July 21, 2014

Jul 21, 2014 | Fukushima Accident Updates

  • The March 11, 2011, earthquake did not start the Fukushima accident. Japan’s Nuclear Regulation Authority has concluded that it was the tsunami which caused the full station electrical blackout. The panel of NRA experts rejected the government’s 2012 NAIIC investigation’s suggestion that the unit #1 accident may have begun with the quake. The NAIIC said that because a few Fukushima workers saw water leakage in the Isolation Condenser room prior to the tsunami and the IC was shut off before the water surge hit, it seemed possible that the quake began the nuclear emergency. But the NRA says their investigation shows that the arrival of the tsunami coincided with the time the reactor lost power. The NRA conducted an on-site inspection at the plant in May 2013 to look into what went wrong and found no evidence for the NAIIC claim. The agency says they will continue their probe and interview members of the NAIIC before releasing a final report on the matter. NHK World; NRA panel: Tsunami led to Fukushima meltdown; 7/15 — http://ajw.asahi.com/article/0311disaster/fukushima/AJ201407190041
  • Personal dosimeter-based radiation monitoring will change decontamination policy. The Environment Ministry says the new program might start later this month. Decontamination efforts have been occurring in locations showing greater than 0.23 microsieverts per hour by airborne monitoring. Continual exposure to the 0.23 µSv/hr equates to the 1 millisievert per year goal set by the government. However, dosimeters issued to 52,000 Fukushima residents from July 2012 through June 2013 revealed that actual exposures in many areas were less than 1 mSv/yr. In fact, a full 70% of the group had exposures below 1 mSv/yr. Survey residents live in the cities of Fukushima, Koriyama, Soma and Date. The lower actual exposures will allow the Ministry to scale back on decontamination work in many areas. A Date official said, “We should break the spell of aerial radiation soon.” Radiation Safety Forum member Junichiro Tada said he agrees with the ministry, “We should change the way radiation doses are managed from an aerial radiation basis to an individual exposure basis. That way, we will do away with ineffective decontamination work.” On the other hand, critic Keizo Ishii of Tohoku University says, “Many residents of Fukushima have deliberately stayed indoors since the nuclear disaster. If they start to go out like they used to before the quake, the individual radiation doses might go up and will not necessarily fall below the 1 millisievert threshold. As such, we should aim for continued use of aerial figures for decontamination.” http://www.japantimes.co.jp/news/2014/07/20/national/new-radiation-measurement-method-spreads-confusion/#.U80AlqNOUdV
  • The Mainichi Shimbun has posted a Q & A on how nuclear safety is determined by the NRA. While most of the article is surprisingly objective, the continuation of doubt was proffered by repeating last week’s statement by NRA Chair Shunichi Tanaka, “We cannot say that a disaster will never happen. The regulations cannot guarantee safety.” http://mainichi.jp/english/english/perspectives/news/20140719p2a00m0na006000c.html
  • Tepco’s treatment process to stop rainwater from becoming contaminated seems successful. The Rainwater treatment System has been tested inside dikes under water storage tanks and a receiving tank. In both cases, rainwater pooled after rainfall was tested. The analyses showed no detectible Cesium isotopes and a barely detectible level of Tritium. http://www.tepco.co.jp/en/nu/fukushima-np/f1/smp/2014/images/rainwater_tank_140717_01-e.pdf
  • Leakage of barely detectible contaminated water at unit #5 makes headlines. Leakage collected from a valve in the spent fuel cooling system was tested for radioactivity. The water contained less than 3 Becquerels per milliliter of Cobalt-60. No other detectible radioactive isotopes were reported. Tepco officials say the leakage-itself could possibly indicate a system deterioration. One Tepco official said, “We are aware that our approach proved to be lax as we were unable to detect the problem until the leak occurred. We are reviewing the way checks should be conducted.” http://ajw.asahi.com/article/0311disaster/fukushima/AJ201407200016 (Comment – The level of radioactive contamination in the leaked water is essentially innocuous. The report seems to be yet another example of Japan’s antinuclear Press trying to make any detectible level of radioactivity seem inordinately dangerous and worthy of headlines.)
  • The Pentagon says the USS Ronald Reagan sailors were not exposed to dangerous radiation levels. In a report sent to Congress due to a January directive from defense committees, Assistant Secretary of Defense for Health Affairs Dr. Jonathan Woodson said that safeguards, put in place to protect service members, worked. He said any illnesses that Reagan sailors have developed are not a result of the Operation Tomodachi relief operation. His report states, “There is no objective evidence that the sailors … experienced radiation exposures that would result in an increase in the expected number of radiogenic diseases over time. The estimated radiation doses for all individuals in the Operation Tomodachi registry, including sailors on the USS Ronald Reagan, were very small and well below levels associated with adverse medical conditions.” 111 sailors have filed a suit against Tepco saying that misinformation allowed them to be exposed to dangerous radiation levels and has caused numerous health problems. Woodson said the health issues were not uncommon for an unexposed population of greater than 5,000 individuals, and the three claimed cancers began well before 3/11/11. http://www.stripes.com/news/uss-reagan-sailors-not-exposed-to-high-radiation-levels-in-japan-report-finds-1.293860
  • Ex-PMs criticize the NRA approval of Sendai plant safety. Antinuclear former Japanese leaders Junichiro Koizumi and Morihiro Hosokawa say that the NRA is not doing its job by allowing the Sendai units to restart. Koizumi called the NRA decision “absurd”. Hosokawa asked the NRA to reconsider its decision, adding that “I’d like those concerned to make an appropriate decision before something irreparable occurs.” The statements were made before a meeting of the PM’s antinuclear group, Japan Assembly for Nuclear Free Renewable Energy. http://mainichi.jp/english/english/newsselect/news/20140719p2a00m0na005000c.html