Friday, June 15, 2012

Tepco's Safety Record At Fukushima


The Fukushima Daiichi nuclear power station was Tepco’s first nuclear plant.  The plant was built in the 1960s by Ebasco, an American general contractor that no longer exists. Reactors one through five at the site were based on General Electric’s Mark I design.

Kiyoshi Kishi, a former Tepco executive heading Tepco’s nuclear plant engineering was interviewed by the Wall Street Journal about the lack of tsunami precations at the plant. Kishi was quoted as stating that at the time the plant was built, a threat posed by a large tsunami at the site was considered “impossible.” 

Later some precautions were taken to protect the plant against a tsunami with a height of 18.8 feet. The tsunami that hit the plant on March 11 was over twice that height.

Tepco engineers interviewed by the Wall Street Journal also reported that the venting systems in reactors one through five were very inefficient. Flooding of the generators and the poor ventilations systems are cited as the causes of the meltdowns and explosions at the Daiichi units one through four.

The four reactors at the Fukushima Daini complex and building six at the Daiich complex used General Electric’s Mark II system and were purportedly tailored more specifically to meet Japan’s earthquake and tsunami risks.  These reactor buildings were reported in this article as having shut down safely.

Tepco’s nuclear plants have been plagued with scandals. In 2002, Tepco’s president, vice president, and chairman stepped down after the utility acknowledged that it failed to report accurately cracks at its nuclear reactors in the 1980s and 1990s. 

Tepco was suspected of falsifying 29 cases of safety repair records after a whistleblower stepped forward. The Japanese Nuclear and Industrial Safety Agency claimed that up to eight reactors could be operating with unfixed cracks, “though the cracks don't pose an immediate threat.”

In 2006, Tepco was found to have falsified coolant water temperatures at the Fukushima Daiichi plant in 1985, 1988. 

The falsified records were used during a 2005 inspection. In the wake of these scandals, Tepco revealed that an uncontrolled chain reaction had occurred in unit 3 at Fukushima Daiichi when fuel rods fell into the reactor. 

Tepco also acknowledged that it had falsified records of safety tests on unit 1’s containment vessel that occurred in 1991 -1992.  In 2010, unit 2 reactor stopped automatically after problems with a generator resulted in a steep drop in the water level inside the reactor by about 1.8 meters.

Other nuclear plants in Japan have also had significant problems. In 1999 a uranium-reprocessing plant had an uncontrolled nuclear chain reaction that killed two employees and released radioactive emissions.  In 2007, Tepco's Kashiwazaki Kariwa nuclear power plant in Niigata prefecture was damaged in a magnitude 6.8 earthquake on 16 July 2007.


REFERENCES

Japan's nuclear power operator has checkered past. Reuters (2011, March 12), http://www.reuters.com/article/2011/03/12/us-japan-nuclear-operator-idUSTRE72B1B420110312

      Norihiko Shirouzu and Rebecca Smith . Plant's Design, Safety Record Are Under Scrutiny
Complex was central to a falsified-records scandal a decade ago that led Tepco briefly to shut down all its plants. The Wall Street Journal (2011, March 16), http://online.wsj.com/article/SB10001424052748704396504576204461929992144.html

      Norihiko Shirouzu and Alison Tudor. Crisis Revives Doubts on Regulation. The Wall Street Journal (2011, March 15 ), http://online.wsj.com/article/SB10001424052748703363904576200533746195522.html

      Norihiko Shirouzu and Alison Tudor. Crisis Revives Doubts on Regulation. The Wall Street Journal (2011, March 15 ), http://online.wsj.com/article/SB10001424052748703363904576200533746195522.html

      New Japanese nuclear power reactors delayed. World Nuclear News (2008, March 26), http://www.world-nuclear-news.org/NN-New_Japanese_nuclear_power_reactors_delayed-260308.html

2 comments:

  1. TEPCO was irrespnsible in makinng reactors in
    Fukushima.At the same time GE is as well.
    US government must have intervened in the sales of the reactor between GE and TEPCO. So US government should join in rescue plan for Fukushima desaster.

    ReplyDelete
  2. I totally agree with this comment. GE and the US government share the responsibility for the Fukushima disaster and should share the costs for clean up and relocation.

    ReplyDelete