Japan researchers use cosmic rays to see nuclear fuel

January 23, 2014
Members of the International Atomic Energy Agency inspect a spent fuel pool at the crippled Tokyo Electric Power Fukushima nuclear power plant, on November 27, 2013

Japanese researchers said Thursday they had succeeded in using cosmic rays to find nuclear fuel inside a reactor, a technology that might be helpful in the complicated decommissioning at Fukushima.

By observing the way the particles behaved near reactors, container vessels and spent , they were able to obtain a clear visual picture of the fuel, they said.

"We are conducting this study carefully as this enables you to find where nuclear fuel is anywhere in the world," said Fumihiko Takasaki, a researcher at the High Energy Accelerator Research Organisation, or KEK, one of the laboratories involved in the research.

The technology could help Tokyo Electric Power Co. in the clean-up at its Fukushima Daiichi plant, he told AFP by telephone.

A massive earthquake and subsequent tsunami knocked out cooling systems at the power station, sparking reactor meltdowns that contaminated land, air and the sea.

Engineers working on the decades-long decommissioning are faced with a series of difficulties, not least of which is that they do not know exactly where the molten fuel is inside the battered reactors.

Present technology is not robust enough to allow them to get a look inside the units, where some fear that fuel has melted through containment vessels and possibly into the ground underneath.

KEK, working jointly with University of Tokyo, University of Tsukuba and Tokyo Metropolitan University, observed particles called muons in experiments.

Muons are constantly falling on the earth and move without hindrance through water, human bodies and many other objects.

But substances with high density such as nuclear fuel reduce their penetration.

A team of researchers monitored muons at three locations outside an off-line nuclear plant in Ibaraki prefecture, east of Tokyo, from February 2012 to December 2013.

They tracked where muon penetration was blocked to produce the image of nuclear fuel at the plant.

Takasaki said the team would propose use of the system to Tokyo Electric Power, adding observations at some five locations for less than two months would enable them to produce visual images of at Fukushima.

Explore further: No uncontrolled reaction at Fukushima: operator

Related Stories

No uncontrolled reaction at Fukushima: operator

November 3, 2011

The operator of Japan's crippled Fukushima atomic plant Thursday played down fears of an uncontrolled chain reaction at the site, despite the discovery of evidence of recent nuclear fission.

Radioactive water 'may have leaked' from Fukushima

April 6, 2013

Radioactive water may have leaked into the ground from a tank at the Fukushima Daiichi nuclear power plant, the operator said on Saturday, the latest in a series of troubles at the crippled facility.

Steam seen at Fukushima reactors: TEPCO

September 13, 2013

Vapour has begun rising again from a reactor at the Fukushima nuclear power plant, more than two-and-a-half years after its core melted down, the site's Japanese operator said Friday.

Fukushima operator gives first glimpse of fuel rod removal

November 19, 2013

The operator of the crippled Fukushima nuclear plant Tuesday offered the first glimpse of the operation to remove its fuel rods, the most dangerous job since the runaway reactors were brought under control two years ago.

Recommended for you

The ethics of robot love

November 25, 2015

There was to have been a conference in Malaysia last week called Love and Sex with Robots but it was cancelled. Malaysian police branded it "illegal" and "ridiculous". "There is nothing scientific about sex with robots," ...

Glider pilots aim for the stratosphere

November 20, 2015

Talk about serendipity. Einar Enevoldson was strolling past a scientist's office in 1991 when he noticed a freshly printed image tacked to the wall. He was thunderstruck; it showed faint particles in the sky that proved something ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.