Culture of Safety

Radioaktivität - Atomkraft 
The Japan Times, March 14, 2014
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Culture of safety can make or break nuclear power plants
by Airi Ryu and Najmedin Meshkati

LOS ANGELES – As we commemorate the somber third anniversary of the March 11, 2011, Tohoku earthquake and tsunami and its devastating impact on Tokyo Electric Power Co.’s Fukushima nuclear power plants, we should also understand why Tohoku Electric Power Co.’s Onagawa Nuclear Power Station — which was closer to the epicenter of the 9.0-magnitude quake — had a drastically different fate.

While the Fukushima and Onagawa power plants shared similar disaster conditions, nuclear reactor types (Boiling Water Reactor BWR, Mark I), dates of operation and an identical regulatory regime, it was only Tohoku Electric’s Onagawa power plant that went unscathed. Fukushima No. 2 Nuclear Power Plant (Fukushima Daini) was damaged by the earthquake and severely hit by the tsunami, but thanks to the heroic efforts of its operators and their epic improvisation managed the cold shutdown of all its four operating reactors.

On the other hand, the Fukushima No. 1 nuclear power plant (Fukushima Daiichi) experienced a fatal meltdown and radiation release, while Onagawa managed to remain generally intact despite its proximity to the epicenter of the enormous earthquake.

Everyone knows the name Fukushima, but even in Japan few people are familiar with the Onagawa power station. Fewer still know how Onagawa managed to avoid a disaster. According to a report by the International Atomic Energy Agency (IAEA)mission that visited Onagawa and evaluated its performance, “the plant experienced very high levels of ground motion — the strongest shaking that any nuclear plant has ever experienced from an earthquake,” but it “shut down safely” and was “remarkably undamaged” (

Even more strikingly, while people near the Fukushima No. 1 plant were ordered to evacuate the vicinity immediately after the earthquake, Onagawa’s nearby residents voluntarily sought refuge at the plant’s gymnasium, because it was the only surviving facility with electricity, clean water, and was “safe.”

Why is there such a stark contrast? How did Onagawa weather the tsunami relatively unscathed, while Fukushima No. 1 didn’t? Answers to these vexing questions and lessons learned are not only important for the future of nuclear power in Japan, but also for every operating and under-construction nuclear reactor in the world.

Most people believe that Fukushima No. 1 plant’s meltdown was predominantly due to the earthquake and tsunami. The survival of Onagawa, however, suggests otherwise. Onagawa was only 123 km away from the epicenter, 60 km closer than Fukushima No. 1, and the difference in seismic intensity at the two plants was negligible. Furthermore, the tsunami was bigger at Onagawa, reaching a height of 14.3 meters, compared to 13.1 meters at Fukushima No. 1. The difference in outcomes at the two plants reveals the root cause of Fukushima No. 1 plant’s failures: a corporate “safety culture.”

The Fukushima No. 1 plant and the Onagawa plant are similar in many ways. The most obvious difference is that Tohoku Electric constructed Onagawa power station’s reactor building at a higher elevation than Tepco’s Fukushima reactor buildings. Before beginning construction, Tohoku Electric conducted surveys and simulations aimed at predicting tsunami levels. The initial predictions showed that tsunamis in the region historically had an average height of about 3 meters.

Based on that, the company constructed its plant at 14.7 meters above sea level, almost five times that height. As more research was done, the estimated tsunami levels climbed higher, and Tohoku Electric conducted period checkups based on the new estimates.

Tepco, on the hand, to make it easier to carry equipment and save construction costs, in 1967, removed 25 meters off the 35 meter natural seawall of the Fukushima No. 1 plant site and built its reactor buildings at a much lower elevation of 10 meters. (The Wall Street Journal, July 12, 2011. )

According to the National Diet of Japan Fukushima Accident Independent Investigation Commission (NAIIC), the initial construction was based on seismological information, but later research showed that tsunami levels had been underestimated.

While Tohoku learned from past earthquake and tsunamis, including one in Chile on Feb. 28, 2010, and continuously improved its countermeasures, Tepco overlooked these warnings.

And according to the NAIIC report, Tepco also “resorted to delaying tactics, such as presenting alternative scientific studies and lobbying.”
Tepco’s tsunami risks characterization and assessment, in judgment of one the world’s renowned tsunami experts, professor Costas Synolakis, director of the Tsunami Research Center at the University of Southern California, was a “cascade of stupid errors that led to the disaster.” (The New York Times, March 26, 2011, )

According to the Nippon Telegraph and Telephone Facilities Research Institute, Yanosuke Hirai, the vice president of Tohoku Electric Power Co. at the time of Onagawa Power Station’s construction from 1960 to 1975, was adamant about safety protocols and became a member of the Coastal Institution Research Association in 1963 because of his concern in protecting against natural disasters (

With an employee in upper management strongly advocating for safety, a strong nuclear reactor safety culture formed within the company. Representatives of Tohoku Electric participated in seminars and panel discussions about earthquake and tsunami disaster prevention held by the Japan Nuclear Energy Safety Organization. The company implemented strict protocols for disaster response, and all workers were familiar with the steps to be taken when a tsunami was approaching.

