Monju Nuclear Power Plant
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Decommissioned Reactors ( gross ):
The Monju nuclear power plant (Japaneseもんじゅ) is a nuclear power plant in Japan, and the only fast breeder reactors in the country. It is named after the Japanese name of the Bodhisattva of wisdom Manjushri. It is located in the city of Tsuruga in Fukui Prefecture. The plant belongs to the Japan Atomic Energy Agency. Construction began in 1985, the plant was commissioned in autumn 1994.
Monju has a sodium-cooled reactor with mixed-oxide fuel (in short: MOX) and three primary cooling circuits, the work in the so-called loop system. He has a net electrical output of 246 MW net (280 MW gross).
After a sodium discharge Monju was dated 8 December 1995 and to 6 May 2010 out of service.
2006 is considered to build a larger reactor successor until 2025. The aim of the government was the commercial use of breeder technology by 2050.
Sodium accident in 1995
On December 8, 1995 - Monju was only about three months on the net - it was a serious incident in a nuclear reactor: from a pipe in the secondary sodium coolant circuit occurred due to strong turbulence at a measuring point at which a thermocouple, the temperature was measured, a leak on. A large amount of sodium - it was estimated 700 kg up to 3,000 kg - came out. As the alkali metal sodium reacts violently and excessive heat, among others, oxygen and humidity. Under corrosive vapors and temperatures of several hundred degrees Celsius, some of the parts of the system made of steel began to melt in the affected area.
At 19:30 clock alarm has been triggered and the automatic control of the reactor disabled. However, it took until 21:00 clock until the vapors were detected and the complete shutdown of the plant was located. In the examination of the leakage was found more than three tons solid sodium.
Since the accident occurred in the secondary cooling circuit, the leaked sodium was not radioactive. The semi-state company that operates the reactor Monju, the Power Reactor and Nuclear Fuel Development Corporation ( PNC Today: Japan Nuclear Cycle Development Institute ), but tried to cover up the extent of the incident, including by publishing false reports, one after the accident recorded video changed and put the employees under secrecy with regard to the existence of undistorted videos. These experiments were, however, in public; and the resulting public reaction was intense. Der Spiegel wrote on 3 February 1997:
"When the manipulation was uncovered, tipped in the Japanese population, the mood against the rays technology. The Breeders operators complained the former Socialist prime minister Tomiichi Marayama [ sic], have destroyed their trust relationship with the public. '"
In January 1996, therefore rushed Shigeo Nishimura, a head of department of the breeder operating company PNC, from a high building. He felt it failed to convince the public after the largest of the Japanese nuclear accident history of the need for fast breeder reactors.
When the Japanese Atomic Energy Commission (Japan Atomic Energy Commission ) announced on 24 November 2000, to take the Monju reactor back in operation, there was again a public outcry and in court has been tried in a number of processes to prevent the re-commissioning. On 27 January 2003 raised a court in Kanazawa, a branch of the Nagoya High Court in its earlier decision of 1983, in which it had the construction of the reactor allowed. However, the Japanese Supreme Court ruled on 30 May 2005 that the reactor Monju is allowed to go into operation again.
In the spring of 2008, the Nuclear and Industrial Safety Agency ( NISA ) approved the final safety analysis report which was necessary for the re-commissioning of the plant.
Further disruption
In March and April 2008, more defective detectors for sodium leaks were discovered, which led to an audit request by the NISA and the recommissioning presented again in question.
On 6 May 2010 the test operation was resumed, the rule is to be run in 2013. Even before reaching the criticality of a faulty detector for gas leak was discovered on reboot. The Nihon Genshiryoku Kenkyu Kaihatsu Kiko (Eng. "Japanese nuclear research and development organization"; engl Japan Atomic Energy Agency; translation of the English translation:. . Japanese Atomic Energy Agency ) made the operation running as planned, because the faulty unit is replaced by two redundant systems will.
On 26 August 2010, there was another accident, as a 3 -ton unit for fuel filling rushed to the reactor vessel and this damaged. On June 24, 2011, we succeeded workers to recover the device. When the reactor can be started up again, is not fixed yet
The Fukushima nuclear disaster ( it began in March 2011) has changed the attitude of the public and government on nuclear energy fundamentally. (see nuclear phase-out section 'Japan ').