Published on Sep.10 ,2014 : The Denki shinbun(The Electric Daily News)
Shojiro Matsuura
Chairman of JANSI

One of the things that impressed me strongly during my recent trip to the U.S. is that an extremely high value is attached to “technical conscience” as a mindset for nuclear operators to voluntary safety improvements. In the past, a number of accidents turned into major disasters even at facilities and structures that seemed to be the progeny of modern advanced technology. Searching for their root causes has revealed the fact that there are quite a number of cases in which minor errors in technical judgment triggered major accidents even though accident prevention measures that deserved to be called complete and thorough were in place. These minor errors in technical judgment can be prevented adequately if the personnel involved have effective technical conscience. This has raised the awareness of technical conscience.

An example of major accidents that typically exemplified this fact is the explosion of the U.S. Space Shuttle Challenger that occurred in January 28, 1986. The Challenger disintegrated immediately after launch and all seven crew members were lost. It was the most tragic accident in the history of space development that made the world deeply shocked.

A Presidential commission (Rogers Commission) was organized to investigate the cause of the accident. Through investigation, the root cause was identified as the O-ring, used to seal the solid fuel booster, malfunctioning during launch. This O-ring was made of a material that lost its hermetical properties due to the degradation of flexibility and strength at low temperatures. Unfortunately, the temperature was especially low on the morning of the day of launch, and the O-ring could not perform adequately. Engineers of the manufacturer concerned about the flaw advised their superiors of the danger of launch. The warning was shelved and the launch was executed forcibly resulting in a major disaster.

The whole story was dramatized on television by the BBC in 2013. The scene of the hearing in which Dr. Richard P. Feynman, a member of the investigation commission and a Nobel Prize-winning physicist, demonstrated how the O-ring material would become fragile in a glass filled with ice and water still remain clear in my own memory.

It clearly demonstrates the importance of “technical conscience” in field engineers, administrators, managers, project promoters, and so forth.

In retrospect, there were cases in which technical conscience did not function effectively in some accidents that had a major impact in the history of Japan’s nuclear development. These include radiation leakage in the nuclear ship “Mutsu”, the JCO criticality accident, and sodium leakage at the prototype fast breeder reactor “Monju”. If engineers and managers had used their technical conscience a little more as technical experts, no social criticism and damage of such magnitude would have resulted.

I am working hard on the restructuring of the Monju project. The cause of sodium leakage goes back to errors in the design of thermocouple sheaths which is not very complicated. This represents how frightful it is to work in the absence of technical conscience.

Technical conscience constitutes integral part of safety culture. Furthermore, technical conscience is far more specific and easier to understand than the attributes of safety culture. It seems far more concrete to promote and maintain technical conscience. It may be effective to try to improve technical conscience as an approach to developing safety culture.

Another thing that impressed me anew during the last and this year’s trips to the U.S. is that more significant attention and efforts are being paid in improving mental attitudes and functions than in physical aspects. It looks like American pragmatism is transforming.

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