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Dismantling a Nuclear Reactor 102

AmiMoJo sends in a BBC story about the hardware used to decommission a nuclear reactor: "The device cost £20m to design and build and will operate in highly radioactive conditions inside Dounreay's landmark Dome. Its detachable tool bits cost £100,000 each and weigh between 37-93kg. They will cut and grab 977 metal rods once used to 'breed' plutonium from uranium. ... Once in place, the device will operate in highly radioactive conditions and in a nitrogen atmosphere. Nitrogen prevents any residue of the liquid metal from reacting. Exposure to water or oxygen would cause the metal to catch fire. ... Up to three tool bits will be in use at any one time and can be replaced by another three carried in a special tool box without the need to remove the tool itself from the reactor. The rest of the tool bits will be stored above the reactor and would be fitted into place during service and maintenance breaks."
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Dismantling a Nuclear Reactor

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  • Obligatory: (Score:2, Funny)

    by kheldan ( 1460303 )
    I, for one, welcome our detachable-bit, multi-pronged, nuclear-reactor-dismantling robotic overlords!
    • ...people who are not nuclear engineers talking about why nuclear engineers are Doing It Wrong.
      Next week, Bricklayers wonder about space.
      • Why isn't this in Ask Slashdot section??
      • It is much worse when space scientists wonder about bricklaying. For while humanity may be better off with space scientists left to do their job, it needs bricklayers to be left to do theirs.

  • Are we talking about sodium coolant?
    • by Hartree ( 191324 )

      DFR, the reactor they're talking about in this case, used a liquid sodium potassium alloy for coolant.

    • by Baloroth ( 2370816 ) on Tuesday July 19, 2011 @10:54PM (#36818916)

      Actually, yes. According to Wikipedia [], this reactor is cooled by liquid sodium-potassium metal. The BBC mentions it several times as "liquid metal", but never by name, likely because "liquid metal" is a much cooler name than "sodium-potassium." Or because the less scientific might think "Sodium and potassium? You mean salt and the stuff in bananas?" This is BBC, so I'll give them the benefit of the doubt and say the latter. Sadly, its also probably what most people would think. Never mind liquid sodium-potassium [] is flammable in air, and the idea of radioactive NaK burning gives me the heeblie-jeeblies, as much as I like nuclear power.

      Long story short: bad nuclear reactor design, should never be done again. Also, its been being decommissioned since 1977. So, yeah, lets not do that again.

      • by lennier ( 44736 ) on Tuesday July 19, 2011 @11:00PM (#36818962) Homepage

        Long story short: bad nuclear reactor design, should never be done again.

        Hi! You must be new here. Let me introduce you to the Slashdot resident "sodium cooled fast breeder reactors are way cool, we should build loads more of them and solve all the world's ecological problems!" contingent.

        • by Hartree ( 191324 )

          "sodium cooled fast breeder reactors are way cool, we should build loads more of them and solve all the world's ecological problems!"

          You've converted to that? Way cool.

          I was beginning to lose hope for you.

        • by Baloroth ( 2370816 ) on Tuesday July 19, 2011 @11:30PM (#36819118)

          Oh, don't get me wrong: I do still think FBRs are really cool. While I was reading about this reactor, my inner nerd was going "Holy shit, using NaK as a coolant is awesome and kinda badass!" even while it was also going "Holy shit, using a material that can spontaneously explode in air as coolant for nuclear material is a really bad idea!". Many bad ideas are also really cool. Doesn't mean they aren't still bad ideas. Can't even imagine what would happen if the public found out about it. Or if, God forbid, one of these things actually exploded.

          Now, something like a Molten Salt Reactor [], on the other hand, is both cool and (probably) not a bad idea. And could possibly solve most of the world's ecological problems.

          • by stair69 ( 680444 )
            Molten Salt Reactors have benefits, but the first one (MSRE) was also a nightmare to decommission (like Dounreay)

            From the Wikipedia MSRE page ( [] ):

            The ensuing decontamination and decommissioning project was called "the most technically challenging" activity assigned to Bechtel Jacobs under its environmental management contract with the U.S. Department of Energy's Oak Ridge Operations organization.

            • by Amouth ( 879122 )

              if i remember correctly one of the reasons it was so challenging to decommission was because they let it sit for nearly 20 years before doing it

          • UF4 at 800C.. what could possibly go wrong? ;)

            Still, might be worth it as a stopgap before fusion.

            I would also like to complain about <sub> not working on slashdot, of all places.

