The “Fukushima Daiichi Investigation Committee on the Accident at the Tokyo Electric Power Company Fukushima Nuclear Power Station” released an interim report on December 26, 2011, over nine months after the March 11 Great East Japan Earthquake. The main report spans 507 pages with a further 212 pages of attachments. There is also a 22 page English translation of the Executive Summary. The Committee aims to produce a final report around summer 2012. (Website addresses Japanese_http://icanps.go.jp/post-1.html, English_http://icanps.go.jp/eng/interim-report.html)
The Investigation Committee was established by the May 24, 2011 Cabinet Decision for the purpose of ascertaining “the causes of the accident and the causes of the damages inflicted by the accident.” The Committee was asked to “to carry out a multifaceted investigation and verification from the point of view of the people” and “to present policy recommendations for preventing the spread of damages caused by the accident and the reoccurrence of similar accidents.” (Quotes taken from the Prime Minister and Cabinet website on June 7, 2011.)
Professor Yotaro Hatamura, renowned for his study of the mechanisms of “failure,” was chosen to chair the Committee, which has ten members in all. The Chairman appointed two technical advisors and the secretariat included bureaucrats from various ministries, along with eight other people with expertise in areas including society and technology, analysis of severe nuclear accidents, and evacuation. The following three teams were formed under the leadership of experts in the respective fields: Social System Investigation Team, Accident Causes Investigation Team, Damage Expansion Prevention Measures Investigation Team.
Special features of this Committee include its independence from the nuclear bureaucracy and the fact that it was tasked with carrying out a comprehensive investigation that focused not only on technical issues, but also on systemic issues.
The Commission based its investigation on the following eight principles:
(Extracted from “Remarks by the Chairperson Dr.Yotaro Hatamura at the First Meeting of the Investigation Committee on the Accident at the Fukushima Nuclear Power Station on June 7, 2011”)
As of December 16, the Committee had interviewed 456 people, representing a total of 900 hours of hearings. Based on these hearings, the Committee investigated in considerable detail the course of events that took place in the responses of the Central Government, Fukushima Prefecture and Tokyo Electric Power Company (TEPCO) to the accident, the evacuation of residents and their exposure to radiation. This aspect of the report should be particularly noted.
Content of the Report
In a nutshell, it became clear that a group of people who believed that human beings could control and use this immensely powerful energy turned out to be almost powerless when it came to the crunch. The following specific examples illustrate the point.
The Fukushima Daiichi accident has not yet been brought under control. The crisis is ongoing, and so the report identified issues and made recommendations on an interim basis. The main points are listed below.
Lessons related to the Unit 1 Isolation Condenser
The first hydrogen explosion occurred at Unit 1. Unit 1 had an item of equipment, called an Isolation Condenser (IC), that was not fitted to the other reactors. When the core pressure rises to dangerous levels the IC is supposed to begin operating automatically, remove high pressure steam from inside the core, condense the steam with heat exchangers, and thus reduce the pressure in the reactor core. The Investigation Committee considered in detail how the operators and TEPCO’s emergency response headquarters dealt with the IC. It concluded that no rupture interfered with the operation of the IC. Rather, it lost functionality as a result of the loss of electric power when the plant was flooded by the tsunami.
However, the Commission said in relation to this item of equipment, “There was no one at the nuclear power plant with many years experience in the operation, including training and inspection, of the IC. Apparently the operators had only exchanged oral accounts amongst themselves about limited operating experiences. Furthermore, although there was some training on the function and operation of the IC, judging from the series of responses on this occasion, we cannot believe this was effective.”
In an emergency, cooling is the highest priority in order to prevent core damage. It can only be concluded that the state of understanding and training in regard to the function and operation of the IC was extremely inappropriate. As the operator of the nuclear power plant TEPCO stands condemned.
An essential condition for maintenance of the integrity of technology is that relevant knowhow be properly passed on to the next generation of operators. People dealing with a technology that is so intrinsically dangerous as nuclear energy must be especially aware of this. At the same time, this should be confirmed at multiple levels by the regulatory body. The lessons from the Unit 1 IC are, therefore, particularly significant.
Impact of the Earthquake
References in the Interim Report to the impact of the massive M9.0 earthquake on the nuclear reactor system are very inadequate. The maximum acceleration in the east-west direction for Units 2, 3 and 5 exceeded the Design Basis Earthquake Ground Motion (Ss*1). The figures recorded in Gals (design basis shown in brackets for comparison) were respectively: 550 (438), 507 (441), 548 (452). I would like to wait for the results of future reports and inspections before commenting in detail on this matter, but based on the experience of the Kashiwazaki-Kariwa Nuclear Power Station after the July 16, 2007 Chuetsu-Oki Earthquake, very careful investigations are called for.
The report mentions a perfunctory analysis carried out by TEPCO for Unit 2. According to this analysis, the load on major equipment and structural components, including the reactor pressure vessel, the containment vessel, and main steam pipes, was within the assessment criteria.*2
However, if the parameters are only slightly altered in this type of calculation totally different figures are derived. Unit 2 was an aging reactor that had been operating for 37 years. I wonder how that fact was considered in the calculation.
Standing up to an evaluation in 100 years time: an ethical issue for engineers and scientists
In its recommendations, the report refers to the need for competent human resources with high professional expertise. However that alone is not enough to prevent the formation of a “nuclear village.” The English version of the Executive Summary uses the word “competent” to translate the Japanese word “yuushuu.” However, “yuushuu” is more commonly translated as “excellent,” or “superior.” Over and above technical or scientific “competence,” it is important that a sense of excellent ethical standards be understood. But how can we expect excellent nuclear safety regulation from Japan’s “nuclear village,” a clique that has demonstrated its lack of ethical standards?
But the problem is of a totally different order than this.
If the Investigation Committee wants to produce a report that will stand up to critical evaluation in 100 years’ time, it needs to come up with insightful recommendations and principles addressing this problem. In my opinion, it is necessary to do much more than just educate experts in universities and the like. It is necessary to go back to the elementary and middle school years and reconsider the essence of what education is all about.
I am looking forward to reading the final report, which is due this summer.
(Yukio Yamaguchi, Co-Director)
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