Cross post from @Mark_Lynas: UK moves a step closer to #nuclear waste solution

This excellent cross-post from Mark Lynas provides a great summary of the proposal for the UK to use Generation IV nuclear technology to exchange its unwanted waste for energy.

 

I know what you are thinking: second cross post in a row. Ben is getting lazy. If I wanted this I could go to the Huffington Post.

Promise, not so, I am working on something original for later in the week. But sometimes a Tweeted link just does not do an article justice. On this occasion, Mark Lynas has superbly captured the current state of play in the UK as one of the most likely prospects for the first development of an Integral Fast Reactor (in this case, the S-PRISM reactor from GE which would need to be paired with the pyroprocessing fuel recycling facility to make true IFR). All of us who want to inform others about IFR will know that people want to know whether/when it will be built. This article is really worth a read to tell a clear story about that. Thanks Mark. This article can be found in original form at his excellent blog.

Mark Lynas

Something potentially rather interesting is happening deep within the Nuclear Decommissioning Authority (NDA), the branch of the UK government responsible for dealing with nuclear waste overall and the country’s 100-tonne plutonium stockpile in particular.

For several years now the wheels of policy been grinding towards a ‘solution’ to the plutonium issue apparently designed to please Areva, the French state-owned nuclear conglomerate which is responsible for the EPR reactor design and is also heavily invested in MOX – ‘mixed oxide fuel’, where plutonium and uranium are blended together into fuel rods for re-use in civil nuclear plants.

Areva has put tens of billions into MOX capability. The problem is, however, as the NDA is clearly now beginning to realise, that MOX is the worst of all possible options for plutonium management. Why? Because it is diabolically expensive, creating a difficult-to-handle fuel that you have to pay utilities to burn. And perhaps worse, it doesn’t even get rid of plutonium – after a full MOX cycle, you in fact end up with more plutonium than you started with because new plutonium isotopes are created from irradiated uranium-238.

So why should the UK government fork out countless tens of billions for this white elephant? It is instructive to note that Areva’s MOX plant under construction in the US at Savannah River, South Caroline is already nine times over budget whilst still being little more than a giant hole in the ground (the cost has gone from $0.5 billion to $5 billion and counting). No-one wants MOX in their reactors, because it is far more expensive than virgin uranium fuel and has to be handled with massively increased security due to the presence of plutonium.

The fact that there are no customers for MOX is unintentionally highlighted in the UK’s latest missive from the NDA which suggests that Japan might be both a customer for MOX fuel, and a co-investor in any fabrication plant. At the moment, it looks like a better business bet would be to try to sell MOX to the Martians – Japan is in the process of (ill-advisedly, in my opinion) shutting down its entire nuclear programme due to the political backlash from the Fukushima accident, and is hardly likely to cough up for a huge offshore investment like this.

The idea of renewed Japanese largesse is especially ludicrous given that the existing Sellafield MOX Plant was closed last year largely because Japan cancelled all its orders following the tsunami disaster. This recent history also begs the rather obvious question: why, having just closed a billion-pound, loss-making MOX plant – following the exit of its one remaining customer – would you want to go and straightaway build a new one?

Luckily the civil servants at the NDA, and their cousins over at DECC, the Department for Energy and Climate Change, are not stupid. They know a MOX plant will never actually be built, and that Areva has wasted billions already on what is essentially obsolete technology. That’s bad for Areva, and therefore the French taxpayer, but isn’t our problem. Hence the very intriguing spin put on the NDA statement, which is that the authority is “seeking proposals on potential alternative approaches for managing the UK’s plutonium stocks” even as it simultaneously “progresses its preferred policy of converting the material into mixed oxide fuel”.

In other words, the NDA is looking for a way out of the MOX dead-end before the policy process grinds so far forward that they find themselves too politically committed. No doubt Areva is knocking loudly on the NDA’s door and vociferously lobbying anyone who will listen, but the fact this they have backed the wrong horse and will lose big-time – because there is a far better option already on the table. That – as this World Nuclear News piece suggests – is GE’s PRISM fast reactor concept.

