As a team from the International Atomic Energy Agency visits Tokyo Electric Power Co.’s crippled nuclear plant today, academics warn the company has failed to disclose the scale of radiation leaks and faces a “massive problem” with contaminated water.
The utility known as Tepco has been pumping cooling water into the three reactors that melted down after the March 11 earthquake and tsunami. By May 18, almost 100,000 tons of radioactive water had leaked into basements and other areas of the Fukushima Dai-Ichi plant. The volume of radiated water may double by the end of December and will cost 42 billion yen ($518 million) to decontaminate, according to Tepco’s estimates.
“Contaminated water is increasing and this is a massive problem,” Tetsuo Iguchi, a specialist in isotope analysis and radiation detection at Nagoya University, said by phone. “They need to find a place to store the contaminated water and they need to guarantee it won’t go into the soil.”
The 18-member IAEA team, led by the U.K.’s head nuclear safety inspector, Mike Weightman, is visiting the Fukushima reactors to investigate the accident and the response. Tepco and Japan’s nuclear regulators haven’t updated the total radiation leakage from the plant since April 12.
Tepco has been withholding data on radiation from Dai-Ichi, Goshi Hosono, an adviser to Japan’s prime minister, said at a press briefing today. Hosono said he ordered the utility to check for any data it hasn’t disclosed and release the material as soon as possible.
“This kind of repetition will invite public distrust,” Chief Cabinet Secretary Yukio Edano told reporters today when asked whether the perception that the government has withheld data since the accident is eroding public trust. “This is a grave situation for the entire nuclear energy administration as much as the accident itself is.”
Japan’s nuclear safety agency estimated in April the radiation released from Dai-Ichi to be around 10 percent of that from the accident at Chernobyl in the former Soviet Union in 1986, while a Tepco official said at the time the amount may eventually exceed it.
“Tepco knows more than they’ve said about the amount of radiation leaking from the plant,” Jan van de Putte, a specialist in radiation safety trained at the Technical University of Delft in the Netherlands, said yesterday in Tokyo. “What we need is a full disclosure, a full inventory of radiation released including the exact isotopes.”
Radiation leakage from Fukushima was raised at a hearing of the U.S. Senate Environment and Public Works Committee this week. U.S. regulations may need to be changed after the Fukushima meltdown, William Ostendorff, a member of the U.S. Nuclear Regulatory Commission said.
The Japanese utility is trying to put the reactors into a cold shutdown, where core temperatures fall below 100 degrees Celsius (212 degrees Fahrenheit), within six to nine months. Ostendorff rated the chance of Tepco achieving that goal at six or seven out of 10.
Tepco took more than two months to confirm the meltdowns in three reactors and this week reported the breaches in the containment chambers. The delay in releasing information has led to criticism of Prime Minister Naoto Kan for not doing more to ensure Tepco is keeping the public informed.
“What I told the public was fundamentally incorrect,” Kan said in parliament on May 20, referring to assessments from the government and Tokyo that reactors were stable and the situation was contained not long after March 11. “The government failed to respond to Tepco’s mistaken assumptions and I am deeply sorry.”
Public disagreements emerged this week between Tepco and the government over whether orders were given to halt seawater injection into reactors to cool them the day after the tsunami.
Tepco is considering whether to discipline the manager of the Fukushima plant, Masao Yoshida, after he ignored an order to stop pumping seawater, Junichi Matsumoto, a general manager at the company, said yesterday.
He was commenting after Kyodo News cited Tepco Vice- President Sakae Muto saying Yoshida will be removed for disobeying the order. Hosono said Yoshida is needed at the plant to contain the crisis.
The earthquake and tsunami knocked out power in the Fukushima plant, depriving reactor cooling systems of electricity. Fuel rods overheated, causing fires, explosions and radiation leaks in the worst nuclear accident since Chernobyl.
Japan’s Nuclear and Industrial Safety Agency on April 12 raised the severity rating of the Fukushima accident to 7, the highest on the global scale and the same as Chernobyl. The partial reactor meltdown at Three Mile Island in Pennsylvania in 1979 is rated 5.
The government needs to investigate the total amount of radiation leaked from the plant to ascertain damage to the ocean from contaminated water, said van de Putte, also a nuclear specialist at environmental group Greenpeace International.
The group found seaweed and fish contaminated to more than 50 times the 2,000 becquerel per kilogram legal limit for radioactive iodine-131 off the coast of Fukushima during a survey between May 3 and 9.
Mol, Belgium-based Nuclear Research Centre and Herouville- Saint-Clair, France-based Association pour le Controle de la Radioactivite dans l’Ouest confirmed they conducted analysis of the samples supplied by Greenpeace.
Ascertaining the cumulative volume of radiation emitted by the plant is possible, van de Putte said.
“Perhaps the government will speak about this matter after the detailed accident analysis,” the University of Nagoya’s Iguchi said. “It’s possible to calculate this with the time- series plant data recorded in the control room. The most important thing we need to know is the amount of fuel left in the reactor core.”
Tepco is planning to treat the contaminated water at Dai- Ichi with a unit supplied by Areva SA (CEI) from mid-June. The decontamination equipment can process 1,200 tons of water a day, Tepco said.
The company had little choice in pouring water on the reactors because the risk of contamination was outweighed by the risk of leaving fuel rods exposed, Peter Burns, a nuclear physicist with 40 years of radiation safety experience, said in an interview.
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