        • Hi! You must be new here. Let me introduce you to the Slashdot resident "sodium cooled reactors have crazy potential safety issues, we should probably use molten salts instead" contingent.
        • by bertok ( 226922 ) on Tuesday July 19, 2011 @11:53PM (#36819276)

          In all seriousness, newer technology is generally safer than old technology, and several proposed reactor designs reduce nuclear waste, which is the biggest issue with nuclear power.

          Most people these days are advocating molten salt reactors, which do not use dangerous liquid metals. Salts are much safer than anything currently used to generate power. There's no risk of the coolant or fuel igniting, for example, which is a risk even with water cooled plants. Fukushima is a practical example: the loss of coolant water allowed Zirconium fuel element cladding to become exposed to air and catch fire. That kind of thing just can't happen with a salt. Meltdown isn't a risk either in a reactor designed to operate in a molten state to begin with!

          • by Anonymous Coward

            "Fukushima is a practical example: the loss of coolant water allowed Zirconium fuel element cladding to become exposed to air and catch fire."

            No. The red-hot zirconium alloy cladding for the fuel reacted with steam at the very high temperatures, which then dissociated into hydrogen and oxygen. The hydrogen escaped, and then ignited outside the reactor. The zircalloy cladding isn't particularly prone to burn all by itself, unlike some of the liquid metal coolant used in some reactor designs, such as the N

        • Re: (Score:1, Flamebait)

          by Radworker ( 227548 )

          I have three words for you "positive temperature co-efficient". Someone care to define why this is not desirable in a nuclear reactor? c'mon anyone? I will give you a hint, it involves reactivity and temperature. OK TIMES UP. The answer is : Think back to Chernoblyl. It used a liquid sodium moderator. When the termperature goes up the reactivity goes up. This makes things a little difficult to stop a runaway reaction. PWR's and BWR's have a negative co-efficient meaning that if you overheat t

      • by Anonymous Coward

        To be fair the Dounreay FBR was not a bad design, it has been a very successful prototype and operated for many years. It can survive complete external cooling failure because of natural convection and many new designs are copying this idea. Although I do agree a liquid Sodium-Potassium mix is not a nice compound, and the newer designs are using better mediums.
        While it has been theoretically in the process of decommissioning since 1977, it has started and paused many times, mainly for good reasons like allo

      • by BlueParrot ( 965239 ) on Wednesday July 20, 2011 @07:12AM (#36821394)

        Long story short: bad nuclear reactor design, should never be done again. Also, its been being decommissioned since 1977. So, yeah, lets not do that again.

        You don't happen to know why alkali metals are useful in a fast breeder?
        Let me see:

        Alkali metals don't corrode the structural materials in the reactor, unlike superheated water, salt or lead.

        The coolant doesn't need to be pressurised, greatly reducing the risk of a leak.

        The heat conductivity is superior to any other coolant, making it much easier to design a passive cooling system

        The coolant is compatible with metal fuel. Metal fuel has much better heat conductivity than
          the helium-ceramic type of fuel bundles used in most reactors, which aids in cooling. Metal fuel
        is also MUCH easier to reprocess ( necessary for a breeding cycle ).

        Unlike salt and lead, sodium alloys are liquid close to room temperature, making service, repair and standby operations much simpler.

        Unlike salt and water, alkali coolants don't undergo radiolysis at any temperature.

        The electrical conductivity in sodium is good enough that you can make electromagnetic pumps with no moving parts ( less risk of pump failure ).

        The neutron spectrum with alkali coolants is quite hard, giving such a reactor excellent breeding and actinide burning potential.

        So basically while the fire hazard is an issue for these reactors, there are numerous advantages with alkali metals that actually give a lot of safety advantages. Also, while a sodium fire would be bad, it's not exactly as if rupture of a pipe carrying superheated steam would be very benign either.

        • > Unlike salt and lead, sodium alloys are liquid close to room temperature

          Minor correction: Many sodium allows have a much higher melting point and are solid at room temperature. NaK, the alloy used in this case, is liquid at temperatures quite a bit below normal room temperature. The melting point is only 12 degrees Farenheit.

        • "The electrical conductivity in sodium is good enough that you can make electromagnetic pumps with no moving parts"

          I'd never heard of liquid metal pumps before. I salute you good sir for introducing me to something fascinating.

          any idea if they work on other liquids? does the liquid simply have to be conductive or what?

  • I'm confused. Is this a "Ack, nuclear stuff is expensive and dangerous!" article or a "Wow, large engineering projects are cool!" article. Should I be AFRAID or IMPRESSED? I don't know!
    • Anything worth being impressed by is also worth being afraid of.

      • by Umuri ( 897961 )

        Anything worth being impressed by is also worth being afraid of.

        So we should be afraid of the Eiffel tower? Ooo, how about the statues of Moai?

