November 23, 2015

Nov 23, 2015 | Fukushima Accident Updates

  • The Strontium level in Fukushima soils and crops is very low. Of the ten locations tested, the highest was 4.7 Becquerels per kilogram in soils, and 0.31 Bq/kg in crops. The United Nation’s Food and Agricultural Organization-recommended limit on Sr-90 in foods is 20 Bq/kg. Belarus has a much more limiting standard of 0.37 Bq/kg. Thus, the concentration found in Fukushima foods is below even the most restrictive standard in the world. Hirofumi Tsukada, professor at Fukushima University’s Institute of Environmental Radioactivity, released this important finding. He said, “This shows that the landward impact of strontium-90 from the Fukushima Daiichi nuclear power plant accident was not that big.” http://www.fukushimaminponews.com/news.html?id=593 — http://www.fao.org/docrep/u5900t/u5900t08.htm (Comment – It is important to note that the FAO standard is based on the ridiculously conservative assumption that all foods consumed contain the Sr-90 limit, and no other foods are consumed, over a one year period. Also taken into account is Sr-90 accumulation, based on its biological half-life of 680 days; i.e. 1.86 years. This would result in an estimated internal exposure of ~5 millisieverts per year, so long as the rate of intake remains constant. Japan’s guideline/goal is to keep internal exposures below 1 mSv/yr.)
  • F. Daiichi’s subdrain operation is lowering inflow to F. Daiichi basements. One of the groundwater in-leakage points (a cable duct) for unit #1’s turbine building has stopped flowing. The in-flow seems to have been intermittent for some time, but could not be confirmed as terminated until Nov. 12th. Tepco says the stoppage is due to the operation of the subdrain system which pumps groundwater out of the ground before it comes in contact with the turbine basement walls. This indicates that the 300 ton/day in-leakage rate is dropping, but exactly how much has not been determined. There are other in-leakage points that need to be monitored before any firm conclusions can be drawn. http://www.fukushimaminponews.com/news.html?id=595
  • Tepco’s latest posting of outdoor area radiation levels at F. Daiichi. The linked graphic shows area radiation readings since April, 2014, for key locations outside units 1 through 4. There is a general trend of decreasing levels through October, 2015, with all but a few locations now showing much less than 1 millisievert per hour. http://www.tepco.co.jp/en/nu/fukushima-np/f1/surveymap/images/f1-sv-20151022-e.pdf
  • Communities battle over lightly contaminated pasture grass. Shiroishi City, Miyagi Prefecture, has been giving grass with detectible levels of contamination, below Japan’s national standard of 8,000 Becquerels per kilogram, to a cattle farm in Namie, Fukushima Prefecture. It was intended to be used as feed for the farm’s 330 cattle rescued from the Fukushima exclusion zone. Farmer Masami Yoshizawa accepted the grass bales, but it appears he found some contained more than 100 Bq/kg and he could not be used for cattle feed. Mayor Tamotsu Baba of Namie handed a written complaint to Toru Sasaki, the Shiroishi deputy mayor, saying the city’s action “lacked consideration” for the sentiments of Namie residents. Sasaki’s responded, “It was a humanitarian act aimed at assisting farmers and stock farms.” An ancillary reason was that local residents opposed incineration of the grass due to radiation fears, so giving it away seemed to be a reasonable alternative. The Farm Ministry and Miyagi government ordered the shipments to stop on Nov. 18 because could spread misinformation. http://ajw.asahi.com/article/0311disaster/fukushima/AJ201511210049