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Japan Science Technology

Cosmic Rays To Reveal the Melted Nuclear Fuel In Fukushima's Reactors 68

the_newsbeagle writes: Muons, produced when cosmic rays collide with molecules in the atmosphere, are streaming through your body as you read this. The particles pass through most matter unimpeded, however they can interact with heavy elements like uranium and plutonium. That's why engineers at Japan's Fukushima Daiichi power plant are using muon detectors to look for the melted nuclear fuel inside the plant's three melted-down reactors. By determining where muons are being diverted from their paths, the detectors create images of the blobs of fuel. That's necessary because nobody knows exactly where the radioactive gloop ended up during the meltdowns.
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Cosmic Rays To Reveal the Melted Nuclear Fuel In Fukushima's Reactors

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  • by mbone ( 558574 ) on Friday February 13, 2015 @03:45PM (#49049853)

    Muon shadowgraphs of the Moon [wikipedia.org], a signature of the Moon's cosmic ray shadow on the upper atmosphere, are a common way of testing neutrino detectors buried under a km or more of rock. (Muons from the atmosphere tend to be the major source of confusion for such detectors; that's why they frequently do best looking down, as muons can't go through 12,000 km of rock.)

    Oh, and archeologists have used muons to look through the Great Pyramid [phys.org].

    • If I remember correctly a Japanese geologist also used Muons or some other high speed particle to map out the insides of a volcano, letting everyone see the vent plug and vent path in 3D.

  • by tlambert ( 566799 ) on Friday February 13, 2015 @03:54PM (#49049921)

    We've been using muon detectors for over 40 years to detect nuclear-related activities in various countries, including reactor installation, stockpiling, bomb-building, and so on. One of the reasons for the ability to move MX missiles around underground was so that long term muon detector observation by the Soviets could not pinpoint the location of the missiles.

    • I saw some documentary on TV not too long ago, that talked about using muon detectors to look for fissionable materials being smuggled for terrorist purposes hidden in transport containers.

      • by Anonymous Coward

        That is an actual use, of CMT, unlike the fantasy of detecting deviations in muon flux through thousands of kilometers of dense, proton-rich material.

        Primer from LANL:
        http://www.lanl.gov/quarterly/q_spring03/muon_text.shtml

    • by Anonymous Coward

      Underground mobile transport was to permit the usage of dummy silos, straining Soviet targeting and soaking up warheads.

  • by danbert8 ( 1024253 ) on Friday February 13, 2015 @04:00PM (#49049971)

    I wonder if we can get some good images of the elephant feet that are all over that building...

  • by Anonymous Coward on Friday February 13, 2015 @04:07PM (#49050023)

    Whenever talk turns to Fukushima, I'm always surprised at how little is known of the dark side of America's nuclear history.

    Did you know the first meltdown in the U.S. was in Los Angeles? And the reactor had no containment.
    https://www.youtube.com/watch?v=-_FCvbc0cNE
    https://www.youtube.com/watch?v=DPk9kEaSyAY

    Did you know about the Santa Susana Field Laboratory and it's ten reactors? Four of which had nuclear accidents.
    http://en.wikipedia.org/wiki/Santa_Susana_Field_Laboratory

    And this is only a very small part of the story. Be glad you are not raising a family in Canoga Park.

    • by ihtoit ( 3393327 ) on Friday February 13, 2015 @04:31PM (#49050215)

      Three words: Port Chicago Fire.

      I'm not at all convinced, from reading eyewitness reports, that that wasn't a nuclear pile going supercritical.

      • nuclear pile going supercritical.

        Note that the word "supercritical" has a specific meaning when it comes to nuclear power - it means that fission rate is increasing. Nothing more.

        Just as "subcritical" means that fission rate is decreasing.

        And "critical" means that fission rate is non-zero and stable.

        Note also that the words have slightly different usages when it comes to nuclear weapons....

      • You're not the first [wikipedia.org] to claim such madness. Maybe you'll finally be the first to find hard evidence, or perhaps disprove the small mountain of evidence (like having precisely zero radioactive debris) against your theory.

        • by ihtoit ( 3393327 )

          riddle me this: why was all the debris buried along with a pile of unexploded ordnance before civilian authorities could even start investigating it?

          I'm not claiming conclusions here, I'm just saying that there are unanswered questions that raise the finger of suspicion that HAVE NOT BEEN DEBUNKED WITH EVIDENCE.

          • by Sarten-X ( 1102295 ) on Friday February 13, 2015 @07:41PM (#49051713) Homepage

            Probably because it was a catastrophe on a military base in the middle of an espionage-heavy war.

            The explosion would certainly have been powerful enough to breach containers holding classified information, which would then be scattered with the rest of the debris. To allow civilians in to investigate would also have opened unnecessary risk that enemy spies could find useful information and smuggle it back to their employers.

            The radioactive fallout from an actual nuclear disaster is particulate. Even if an attempt were made to bury the debris, there would be enough dust in the air that the whole area would still have detectable radiation levels decades later.

