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A Very Quick Administration Update and Nuclear Energy Concluded
Dear Members,
As I was writing this article in February would still be somewhat precipitous to start trying to write in greater detail about what the administration here’s going to be doing about critical minerals. With little clarity on so many fronts, including that, it would, to say the least, be foolhardy.
I suppose it is, though, worth noting a couple of things that have recently hit the mainline press: Greenland and Ukraine.
In the first instance, I believe it’s safe to say that access to “rare earths” constitutes one term in the wider security “equation” around the island that Mr Trump is seeking to solve. In the second instance, I also saw it reported by the Financial Times that the president said: “ … he wanted a deal granting the US access to Ukraine’s rare earths resources in exchange for military and economic aid to Kyiv as it struggles to halt Russia’s invasion.” 1
More updates will be forthcoming as/if the picture(s) become clearer and the details come more into focus.
In the meantime, I should, this month, like to start to conclude our look at “matters nuclear”. Last month, I looked very briefly at the three different “categories” of fission reactors: water, fast neutron and molten salt. And some of the metals they all use. This month, I shall look further at the different types of nuclear reactor, how they work, the different metals they use and why they are used.
To kick off with, a quick reactor refresher course! Water: These reactors come in two “flavours” – pressurised water and boiling water. In both, water is the coolant that carries the heat away from the reactor. However, in the former, preventing it from actually boiling, the water is kept under high pressure and, then, transferred to a separate steam generator to create steam. In the latter, the water is allowed to boil in the rector core, produce steam and, then, drive the turbines.
Fast neutron: Also known as “fast breeder”, in these reactors fast neutrons are used to sustain the fission chain reaction (And, this being the case, there’s no need for a neutron moderator as the neutrons are already zipping about fast enough already!) Perhaps the most significant difference between these and water reactors is that their use of molten metals, such as either lead or sodium, as a coolants, not water.
Molten salt: As the name implies, these reactors use molten salt, either as a coolant or fuel, or, indeed, both. That said, however, there are currently, that I know of, no working commercial molten salt reactors. And, whilst conceptually they are a favourite of many, there is also skepticism, amongst other things, as to both their viability and safety. Here in the US, the Oak Ridge National Laboratory did build such a reactor (the Molten Salt Reactor Experiment) in the late-‘60s (it was closed down in December 1969) 2 and none has been built since.
Having outlined the differences in how each category of reactor works, the differences in the metals they use should now be a little clearer. I’ve already mentioned the use of zirconium in the cladding of fuel rods. Another metal to be found in water reactors, this time in the fuel pellets, is the rare earth gadolinium. With its high neutron absorption cross section, as the nuclear fuel burns, gadolinium (as a nitrate or oxide) is used as a “burnable poison” to help control the fission chain reaction.
While sodium has been the metal most usually used as a coolant in fast breeder reactors, lead as a coolant has also been known to be used – certainly in some Soviet/Russian nuclear-powered submarines. A lead-bismuth eutectic (lead – 44.5%, bismuth – 55.5%) was also used as a coolant in Soviet Alfa-class nuclear-powered submarines. (Currently, developers are also looking at both lead and lead-bismuth eutectic as possible coolants in commercially viable small modular reactors SMRs.)
Were anybody interested (as are some SMR developers), once again, in building an efficient, functional molten salt reactor, it would be interesting to see if, as did the Molten Salt Reactor Experiment, they might use a lithium and beryllium fluoride-based molten salt coolant.
So, I think that’s it (for the time being) on fission.
What about fusion?
As you can imagine, fusion is a totally “other” kettle of fish. Not least because there appears to be a significant variety (as least five main ones that I know of) in the approaches to solving the fusion “problem”.
And, whilst there has been some degree of success recently, a commercially viable way of generating electricity using fusion stubbornly remains a (very) long away.
Of the different approaches, the two main are: inertial confinement and magnetic confinement. Setting aside inertial , magnetic confinement, as its name implies, relies upon the use of a super-strong magnetic field to hold the plasma in place within a confined space.
However, one significant issue is generating such a magnetic field. And this is where ReBCO superconductors have the potential to prove quite handy. What is ReBCO? ReBCO is the acronym for rare earth barium copper oxide, where the specific rare earth might be any one of following: europium, gadolinium, lanthanum, neodymium, samarium or yttrium. The attraction of ReBCO superconductors, in addition to being able to create hugely strong magnetic fields, is that they are HTS (high temperature superconductors): i.e. they do not have to be cooled down to near absolute zero to work. This is potentially extremely important for those hoping to make the dream of commercially viable nuclear fusion a reality.
Having kicked off my look at fusion in this missive, I shall continue in the same vein next month, together with taking a concluding look at fission by reviewing quickly where things stand currently with SMRs: the number of different technologies being pursued is truly surprising. And interesting.
Looking a little further forward, I believe the nuclear “theme” could see some interesting developments this year, on Earth and in space. Not least as the debate on climate risk management (CRM), together with wind and solar, continues and countries casting about for high-capacity alternatives to oil/gas.
I wish, though, if only for a few days, that Cleveland Heights could become just a little “HT”. I am just getting a wee bit bored of this particular winter!
Maybe it will as I wish you farewell ‘til next month.
I remain, as always,
Yours
Tom
PS I have to say I felt a little chuffed recently. I got an invitation from The Royal Society for Asian Affairs (of which I have been a member for many years) to pen a piece on Laos: I was there mucking about some 35 years ago. I’m only sad that I’ve not been back since, it would be great to be able to write a piece for The Crucible on what’s going on there on the “minor metals” front. Pip, pip! tb
©2025 Tom Butcher
1 Financial Times: Donald Trump wants Ukrainian rare earths deal in return for US military support, February 3, 2025.
2 Bulletin of the Atomic Scientists: Molten salt reactors were trouble in the 1960s—and they remain trouble today, June 20, 2022.
