TOKYO —Japan Today -- National Aug. 16, 2013 - Friday - 12:55PM JST The operator of Japan’s crippled Fukushima nuclear plant is preparing to remove 400 tons of highly irradiated spent fuel from a damaged reactor building, a dangerous operation that has never been attempted before on this scale. Containing radiation equivalent to 14,000 times the amount released in the atomic bomb attack on Hiroshima 68 years ago, more than 1,300 used fuel rod assemblies packed tightly together need to be removed from a building that is vulnerable to collapse, should another large earthquake hit the area “They are going to have difficulty in removing a significant number of the rods,” said Arnie Gundersen, a veteran U.S. nuclear engineer and director of Fairewinds Energy Education, who used to build fuel assemblies. The operation, beginning this November at the plant’s No. 4 reactor, is fraught with danger, including the possibility of a large release of radiation if a fuel assembly breaks, gets stuck or gets too close to an adjacent bundle, said Gundersen and other nuclear experts. That could lead to a worse disaster than the March 2011 nuclear crisis at the Fukushima plant. No one knows how bad it can get, but independent consultants Mycle Schneider and Antony Froggatt said recently in their World Nuclear Industry Status Report 2013: “Full release from the No. 4 spent fuel pool, without any containment or control, could cause by far the most serious radiological disaster to date.” The process will begin in November and TEPCO expects to take about a year removing the assemblies, spokesman Yoshikazu Nagai told Reuters by e-mail. It’s just one instalment in the decommissioning process for the plant forecast to take about 40 years and cost $11 billion. “The No. 4 reactor was not operating at the time of the accident, so its fuel had been moved to the pool from the reactor, and if you calculate the amount of cesium 137 in the pool, the amount is equivalent to 14,000 Hiroshima atomic bombs,” said Hiroaki Koide, assistant professor at Kyoto University Research Reactor Institute. Removing the rods from the pool is a delicate task normally assisted by computers, according to Toshio Kimura, a former TEPCO technician, who worked at Fukushima Daiichi for 11 years. “Previously it was a computer-controlled process that memorised the exact locations of the rods down to the millimeter and now they don’t have that. It has to be done manually so there is a high risk that they will drop and break one of the fuel rods,” Kimura said. And if an another strong earthquake strikes before the fuel is fully removed that topples the building or punctures the pool and allow the water to drain, a spent fuel fire releasing more radiation than during the initial disaster is possible, threatening about Tokyo 240 kilometers away.
Posted on: Fri, 16 Aug 2013 08:48:41 +0000
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