23 Août 2013
August 22, 2013
By Yuji Okada, Jacob Adelman & Peter Langan - Aug 22, 2013 4:54 AM GMT+0200
The crippled nuclear plant at Fukushima is losing its two-year battle to contain radioactive water leaks and its owner emphasized for the first time it needs overseas expertise to help contain the disaster.
Tokyo Electric Power Co. (9501) is grappling with the worst spill of contaminated water since the March 2011 earthquake and tsunami caused a meltdown at the Fukushima Dai-Ichi plant. The call for help from Zengo Aizawa, a vice president at the utility, follows a leak of 300 metric tons of irradiated water. Japan’s nuclear regulator labeled the incident “serious” and questioned Tepco’s ability to deal with the crisis. Prime Minister Shinzo Abe made similar comments earlier this month.
“We will revamp contaminated-water management to tackle the issue at the Fukushima Dai-Ichi plant and seek expertise from within and outside of the country,” Aizawa said at a press conference last night in Tokyo. “There is much experience in decommissioning reactors outside of Japan. We need that knowledge and support.”
The International Atomic Energy Agency in Vienna and the U.S. Nuclear Regulatory Commission said they are prepared to help.
Tepco was storing 330,000 tons of radioactive water as of Aug. 13 in tanks covering an area equal to 37 football fields, according to the company. The utility is clearing forest to make room for more tanks as it adds to the stored water at a rate of 400 tons a day after pumping it out from under the plant’s reactors, which melted down as a result of the March 2011 earthquake and tsunami.
The water is treated to remove some of the cesium particles before it is stored, which has left 480 filters clogged with the radioactive material at the site. Each weigh 15 tons and are warehoused in what the utility calls temporary storage, though it will take hundreds of years for the radiation to decay. Other radioactive contaminants remain in the water even after treatment. That includes strontium, which has been linked to bone cancers.
Besides radiated water, the site north of Tokyo has more than 73,000 cubic meters of contaminated concrete, 58,000 cubic meters of irradiated trees and undergrowth, and 157,710 gallons of toxic sludge, according to the utility.
Japan’s nuclear watchdog has ratcheted up alarm over the potential for more leaks of highly radioactive water from the hundreds of storage tanks at the Fukushima atomic plant.
The possibility of leaks from other tanks “is the biggest concern,” said Nuclear Regulation Authority Chairman Shunichi Tanaka at a press conference yesterday. “This will need to be handled carefully on the assumption that one incident could bring another.”
Late last night, Tepco said water leaking from the storage tank probably ran into the ocean, citing high radiation readings in a drainage ditch.
As much as 20 trillion becquerels of cesium and 10 trillion becquerels of strontium leaked into the ocean since May 2011, Tepco spokeswoman Mayumi Yoshida said today. The total amount of cesium and strontium is equivalent to about 100 times the annual limit on radiation from the plant to the ocean under normal conditions, according to calculations based on Tepco data.
The release is about a million times less than the contaminants spilled into the world’s oceans after nuclear bomb tests in the 1950s and 60s, said Peter Burns, a radiation physicist based in Melbourne, who was formerly Australia’s representative on the United Nations’ committee on the effects of atomic radiation.
Radiation levels are rapidly diluted by the ocean and should pose few hazards outside of the harbor that is directly receiving the contaminants, said Kathryn Higley, a radiation health physicist at Oregon State University in Corvallis.
At least one commissioner at Japan’s nuclear regulator questioned the accuracy of data being released by Tepco and whether the incident had been fully reported. The leak, along with a separate spill of 300 tons of radioactive water a day into the Pacific Ocean, is raising doubts about the utility’s ability to handle the 40-year task to decommission the nuclear site.
Tepco is providing the regulator with information, company spokesman Yoshikazu Nagai said by phone, declining to comment further. The company’s shares fell as much as 15 percent in Tokyo yesterday, their biggest intraday slide since June 5, and were down 4.9 percent to 530 yen at 10:57 a.m. in Tokyo.
Japan’s government has ordered an investigation into the safety of hundreds of other tanks storing contaminated water in Fukushima, the site of the world’s worst civilian nuclear disaster since the Chernobyl reactor exploded in 1986.
There are 226 tanks of similar bolted design to the leaking unit with the same 1,000-ton capacity at the site, said Tatsuya Shinkawa, director of the nuclear accident response office in the government’s Agency for Natural Resources and Energy, which called for the probe.
