Unlike Sizewell A the waste from Sizewell B and from the proposed Sizewell C&D are to be stored on site until at least 2130¹. This will turn the Sizewell area into a massive nuclear waste dump for at least the next 110 years. The site will contain over 100 times the amount of radioactivity released by Chernobyl.

I have previously looked at the total mass of waste that might be produced (see here for Sizewell B and here for SIzewell C&D). Now I want to have a look at what that means in terms of radioactivity.

There are many radioactive fission products in nuclear waste, but I am going to concentrate on one isotope in particular – Caesium-137 (Cs-137). The reason for this is that it is produced in reasonably large quantities, has a half-life of 30 years and is easily absorbed by the human body. For this reason, it is the Cs-137 which dictates the exclusion zones around Chernobyl and Fukushima.

The data is based on my previous posts.

In figure 1 have have shown an estimate of the total amount of waste Cs-137 in storage compared to that of Chernobyl.  Since in a typical reactor one third of the fuel is replaced a year then three years waste is equivalent to the Cs-137 content of the reactor core. The amount of Cs-137 in spent fuel ponds therefore quickly exceeds that in the reactor.

How Will It Be Stored

The spent fuel at Sizewell B is currently in cooling ponds although they plan to transfer it to ‘Dry Storage’². However, it is planned to store the waste from Sizewell C in cooling ponds until at least 2130¹. It is generally acknowledged that dry storage is much safer than storage in cooling ponds since cooling ponds are much more vulnerable to terrorist attack or leakage leading to fires^3,4.

EDF have admitted themselves¹ that the reason for keeping the spent fuel for Sizewell C in cooling ponds is that it is ‘too hot to handle’⁵. (Edit: At a recent consultation event I was told that this is incorrect  and that the reason why dry casks were not being used was not that the increased decay heat but the fact that they did not know if the fuel rods would disintegrate!).

I have been unable to find any spent fuel pond larger than those proposed at Sizewell and Hinkley. The three Dresden plants in the USA have a total of 11,602 spent fuel rods containing 2,146T of spent fuel. The total activity is given as 350,380,400 curies (1.3×10¹⁹Bq). However the fuel is split between three different spent fuel pools while that at Sizewell C&D will be going to one spent fuel store. Sizewell C&D will have fewer fuel rods (6800) but the fuel is of higher burnup and therefore more radioactive.

¹ Spent Fuel Management – EDF Energy Perspective,EDF Energy March 2012 (http://www.nuleaf.org.uk/nuleaf/documents/Nuleaf_presentation_09032012_final.pdf)

² Managing spent fuel at Sizewell B, EDF ENergy (http://www.british-energy.com/documents/Spent_Fuel_brochure.pdf)

³ Spent Nuclear Fuel Pools in the U.S.:Reducing the Deadly Risks of Storage, Robert Alvarez, Institute for Policy Studies, March 2011 (http://www.ips-dc.org/files/3200/spent_nuclear_fuel_pools_in_the_us.pdf)

⁴ Safety and Security of Commercial Spent Nuclear Fuel Storage, Board on Radioactive Waste Management, NATIONAL RESEARCH COUNCIL OF THE NATIONAL ACADEMIES (http://www.nap.edu/openbook.php?record_id=11263&page=R1)

⁵ Nuclear super-fuel gets too hot to handle, New Scientist 2008 (http://www.robedwards.com/2008/04/nuclear-super-f.html)

⁶ Spent Nuclear Fuel Pools in the U.S.: Reducing the Deadly Risks of Storage, Robert Alvarez Institute of Policy Studies, May 2011 (http://www.ips-dc.org/files/3200/spent_nuclear_fuel_pools_in_the_us.pdf)