Sunday, October 24, 2021

Nuclear Theddlethorpe 05

In Part 03 of this blog series about the proposal for a Geological Disposal Facility (GDF) for high and intermediate level nuclear waste at Theddlethorpe or some other location in eastern Lincolnshire, I outlined the geology.

Let's have a quick recap and reminder to help people make their arguments. The purpose of a GDF is to ensure that the waste and any radioactive particles that eventually escape the containers do not reach the biosphere at the surface for a long time, 100,000 years or more, despite climate change, sea level rises, glaciations or earthquakes.

Rock suitable to store nuclear waste must be impervious. That means that water must not be able to flow through it. Chalk, limestone and sandstone are as much use as a wet sponge but clay, shale and mudstone are good. It's not that water can't flow through such rock, given enough time, but the rate is measured in millimetres per year so a few hundred metres of such rock does the job.

Such rocks do occur under the Lincolnshire Marsh and in the inshore area off the coast. There's the Jurassic age Oxford Clay. This is the layer that the French propose to use, but it is much thicker in France. More usefully there is the older and lower Mercia Mudstone Group of Triassic age. This would be the most likely target for a depository here. Just off the coast of Cumbria this same rock is much thicker and so better suited there. It is close to Sellafield, as it conveniently happens.

The most important aspect of Lincolnshire's geology is the existence of oil and gas at various horizons in the Jurassic, Triassic and underlying Carboniferous rock, which also contain the Coal Measures. In some places it occurs in high enough concentrations to be exploited in today's commercial situation and with today's technology. In the far distant future, under unforeseeable economic conditions and with technologies that we have no knowledge of, a future civilisation may seek to exploit these fossil carbon resources and in so doing inadvertently breach the waste depository's barriers that were designed to stay unpenetrated for hundreds of thousands of years.

That's why a GDF must not be built at Theddlethorpe or anywhere else on the Lincolnshire Marsh. It is our duty to place our dangerous waste where there is the least likelihood of it posing a danger to our far descendants. All other arguments are secondary.


Some people argue that since a GDF can never be 100% secure, it should not be built anywhere. But don't let the perfect be the enemy of the possible. The nuclear waste is currently in temporary storage and in various states of security. Some of it may be an accident waiting to happen. Delay in permanent burial only adds to the risk of a near-term accident. Delay also pushes the problem on to the next generation, who did not agree to the creation of the waste n the first place and should bear no responsibility for it's care. We must deal with our problem, now, and in the best way we can conceive. 

There is little reason for delay. A good enough site has been identified (the Mercia Mudstone Group rocks of the Irish Sea Basin, inshore south-west Cumbria). The whole process that RWM are engaged in just creates a ten or more year delay in spending the billions of pounds required to construct a GDF, and is, of course, the Treasury's preferred option as it makes the spending somebody else's problem, while their backs are covered in case of accident by appearing to be addressing the matter now.

An often stated argument is that the GDF should be sited somewhere remote. This is a poor argument. It implies acceptance of the idea that a GDF might not be safe. If it isn't safe it cannot be built. Anywhere. Nowhere remote enough for an unsafe facility exists. Even somewhere that looks remote today may not always be so.

There are good geological reasons why the Outer Hebrides would be a suitable place. The Lewisian Gneiss is our oldest, hardest, most stable, most impermeable rock. It is similar, geologically, to the sites chosen by Finland and Sweden for their depositories, unlike the soft-rock options available in England and apparently favoured by RWM.

People may consider the Outer Hebrides to be remote (the good folk of Stornoway probably have a different perspective) but it may not always remain so. If global heating continues on its current trajectory (and there's precious little evidence that it won't) then we may see a rise in average global temperatures of 3 to 5 degrees. The west coast of Scotland may become the 22nd century's New Riviera, the most densely populated part of the world, with the EU Parliament relocating to Stornoway once the re-United Kingdom's membership application has been accepted.

Thailand Today, Tobermory Tomorrow

See also previous part to this series:



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