Thursday, 27 July 2017

Melted fuel found at Fukushima - Corium up to 6 feet thick below reactor

Expert: Melted fuel found at Fukushima — Corium up to 6 feet thick below reactor — Nuclear waste “piling up at bottom” — Lava-like material has spread all over… “hanging like icicles” — Mystery orange substance seen (VIDEO)


ENENews,

24 July, 2017


Kyodo, Jul 22, 2017 (emphasis added)): In big step forward, Tepco finds melted fuel at bottom of reactor 3 in Fukushima… The debris was clearly identifiable to at least one nuclear expert. “The images that appear to be melted fuel debris match those found in the (1986) Chernobyl crisis,” said Tadashi Narabayashi, a specially appointed professor of nuclear engineering working at Hokkaido University. “It’s definitely fuel debris… It’s an epoch-making event.”


New York Daily News, Jul 22, 2017: Underwater robot captures images of melted fuel at wrecked Fukushima nuclear plant — An underwater robot captured photos of 3-foot thick lumps of melted nuclear fuel covering the floor

Sky News, Jul 24, 2017: Melted nuclear fuel spotted in Fukushima reactor — The radioactive material has been spotted and pictured by a submersible robot…
CNN, Jul 24, 2017: [The robot] has revealed appears to be stalactites of melted nuclear fuel, [Tepco] said… the robot sent back 16 hours worth of images of massive, lava-like fuel deposits

AP, Jul 23, 2017: [Images] showed massive deposits believed to be melted nuclear fuel covering the floor

Asahi Shimbun, Jul 23, 2017: Melted nuke fuel images show struggle facing Fukushima plant— Images captured on July 22 of solidified nuclear fuel debris at the bottom of a containment vessel of the crippled Fukushima No. 1 nuclear power plant show the enormity of decommissioning of the facility… [TEPCO] also discovered that the nuclear fuel debris has spread throughout the containment vessel.

AP, Jul 22, 2017: [TEPCO] said the robot found large amounts of lava-like debris apparently containing fuel that had flowed out of the core… TEPCO spokesman Takahiro Kimoto said it was the first time a robot camera has captured what is believed to be the melted fuel. “That debris has apparently fallen from somewhere higher above. We believe it is highly likely to be melted fuel or something mixed with it,” Kimoto said…

Kyodo, Jul 23, 2017: The robot was sent closer to the bottom of the reactor on Saturday and found possible fuel debris scattered in a wide area.
Japan Times, Jul 21, 2017: Fukushima robot finds potential fuel debris hanging like icicles in reactor 3… The objects spotted this time look like icicles… Tepco is pinning its efforts on technology not yet invented to get the melted fuel out of the reactors.

Reuters, Jul 21, 2017: Tepco detected black-colored material that dangled like icicles that could be nuclear debris near the bottom of the reactor’s pressure vessel that contained the fuel rods, the report said, citing unnamed sources.
Bloomberg, Jul 21, 2017: New images show what is likely to be melted nuclear fuel hanging from inside one of Japan’s wrecked Fukushima reactors… [Tepco] released images on Friday showing a hardened black, grey and orange substance

Financial Times, Jul 24, 2017: [Kimoto] was reluctant to speculate on the nature of seemingly corroded orange patches in the images.

NHK, Jul 23, 2017: [TEPCO] says Saturday’s probe found lumps that are highly likely to be fuel debris piling up at the bottom of the containment vessel… The deposits are estimated to beone to two meters thick. Images released on Saturday show black, rock-like lumps and what appear to be pebbles and sand accumulating at the bottom.


From 2014

Studies show multiple fuel cores ejected from Fukushima reactors – Hot particles of uranium and plutonium fuels detected nearly 300 miles away



27 August, 2014

Marco Kaltofen, Nuclear Science and Engineering , presented at Worcester Polytechnic Institute, March 19, 2014: High Radioactivity Particles in Japanese House Dusts… The Fukushima Dai‐ichi accident released very high activity inhalable dust particles that travelled long distances… Airborne dusts can transport radioactive materials as isolated individual particles containing high concentrations of radioisotopes. Alpha and beta emissions related to fission wastes and dispersed fuel particles are hazardous when inhaled or ingested. Radioactively‐contaminated environmental dusts can accumulate in indoor spaces, potentially causing significant radiation exposures to humans via inhalation, dermal contact, and ingestion… a micron‐scaled particle [had] activity greater than 1.0 PBq kg [1 Quadrillion Bq/kg]. The par6cle was collected from a home in Nagoya, Japan. Nagoya is 460 km from the accident site… It contained both fission products and decay products of 238U… tellurium up to 48.0 %, cesium up to 15.6 %, rubidium up to 1.22 %, polonium up to 1.19 %, dysprosium up to 0.18 %, as well as trace amounts of Sn, lead, nickel, iron, and chromium… 226Ra, 134Cs, and 137Cs, 241Am, and 230Th [were] the most commonly detected gamma photon-emitting isotopes… about 25 % of dusts sampled [were] autoradiographically positive for hot particles… the majority of these hot particles were 10 um [micrometers] or less in size, meaning that they were potentially inhalable… Radioactively‐hot particles on the respirable size range were routinely detected, with one as far as 460 km [285 miles] from the release site.
Kaltofen : Radioisotopes in dusts released by Fukushima Daiichi units [include] Uranium and plutonium fuels and transuranics such as americium and neptunium… individual radioactive particles [in an] Ibaraki dust sample [include] Eu, Y, Zr, Th, Ce, Sr… in 1 to 15 um size range…
Kaltofen : The Japanese samples came from as far north as Sapporo in Hokkaido Prefecture and as far south as Tokyo, a range of 780 km. Fifty nine samples of dust from Japan were analyzed… Radioisotopes specific to the Fukushima Daiichi accidents, including Cs134, Cs137, and Co60 were detected in dust samples taken throughout Northern Japan, including areas more than 200 km outside of the accident exclusion zone. Cs134 was detected at all of the Japanese sites tested… Japanese samples… analyzed in the first month after the accident also contained I131 and Am241… Radioactive dust has become a ubiquitous part of life in northern Japan.
Chris Harris, former licensed Senior Reactor Operator & engineer, Aug 21, 2014 (at 24:00 in): NHK just [broadcasted] that many studies are showing… that multiple cores — parts of it, or some, or even most of it — had been ejected. We thought that too. Once you breach containment, that was one of my big concerns — where did the core go after an explosion like? Whether it be steam or hydrogen explosion or a combination of both… it got ‘sneezed out’ all over the place. It’s totally – it’s a huge mess.
Source: Enenews


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