Office for Nuclear Regulation

Nuclear materials balance - 2014/15

Nuclear materials balance figures (also known as 'Material unaccounted for', and described in the industry as inventory differences) for the processing of civil nuclear material were published annually from 1977 onwards by UKAEA on behalf of the UK nuclear industry. Changes in the structure of the industry which followed from setting-up the Nuclear Decommissioning Authority (NDA) meant that figures for 2004/5 and 2005/6 were released, on behalf of the industry, by the then DTI. The transfer in April 2007 of operational aspects of the work of the UK Safeguards Office (UKSO) from DTI to the HSE/ONR means that the figures for 2006/7 onwards have been released, as a matter of routine, on the ONR website.

Site Plutonium
kg 1
kg 235U 2
tU 3
Natural U
tU 3
Depleted U
tU 3
(Dounreay Site Restoration Ltd)
+0.027 +0.318 <+0.001 +0.005 -0.011
(Research Sites Restoration Ltd)
+0.150 +0.017 NIL <+0.001 NIL
(Sellafield Ltd) 4
+0.954 +0.001 -0.298 NIL <+0.001
(Research Sites Restoration Ltd)
<+0.001 +0.001 NIL NIL NIL
(Sellafield Ltd)
-1.735 -0.002 +0.814 +0.016 -4.683
(Springfields Fuels Ltd)
NIL NIL -2.179 +22.222 +3.033
Capenhurst 5
N/A N/A <------------------- +2.309---------------->

+ apparent increase
- apparent decrease

  1. the figures for plutonium are the total amount of all plutonium isotopes.
  2. the figures for highly enriched uranium (HEU) are for the uranium 235 content of uranium enriched to above 20% of that isotope.
  3. low enriched uranium (LEU), natural uranium and depleted uranium cannot be used to make explosive devices. The published figures include these grades for the sake of completeness.
  4. for which Sellafield Ltd became the site licensee on 1 April 2008
  5. the figure for Urenco Capenhurst is a consolidated figure for Urenco UK Ltd, Enrichment Technology UK Ltd and Capenhurst Nuclear Services

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