            The "unanswered questions" line is an old staple of conspiracy theories. Unfortunately, the reality is usually that the questions don't need to be asked, because their answers don't actually disprove the commonly-accepted theory.

            • by ihtoit ( 3393327 )

              so why are the radiation levels at Hiroshima and Nagasaki equal to the world average terrestrial background? Those two places we KNOW from file footage and multiple eyewitness accounts to have been subjected to nuclear ground detonations which threw up stupendous amounts of fallout. Hiroshima now has a resident population of nearly 2 million.

              • The bombs dropped on Hiroshima and Nagasaki [zidbits.com] were detonated in the air, so they produced very little radioactive fallout, which spread out over a very large area. In contrast, an explosion at ground-level like you're proposing happened at Port Chicago would pull debris from the ground into the fireball, so the resulting fallout dust would have been bigger and heavier, and created a more concentrated contamination in the local area. It would be similar to what was seen during the Chernobyl disaster, where an

                • by ihtoit ( 3393327 )

                  the two bombs weren't dropped to maximise radiation effects, they were dropped for maximal burst effects (and maximum casualties) based on the drop accuracy (off by 500 feet in any direction, meaning for optimal blast effect they had to be detonated 2-3 times the height of the offset - which is the default for any nuclear weapon not built for EMP yield). Little Boy detonated at less than 500m (~1800 feet) for maximal blast radius (3 miles, everything in the Mach cloud area below zero point out to a radius o

                  • Um, yes.

                    My point was to illustrate how atmospheric nuclear fallout behaves in a ground burst vs. an air burst, which is quite well understood, thanks to the many tests conducted during the Cold War. Chernobyl was simply a convenient example of ground-based fallout. The Japan bombings are good examples of air-burst fallout, but that's irrelevant to the Port Chicago explosion.

                    That brings us back to the original point: if the Port Chicago explosion had been a nuclear accident in any way, it would have had dete

                    • by ihtoit ( 3393327 )

                      the official line maintains that the Salomon Brothers building fell at 4.58pm when in fact it was still standing behind a BBC reporter for an entire 23 minutes after that while she was on the air delivering a live report from the scene.

                      I do not believe the official reports when they blatantly lie like that. I want to see the EVIDENCE.

                    • the official line maintains that the Salomon Brothers building fell at 4.58pm when in fact it was still standing behind a BBC reporter for an entire 23 minutes after that while she was on the air delivering a live report from the scene.

                      A quick check [wikipedia.org] shows that the official reports claim it remained standing for an entire 23 minutes after 4:58pm.

                      I do not believe the official reports when they blatantly lie like that. I want to see the EVIDENCE.

                      You have the evidence at your disposal. You can do the research to understand the entirety of the situation, and reach a valid conclusion. Instead, you've choose to ignore reality and ask for "evidence" that you refuse to understand.

                      At least your world will always remain exciting.

              • by khallow ( 566160 )

                so why are the radiation levels at Hiroshima and Nagasaki equal to the world average terrestrial background?

                They are at similar levels, but they are not equal. There are plenty of trace elements that allow us to determine a nuclear explosion happened nearby.

                Second, it's worth noting that the detonation in question was really small for an atomic bomb (up to a bit over 1 kiloton). It took decades of work for the US to develop nukes in that range. A small nuclear detonation like that in 1944 would be a "fizzle", something that used up only a small part of the fissionable material. That would have spread the rest

      • You can walk to the Port Chicago site; I've been there. It's a nice walk by the Suisin Bay on the Carquinez Straight between Martinez and Pittsburg. There is a national historical monument [nps.gov] to the disaster, but it's not at the explosion location.

        The speculation that it was an atomic explosion is a paranoid fantasy. Given the technology of the time, a ground level explosion would have produced so much radioactive fallout that it would still be detectable today.

        Then there is the issue of the situation at the

        • by ihtoit ( 3393327 )

          yes, and there are two million people living in the city of Hiroshima TODAY. What the fuck is your TL;DR point??

    • by khallow ( 566160 )

      Did you know the first meltdown in the U.S. was in Los Angeles?

      No, it was the Experimental Breeder Reactor 1 [wikipedia.org] in Idaho, a bit over three and a half years earlier.

      • There is an interesting and rather exhaustively detailed book covering ALL the nuclear accidents that have taken place around the world. It's rather amazing how offhanded they were about some of these things in the early days. http://www.amazon.com/Atomic-A... [amazon.com]
  • You know... (Score:3, Funny)

    by jamiesan ( 715069 ) on Friday February 13, 2015 @04:20PM (#49050109) Homepage Journal

    You've got to remember that these are just simple sub-atomic particles.

    They are unstable. Common clay of the elements.

    You know... Muons

  • I thought the term of art was Corium [wikipedia.org]
  • Radon's transform [wikipedia.org] is really useful here

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