Cutaway view of S-PRISM reactor

Last month I had a meeting with some of GE’s top people, including the chief engineer for the PRISM – and I have to say I found their strategy highly compelling. The PRISM is a metal-fuelled fast reactor cooled by molten sodium. It operates at atmospheric pressure – meaning no expensive pressure vessel – and the characteristics of the fuel and the molten-sodium coolant (which conducts heat away from the core 90 times more effectively than water) make it fully passively-safe. (An early version, called the Experimental Breeder Reactor, was subjected to a loss-of-coolant flow experiment in 1986 – it duly shut itself down with no outside intervention.)

Perhaps more importantly, fast reactors can burn up all the energy in the uranium and plutonium fuel, whilst utilising MOX only increases the energy use from 0.6% to 0.8%. Because of this, as the Guardian recently reported, if all the UK’s spent fuel, depleted uranium and plutonium stockpiles are combined, they include enough energy to run the country for 500 years at current electricity use rates – without the need to mine another scrap of uranium, and without the emission of a single tonne of CO2. (Greenpeace is vociferously opposed, despite its supposed great concern for global warming, no doubt because a solution to nuclear waste leaves it high and dry after 35 years of misguided anti-nuclear activism.)

Areva’s submission to the NDA’s original plutonium consultation asserted that fast reactors are not an option until 2040 or later. However GE’s executives told me that they could get one up and running in 5 years – the PRISM is fully proven in engineering terms and basically ready to go. Nor will the UK taxpayer be asked to fund upfront capital costs – instead the proposal is for the NDA to pay a fixed price per kg of plutonium dealt with, whilst the PRISM plant will also generate a return by selling commercial electricity. (1 PRISM block has a rated capacity of 600 megawatts.) The risk of going over-budget – always a concern for first-of-a-kind projects – remains with GE.

Making plutonium unusable for bombs is only part of the deal, and not even the best part. (It is actually already unusable for bomb, because of different plutonium isotopes like pu-240, which make it non-weapons grade, so this entire thing is a political rather than a technical concern anyway.) For me, the most compelling reason to look seriously at the PRISM is that it can burn all the long-lived actinides in spent nuclear fuel, leaving only fission products with a roughly 300-year radioactive lifetime. This puts a very different spin on the eventual need for a geological repository – instead of something that will be designed to safeguard radioactive material for a million years (technically a very improbable idea), safeguarding waste for 300 years is a very different, and much less challenging, proposition.

Choose your desired pathway for spent fuel

The PRISM is not going to be a shoo-in, however. Politically the term ‘fast reactor’ reminds British people – and the government – of Dounreay, a fast reactor built in Scotland that operated as a prototype for many years but has had problems with waste management and decommissioning. Dounreay, however, whilst it was sodium-cooled, did not share many of the PRISM’s key engineering advances – in particular the pool versus loop coolant design, and metal versus oxide fuel. (Metal fuel expands if it overheats, shutting off the fission reaction and making a meltdown physically implausible.)

So don’t expect the PRISM to be selected as a preferred technology just yet. GE has a lot of work to do to convince the NDA and other stakeholders that the metal-fuelled fast reactor is a serious, and commercially-viable proposition. But I think the NDA’s latest statement is another nail in the coffin of MOX – and that has to be a good thing.

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7 thoughts on “Cross post from @Mark_Lynas: UK moves a step closer to #nuclear waste solution

  1. Huon

    This is miraculous stuff. One would think that as people in the UK, US, Australia and elsewhere understand the potential of this technology, they’ll increasingly embrace it.

    Reply
    1. Decarbonise SA Post author

      In my experience Huon it can change the entire direction of a conversation. It is quite incredible, I agree. The comprehensive work on the topic, “Plentiful Energy” by Till and Chang has just been published, available through Amazon. “Prescription of the Planet” provides a more accessible and still excellent introduction.

