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Debris in sediment, bottom of Fukushima Unit 1 Neutron radiation detected at high levels

Debris deposits at the bottom of the containment vessel of the Fukushima Daiichi Unit 1 reactor on March 17 (International Nuclear Decommissioning Research and Development Organization, Hitachi GE Nuclear Energy, Inc. (Courtesy of International Nuclear Decommissioning Research and Development Institute, Hitachi GE Nuclear Energy)

May 26, 2022
On May 26, TEPCO announced that it had detected high levels of neutron radiation, which is emitted when uranium and plutonium contained in nuclear fuel undergo nuclear fission, in sediment found at the bottom of the containment vessel at the Fukushima Daiichi Nuclear Power Plant’s Unit 1 reactor. TEPCO announced that it had detected high levels of neutron radiation, which is emitted when uranium and plutonium contained in nuclear fuel fuse. A TEPCO representative said, “It is presumed to be derived from molten nuclear fuel (debris). It is natural to assume that the debris is contained in the sediment.
　TEPCO will focus on examining the thickness of the deposits near where the neutron rays were detected and the types of radioactive materials contained in the deposits.
　According to TEPCO, on March 20 and 21, underwater robots were used to survey four locations at the bottom of the containment vessel, and neutron rays were detected in all of them. The values at three locations near the openings in the base of the pressure vessel were particularly high.
https://www.tokyo-np.co.jp/article/179742?fbclid=IwAR0oljxEJF2Q5XzUE859cfr1DfSmtvct8xkg6FcU2uIEpIKvtlrh3qm9aag

May 29, 2022 Posted by dunrenard | Fuk 2022 | Fukushima Daiichi, Molten Fuel, neutron radiation, nuclear fission, plutonium, Unit 1, uranium | Leave a comment

Tepco admits molten nuclear fuel is transferred in multiple places of Reactor 2

Tepco-admits-molten-nuclear-fuel-is-scattered-in-multiple-places-of-Reactor-2-july 3 2016.png

Tepco admitted the molten fuel is transferred to multiple places in Reactor 2 by 6/30/2016.

Tepco had been implementing the muon scanning investigation with KEK (High Energy Accelerator Research Organization).

Tepco describes the research result as it is highly likely that major part of the molten nuclear fuel remains in the bottom of the reactor with structures of the inside of the reactor. They also detected a part of the molten fuel on the wall of the reactor. This means the molten fuel was separated and remaining in different locations. Tepco did not mention the percentage of the detected fuel.

Tepco did not identify the location either so it is not clear if the fuel remains inside of the Reactor Pressure Vessel or its outer structure, Primary Containment Vessel.

http://nstimes.com/archives/64086.html

http://photo.tepco.co.jp/date/2016/201605-j/160526-01j.html

http://fukushima-diary.com/2016/07/tepco-admits-molten-nuclear-fuel-is-transferred-in-multiple-places-of-reactor-2/

July 4, 2016 Posted by dunrenard | Fukushima 2016 | Fukushima Daiichi, Molten Fuel, reactor 2 | Leave a comment