Radioactivity at Hinkley

The City lads are worrying a bit about this report of uranium in the soil at Hinkley.

I\’m not competent to judge the method that this would be Green MEP has used to do his calculations. But I\’d just point to two things:

1) However, this value of 330Bq/kg is for high-uranium granite areas like Dartmoor and Aberdeen, so this statement is highly misleading. 330Bq/kg is far too high for normal soils (Eisenbud and Gesell 1997, NCRP94 1981). Data is available for background Uranium in the UK from the Environment Agency 2007 report (Beresford et al 2007), as the authors must have known. The range of Uranium activity given in that report for the area is 1.6 to 2mg/kg or about 18-24Bq/kg. The map of Uranium levels from Beresford et al 2007 is reproduced in Fig 2. High levels above 100Bq/kg are only indicated in the granite areas. We conclude (conservatively) that the levels of Uranium (below 0.4 m depth) in the EDF survey site are up to 40Bq/kg greater than expected.

That is, that if the contamination by enriched uranium is exactly as he\’s calculated it to be, the power station has made one corner of Somerset as much as 10% more like another corner of Somerset: radiation levels at Hinkley Point have risen by 10% (ish) of the natural radiation levels on Dartmoor.

Decide for yourself how big a problem this is.

2) an increase of 40Bq/kg over the background natural uranium represents about 10 tonnes of uranium which must have been added from the historic releases

Again, if his calculations are correct, 10 tonnes of uranium has been deposited on the site.

Hmm.

A 1,000 MW coal-burning power plant could have an uncontrolled release of as much as 5.2 metric tons per year of uranium (containing 82 pounds (37 kg) of uranium-235) and 12.8 metric tons per year of thorium.[17]

We\’d have to play around a little with the numbers (note, he does not say 10 tonnes U235, he says 10 tonnes enriched uranium, and we don\’t know what the level of enrichment with U 235 is) but it\’s not immediately apparent that those releases from a nuclear power plant are higher than those from a coal fired one. for do note, those coal figures are annual ones and Hinkley B has been running for 34 years now.

It\’s true that there shouldn\’t be such emissions. And it may be true (as I say, I don\’t know) that our Green friend has shown that there are emissions which there shouldn\’t be.

But by his own calculations, we can see that even if he is right, it\’s not actually important, the level of contamination. Even if we reject hormesis and so on, he\’s shown that the danger is around 10% of the danger of moving 30 miles to Dartmoor.

9 comments on “Radioactivity at Hinkley

  1. Let’s remeber that a bequerel is a tiny unit. It’s one atom decaying per second.
    So is 40bq / kg a lot?
    Depends on how heavy you are, maybe. The human body gives out 4,000 bq from natural potassium alone, which I’d say was roughly 50bq/kg.
    Of course, “Human Beings more radioactive than Power Station” might not be a helpful headline.

  2. Yes, even a curie isn’t considered a huge amount of activity and that’s 37 billion Bq. You can expect to get about 1 mSv a year from background sources. This is about 80 mJ whole body dose in a year or about 5 × 10^17 eV. Uranium’s an α-emitter with energies in the 5 MeV range. I doubt this is a significant problem

  3. A Beqerall is a buggerall which unfortunately charlatan Busby doesn’t realise he is.

    Anyone wanting to check his credibility ring the press office at Liverpool Uni and see how enraged they are.

    Of course there is a load of enriched uranium around the A station at Hinkley. The source is actually in public documents (published on goverment websites). If the learned proffessor hasn’t done enough research to find the source of this information which if you use the right search terms comes up on google.co.uk as the fourth hit (I suspect EdF et al are keeping this quiet to knock down poor shoddy research which isn’t balanced) then credibility lessons.

    Tim adds: Well, come on then, what is the doc? What are the correct search terms?

  4. That really does not make sense.

    Fresh nuclear fuel is solid and contained. For Magnox [like Hinkley A] the fuel is a uranium metal rod clad with a magnesium alloy. For Hinkley B it’s uranium dioxide pellets contained in stainless steel tubes. To get them dispersed into the ground they’d have to be ground up and ploughed in.

    Now spent fuel is kept in water and the fuel cladding can leak, and then this contaminated water could leak, but if they’d had tons of uranium dissolve and leak away the uranium would be a tiny concern next to the ceasium which is both much more likely to escape from the fuel and much, much more radioactive. You could not do a survey and find 40bq/kg and not notice this.

    So it didn’t come from the powerstation. Assuming it isn’t natural [frankly, I'd guess this is natural origin] it likely came from somewhere uranium is handled as liquid, gas or machined to produce dust. Something easy to loose. Can’t think of anywhere around there that fits the bill. There’s a Royal Ordnance factory in Bridgewater; wonder if they ever handled depleted uranium?

    Anyway, if they want to prove it’s not natural, they should get the isotopics analysed, it’s rare that material that’s been processed escapes without some changes.

  5. There’s another issue that may be playing a part – dense particle concentration.

    Uranium is incredibly dense (it’s why the chaps in camoflage like to use it in their anti-tank shells). If the stuff is scattered across the landscape as dust particles then it is natural to assume it will immediately become part of the soil. And just as soil is subject to the actions of things like wind, rain and even human activity (plough etc) so will be the uranium. But since it is dense, uranium will behave differently to other materials in the soil. More particularly, there is a chance it will concentrate in certain areas.

    If the sampling was not done properly it is possible (and I stress the caveat) the sampling could be biased which would, in turn, skew the results of the survey and hence its conclusions.

  6. Pingback: Radioactivity | ZuiDot

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