Originally I was going to write something just about Fukushima Unit 4 Spent fuel pond. There has been some reports about ‘the end of civilisation’ if the fuel pond fails. I thought this is a bit of an exaggeration.

To put it in perspective I worked out what the area would need to be evacuated if all the caesium 137 in the fuel pond was deposited evenly over a certain area at 1MBq/m² -the evacuation levels are given by the IAEA⁴. This is extremely unlikely to happen – not all the Caesium would be lost and it would not be evenly distributed. However, it does give some sort of perspective of what the dangers are.

Having done this I have also included the amount of Caesium-137 which will be stored in a single fuel pond at Hinkley and Sizewell if the new reactors are built. I have also shown the land area of the UK and Europe for comparison. Note that the fuel ponds at the proposed Hinkley and Sizewell reactors will contain over 42 times that amount of Cs-137 that was in the reactor at Chernobyl and 85 times that amount that was released during the accident.

¹ Cs-137 Inventories in Spent Fuel, This Blog (http://www.plux.co.uk/cs-137-inventories-in-spent-fuel)

² Xenon-133 and caesium-137 releases into the atmosphere from the Fukushima Dai-ichi nuclear power plant: determination of the source term, atmospheric dispersion, and deposition, A. Stohl et al, Atmos. Chem. Phys., 12, 2313–2343, 2012 (http://www.atmos-chem-phys.net/12/2313/2012/acp-12-2313-2012.pdf)

³ Chernobyl Disaster, WIkipedia (http://en.wikipedia.org/wiki/Chernobyl_disaster#Radioactive_release)

⁴ IAEA says Fukushima fallout warrants more evacuation, New Scientist, 2011 (http://www.newscientist.com/article/dn20324-iaea-says-fukushima-fallout-warrants-more-evacuation.html)