London, (Parliament Politics Magazine) – For decades, nuclear power has been a subject that most people (and therefore a majority of politicians) have refused to discuss, other than to talk about nuclear waste and power plant accidents such as Chernobyl and Fukushima.
While climate change has captured the news agenda, and such alternative fuels as hydrogen have been promoted as complementary to renewable energy sources such as solar-, wind- and water-powered installations, the reality is that carbon-emitting oil, coal and gas are still needed to meet more than half of the world’s present demand for electricity. This is mainly because renewables are dependent upon the sun shining, the wind blowing and water flowing at the right time; and demand is as constant as these factors are intermittent.
Similarly, hydrogen is an example of a “clean” fuel, but it is important to note that, currently, the electrolysis required to produce it takes up to 2.4 times as much power as the hydrogen energy it generates. This means that we will need to continue to rely on other carbon-free ways to make enough electricity to keep the lights on when renewables cannot; and to create alternatives that, while they undoubtedly have their uses (such as for aviation and heavy goods vehicles), consume more power than they emit.
There is only one energy source that meets these requirements, and that is nuclear power: in time, we will see nuclear fusion become a clean energy source that is readily available and does not leave a radiation footprint like that produced by nuclear fission – the process used by all the world’s nuclear power plants today. However, for the time being, nuclear fission is the answer: and, during the past several years, the private sector has explored ways of doing it better.
Traditional nuclear power stations burn Uranium as a solid compound (U₃O₈) in the form of Uranium Oxide pellets which, in the event of overheating to the point of meltdown, release radioactive gases into the atmosphere often over wide areas. In gaseous form, Strontium-90, Caesium-137 and Iodine-131 isotopes are particularly carcinogenic and are the principal causes of disease and fatalities from the fall-out of nuclear weapons and power plant accidents.
All nuclear power stations require a coolant both to maintain an acceptable temperature for their core, and to capture and transfer the heat released by fission for use in electricity generation. In most cases, the coolant is stored in an artificial state: for example, water is kept at a pressure of approximately 300 bars in order to prevent it from boiling at its normal temperature; carbon dioxide, on the other hand, is simply too capacious and is also much less efficient at transferring heat.
Any rupture of the containers of these coolants caused, for example, by the meltdown and subsequent explosion of the nuclear core instantly (and catastrophically) converts the coolants back to their normal state with commensurately devastating effect. The physics of an inherently dangerous nuclear core cooled by another chemical (usually) artificially altered in order to stabilise it is thus clearly that of one potentially explosive substance surrounded by another.
In order to prevent any such accident, nuclear power stations now have substantial safety features that minimise the risks of the spread of any fall-out from either the meltdown of their cores or the rupture of their coolant containers, or both. These measures contribute substantially to the construction cost of nuclear facilities to the extent that, until relatively recently, nuclear power stations were considered to be too expensive to build and commission in comparison to those powered by fossil fuels such as coal, gas or oil.
By contrast, molten salt (or Uranium Fluoride, UF₄) as a fissile fuel can be cooled by an unpressurised salt solution and, instead of emitting dangerous gases, all radioactive material remains in liquid form. This means that molten salt reactors can operate at much higher temperatures so that they burn most of the actinides that solid-fuelled reactors leave behind as waste; and they can store heat (again, in a salt form) for long periods with minimal deterioration.
For the purposes of clarification, a solid fissile-fuelled nuclear reactor generates electricity for the grid continuously and at a constant rate whether or not its output is required, while a molten salt fissile-fuelled reactor can both divert its output to heat storage when demand is low; and generate up to double its normal operating capacity when demand is high.
The use of molten salt in nuclear reactors reduces their construction cost because fewer safety measures are required, and this makes their nuclear-generated electricity much cheaper. Further, it will be possible to process existing nuclear waste into a salt solution that can be burnt in these new-style reactors, thus helping to clean up the stockpiles of waste produced since the 1950s. Finally, and on a smaller scale, molten salt reactors can become stand-alone purpose-built Uranium batteries that generate enough power for industrial sites such as steel and paper mills for up to fifteen years at a fraction of the cost of power provided by the electricity grid.
That is how to do nuclear better, safer and cheaper: and it may even help to save rather than pollute our planet.
Ian Lyon is a former Portsmouth City Councillor and Parliamentary candidate in 2004. He works principally as a management consultant, and had been involved for the past six years with Moltex Energy Ltd, a leading proponent and innovator of molten salt nuclear fission.