the Fukui prefecture". It may refer to:- Places :* Fukui Prefecture** Fukui, Fukui - the city of the same name in the prefecture...
their decision not to start the test-run.
Possible Decommissioning
On 21 October 2011 the Japanese government installed a commision to study ways to cut wasteful spenditures, one possibility would be decommissioning the Monju prototype fast-breeder reactor. The Government Revitalization Unit took up this issue, because the calls to abolish this reactor were growing after the crises with the nuclear reactors in Fukushima. As the crisis at the Fukushima Daiichi power plant made it difficult, if not impossible, to build new nuclear power plants, the government panel would also review subsidies for localities with atomic power plants as well as functions of related entities such as the Japan Atomic Energy AgencyOn 27 November nuclear disaster minister Goshi Hosono said that scrapping the Monju-fast-breeder reactor is an options, that is given a serious thought. The remark was made after a visit to the plant. Politicians and private-sector experts of the ruling Democratic Party of Japan made proposals for a thorough operational and budgetary review in the government's energy policy screening session earlier in the week before his visit.
Hosono said: "There are various opinions and (the government) should consider them including such a possibility. The long-running Monju program has come to a "crossroads."
At the same time a committee of the House of Representatives was planning to demand in December 2011 a review of the Monju-program.
2012 budget
At the end of the fiscal year 2011, a budget of 29 million dollars was asked to continue the Monju project. This money would cover the costs of maintenance and the costs of the test-run, planned in the summer of 2012. On 20 November a seven member Japanese government commission decided that the future of the Monju-reactor should be thoroughly reviewed before a decision could be made for this 2012 budget. Some members of the commission thought that there would be only little public support to restart the fast-breeder project, and that it was uncertain that the reactor could be taken into commercial service in 2050 as originally planned. Other members said that the Monju project should be stopped completely, and that all efforts should be put into the international fusion-reactor project ITER instead. Decisions about the 2012-budget would be taken after the discussions in a panel of cabinet members about the nuclear policy of Japan, including the fast-breeder reactor project, would be complete."In‐Vessel Transfer Machine" falling accident
On August 26, 2010, a 3.3-tonne "In‐Vessel Transfer Machine" fell into the reactor vessel when being removed after a scheduled fuel replacement operation.In October 13, 2010, an unsuccessful attempt was made to retrieve the machine. The JAEA tried to recover the device used in fuel exchange but failed as it had become misshapen, preventing its retrieval through the upper lid.
The JAEA began preparatory engineering work on May 24, 2011 to set up equipment to be used to retrieve the IVTM that fell inside the vessel The fallen device was successfully retrieved from the reactor vessel on June 23, 2011.
Other FBR programs in Japan
JōyōJoyo (nuclear reactor)
is a test sodium-cooled fast reactor located in Ōarai, Ibaraki, Japan, operated by the Japan Atomic Energy Agency. The name comes from the previous country name of the area around Ibaraki....
is a test fast breeder reactor located in Ōarai, Ibaraki
Oarai, Ibaraki
is a town located in Higashiibaraki District, Ibaraki, Japan.As of 2003, the town has an estimated population of 19,606 and a density of 845.45 persons per km²...
. The reactor was built in the 1970s for the purpose of experimental tests and the development of FBR technologies. The reactor is still in operation today.
The successor to Monju is expected to be a larger demonstration plant that will be completed around 2025, built by the newly formed Mitsubishi FBR Systems
Mitsubishi FBR Systems
Mitsubishi FBR Systems, Inc. is a company formed on July 1, 2007 by Mitsubishi Heavy Industries to develop Fast breeder reactor technology. The establishment of the company was based on the April 2007 decision by the Japanese government to select Mitsubishi as the core company for FBR development...
company.