    • I'm confused. Is this a "Ack, nuclear stuff is expensive and dangerous!" article or a "Wow, large engineering projects are cool!" article. Should I be AFRAID or IMPRESSED? I don't know!

      Makes me think - wow, we need a better way to make electricity.

  • After all, the japanese managed to dismantle a reactor for free.

    Too soon?

  • At last! (Score:5, Interesting)

    by dbIII ( 701233 ) on Tuesday July 19, 2011 @10:38PM (#36818800)
    Something to rub real science in the face of the cargo cult fanboys that think reprocessing and decomissioning is easy and 1970's technology is all we need.
    Small units, reuse of high grade waste with something like accelerated thorium, and actual containment of the remaining waste are the way to go instead of treating it all as a solved problem fixed by magic.
    • Not really, this is a device for a one-off reactor design. Removing the fuel rods from a normal reactor isn't a big deal. Still, the costs of decommissioning a reactor in the U.S. is estimated at over $300M
      • by dbIII ( 701233 )
        You are not the sort of person I am criticising because you do not have the illusion that it's all magic with no tricky and expensive bits.
    • Sooo. We implement a technology (thorium breeders) that we have far less engineering experience with than the standard reactors and it will automagically instantly be better?

      Uh. Who's doing cargo cult again?

      (I favor thorium fueled reactors, but it will not automatically be a solution to all problems without further engineering and experience. Nothings easy.)

      Oh, and are we talking about using 70s tech to clean sites up to 70s de facto standards of safe it, lock the place up and monitor it forever?

      Or the mass

      • The words "something like" were in there to provide a clue to the reader as to what the sentence was about. I think we should be moving on towards the future instead of pretending that the failures of the past are good enough, and I mentioned a promising lead so that idiots would not instantly assume that I'm against the entire concept of nuclear power for the hell of it.
        It's very clear to all who take things seriously that the currently running reactors are just not good enough so the "engineering experie
        • "It's very clear to all who take things seriously"

          There's an old joke that when you see a phrase like that in a paper, it means "I think so."

          The biggest problem with the currently running reactors in the US is that promises that were made about storing, reprocessing or otherwise dealing with the waste were unfullfilled here.

          Purex processing wasn't an ideal solution, but was a possible one. It was made impossible for political/arms control reasons.

          Entombment at Yucca Mountain wasn't an ideal solution but was

      • I'm trying to map the phrase "cargo cult" onto the situation you've described and I'm coming up blank. Leaving aside the issue of whether or not thorium breeders are a good idea or not, the only meaning of the phrase "cargo cult" I can divine that might be relevant appears to be the usage of the phrase itself!

        On the reactor type issue, though, thorium breeders are the future of energy production - there are orders of magnitude more of it accessible than uranium, although we do have an awful lot of availabl

        • The "cargo cult" was a expectation that the form of something would produce results without any of the hard work of knowing anything at all about the function (fake military infrastructure in the Pacific Islands to get supplies to turn up by magic). Get something to about the right shape and it's good enough and the rest is magic not worth bothering about. Thus I apply this label to the people that are unquestioning fans of something but get quite irate when practicalities are discussed in any way apart f
    • Re:At last! (Score:4, Insightful)

      by Fordiman ( 689627 ) <fordiman@[ ] ['gma' in gap]> on Tuesday July 19, 2011 @11:51PM (#36819270) Homepage Journal
      Reprocessing hasn't exactly stood still since the 1970's. And, I mean, it's not easy or anything, but AREVA does it every day.

      Now, while I agree that waste reuse (and, of course, avoiding the isotopic mess that comes with natural uranium) and thorium breeding are a good idea to develop, I think you may be a little out of your depth on the subject of "accelerated thorium"; the fission-fusion reaction hasn't even demonstrated the ability to reach 10% break-even from the energy used to accelerate the Th beam, and was largely designed to produce high-neutron isotopes of transition elements. It's not geared for power production.

      That's a bit ironic, yeah? I mean you basically said, "Don't pretend [older, difficult magic process] will fix everything, but hey, [new, poorly understood magic process]!"
      • by dbIII ( 701233 )

        but AREVA does it every day

        Really? They started up again after a halt of a few years and are running every day and there has been nothing in the press about it? Saturdays and Sundays as well? Where did you get that from, I'd really be interested in reading something that shows that you didn't just make that up.
        I know that reprocessing has been done in the past but implying that it is an everyday industrial process of little consequence is just a little bit dishonest and misleading don't you think?
        If you

        • by dargaud ( 518470 )
          Is this the info you are looking for [] ?
          • by dbIII ( 701233 )
            Yes but 2005 as mentioned there is not now. A while after that reprocessing was halted indefinately until at least a couple of years ago - do you have anything that mentions that it has it started again in recent years?
            Now do you understand what I'm getting at? No reprocessing anywhere on earth for a few years is a bit different to "every day". Prove me wrong with something about reprocessing being carried out any time this year or last year and I'll concede the "every day" as an honest exaggeration and
            • by Anonymous Coward


              This plant has 2 production lines with a current capacity corresponding to electricity production of 450 tWh per year (1,700 tons of used fuel per year). Almost 929 tons were treated there in 2009.

