17 Mar (NucNet): Differences in safety culture between Tokyo Electric Power Company (Tepco) and Tohoku Electric Power Company led to the meltdowns at Tepco’s Fukushima-Daiichi nuclear power station in the aftermath of the March 2011 earthquake and tsunami, while Tohoku’s Onagawa nuclear station was “remarkably undamaged,” researchers have said.
In a research paper on human factors in work design, Dr Airi Rye and Dr Najmedin Meshkati of the University of Southern California conclude that it was ultimately Tepco’s “mindset” which led to the meltdowns at Fukushima-Daiichi.
While three nuclear power stations in the north of Japan – Fukushima-Daiichi, Fukushima-Daini and Onagawa – shared similar disaster conditions, nuclear reactor types and an identical regulatory regime, their fates were very different, the paper says.
Despite being closer to the earthquake’s epicentre than Fukushima-Daiichi, Onagawa “shut down safely” was “remarkably undamaged”, the paper says. Onagawa is about 120 km north of Fukushima-Daiichi.
One of the main factors was that Onagawa nuclear station was built 14.7 metres above sea level because initial estimates of an average tsunami height of three metres in the area.
According to the paper, Fukushima-Daiichi was built at an elevation of 10 metres by reducing ground which initially stood at 35 metres above sea level to facilitate the transportation of equipment to the construction site and the pumping of seawater for the reactor’s cooling systems.
Also, Tohoku Electric’s vice-president from 1960 to 1975, Yanosuke Hirai, was strict about the promotion of safety protocols, which led to the establishment of a strong safety culture. “A general prioritisation for nuclear reactor safety formed within the company,” the researchers say.
As a result of the more established safety culture, Tohoku Electric also had a different approach to emergency response from Tepco – one that was more organised, collaborative and controlled, the researchers say.
According to the paper, all workers at Onagawa were familiar with the steps that must be taken when either a tsunami warning was issued, or when a tsunami was approaching. Periodic training sessions to remind workers of extreme situations also allowed employees to “stay poised” during a disaster.
Such initiatives could not be found in Tepco culture. There also existed within Tepco a mindset that the company’s domination in the market was an indication of flawlessness, the paper says.
“If safety and disaster response was properly recognised, addressed, and implemented like it was in Tohoku Electric Power Company’s culture, perhaps the Fukushima-Daiichi meltdowns could have been prevented,” the paper says.
“With most other factors being similar, it was Tohoku Electric’s overall organisational practices and safety culture that saved the day for Onagawa”.
The research paper is online:
www-bcf.usc.edu/~meshkati/Onagawa%20NPS-%20Final%2003-10-13.pdf
