Association for the Study of Failure

Annals of Failure 2006: The Hamaoka Nuclear Power Plant Accident

        On August 15, 2006, Chubu Electric Power, which boasted the world's largest Adanced Boiling Water Reactor (ABWR), shut down the Hamaoka Unit 5 reactor when the turbine developed abnormal vibrations. The cause was identified as damage sustained to a specific area of the turbine fan during 20% load test levels, a consequence that hadnot been anticipated nor planned for during test runs. Expenditures for inspections, fact-finding regarding the cause of the incident, and countermeasures were all paid for by the original designer and manufacturer of the turbines, Hitachi.

        This incident could be seen as a quintessential "good failure." Until that time, 1,100 MW power outputs were the norm, but the ABWR operated at 1,350 MW. In particular, Hamaoka-5 had a power output rating of 1,358 MW. At most, the Association for the Study of Failure's head office expends about 2 kW of power. Hamaoka-5's Unit 1 could power our office 69,000 times over.
        The turbine fan was built on a new design. Whereas previous designs were linear, the Hamaoka fan traced beautifully curved lines. While no radiation leaks were caused by the incident, it must be stressed that the emergency stop was pulled on the reactor before a large-scale accident could occur. This accident thus makes clear that newly developed technology can act in unanticipated ways.

        It is natural for unanticipated problems to occur during the development of new technologies. In order for us to create trustworthy technologies, it is necessary to put into place a system that can respond to emergency situations that are beyond the realm of expectation. This is important not because of the mass media hype that occurs in the wake of any accident, but rather in order to understand the event and to be able to gain knowledge about how we might create a system that preserves safety even in unforeseen situations. Above all, we wish to express that this is the goal that we are working to achieve.

        Tokyo Electric Power's Kashiwazaki-Kariwa Unit 7, which was shut down following the 2007 Chuetsu Earthquake, resumed operations(in Japanese) last year.

        ASF Annals of Failure 2006 Articles
>> "Hamaoka Nuclear Power Plant Turbine Accident"(in Japanese)

>>Click here for a list of articles from ASF Annals of Failure (in Japanese)

[Original article in Japanese by Kenji IINO (1/14/10),
translated by Carla TAKAKI and posted (4/6/10)]