October 28, 2011

Oct 28, 2011 | Fukushima Accident Updates

  • The first results of a nuclear “stress test” were submitted today. Kansai Electric submitted the results of a stress test on the Oi No.3 reactor in Fukui Prefecture. Kansai Electric mentioned their results showed the plant structures and cooling systems could survive quakes nearly 2 times the worst ever recorded for their region, and a tsunami 4 times greater than an historical worst case. NISA says it could take them months to assess all the data and decide the fate of Oi #3. Then, the results will have to be copied to all local governments and explained in detail before the plant could possibly be restarted. (NHK World)
  • Japan Atomic Energy Agency and the National Agriculture and Food Research Organization may have found a possible solution to the contaminated soils issue. They placed 10 kilograms of Cesium-laced soil in an oven and heated it to 800 oC for ~10 hours. Cesium evaporates at 640 oC, so most, if not all of the contamination should have left the soil. This process is not burning, but is rather termed “high temperature roasting”. The team used nuclear grade filters on the outlet of the oven to trap the evaporated isotopes. The soils and filters must now be analyzed for efficiency of the process. “Soil would no longer have to be treated as waste if its cesium content could be brought down to a fraction of what it was,” said Minoru Okoshi, a senior principal engineer at the JAEA. “We hope to investigate if it could be reused as farmland soil.” (Asahi Shimbun)
  • A group of Japanese researches believe they have created the world’s first hand-held decontaminator. The project has been under way for more than seven years, and was originally intended for routine nuclear plant decontamination practices. The hand-held unit is 30 centimeters high and wide, and 40 centimeters long. Although the team has only given the most basic explanation in order to protect their idea, the device uses laser beams to loosen surface contamination, then vacuums the dust into a high efficiency filter. Since only the surface is scraped off, the machine generates one thousand times less radioactive waste than conventional methods. The researchers want this device to be field tested at Fukushima Daiichi. (JAIF)
  • Japan’s Nuclear safety Commission estimates that it could take until 2015 to remove all the fuel bundles from the Spent Fuel Pools (SPF) of units 1-4. After that, it could be 2022 before the actual removal of damaged/melted fuel from units 1-3 RPVs can begin. The SPF’s have little or no fuel damage so they will be emptied of fuel cells first, using special cranes for units 1, 3 & 4. Since unit #2 experienced no hydrogen explosion, spent fuel will be removed using installed equipment. Next, robots will be used to decontaminate the interior of the reactor buildings before damaged parts of the containment vessels can be repaired. After that, the containment vessels can be filled with water so that the work to recover melted nuclear fuel can begin. (Mainichi Shimbun)
  • TEPCO has decided to not build underground retaining walls between the plant buildings and groundwater. Why? Because groundwater always flows towards the nearest large body of water, which in this case is the Pacific Ocean. Thus, local drinking and irrigation waters are not in danger of contamination from the 77,000 tons of waste waters still in the turbine basements. Further, the “quay” adjacent to the power complex has been completely barricaded from the sea, so any leakage out of the basements will be into a contained area. Lastly, the flow is now understood to be from the surrounding groundwater and into the basements, not vice-versa. (Mainichi Shimbun)
  • Kashiwa City officials in Chiba Prefecture have warned their residents of a decontamination scam. Residents might be deceived by anyone passing themselves off as a local government official, offering to measure and remove radioactive substances for money. A man has been putting fliers in mailboxes telling residents he is from the municipal government. He reportedly offers to measure radiation for 5,000 yen and remove radioactive substances for 10,000 yen. The local government has nobody doing this, and the prices quoted are far below the cost that designated decontamination firms charge. A 57-year-old business manager of a radiation measuring company operating in Kashiwa said, “You can’t do decontamination work for that kind of (cheap) price.” He added, “We don’t want to be lumped in with the fraudsters.” (Mainichi Shimbun)
  • On the other hand, the city of Kashiwa has done nothing with the hot spot discovered a week ago, caused by a broken cement drainage line. The city says they can find no-one to attend to the problem because of the high (57.5 microsievert) contact reading after digging 30 centimeters into the soil. The exposure level at one meter above the ground is 2 microsieverts. “It’s difficult to find a company to decontaminate [the site] given the extremely high level of radiation,” a city government official said. “The situation is more than we can handle as a local government.” In other words, they want the Tokyo government to handle it. (Yomiuri Shimbun) All they have to do is have someone in full anti-contamination attire dig the material up, bag it, and bury it deeply where there is no pedestrian traffic. What’s so tough about that?
  • The Health, Welfare, and Labor Ministry will officially lower the internal exposure limit for food and drink in April. The current limit is 5 millisieverts per year. The new limit will be 1 millisievert per year. “The current provisional safety limit, which was set in response to emergencies, is safe enough, but it will be tightened in order to ensure increased food safety and security,” Health, Welfare and Labor Minister Yoko Komiyama said. The Ministry explains they based the change on background research showing long term health effects are theoretically possible at 100 millisievert exposure, thus 1 millisievert per year will keep everyone below this threshold. “Under the current provisional safety limit, consumers are experiencing increased anxiety as they watch radiation measurements. Tightening the safety limit will reassure many people,” said Hisa Anan, secretary-general of the National Liaison Committee of Consumers’ Organizations. (Asahi Shimbun; Mainichi Shimbun) Will it really reassure anyone while “detectable is dangerous” news stories abound? This remains to be seen.