light relief a change from our inevitably lengthy recent blog postings (hey - we could have published the commentary on Gordon Brown's Chatham House speech and the European Commission's internet and media censorship policy development plan as single posts) , so here is something a bit shorter:
An item from The Times caught our eye today via their syndication feed via Bloglines.
Sellafield operator fined £500,000 for leak
The operator of the Sellafield nuclear reprocessing plant in Scotland has been hit with a second fine following an 80,000 tonnes radioactive leak....
A couple of questions sprang to mind:
- Since when was Sellafield in Scotland ?
- How much radioactive nitric acid really leaked from the THORP nuclear re-processing plant in Sellafield ?
This inaccurate story has already been propagated via the internet e.g. to the Google news service search for "Sellafield Scotland"
Clicking on the link pulls up a version of the story where Sellafield is now correctly located in Cumbria.
However 80,000 of nitric acid is an awful lot, even for a leak which went unnoticed for months.
What is the density of nitric acid ? a few seconds with the Google search engine gives the answer - pure fuming nitric acid, as used as a rocket fuel oxidiser has a density of about 1.5 ×10 3 kg/m 3 i.e. 1.5 tonnes per cubic metre.
Concentrated nitric acid is usually around 70% pure, the rest being water with a density of 1 tonne per cubic metre i.e. the density of 70% nitric acid is 1.42 x 10 3 kg/m 3 i.e 1.42 tonnes per cubic metre
Density is mass divided by volume, so 80,000 tonnes of nitric acid, with a negligible mass of dissolved uranium and plutonium - obviously not negligible in respect to its radioactivity) would have a volume of 56,388 cubic metres.
This is equivalent to the displacement of water of an ocean going ship, the size of a large oil tanker or an aircraft carrier
Sellafield firm fined over leak
The leak occurred at the Thorp complex at Sellafield
The operator of the Sellafield nuclear reprocessing plant has been fined £500,000 following a radioactive leak.
About 83,000 litres of acid containing 20 tonnes of uranium and 160kg of plutonium escaped from a broken pipe into a sealed concrete holding site.
i.e. about 120 tonnes of nitric acid
Therefore 20 tonnes of dissolved uranium (less than 5 % of which would actually have been radioactive, because this comes from are re-processed fuel rods), and 160Kg of plutonium (all of which is radioactive) is a significant figure in this case.
Another BBC report gives the dimensions of the concrete containment tank as
The cells, which are 60 metres long and 20 metres high, are not accessible to staff and no-one was exposed to radioactive material.i.e, even if had been full to the brim with nitric acid, there could only have been about 1700 tonnes,
83,000 litres would be equivalent to a couple of petrol tanker vehicles, which typically have a volume capacity of between 40 to 60 cubic metres i.e. 40,000 to 60,000 litres. The fuel capacity of a family car is around 40 to 60 litres.
Is the supposed pressure to pump out "news" stories reducing the amount of fact and sanity checking which mainstream media companies are doing these days ?
You do not have to be an engineer or a scientist, or even especially numerate, to be able to sanity check the details of a story for the difference between the volume of a couple of road haulage tankers, and that of a very large ocean going ship, especially when the story concerns something as important as leaks of radioactivity.
We will be bearing this story in mind the next time that The Times or any Murdoch owned newspaper reports about "dirty bomb" threats.