The Hamaoka Nuclear Power Plant (Hamaoka Genshiryoku Hatsudensho, Hamaoka NPP) is a nuclear power plant located in Omaezaki city, Shizuoka Prefecture, Japan managed by the Chubu Electric Power Company. There are five units contained at a single site with a net area of 1.6 square kilometers (395 acres, about a fourth of fifth of a typical US plant). A sixth unit began construction on December 22, 2008. On completion, it is expected to replace Hamaoka-1 and Hamaoka-2.

The area is in a possible epicenter of future earthquakes according to predictions. In fact, a fault line runs straight through the site. Earthquake resistance is a very important aspect of this plant, and difficulties have been seen in previous events.

Unit Reactor Type Average Power Output Capacity Beginning of Construction Finish of Construction First Criticality
Hamaoka-1 BWR 515 MW 540 MW June 10, 1971 August 13, 1974 March 17, 1976
Hamaoka-2 BWR 806 MW 840 MW June 14, 1974 May 4, 1978 November 29, 1987
Hamaoka-3 BWR 1056 MW 1100 MW June 18, 1983 January 20, 1987 August 28, 1987
Hamaoka-4 BWR 1092 MW 1137 MW October 13, 1989 January 27, 1993 September 3, 1993
Hamaoka-5 ABWR 1325 MW 1380 MW July 12, 2000 June 26, 2004 January 18, 2005

Performance

The plant showed stellar performance through the 1990s, however, problems that caused Unit 1 to be shut down from 2001 to present, and Unit 2 from 2005 to present significantly hurt the capacity factor figures in the recent history of the plant.

Unit 1 HPCI Rupture

On November 7, 2001 a valve in the HPCI system of Unit 1 ruptured during a Periodical-manual-startup-test. Since this is considered a part of the ECCS, the implications reach further the event itself, and drew into question the reliability of the emergency safety system. Unit 2 was also shut down for the purpose of investigating similar structures.

Unit 2 Steam Turbine Problems

Unit 5 Steam Turbine Problems

Too recent to cover the entire relevant time frame in the data above, on June 15, 2006 Unit 5 was shut down due to excessive turbine vibrations. It was discovered that a number of turbine vanes had actually completely broken off. In the turbine that failed, nearly all vanes showed fractures or cracking while the majority of the vanes of the other two low pressure turbines also showed problems. Fault for the problems were placed on Hitachi, the NSSS supplier.

Previous Events

  • 1991, April 4 - Unit 3 reactor coolant supply lowered, automatic SCRAM
  • 2001, November 7 - Unit 1 pipe burst accident
  • 2001, November 9 - Unit 1 coolant leak accident
  • 2002 - In an independent inspection, it was discovered that 16 unique signs of cracks in steam pipes were known by the utility but failed to report to the prefecture level authorities.
  • 2002, May 24 - Unit 2 water leak
  • 2004, February 21 - Unit 2 outbreak of fire in room above turbine room.
  • 2004, August - Unit 4 problem with fabrication of data by utility.
  • 2005, November 4 - Unit 1 pipe leak incident
  • 2005, November 16 - Unit 3 outside pipe leak due to corrosion
  • 2005, November 16 - Unit 1 spent fuel pool had foreign matter detected in it
  • 2006, June - Unit 5 damage to turbine blades
  • 2007, March - Utility admitted to 14 cases of unfair business practices
  • 2009, August 11 - Units 4 and 5 (the only ones operating) automatically shut down due to an earthquake
Hamaoka Nuclear Power Plant
Image taken from the air (1988). In this image, all units through Hamaoka-3 are operating. Copyright National Land Image Information (Color Aerial Photograph), Ministry of Land, Infrastructure and Transport.
Image taken from the air (1988). In this image, all units through Hamaoka-3 are operating. Copyright National Land Image Information (Color Aerial Photograph), Ministry of Land, Infrastructure and Transport.
Data
Country Japan
Operator Chubu Electric Power Company
Built 1967
Start of commercial operation March 17, 1976
Reactors
Reactors active 5 (4,997 MWth)
Power
Total power generation in 2006 12,920 GW·h
Average annual generation (last 5 yrs) 17,997 GW·h
Net generation 468,336 GW·h

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