11863
From: ryan, [DNS_Address]
Subject: Fukushima operators send robot into worst-hit melted reactor
URL: https://www.sfgate.com/news/article/Fukushima-operators-send-robot-into-worst-hit-16840677.php
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Fukushima operators send robot into worst-hit melted reactor MARI YAMAGUCHI, Associated Press Feb. 8, 2022 FILE - The damaged Unit 1 reactor, back, and the exhaust stack shared with the Unit 1 and 2 reactors at the Fukushima Daiichi nuclear power plant stand along the coast of Okuma town, Fukushima prefecture, northeastern Japan, Saturday, Feb. 27, 2021. A remote-controlled robot was used on Tuesday, Feb. 8, 2022, to probe the hardest-hit nuclear reactor at Japan's wrecked Fukushima plant, as officials push forward with recovery and clean-up operations that have been mired in delays and controversy. FILE - The damaged Unit 1 reactor, back, and the exhaust stack shared with the Unit 1 and 2 reactors at the Fukushima Daiichi nuclear power plant stand along the coast of Okuma town, Fukushima prefecture, northeastern Japan, Saturday, Feb. 27, 2021. A remote-controlled robot was used on Tuesday, Feb. 8, 2022, to probe the hardest-hit nuclear reactor at Japan's wrecked Fukushima plant, as officials push forward with recovery and clean-up operations that have been mired in delays and controversy.Hiro Komae/AP TOKYO (AP) — A remote-controlled robot on Tuesday was used to probe the hardest-hit nuclear reactor at Japan's wrecked Fukushima plant, as officials push forward with clean-up operations that have been mired in delays and controversy. An earthquake and tsunami in 2011 unleashed a disastrous meltdown at Fukushima Daiichi's three reactors that partly sunk their radioactive cores into the plant's concrete foundations, making removal extremely difficult. The plant's operator, Tokyo Electric Power Company Holdings, said the submersible robot was sent into Unit 1's primary containment vessel to install a guiding path for five subsequent robots, which will attempt to asses and take samples of the melted fuel that emits fatally high radiation. Tuesday's probe followed five years after the operators sent another robot into the same and badly-damaged reactor, but failed to get any images of the melted fuel. The robot-led work, which was postponed from mid-January due to mechanical glitches, is expected to last for a few days before full-fledged probes begin. Earlier probes showed that the fuel at Unit 1 is submerged by highly radioactive water as deep as 2 meters (6.5 feet). Five other robots, co-developed by Hitachi-GE Nuclear Energy and the International Research Institute for Nuclear Decommissioning, a government-funded consortium, will be separately sent in for the investigation over the next several months. The probe at Unit 1 aims to measure the melted fuel mounds, map them in three dimensions, analyze isotopes and their radioactivity, and collect samples, Tokyo Electric officials said. Those are key to developing equipment and a strategy for a safe and efficient melted fuel removal. About 900 tons of melted nuclear fuel remain inside the plant's three reactors, including about 280 tons in Unit 1, and its removal is a daunting task that officials say will take 30-40 years. Critics say that’s overly optimistic. Remote-controlled robots with cameras have provided only a limited view of the melted fuel in areas too dangerous for humans to reach. In 2017, super-high levels of radiation and structural damage hampered investigating Unit 1. Details of how the highly radioactive material can be safely removed, stored and disposed at the end of the cleanup have not been decided. Tokyo Electric hopes to use a robotic arm to remove a first scoop of melted fuel later this year from Unit 2, where internal robotic probes have made the most progress. Fisherman and residents of Fukushima's outlying areas have protested the operator's plans to discharge into the nearby sea radioactive waters from the reactors, after treating and diluting them to safely releasable levels. |
11864
From: ryan, [DNS_Address]
Subject: Re: Fukushima operators send robot into worst-hit melted reactor
URL: https://www.sfgate.com/news/article/Robot-photos-appear-to-show-melted-fuel-at-16847300.php
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Robot photos appear to show melted fuel at Fukushima reactor MARI YAMAGUCHI, Associated Press Feb. 10, 2022 Images from a remote-controlled submersible robot show damaged areas inside the Fukushima nuclear power plant damaged in the 2011 earthquake and tsunami, Wednesday, Feb. 9, 2022, in Fukushima, Japan. The robot captured images of what appears be mounds of damaged fuel that had melted and fell to the bottom of the hardest-hit reactor at the nuclear plant for the first time since the 2011 disaster. (IRID/Hitachi-GE Nuclear Energy, Ltd. via AP) TOKYO (AP) — A remote-controlled robot has captured images of what appears to be mounds of nuclear fuel that melted and fell to the bottom of the most damaged reactor at Japan’s wrecked Fukushima nuclear plant, officials said Thursday. A massive earthquake and tsunami in 2011 damaged cooling systems at the power plant, causing the meltdown of three reactor cores. Most of their highly radioactive fuel fell to the bottom of their containment vessels, making its removal extremely difficult. A previous attempt to send a small robot with cameras into the Unit 1 reactor failed, but images captured this week by a ROV-A robot show broken structures, pipes and mounds of what appears to be melted fuel and other debris submerged in cooling water, plant operator Tokyo Electric Power Company Holdings said Thursday. About 900 tons of melted nuclear fuel remain inside the plant’s three damaged reactors, including about 280 tons in Unit 1. Its removal is a daunting task that officials say will take 30-40 years. Critics say that’s overly optimistic. The robot, carrying several tiny cameras, obtained the internal images of the reactor's primary containment vessel while on a mission to establish a path for subsequent probes, TEPCO said. TEPCO spokesperson Kenichi Takahara said the piles of debris rose from the bottom of the container, including some inside the pedestal — a structure directly beneath the core — suggesting the mounds were melted fuel that fell in the area. Takahara said further probes will be needed to confirm the objects in the images. At one location, the robot measured a radiation level of 2 sievert, which is fatal for humans, Takahara said. The annual exposure limit for plant workers is set at 50 millisievert. The robot probe of the Unit 1 reactor began Tuesday and was the first since 2017, when an earlier robot failed to obtain any images of melted fuel because of the extremely high radiation and interior structural damage. The fuel at Unit 1 is submerged in highly radioactive water as deep as 2 meters (6.5 feet). TEPCO said it will conduct additional probes after analyzing the data and images collected by the first robot. Five other robots, co-developed by Hitachi-GE Nuclear Energy and the International Research Institute for Nuclear Decommissioning, a government-funded consortium, will be used in the investigation over the next several months. The investigation at Unit 1 aims to measure the melted fuel mounds, map them in three dimensions, analyze isotopes and their radioactivity, and collect samples, TEPCO officials said. Those are key to developing equipment and a strategy for the safe and efficient removal of the melted fuel, allowing the reactor's eventual decommissioning. Details of how the highly radioactive material can be safely removed, stored and disposed of at the end of the cleanup have not been decided. TEPCO hopes to use a robotic arm later this year to remove an initial scoop of melted fuel from Unit 2, where internal robotic probes have made the most progress. |
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11865
From: chaskuchar@stcharlesmo, [DNS_Address]
Subject: thank you nt
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