April 13, 2015

Apr 13, 2015 | Fukushima Accident Updates

  • The shape-shifting robot inspection inside unit #1 containment began Friday, then stopped moving after about three hours of use. In its snake configuration, the robot was inserted into a pipe running from a relatively low radiation location outside the PCV, through the thick steel and concrete primary containment wall, and into the inner part of the PCV. Once inside, it was slowly lowered down to the walkway that surrounds the reactor vessel pedestal. While being lowered, the robot was re-shaped into its rectangular configuration. Once on the walkway’s grating, it began to slowly move and transmit data back to its operators. After moving about two-thirds of its planned traverse on the walkway, it stopped for an unknown reason. The device continued to transmit pictures, temperature readings, and radiation levels. Tepco says the reason for the problem is probably not the detected 10 sievert per hour radiation level because the robot was designed to handle much higher exposures. On Monday, Tepco said the robot or control cable may have hung up on something on the walkway and could be freed, so on Sunday they decided to sever the cable and abandon it. The robot’s camera and monitoring devices operated continually until the connecting cable was cut. The first Tepco link (below) show pictures and video from inside the PCV, depicting debris on the walkway at times. Monday’s detailed Press handout is the last link. In it, the company speculates that a fallen pipe and/or displaced grating may have caused the robot to become stuck at a “narrow point” along the planned path. http://www.nbcnews.com/news/world/japans-fukushima-nuclear-plant-reactor-examined-snake-shaped-robot-n339091 — http://mainichi.jp/english/english/newsselect/news/20150411p2a00m0na005000c.html — http://www3.nhk.or.jp/nhkworld/english/news/20150413_02.html — http://photo.tepco.co.jp/en/date/2015/201504-e/150413-01e.html — http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2015/images/handouts_150413_01-e.pdf
  • A government group proposes three methods for melted fuel removal. The Nuclear Damage Compensation and Decommissioning Facilitation Corp (NDF) advised Tepco on possible methodologies associated with decommissioning F. Daiichi. NDF said the preferred method would be to fill the primary containments and reactor vessels with water, reducing radiation exposures to workers to a manageable level and minimizing the possibility of radiation releases. However, leaks from the containments, both confirmed and suspected, could make this infeasible. NDF Vice President Hajimu Yamana said, “The water-covered method is desirable from the viewpoint of safety. But it is not certain whether we can completely prevent water leakages from the containment vessels.” Thus, NDF presented two alternative “airborne” possibilities. One would be to fill only the bottom of the containment and lift the corium (melted fuel and inner reactor components) out of the water and through the air before placing it in a protective container. The other would be to drill a large-enough horizontal hole through the containment and RPV pedestal to remove the corium. In both cases, personnel exposure would be more than with the preferred option, and possibility of a release of radioactive material would be greater. http://ajw.asahi.com/article/0311disaster/fukushima/AJ201504100053
  • Fukushima Prefecture will use electronic data to better monitor the health of evacuees. Social workers keeping an eye on the currently 71,000 Tokyo-mandated refugees in temporary housing will be able to electronically document their mental and physical condition, later this year. The prefecture will be divided into five zones with 70 social workers per zone. Tandem teams will visit the homes and transmitted to a data bank where other social and medical experts can access it quickly. Suspected medical or psychological problems can then be expeditiously addressed by local medical institutions, municipal healthcare centers, the Fukushima Center for Disaster Mental Health and/or other appropriate organizations. http://www.fukushimaminponews.com/news.html?id=492
  • More insight into the non-impact of Pacific Ocean contamination on North America. Oregon’s Statesman Journal responded to five reader questions, with the help of Wood Hole Oceanographic researcher Ken Buesseler.  One is why report on something that poses no harm to anyone? In response, The Journal says Fukushima radiation has been blamed for everything from starfish die-offs to seal tumors…none of which are possible at the trivial radiation levels found in the sea. Buesseler explains, “The lack of information leads to some very alarming claims. I think low numbers are just as important as high numbers.” Buesseler adds that he is not concerned about the isotopic concentrations now in the sea, but he does worry about the hundreds of thousands of tons of wastewater stored at F. Daiichi containing radioactive Strontium. He says a massive earthquake might rupture the tanks and dump the Sr-90 into the sea, which could have health repercussions. He also answers why comparisons are made to x-ray diagnostics when we’re dealing with potentially ingestible Cesium isotopes in water. Buesseler says, “The bottom line is that the drinking water standard in the U.S. is 7,400 Becquerels per cubic meter (Bq/m3), and that would be consuming the water every day.” The combined Cesium levels in the sea are about 6.5 Bq/m3 and Cesium flushes through sea life rapidly and has little accumulation, thus “I don’t see how that could be of any concern.” http://www.statesmanjournal.com/story/tech/science/environment/2015/04/08/five-questions-fukushima/25498007/
  • Fukushima InFORM also reports there has been no Cesium uptake in Pacific kelp. Kelp Watch 2015, home-based in California, analyze samples taken near the Pacific coastline of Canada. No radioactive isotopes from Fukushima were detected in kelp growing at sampling sites spread along our Pacific coast during the first three months of this year.  http://fukushimainform.ca/2015/04/12/kelp-watch-2015-most-recent-results-looking-for-fukushima-contamination/  Kelp Watch 2015 explains that Kelp may look like vegetation, but it is actually a type of seaweed. Seaweed is actually algae found only in saltwater. Like most algae, it uses photosynthesis to provide food for itself and consumer sea life. Kelp is believed to be a prime species for detecting uptake and concentration of Cesium and Strontium isotopes. Some Fukushima Iodine was detected in the kelp after the Fukushima releases began, carried across the Pacific by the weather and deposited in the sea. The Iodine was gone after eight months because of its relatively short eight day half-life. It is felt that once water-borne Cesium reaches the California coast, the Kelp should show some uptake and concentration. http://kelpwatch.berkeley.edu/why-kelp