            • by dargaud ( 518470 )
              Although I do work in that field, I know nothing about the Hague. Where do you get your info that it stopped in 2005 ? It stopped producing Pu, but not reprocessing civilian leftovers.
              • by dbIII ( 701233 )
                It was in the print media back then, some time after 2005 (when it was being done in France) - I'm having trouble tracking it down apart from more recent references to a large backlog of unprocessed fuel and a few possibly biased pages that say reprocessing has halted but do not provide a source. I'll keep looking later but I'm unlikely to find anything today.
    • I'm not in the nuclear fanboi camp at all - I think there are better, cheaper sources of electrical energy. I'm definitely not siding with whoever your argument is pointed at.

      That said, it seems likely that electricity generation was a waste heat recovery operation at this plant. Its true purpose was probably to generate weapons-grade nuclear materials and to help learn about the effects of fission to transmute elements, not to generate power. This makes your comment off point. As abhorrent as the risk

      • Interesting notion. Could you provide a link to any articles about either prototype or production units?

        • Prince Piero Ginori Conti tested the first geothermal power generator on 4 July 1904 in Larderello, Italy. - Wikipedia []

          I guess the best reference would be The Geysers [] in California, generating electricity since 1960. You'll find five countries that (as of 2004) generated more than 15 percent of their electrical power from geothermal energy here. []

          Typically geothermal plants produce more widely distributed energy than nuclear power. This isn't necessarily a bad thing. The closer the generation is to the use the less the transmission losses waste.

          You should find sufficient citations in the wikipedia articles to continue yo

    • The frustrating thing is that almost every reactor design more complex than a boiling water reactor has had serious problems. Most high-temperature gas-cooled reactors have had major problems, although Peach Bottom continues to generate power profitably. The German AVR reactor [], which was a pebble-bed design, had a pebble jam and can't be dismantled at all. About a dozen sodium-cooled reactors have been built, with few successes and several sodium fires.

      That's why reactors are still BWRs and PWRs. Everyth

      • The Russian BN-600 sodium cooled fast reactor has run for more than a couple of decades and is the most reliable power reactor in the Russian fleet. They are building an upgraded version called the BN-800 and China is buying two. Russia has been making a lot of noises lately about fast reactors being their energy future. France has the Astride fast reactor development program which recently received renewed funding. India is bringing it's first power fast reactor on line soon. The EBR-II ran successfully at

      • There are 14 gas cooled reactors in the UK. I'm not going to say that they're better than PWRs and BWRs, but AGRs [] are out there too.

  • It would be awesome to see a "top kill" using nucular waste.
    (Yeah, nucular)

    • No, you see, people who deal with nuclear energy are /responsible/ humans that clean up after themselves.
  • A repetitive dangerous task and, while I could say the obligatory "what could go wrong", often the robotic type of setup does better than people (simply because one doesn't have to worry about risk to self). I've seen this kind of thing before. They use them in commercial large scale breweries to clean the brew tanks (which is another dangerous and repetitive job for people).
    • by KDR_11k ( 778916 )

      The difficult part is that robot electronics are vulnerable to the radiation inside the reactors, that drives the price and engineering difficulties up.

  • by cronb ( 994958 ) on Tuesday July 19, 2011 @10:55PM (#36818924) Homepage
    This story is a bit misleading because the reactor being dismantled is an experimental fast neutron reactor. The materials it is made of were not really designed to be easily disassembled. This is different from a commercial light water reactor where part of the design requirements are being comparatively straightforward to dismantle.
    • by makomk ( 752139 )

      As far as I can tell there aren't any LWRs in the UK. We have one PWR reactor (Sizewell B) and a bunch of AGR and Magnox reactors. Sizewell B was apparently supposed to be AGR too originally...

  • by Anonymous Coward

    Here they use an illegal alien in lead jockey shorts.

