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Saturday, September 7, 2013

Suzuki's Fukushima updates

Suzuki's Fukushima updates

Update: As of today, the highest radiation level detected near the tanks is now 2,200 millisieverts per hour, up from the 1,800 millisieverts per hour that I reported yesterday.

Tatsujiro Suzuki

Tatsujiro Suzuki

Suzuki is the vice chairman of the Japan Atomic Energy Commission (JAEC) and a member of the Pugwash Conferences on Science and...
SEPTEMBER 6, 2013—I have received encouraging feedback and questions to the first column, and would like to express my sincere thanks for your kind support; please excuse me for not responding to those directly through email, Twitter, or Facebook. I will try to respond to your questions in my updates.
 
Update: As of today, the highest radiation level detected near the tanks is now 2,200 millisieverts per hour, up from the 1,800 millisieverts per hour that I reported yesterday.
 
On September 3, 2013, Tokyo Electric Power Company (Tepco) and the Ministry of Economy, Trade, and Industry (METI) announced the following three principle countermeasures against the ongoing contaminated water crisis at the Fukushima Daiichi Nuclear Power Station: removing the source of contamination, isolating ground water from the contamination, and preventing any leaks of the contaminated water. But there are major challenges to the countermeasures that are currently employed or that planned to be employed. These issues are as follows:
 
Removing the source of contamination. On August 22, Tepco started pumping contaminated water from the trench and will have this water isolated by the end of 
October. The multi-nuclide removal equipment—known as the Advanced Liquid Processing System, or ALPS—has three lines and a daily capacity of 750 tons; currently, it is undergoing a “hot test,” which means that the facility uses radioactive materials during the test run. However, two of its three lines are currently shutdown due to technical problems. While ALPS was planned to begin full-scale operation by the end of September, it remains uncertain if this will happen; this is why the government decided to provide financial support for a second and improved facility, which will have a similar function as ALPS, but has not yet been named.
 
Isolating groundwater from the contamination. On July 8, Tepco started injecting sodium silicate into the ground; the company completed enclosing the soil between units 1 and 2 on August 10. Tepco also started enclosing the soil between units 2 and 3 as well as units 3 and 4—the completion date is planned for October. Tepco will examine a freezing method to block the water flow between the turbine buildings and the trenches. This is an expensive operation (first suggested by the government's accident response office in April of 2011, but rejected by Tepco due to high costs); therefore, the government has decided to provide financial support for the effort.
 
Preventing leakage of the contaminated water. Tepco has installed wells—located near the reactor building that faces the mountains—to pump up groundwater so that the water will not flow into the reactor buildings. The company is currently negotiating with local residents and the fishing industry on the details surrounding the startup of these wells. On September 5, Tepco found that the underground water taken from the wells was contaminated—650 becquerel per liter—which implies that contaminated water may have leached into the underground water; heavy rainfalls this summer likely influenced this. Bypassing the underground water may not be effective if it already has been contaminated. Exact routes and the scale of contamination are still not known. 
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SEPTEMBER 5, 2013—Given the increased concern over the contaminated water leak at the Fukushima Daiichi Nuclear Power Station, I will resume my online column to provide frequent updates of the situation at Fukushima.
As the Ministry of Economy, Trade, and Industry (METI) summarizes, the events at the Fukushima Daiichi station picked up again on June 19, 2013, when Tepco announced that groundwater was contaminated with radioactive materials in the area between the turbine buildings and the plant port. The next month, on July 22, some of this contaminated water seeped into the plant port, though the radioactive materials that were found there and in the ocean were below the detection limit. Nevertheless, the Ministry announced that countermeasures be imposed, including the removal of the contamination source; isolation of the ground water from the contamination source; and overall leak prevention of the contaminated water.
Tepco responded, agreeing, within two years, to enclose the contaminated soil with sodium silicate walls, pump out the contaminated water from the trenches and isolate them, and bypass groundwater.
But last month, on August 18, Tepco discovered that contaminated water has leaked from above-ground storage tanks into the surrounding soil, which prompted the Nuclear Regulation Authority to rate this event as a three on the International Nuclear Event Scale—an action that made headlines around the world.
On August 26, the Ministry directed Tepco to enhance management of the tanks and the surrounding area; reinforce patrols; accelerate replacement from bolted joint tanks to welded joint tanks; accelerate the highly-contaminated water treatment and decrease the radiation dose of the surrounding area by collecting the contaminated soil; and identify the risks of storing highly-contaminated water and take actions against the risks.
Today, there are three important issues to consider and follow:
1)    Highly contaminated water—containing tritium, strontium 90, and cesium 137—was detected leaking from the plant, possibly from the trench. Over the past two years, it is estimated that strontium 90 and cesium 137 discharged from the plant at about 100 times their annual levels, whereas tritium discharged at about two times its annual rate.
2)    About 1,000 tons of underground water is estimated to flow into the site on a daily basis, out of which 400 tons flows daily into the reactor and turbine buildings, i.e. mixed with contaminated water. Water is circulated for core cooling, and contaminated excess water has been stored in tanks. The water decontamination facility has not been functioning due to operational issues. Leaks have been found in various tanks that store about 340,000 tons of contaminated water; the current storage capacity is about 400,000 tons. Replacing these tanks with welded tanks instead of bolted tanks currently employed will take time, and monitoring efforts have been intensified. The highest level of radioactive materials leaked is 1,800 millisieverts per hour (mostly beta ray, only 1 millisievert per hour for gamma ray, as of September 3). It cannot be denied that contaminated water from these tanks might have leaked into the sea; though this has not yet been confirmed.
3)    So far, the sea near the site and outside the port do not show a significant increase in radioactivity. Nevertheless, on September 1, the local fishing industry decided to stop test fishing—that is, fishing on a limited, not commercial, scale and testing the fish for radioactivity; test fishing had been conducted since June 2012.
Last month, the Japanese government announced it would involve itself in the events at Fukushima, and announced on September 3 the various measures it would pursue to deal with this ongoing crisis, such as: establish an inter-minister level council; establish an inter-governmental liaison office near Tepco’s Fukushima site; establish an inter-governmental council for coordination near the Fukushima site; provide $470 million in financial support (to install a frozen soil wall, estimated at $320 million and provide multi-nuclide removal equipment, priced at $150 million); enhance monitoring and risk management efforts
The total cost of decontaminating the Fukushima Daiichi site is currently estimated to be around $10 billion.

http://thebulletin.org/suzukis-fukushima-updates

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