These initiatives were not part of Tepco’s culture. The company took its domination of the electricity industry as an indication of flawlessness. After the disaster, Toru Hasuike, a former Tepco engineer, described how management lengthened the expected life of power plants, even if there were severe safety consequences (

Safety culture was also implicated by the IAEA as a root cause of the Chernobyl accident: “the (Chernobyl) accident can be said to have flowed from deficient safety culture, not only at the Chernobyl plant, but throughout the Soviet design, operating, and regulatory organizations for nuclear power that existed at the time” (

Government investigations of the Fukushima accident, such as the “Report of Japanese Government to the IAEA Ministerial Conference on Nuclear Safety: The Accident at Tepco’s Fukushima Nuclear Power Stations” (June 2011), explicitly referred to safety culture as a root cause of the Fukushima accident.

The following excerpts from these two authoritative reports are noteworthy in this context: “[Lessons in Category 5:] Thoroughly instill a safety culture, raise awareness of safety culture. …

“All those involved with nuclear energy should be equipped with a safety culture. …

“Learning this message and putting it into practice is the starting point, duty and responsibility of those who are involved with nuclear energy. Without a safety culture, there will be no constant improvement of nuclear safety” (from pages XII-13-14).

According to a recent policy statement by the U.S. Nuclear Regulatory Commission, safety culture is defined as “the core values and behaviors resulting from a collective commitment by leaders and individuals to emphasize safety over competing goals to ensure protection of people and the environment” (
The July 2012 report of the NAIIC described the Fukushima accident as “made in Japan,” because Japan’s nuclear industry failed to absorb the lessons learned from Three Mile Island and Chernobyl. In the words of NAIIC chairman Dr. Kiyoshi Kurokawa, “It was this mindset that led to the [Fukushima No. 1] disaster.”

Fukushima No. 1′s meltdown was not due to the natural disaster, but was a result of a series of decisions by Tepco to not be proactive with safety considerations, dating back to when the reactors were being constructed. Other things about Fukushima No. 1 and Onagawa being similar, it was Tokohu Electric’s overall organizational practices and culture that demonstrated foresight, informed, adaptive and learning characteristics that “saved the day.”

If safety and disaster response had been properly recognized, addressed and implemented — as they were within Tohoku Electric’s corporate safety culture — perhaps the disastrous meltdown could have been prevented.

As with all nuclear power plants worldwide, this preventable tragic disaster at Fukushima No. 1 nuclear power plant, when compared to the undamaged fate of Onagawa, highlights the paramount importance and extreme urgency of safety culture at nuclear utilities (

The newly created and promising Nuclear Regulation Authority (NRA) should devise an interdisciplinary, systematic actionable plan for improving nuclear safety culture, especially as Japan is embarking on its newly announced Basic Energy Plan, which could revive and expand the country’s nuclear power sector.

This is becoming more urgent and vital now as, according to news reports, “this month the NRA is due to choose which few reactors it wants to fire up first.” (The Economist, March 8)

The decisions that nuclear plant managers, utility company executives and government officials make now will have a major impact on nuclear power safety and may result in possible consequences in Japan, as well as the world.

As a new seminal investigative book on Fukushima concluded: “Other methods of generating energy also carry risks, in terms of environmental costs as well as human health and safety impacts. But that is no excuse for continuing to hold nuclear power only to the inadequate safety standards that made the Fukushima disaster possible.

“Nuclear technology is an unforgiving technology, and the consequences of a mistake can be catastrophic” (“Fukushima: The Story of a Nuclear Disaster,” by David Lochbaum, Edwin Lyman and Susan Q. Stranahan, all of the Union of Concerned Scientists, 2014)

We have experienced this, once, on March 11, 2011. It may be worthwhile to revisit nationwide nuclear safety standards before moving forward with the New Basic Energy Plan.

Airi Ryu is a senior student and research assistant in the Daniel J. Epstein Department of Industrial and Systems Engineering at the University of Southern California. Najmedin Meshkati is a professor at the Viterbi School of Engineering, University of Southern California. He teaches and conducts research on human performance and safety culture in the nuclear power industry, and has inspected many nuclear power plants around the world, including Chernobyl (in 1997) and Fukushima No. 1 and No. 2 nuclear power plants (in 2012).This is a condensed version of a research paper adapted specially for The Japan Times that is available on: A different version is published by the Bulletin of the Atomic Scientists. This article is adapted from a research paper based on material available in public domains of Japan and the U.S.


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