Sellafield Clean Up.

Sellafield is having a big clean up. It is called Britain's most dangerous building. It has 10,000 m3 of radioactive sludge. The sludge is being put into big backed bean tins and covered in Polyfilla. A robotic arm is being used to handle the sludge. But a comforting thought perhaps is that Hanford in the U.S.A. has 20 times the amount of high level nuclear waste as Sellafield. (or perhaps not so comforting after all).

Source: Not the Daily Mail.

Z.

  • That is why I am not really in favor of nuclear as a panacea to all our future supply needs. I have yet to be convinced that a safe method exists for disposing of the waste. Bury it, put it in concrete-filled oil drums, put it in a cave or mine.........nature has a nasty way of coming back out of the blue and poisoning your backside at some future date. What goes round comes round, and as with raw sewage, we always end up 'getting our own back'.

  • Maybe what we should be asking is why hasn't anyone researched a way to  stop radioactivity from being produced I'm thinking something that could stop the reactions stone dead thereby rendering all the waist nasties harmless. Maybe it isn't possible but surely if you can start a reaction you can stop it. I did wonder if dissolving it in acid mite work

  • You can start and stop a chain reaction, but the emission of particles is a natural phenomenon.

    Let's not forget that the nuclear programme was set up to make weapons and not primarily electricity. The generation of "free" electricity was a smokescreen.

  • I admit I know little about how radio activity works  although I ro try to learn I still seriously think they need to look at ways to contain it even if it can't be stopped we need to look at containing it to put it over simply we need to make it behave

  • Radio activity is unstoppable, but by arranging for most of the bits that fly off as nuclii decompose to get stuck into something that is not your DNA is the usual solution. As such putting several metres of concrete or water between it and  you are the normal techniques to get from 'hot' down to 'compares with natural background'

    (XKCD has a novel slant on this - and considers the wisdom or not of swimming in a reactor cooling pool  as one of its readers questions )

    To understand why there is no single answer, realise there are several grades of radioactive material firstly in terms of decay rate

    - things that are decaying fast are more dangerous today, but do not need such long term storage. Things that decay over millennia may sound frighting, but in reality, you can go and sit on a block of it, as the number of the atoms that actually decay during the time you are there is relatively few.

    Then in terms of the type of decay - alpha particles can be pretty much stopped by a bit of card, beta particles - fast moving free electrons can be stopped by thin sheet metal.  Gamma rays are more like super high energy X rays, and go through most things, getting only gradually dimmer.

    The gamma sources with medium term half lives are the ones that are most hazardous to us. Luckily most of the waste does not fall into this category, and some of the more sensational articles do not make clear the distinction.

    That's not to say that there is not some nasty stuff at sellafield that needs to be stored properly, but compared to disposal of some of the nasty chemicals we make, it is a more tractable problem, and these days far better controlled than it was in the early days.

    10,000cubic metres is equivalent to a tank 100m by 100m and 1m deep. For the whole country, not such a lot, indeed it would all fit in the car park at work for example. Mind you, I'd be a bit hacked off if they did that - I'd have to park somewhere else  ;-) .

    Mike.

    Mike.

  • The first question is why is it Britains most  dangerous building? It contains contaminated and activated fuel rod cladding from Britains gas cooled reactors. What are the dangers, some radiation, some fire risk from the light metals used in the cladding?

    It is certainly not representitive of the byproducts of current nuclear power generation. The Magnox and AGR reactors were designed for short burn up times and online refueling for making plutonium for nuclear weapons. Newer generation reactors have much longer burn up times which reduces the total amount of byproducts and produces plutonium that is not suitable for nuclear weapons due to contamination with other plutonium isotopes.

  • You cannot destroy this very toxic and dangerous waste you can only store it for several hundred years in secure storage.

    Every day more waste is generated down to contaminated gloves.

    Whilst it may be so called "clean" energy we are leaving this very dirty waste for future generations.

    We even have all of our old nuclear submarines tied up in harbor with continued maintenance as no one as yet has worked out a way of decommissioning them. But good news the plans to dismantle them are inching moving forward! See here www.navylookout.com/.../

  • I saw that item a while ago John, and was about to post the same link.

    It makes for disturbing reading doesn't it.

    Mind you, Murmansk is even worse, where no attempts have been made at all to recover the reactors out of their growing and aging submarine hulks. The Barents sea is not one of the nicest places on the planet.

  • The nuclear submarine article is an interesting read and notes the same problem as for early land based nuclear power plants, the military requirements were key, no one thought about longer term disposal.

    What is not mentioned is the time element. As Mike says highly active materials decay faster than less active ones. The reactor structures of land based reactors can be left for 10s of years to decay enough to make dismantling easier. There is a benefit in waiting before dismantling, but as the article says for submarines there is also a significant maintenance cost.

    The real risks from ionising radiation are also not discussed. It is fairly well established from the atomic bombs dropped on Japan and from various accidents that a rapidly received dose of 100 mSv or more will increase the risk of cancer, a dose of 4 Sv will be fatal without medical intervention and a dose of 10 Sv will be fatal. When the dose is less than 100 mSv or is delivered over an extended time the science becomes much more woolly.

    The current legislative requirements are based on collective dose and the Linear Non Threshold (LNT) principle.  These state that there is an increased cancer risk for any dose and that if 100 people receive 1 mSv this carries the same risk as one person receiving 100 mSv. It also follows from them that the risk of 2 mSv per year for 50 years is the same as the risk of a one off 100 mSv dose. There is no scientific basis for this and it is not supported by the large differences in background radiation levels around the world.

    The average background dose in the UK is 2.5 mSv per year. Parts of Cornwall and around Aberdeen can be three times this. Do we see three times the incidence of cancer in Cornwall? Other areas of the  world have more than 10 times the average background radiation level. This does not show as an increase in cancers.

    https://radwatch.berkeley.edu/background-radiation/

    So what are the real risks? There have been a lot of extrapolations based on mathematical models and a lot of emotional outbursts without much fact, a bit like AGW  Thinking

    If I take a piece of granite into a nuclear power plant it becomes radioactive waste and has to be disposed of accordingly. Are the current rules sensible?

    This HPA document goes into some detail of what is real and what is conjecture.

    Ionising radiation: risks from exposure - GOV.UK (www.gov.uk)

  • A very sensible document. In the context of decontaminated land having to be below 10uSv/yr, the figures given

    "Hence the total risk of dying of cancer for a person exposed to 1 mSv increases on average from 25% to 25.005%, and for a person exposed to 10uSv the average risk increases from 25% to 25.00005%."

     hammer home how the limits are a long way back from really existentially dangerous.  Only the high level waste, and things that are dangerous for non nuclear reasons, such as being poisonous -like lead based paints, or other ways harmful -like asbestos, really require the full treatment, and in the scale of the country, there really is not that much volume to be handled.
    With a slightly more lenient threshold, one could probably bury the remaining bits of the submarines whole and grass over them without too much going wrong, and have a condition where walking over the top would carry a similar risk to living a year in Cornwall, probably less risky than walking around Salisbury Plain  today, or at least whenever it is next open .

    Mike