Noda's declaration on Fukushima met with cynicism
http://mdn.mainichi.jp/mdnnews/news/20111216p2a00m0na002000c.html
Noda's declaration on Fukushima met with cynicism Fukushima nuclear accident AFP
TOKYO —
Prime Minister Yoshihiko Noda’s announcement Friday that Japan finally had control of leaking reactors at Fukushima was met with criticism from various quarters.
In a live press conference, Prime Minister Yoshihiko Noda told the country the crippled reactors “have reached a state of cold shutdown.”
Stabilization of the reactors, whose molten cores spewed radioactive particles into the air and sea, marks the end of what the government has dubbed “Step Two” of the nuclear clean-up.
The initial success of “Step One”—the stable cooling of reactors and used fuel pools—was announced in July, after the quake-triggered tsunami pummelled the plant on March 11 and laid waste to much of the northeast coast.
“Today we have reached a major turning point with regard to the nuclear accident,” said the prime minister.
Yuhei Sato, the governor of Fukushima prefecture, who has been an outspoken critic of Tokyo’s response to the disaster, said the cold shutdown changed little.
“I wish this was a new step toward helping evacuated residents go home. But there is no change in that. There is a long and rocky road ahead toward the resolution of the accident,” he said.
Takashi Sawada, vice chairman of the Atomic Energy Society of Japan, a pro-nuclear group of academics and industry specialists, said Noda’s declaration of cold shutdown was not a dramatic shift.
Sawada stressed that the use of the term “cold shutdown” did not indicate that all four disaster-hit reactors were now completely normal.
Environmental campaign group Greenpeace dismissed the announcement as a “smokescreen”.
“By triumphantly declaring a cold shutdown, the Japanese authorities are clearly anxious to give the impression that the crisis has come to an end, which is clearly not the case,” said Junichi Sato, executive director of Greenpeace Japan.
“Instead of creating a PR smokescreen… the government’s priority should be to ensure public safety and begin the shutdown of all nuclear reactors in Japan.”
“The ongoing radiological threat posed by the Fukushima nuclear disaster remains enormous.”
Akira Yamaguchi, a nuclear physicist at Osaka University, said that the government’s definition of cold shutdown is disputable.
“But what’s most important right now is that there aren’t any massive radiation leaks any more,” he said.
Putting longer-term issues aside, he warned that much of the backup equipment installed at the plant since the crisis began is makeshift and may break down. He said winter cold could test their strength.
“A turning point was to have successfully established a circulation system for cooling water,” said Kazuhiko Kudo, a nuclear reactor expert and professor at Kyushu University in Fukuoka.
“But the circulation system is not a proper one for nuclear reactors and is still a stop-gap measure,” Kudo said.
“The system in Fukushima, which is placed outside the reactor and connected with long pipes, is quite unstable,” he added. “It is necessary to further improve the system as quickly as possible.”
With ongoing fears of high radiation levels, workers have since battled to maintain the cooling system so that reactor water temperatures remain below 100 degrees centigrade (212 Fahrenheit)—a condition necessary for Friday’s “cold shutdown” declaration.
One of the major challenges TEPCO will face in the longer term is the removal of spent fuel from containment vessels.
“Removing fuel is quite challenging as the status of the fuel rods has yet to be confirmed,” Kudo said.
One option under consideration is the possible covering of reactors with outer shells, a measure technicians hope will prevent further radioactive release.
The construction of wave barriers to guard against the effects of another tsunami in geologically unstable Japan is also a key priority, as is the containment—and eventual disposal—of contaminated water.
“Cooling water itself is still seeping out through cracks into underground water, which is eventually leaking into the sea,” said Tetsunari Iida, director of the Institute for Sustainable Energy Policies, an anti-nuclear body.
“We now need to worry about different isotopes, such as strontium, which are more water soluble and could contaminate the marine food chain,” he said.
The Wall Street Journal wrote: “There can be few firm declarations about the plant’s status. Daiichi’s reactors are littered with debris. Many measurement and control systems are on the blink. Radiation levels are too high for people to get close to the reactors, leaving engineers and scientists to make important judgments using computer simulations, scattered bits of data and guesses.
The New York Times said that Noda’s declaration was out of touch with reality.
This process is called “radioactive decay.” This drop in the level of radiation means that the level does not stay constant through the lifetime of the fish. While Cesium isotopes have longer half-lives (Cs-134 has a half-life of about two years, Cs-137 a longer half-life of about 30 years), the radionuclides also 