Nuclear incidents and accidents are ranked by order of severity on the International Nuclear and Radiological Event Scale or INES, which has seven categories and was set up by the International Atomic Energy Agency.
On Aug. 19, Tepco said about 300 tons of highly radioactive water had leaked from a storage tank and was ranked as category one on INES, the lowest.
Japan’s NRA raised that to category three yesterday, or a “serious incident.” The 2011 meltdown of the three reactors at Fukushima is in the highest severity category of seven on the INES scale, the same as Chernobyl.
“This INES evaluation is based on the 300-ton leak, but I really wonder if we can trust data provided by Tepco,” Toyoshi Fuketa, a commissioner at the NRA, said at a meeting in Tokyo. “I really wonder if we should judge based on Tepco’s data.”
In two separate incidents this month, workers were exposed to radioactive releases at the plant.
Prime Minister Abe has said that Tepco alone isn’t able to handle the clean-up, promising more government funds without detailing how they’d be used.
Tepco needs “to stop going from crisis to crisis and have a systematic approach to water management,” Dale Klein, the chairman of an advisory panel to Tepco and a former head of the U.S. Nuclear Regulatory Commission, said yesterday in an interview.
INES is a means to measure nuclear accidents in terms of their effects on health and the environment, according to the International Atomic Energy Agency. Each of its seven steps represents a ten-fold increase in severity. The IAEA last night said it takes the leaks in Japan “seriously” and that it “remains ready to provide assistance on request,” according to a statement on its website. The U.S. Nuclear Regulatory Commission is also ready to provide assistance if requested, agency spokesman Scott Burnell said.
A seven rating means there has been a “major release of radioactive material with widespread health and environmental effects requiring implementation of planned and extended countermeasures,” according to the INES fact sheet.
Japan’s regulator raised the INES rating on the water leak based on radiation levels reported by the utility this week and on an evaluation of measures at the plant to prevent such incidents. The IAEA will be the final arbiter of where the leak will sit on the severity scale.
For the first time since Japan’s nuclear catastrophe erupted two and half years ago at the Fukushima Daiichi nuclear power station, Tokyo Electric Power Company (TEPCO) requested international aid in an increasing desperate fight to bring the worsening disaster under control.
TEPCO Vice President Zengo Aizawa sent the country’s first international SOS since the March 2011 catastrophe as highly radioactive water continues to leak at higher rates and in greater concentrations of contamination into the aquifer that flows under the reactor wreckage into the Pacific Ocean. Another storage tank has failed spilling 300 more tons of radioactive water onto the site from the growing number of units in a makeshift tank farm now containing nearly 400,000 tons of highly contaminated water. Contaminated water used to keep the melted reactor cores cool is being continuously pumped up out of reactor building basements into the tank farm. The continuous pumping operations are overwhelming an already dubious plan to decontaminate the growing toxic backlog before release. The storage tanks themselves are now beginning to fail.
Efforts to divert and dam the movement of groundwater flowing from the mountains, under the damaged reactor site and on into the Pacific Ocean have not only failed but are increasing the risk of a new and larger catastrophe as the site is increasingly unstable. More than 1000 tons of groundwater are estimated to flow daily under Fukushima Daiichi towards the ocean. A glassified dam, five feet tall, injected below grade into the earth between the reactors and the ocean has failed to stop the radioactive flood into the Pacific. This build-up of contaminated groundwater is now topping the glass dam and saturating the ground around and under the reactor site so that another significant earthquake could liquefy the earth under the damaged complex including a huge nuclear waste storage pool that is common to all six units. In total, Fukushima Daiichi’s nuclear waste storage pools contain an estimated 2,000 tons of irradiated nuclear fuel bundles that must remain gamma ray-shielded underwater as well as continuously cooled. Hundreds of tons of this high-level nuclear waste remain in precarious roof top storage ponds elevated more than fifty feet up in the remains of six units, including the four that are severely damaged after multiple reactor meltdowns and hydrogen explosions. If any of these storage pools were to catastrophically fail, a renewed atomic fire could ignite and burn in the open atmosphere in an expanding nuclear catastrophe of global proportions.
An international aid program will need to be a generous, open ended and most importantly transparent if its agenda is to protect the public health, safety and the environment rather than continue to shield and promote an increasingly desperate global nuclear industry.