Editor's note: This is the second in a four-part series on the problems, such as the safety myth, inherent in the nation's nuclear power generation industry.
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In late March, as the crisis at the Fukushima No. 1 nuclear plant worsened, Shojiro Matsuura, president of the Nuclear Safety Research Association, had many concerns about what was happening.
"What kind of training did plant operators have about severe accidents and what kind of image did they have about such accidents?" Matsuura asked. "The generation that faced many problems in the first nuclear plants that had many defects could not help but always think about what to do during an emergency. I wonder if knowledge based on such experiences have been passed on to younger generations."
To Matsuura, workers for Tokyo Electric Power Co., the plant operator, always seemed to be one step behind, as though they had not drawn up a worst-case scenario from the very beginning, as they dealt with a series of events at the Fukushima plant, from repeated hydrogen explosions, the core meltdown at the three reactors, damage to the containment vessels, the release of large volumes of radioactive materials and the production of water contaminated with high levels of radiation.
His predecessor as chairman of the Nuclear Safety Commission, Kazuo Sato, agreed. "The accident management implemented was more concerned with form."
Some experts predicted a core meltdown at the Fukushima No. 1 nuclear power plant as the crisis unfolded from the night of March 11, when the Great East Japan Earthquake struck.
For example, at about 10 p.m., about six-and-a-half hours after a tsunami struck the No. 2 reactor at the plant and wiped out all power sources, the Nuclear and Industrial Safety Agency had already made calculations for one forecast.
A memo said, "10:50 p.m., (March 11) fuel rods exposed. 11:50 p.m., damage to metal covering of fuel rods. 12:50 a.m, (March 12) fuel rods melting."
While that document was initially not made public, it was included in a batch of documents the central government subsequently released.
At about the same time, a TEPCO employee, appeared before reporters at a 1st-floor conference room at company headquarters to explain what was happening.
"The situation is approaching what we refer to as a severe accident, the most serious situation that can develop of all the different scenarios we consider," the employee said.
A severe accident involves major damage to a reactor core and can lead to the leaking of large amounts of radioactive materials.
TEPCO executives stressed that the 14-meter high tsunami that struck the nuclear plant was much higher than anyone expected. However, there were many experienced engineers at TEPCO and in the central government who clearly understood that a core meltdown would occur in a short period of time if all power sources were lost and the cooling system became inoperable.
The reason is that from about 20 years ago Japan has been promoting accident management, or safety measures designed to respond to severe accidents at nuclear plants.
Some of the measures used as a last-gasp measure to deal with the Fukushima nuclear accident, such as venting the containment vessel or pumping in water using firefighting pumps, were ones electric power companies began implementing from the late 1990s as accident management measures.
The concept of accident management arose from safety research that sought to reduce the risks associated with nuclear power plants on the assumption that an accident will occur.
Progress in the research involved a constant battle with the "safety myth" that claimed a major accident would never occur at a nuclear plant in Japan.
One pioneer in such research was Sato, 77, a former chairman of the Nuclear Safety Commission.
"In the 1970s, there was an atmosphere within business, bureaucratic and academic circles that said, 'Don't say anything that will stimulate concerns among the general public,'" Sato said.
Sato is now affiliated with the Nuclear Safety Research Association.
A core meltdown became a reality after the March 1979 accident at Three Mile Island nuclear plant in the United States.
In an effort to understand the science behind the accident, experiments were conducted in various nations to melt nuclear fuel rods.
One researcher from that time said, "When we were planning an experiment in Japan to melt fuel rods, we were scolded and told, 'Fuel rods are never damaged.' We were only able to do the experiment after we referred to the rods as 'test units.' "
A more serious accident occurred in April 1986 at Chernobyl. From the 1980s, the United States, France and Germany began installing venting equipment as a means of dealing with serious accidents.
In Japan, the NSC recommended in 1992 the voluntary introduction of accident management measures.
Electric power companies grudgingly began installing such measures from 1994 while continuing to argue that safety measures already implemented were more than sufficient.
Sato put together the recommendation and he still had doubts.
"What accident management really seeks is how to heighten the ability to deal with unexpected accidents," Sato said.
When he worked for the Japan Atomic Energy Research Institute, Sato was in charge of the team that operated the JRR-1 reactor that began operations in 1957. Sato experienced a series of unexpected developments.
That background led Sato to include in the recommendation for accident management wording that said, "accident management should normally involve electric power companies utilizing the technological knowledge they possess to respond flexibly to any actual situation that arises."
By 2002, electric power companies had installed accident management measures at all nuclear power plants, including the installation of venting equipment and the preparation of operation manuals.
At that time, electric power industry officials boasted, "The probability of damage to a reactor core has decreased further from a one chance in about 10 million years."
At an April 1 news conference, Matsuura apologized and said, "We did not pursue every line of thought in order to prevent such a situation from occurring. We must apologize to society."
A list of measures to strengthen the response to nuclear accidents that was presented to the government was signed by Matsuura and Sato, among others.
On May 17, more than two months after the initial accident, Sakae Muto, the TEPCO executive vice president in charge of the nuclear power sector, was asked if TEPCO's initial understanding of the possibility of a core meltdown at the reactors was lax.
Muto responded, "In order to pump in water, the condition of the fuel rods makes very little difference. That would have had no effect on the cooling operation."
The obvious inability of TEPCO officials to face reality even after a serious nuclear accident has occurred shows that the roots that produced the safety myth are very deep.
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