      Reply
  2. Denys Vlasenko

    > Metal fuel expands if it overheats, shutting off the fission reaction and making a meltdown physically implausible.

    You know enough about nuclear reactor operation to be aware that fuel CONTINUES TO HEAT UP even after fission reaction has stopped. Therefore, you know that quoted sentence is a lie.

    Reply
    1. Decarbonise SA Post author

      Denys,

      I have been over the framework for this blog with you repeatedly.

      Your own knowledge has been shown repeatedly to be completely inadequate for you to make definitive statements without providing supporting references. Once again, you have not done so.

      You have repeatedly been disinclined to attend to the very expert references on this technology that others including I have provided, so keep making statements that show off only your bias.

      I moderated this in purely as an example for others.

      The metal fuel is advantageous over the oxide fuel in regard to the passive shutdown. I do acknowledge, the statement you quote is incomplete, but calling Lynas a liar is just ridiculous. Further up the same article we find this more fullsome statement covering the same issues:

      The PRISM is a metal-fuelled fast reactor cooled by molten sodium. It operates at atmospheric pressure – meaning no expensive pressure vessel – and the characteristics of the fuel and the molten-sodium coolant (which conducts heat away from the core 90 times more effectively than water) make it fully passively-safe. (An early version, called the Experimental Breeder Reactor, was subjected to a loss-of-coolant flow experiment in 1986 – it duly shut itself down with no outside intervention.)

      Honestly Denys, you make my job easy by cherry picking so gratuitously and making such aggressive statements.

      Reply
      1. Denys Vlasenko

        > Further up the same article we find this more fullsome statement covering the same issues:
        >> The PRISM is a metal-fuelled fast reactor cooled by molten sodium. It operates at atmospheric pressure – meaning no expensive pressure vessel – and the characteristics of the fuel and the molten-sodium coolant (which conducts heat away from the core 90 times more effectively than water) make it fully passively-safe.

        And this is a lie (or if you prefer, “incorrect”) too. The more efficient heat conduction by metal coolant would not help one iota in Fukushima-like disaster.

        In Fukushima disaster:
        Were all reactors scrammed and fission reaction stopped?
        Yes.
        Was water efficiently cooling fuel rods?
        Yes. Entire reactor vessel was at the same temperature.

        If F1 reactors would have metal coolant, the situation with temperature wouldn’t be different at all. The cores would still melt down.

        Which means that metal coolant by itself DOES NOT make reactors passively safe.

        Reply
        1. Decarbonise SA Post author

          Denys,

          My blog is not a place for you to repeatedly express your ignorance while refusing to read up on the topics at hand. You clearly have no interest in learning anything and basing your comments from a position of knowledge. You are no expert in nuclear, not even close, a quick scan of your qualifications and employment make that much clear. Yet you see fit to keep contradicting actual experts. You were previously moderated. Now your comments are simply going straight to trash. I don’t want them to pollute my life any further.

          Just in case you would like to actually know about and understand IFR, the men who were chiefly in charge of designing it have just published a book going into great detail. It’s a good read, and talks in great detail about why what you have said is not true, is.

          Who should I believe? It’s a tough one…

          Reply
    2. john morgan

      Denys, do you understand that there is a difference between heat and temperature?

      While fuel continues to generate heat after a reaction is shut down for a time, in the IFR design the temperature does not rise because the heat is removed by passive means as fast as it is generated.

      Even when the reaction is running, and the reactor is producing vastly more heat, if the fuel temperature gets too hot it expands beyond the point where it can sustain a chain reaction. The reactivity drops, the rate of heat generation drops, and the fuel temperature settles to the point where heat production and heat removal exactly balance.

      There is no lie. But you show an obstinate determination to remain just ignorant enough to believe that there is.

      Reply

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