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Sunday, March 27, 2011
Signs of disaster were there to see
Seismology experts warned for years nuclear plants can't withstand true worst-case scenario
By JUN HONGO
On Feb. 23, 2005, Kobe University professor Katsuhiko Ishibashi appeared before the Lower House Budget Committee and pointed out the risks of operating nuclear power plants in earthquake-prone Japan.
"An earthquake and its seismic thrust can hit multiple parts (of a nuclear plant)" and induce not one but a variety of breakdowns, Ishibashi, an expert on Earth and planetary sciences, told the lawmakers.
Such a scenario could knock out even the backup safety system and possibly result in a "severe accident," such as overheating of the reactor core or even a runaway nuclear reaction, he warned.
Warnings like this from Ishibashi and other experts went largely unheeded.
Two weeks after the tragedy struck the Tohoku region, the situation at the Fukushima No. 1 nuclear facility has shown at best only incremental improvements. Ishibashi's prediction of a chain of catastrophes proved all too prophetic.
The quake caused tsunami that obliterated cities on the coast and severely damaged the nuclear plant, which has resulted in contamination of local vegetables and tap water as far away as Tokyo, as well as other radioactive discharges.
Tokyo Electric Power Co. quickly said after the quake that the tsunami was bigger than it could have imagined, but pundits say otherwise and claim the signs were clear for anyone to see.
"Safety measures were not sufficient," Nagoya University professor Yasuhiro Suzuki, who teaches at the Research Center for Seismology, Volcanology and Disaster Mitigation, told The Japan Times.
Although it was determined only in 2005, after extensive research, that large tsunami could be generated by an earthquake off the coast of the Tohoku region, the government was in a position to take immediate action and ensure the safety of the nuclear power plants in Fukushima Prefecture, Suzuki said.
Warnings by seismologists prior to March 11 were not only based on scientific data but on historic fact as well.
The area devastated by the tsunami was hit by similar or even bigger waves when what is known as the Jogan earthquake occurred on July 13, 869.
Details recorded in some history texts, including "Nihon Sandai Jitsuroku" compiled in 901, suggest the seismic thrust was in the neighborhood of magnitude 8.6. Geologists have found sand deposits caused by the tsunami a couple of kilometers inland, meaning the quake was accompanied by massive killer waves as well.
Eastern and western Japan lie on different tectonic plates, with the Tohoku region sitting near the edge of a third. Experts have calculated that an earthquake and tsunami the size of the one that hit the area in 869 were prone to take place every 800 to 1,000 years.
This wasn't groundbreaking news or a passing concern.
In fact, NHK aired a special program on March 14 of last year that touched on killer tsunami hitting the Sendai area.
Tepco has so far refused to admit its precautions fell short.
In the days after March 11, Tepco said both the Fukushima No. 1 and No. 2 nuclear plants were designed to resist a 5.5-meter wave based on standards set by the Japan Society for Civil Engineers.
The utility said it simply didn't anticipate the 10-meter-plus March 11 tsunami.
"Japan's nuclear power plants are designed to withstand any earthquake imaginable and not to release radioactive materials to the surrounding area even if its facilities are damaged," Tepco still says on its website, even though the March 11 tsunami has proven otherwise.
The utility ran simulations on the largest possible killer wave that could hit the area based on historical data and implemented sufficient safety measures, it also claims.
Meanwhile, other power utilities have finally acknowledged their nuclear plants may also be at risk.
On Thursday, Hokkaido Electric Power Co. held a news conference to announce it will beef up tsunami measures at its nuclear plant in Tomari. Until then, the company had said the biggest tsunami the region could expect would be 9.8 meters high, and Tomari would be out of its reach because it is situated 10 meters above sea level.
Many experts, however, point to the Hamaoka nuclear plant in Shizuoka Prefecture as being at the greatest risk, since it stands atop an area where a fourth plate meets Honshu's two main plates. A quake likely to exceed magnitude 8.0 is expected there.
The region has had a major quake approximately every 150 years, with the last, at magnitude 8.4, hitting in 1854.
Any serious damage to the Hamaoka facility would impact central Japan and beyond, and experts say people in Tokyo could be forced to evacuate if the plant were to start leaking radiation.
Kobe University's Ishibashi has stated in his reports that catastrophic failure at Hamaoka would be "a fatal blow to Japan" and affect generations to come.
On March 15, Chubu Electric Power Co. revealed plans to build a 12-meter wall around the Hamaoka complex in the next couple of years to prevent damage from tsunami.
But many experts point out that Japan's nuclear power plants all need major overhauls, because construction of many operating plants, including the one at Hamaoka, kicked off in the 1960s and 1970s just as studies on earthquakes were being revised.
The likelihood of a major temblor is a clear and present danger in many areas, and bringing the reactors and the buildings housing them up to survive the threat as it is now understood hasn't been able to keep pace, these experts say.
Nagoya University's Suzuki said power companies don't deserve all of the blame.
"It is in the government's hands and the nuclear safety agency to deal with the safety of the power plants. They are to be held responsible for not having ordered electricity companies to take appropriate measures" against tsunami, Suzuki said.
Nuclear plant safety guidelines were revised in 2006 to boost tsunami defenses, he stressed. Although too late for Tohoku, implementing them to avoid future disaster is still possible, he added.
"Government officials need to take responsibility, even if they have to halt the operations of every nuclear power plant," Suzuki said.