  • by etudiant ( 45264 ) on Tuesday July 19, 2011 @11:34PM (#36819146)

    The Japanese have built and used a similar tool for removing fuel from their troubled Monju fast breeder reactor prototype. The latest glitch was that the tool fell into the reactor and got stuck. The senior engineer on the effort committed suicide after this.
    The tool was retrieved last month, after much effort.
    It would be a shame if the Brits ran into similar problems, so hopefully they are talking to the Japanese and getting some lessons learned.

    • by Fordiman ( 689627 ) <fordiman@[ ] ['gma' in gap]> on Tuesday July 19, 2011 @11:59PM (#36819312) Homepage Journal
      "The senior engineer on the effort committed suicide after this."

      That is truly a shame, and one of the few things I really dislike about Japanese culture.

      You don't learn without making mistakes. Epic mistakes deliver epic lessons. Suicide deprives /everyone/ of your experience, and has literally /nothing/ to do with some antique sense of "honor". It's cowardice; you can't stand the embarrassment, so you run away. If the Japanese had any sense in the matter, they'd shame the families of those that have committed suicide, so as to disincentivize that as a solution to shame.

      Live through it. You'll be better for it.
      • by SHaFT7 ( 612918 )
        good luck with that. i agree btw.
      • How was nothing learned from his mistake?

        Its not like the mistake wasn't obvious to others.

        The Japanese have a since of honor and pride, the rest of the world would do good to have some of it. America most certainly needs some. We think we deserve to rule the world Because. When we fuck up and kill 10k people ... its the 10k peoples fault they died, not the CEO or Engineers.

        Unless this guy was playing around with the robot inside the reactor with no one watching (let me give you a hint, he wasn't, since

        • When has the US f'd up and killed 10k people? Are you talking about the wars? Because I don't think that they map very well to reactor design and maintenance programs. I don't think it counts an engineering f-up if you intended to kill people...

          Maybe you're talking about our transportation system, which focuses largely on individually-controlled discrete transportation units to offer maximum flexibility to the users of the system? I don't think we're going to reduce road deaths much more than we alread

        • "When we fuck up and kill 10k people ... its the 10k peoples fault they died, not the CEO or Engineers."

          a) I don't think anyone in the US behaves like that
          b) I don't see how that's relevant.

          "The Japanese have a since of honor and pride, the rest of the world would do good to have some of it....some people actually feel bad when they fuck up"

          There is no honor in suicide, and pride, when injured, does not justify giving up. If you feel bad, you help fix the problem. Committing suicide because you don't want
        • Additionally, I did not say no one learned from the mistake - but a lead engineer is a man with 10 or more years of engineering experience and education. The project is now deprived of that because a culture has a self-indulgent pride issue.
    • by Anonymous Coward

      The Brits are taking seppuku lessons?

    • by Anonymous Coward

      You are most likely confusing things.

      The senior engineer who comitted suicide was involved in the conver up of a severe incident in the mid 90's - a sodium leak occured. The operator and authorities attempted to cover-up things, and most likely because of being deeply disappointed about the company and yet feeling responsible the guy comitted suicide.

      Noone comitted suicide because of the recent incident about the device falling into the reactor.

      • by etudiant ( 45264 )

        Sorry, that is unfortunately incorrect. There was an earlier disaster, with the cover up of a massive sodium leak leading to a senior executive's suicide, back in Jan 1996.
        This is a separate event, involving the plant manager in charge of the fuel section, a hard core engineer, in February of this year.

  • Anybody know how much it costs to decommission such a reactor (or similar)? I'd heard it's a pretty costly business. A few hippies I know have his theory that the total life cycle cost of commissioning, running, and decomissioning a reactor is more than the value of the electricity produced in its lifetime. But I'd love to get some figures before arguing further with them. Any thoughts? How long / how much does it cost to decommission a reactor of this type (or similar)?

    • I believe IEA estimates are 15-20% of the original capital cost. When discounted a fair way into the future, they have a surprisingly small effect on the Levelized Cost of Electricity. The effect on the latter is heavily influenced by assumed discount rate. People sometimes like to confuse matters by equating costs of decommissioning of light water power reactors with the costs for older designs such as UK Magnox reactors or cleaning up some of the mess left from the cold war weapons and dual use facilities

  • This story is probably highly misleading but I would still give it a 5-star rating just for being so /.
  • When I was in high school, I did a week's work experience in the computing department at Dounreay

    We worked on the ground floor of the building that houses the old DFR control room (it was just upstairs from us). We were right in the shadow of the spherical reactor housing (affectionately known as "the Golf Ball".

    They had all sorts of old tech in their computing department - DEC VAX systems, racks full of old Gandalf kit, etc. It was 16 years ago now, and I can't remember what else they had in there. Ther

  • Gee for windmills all you need is a wrench

I've noticed several design suggestions in your code.