page_title: Monju Nuclear Power Plant
section_title: 2010 Restart
hierarchical_section_title: Monju Nuclear Power Plant / Detailed history / 2010 Restart
caption_attribution_description: Monju, fast breeder reactor, Japan 2007. Photo Credit: The Nuclear Fuel and Power Reactor Development Corporation (PNC)
context_page_description: Monju was a Japanese sodium-cooled fast reactor, located near the Tsuruga Nuclear Power Plant, Fukui Prefecture. Its name is a reference to Manjusri.
  The reactor has been inoperative for most of the time since it was originally built. It was last operated in 2010 and is now definitely closed.
  Monju was a sodium cooled, MOX-fueled, loop-type reactor with three primary coolant loops, designed to produce 280 MWe from 714 MWt. It had a breeding ratio of approximately 1.2.
  The plant is located on a site that spans 1.08 km², the buildings occupy 28,678 m², and it has 104,680 m² of floor space.
context_section_description: On November 24, 2000, Japan Atomic Energy Agency 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 nuclear fuel was replaced for the restart. The original fuel loaded was mixed plutonium-uranium oxide with plutonium content of around 15–20%, but by 2009, due to natural radioactive decay, the fuel had only half of the original plutonium-241 content. This made achieving criticality impossible, requiring fuel replacement.
  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, beginning "full fledged" operation.
caption: Monju in 2007
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