Mihama Nuclear Power Plant
From Wikipedia, the free encyclopedia
The Mihama Nuclear Power Plant (美浜発電所 Mihama hatsudensho?, Mihama NPP) is operated by Kansai Electric Power Company and is in the town of Mihama in the Fukui Prefecture, about 320 km west of Tokyo.[1]
Contents |
[edit] Reactors on Site
| Unit[2] | Reactor Type | Average Electric Output | Electric Power Rating | Begin of Construction | End of Construction | First Criticality |
|---|---|---|---|---|---|---|
| Mihama - 1 | PWR | 320 MW | 340 MW | 01.02.1967 | 08.08.1970 | 28.11.1970 |
| Mihama - 2 | PWR | 470 MW | 500 MW | 29.05.1968 | 21.04.1972 | 25.07.1972 |
| Mihama - 3 | PWR | 780 MW | 826 MW | 07.08.1972 | 19.02.1976 | 01.12.1976 |
[edit] Events
The Mihama NPP has been notable beyond most nuclear plants due to the severity of accidents that have happened there, the 2004 steam explosion in particular.
[edit] September 2, 1991
Unit 2 steam generator had one tube fully break. This triggered a SCRAM with full activation of the Emergency Core Cooling System. Eventually, a small amount of radiation was released to the outside.
[edit] May 17, 2003
Unit 2 steam generators had two holes open simultaneously. There was no radioactive release to the environment.
[edit] August 9, 2004
On 9 August, 2004, an accident occurred in a building housing turbines for the Mihama 3 reactor.[3] Hot water and steam leaking from a broken pipe killed five workers and resulted in six others being injured. The accident has been called Japan's worst nuclear power accident.[4][5]
The Mihama 3 is an 826 megawatts electric, 3-loop Westinghouse type pressurized-water reactor (PWR) which has been in service since 1976. The pipe rupture occurred in a 55.9 centimeter (cm) (22 inch) outside diameter pipe in the ‘A’ loop condensate system between the fourth feedwater heater and the deaerator, downstream of an orifice for measuring single-phase water flow. At the time of the secondary piping rupture, 105 workers were preparing for periodic inspections to commence.[6]
A review of plant parameters did not uncover any precursor indicators before the accident nor were there any special operations that could have caused the pipe rupture. An investigation concluded that water quality had been maintained since the commissioning of the plant.[7]
Japan's previous most deadly accident at a nuclear facility took place at a uranium processing plant in Tokaimura, north of Tokyo, on September 30, 1999, when an uncontrolled nuclear chain reaction was triggered after three poorly trained workers mixed Uranium nuclear fuel in a bucket. The resulting release of radiation killed two workers, and exposed hundreds more to radiation above legal limits.[8]
The Mihama NPP started back up in January 2007 after making various changes and obtaining permission from Fukui Prefecture and industry regulators.[9]
[edit] 2006
Another fire occurred in 2006, two workers sustained injuries. There were no fatalities and no release of radioactivity detected, though the ash involved in the fire included some low level radioactive waste.
[edit] References
- ^ Four killed in nuclear plant accident
- ^ Power Reactor Information System der IAEA: „Japan: Nuclear Power Reactors“
- ^ Four killed in nuclear plant accident
- ^ Japan's shaky nuclear record
- ^ Japanese utility to shut reactor after admitting accident cover-up
- ^ Secondary piping rupture at the Mihama Power Station in Japan
- ^ Secondary piping rupture at the Mihama Power Station in Japan
- ^ Japan's shaky nuclear record
- ^ Kepco's public announcement on restarting of plant
[edit] External links
- Japanese nuclear operator to shut 11 plants
- Worst Japanese Nuclear Accident Claims Fifth Life
- BBC News Report on the Steam Accident
|
||||||||
