March 6, 2013

Mar 6, 2013 | Fukushima Accident Updates

  • The Tokyo Electric Company (Tepco) has begun a new inspection of Fukushima Daiichi unit #2 using a sophisticated robot. During the first day’s investigation, no evidence was found for leaks out of the Primary Containment’s (PCV) suppression pool (torus). This is the latest of several remote-controlled inspections inside the torus room and none have found evidence of structural compromise. Before these inspections, it was assumed that leaks had been sprung out of the torus due to over-pressurization during the first days of the crisis. There is strong evidence that water is currently leaking out of the piping connected to the reactor pressure vessel (RPV), and finding its way into the outer reactor building and turbine building basements. The question is where the leak(s) exist. So far, it seems the torus was not, nor is the source. Tepco wants to find the leaks, seal them and subsequently fill the RPV and PCV in order to lower worker radiation exposures and expedite opening the RPV itself. Regardless, the robot being used is an upgraded model of the one that has failed previously by, literally, falling down stairs and entangled itself in its power cord. The new model has been upgraded to avoid these problems. (Mainichi Shimbun; Kyodo News) Tepco has released the robot’s first pictures of the torus room as part of a press handout… Results of Investigation of the Lower Part of Unit 2 Vent Pipe at Fukushima Daiichi Nuclear Power Station
  • As the second anniversary of the Fukushima accident approaches, the Japanese Press is visiting the station. The first was reporters from NHK World. They were allowed to walk near unit #1 for 10 minutes. This is the first time the news media has seen the new enclosure on foot. Until now, the reporters had to stay in a bus as it slowly passed the structure. The bottom of the enclosure has been covered in 4 centimeter-thick steel plates to reduce the radiation field near the building. The reporters were next shown the enclosure being built around unit #4. Finally, they saw the 930 eleven-meter-high steel tanks that contain the partially decontaminated waters that have been processed. Each tank holds 1,000 tons. The tanks now hold about 235,000 tons of water. Another 35,000 tons of deconned water are contained in tanks internal to the plant buildings, so the reporters did not see them. Fukushima staff closely monitored the reporter’s radiation exposures so that none of them would exceed the national standard of 1 millisievert, and none did. (NHK World)
  • A survey of 118 Fukushima evacuees revealed that 80% might not go back home after decontamination is complete. 22% have decided to stay in the Prefectures where they now live, and 58% say they are considering living in another Prefecture. However, only 20% said they would make their new homes permanent. Half of the rest who are not planning on going back to their former homes, say they fear the possibility of radiation exposure. The other half said they currently feel there are no guarantees they will ever be allowed to go home by the government. 47% currently live in government-designated apartments for free, paid for by Tokyo. 27% live in apartments they found for themselves, paid for by the prefectural governments of Iwate, Fukushima and Miyagi. Evacuees come from all three prefectures, with nearly 80% from Fukushima. 60% complain of financial distress, even with the compensations from Tepco that are mandated by the Tokyo government. 58% of those surveyed say they remain concerned about radiation hazards and the future health of their children. Half of the Fukushima evacuees were forced to leave their homes by the government because they lived inside the no-go-zones. The other half come from outside the exclusion zone and evacuated voluntarily. Finally, 20% of the 118 respondents said they have been discriminated against through offensive remarks and/or disapproving looks. (Mainichi Shimbun)
  • Tepco is considering releasing Fukushima Daiichi’s decontaminated waters to the sea…eventually. Currently, some 270,000 tons of Cesium-stripped waters are in storage. A new system (ALPS) will soon be in operation to remove 62 of the remaining 63 radioactive isotopes remaining in the liquids. That’s the good news. The bad news is that the remaining isotope, Tritium, cannot be removed by ALPS, so it is unlikely Tepco will be allowed to expunge the water after all. Tepco will need Nuclear Regulatory Authority and local fisheries permissions to do it. Because of the Tritium, a naturally-occurring isotope of Hydrogen, it is unlikely that the required permissions will be given. Currently, the Tritium concentration in the waters is 1,300 Becquerels per cubic centimeter, and Japan’s national limit for release is 60 Bq/cc. The Fukushima Prefectural Federation of Fisheries Cooperative Associations has been urging TEPCO to pledge never to release water into the ocean with detectible contamination. Tritium removal can only be done with a costly system that currently does not exist in Japan. Canada has such a system, but whether or not Tepco will buy one remains to be seen. The Canadian system can remove most of the Tritium, but not all of it. (Mainichi Shimbun) [comment – Tritium has an extremely weak radioactive emission – 50 times weaker than radioactive Cesium. It should also be noted that the World Health Organization’s recommended limit for release is 10,000 Bq/cc. Canada’s limit is 7,000 Bq/cc. Australia’s is a whopping 76,000 Bq/cc. Once again, Japan’s ridiculously-low radiation standards are unnecessarily inhibitive.]
  • A blog posted under the Federation of American Scientists has a new overview of the biological effects of radiation exposure. It is entitled, “Back to the Basics: How Radiation Affects Our Health”. Here’s the link… http://www.fas.org/blogs/sciencewonk/2013/02/back-to-the-basics-how-radiation-affects-our-health/#comment-10530 I suggest that all Japanese readers share this with their friends and colleagues.