2015/02/12
TEPCO is turning to cosmic rays to get a look inside the stricken power station’s wrecked reactors, and help decide how to extract the melted nuclear fuel inside.
Since the March 2011 nuclear disaster at the Fukushima No. 1 plant, due to high radiation levels it’s been impossible to see inside the three reactors affected to ascertain the state of the fuel — specifically how much is left in the pressure vessels and how much melted through to the containment vessel. As poking a hole in the reactor vessels would be far too dangerous, TEPCO is turning to a technique similar to X-ray exams at a doctor’s office: muon detectors.
Muons are subatomic particles produced when cosmic rays strike Earth’s atmosphere, and rain down constantly onto the planet’s surface. Muons pass through most materials, including concrete and steel, unhindered, but they are blocked by very dense substances such as nuclear fuel. As such, the melted fuel in the Fukushima No. 1 reactors will block muons passing through the pressure vessels, and show up as shadows on a muon detector readout. The same technique is used to study magma in volcanoes.
<Media Report>
TEPCO turns to cosmic rays to get peak inside Fukushima reactors (Mainichi Newspaper)
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