Office for Nuclear Regulation

This website uses non-intrusive cookies to improve your user experience. You can visit our cookie privacy page for more information.

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
HEU
kg 235U 2
LEU
tU 3
Natural U
tU 3
Depleted U
tU 3
Dounreay
(Dounreay Site Restoration Ltd)
+0.027 +0.318 <+0.001 +0.005 -0.011
Harwell
(Research Sites Restoration Ltd)
+0.150 +0.017 NIL <+0.001 NIL
Windscale
(Sellafield Ltd) 4
+0.954 +0.001 -0.298 NIL <+0.001
Winfrith
(Research Sites Restoration Ltd)
<+0.001 +0.001 NIL NIL NIL
Sellafield
(Sellafield Ltd)
-1.735 -0.002 +0.814 +0.016 -4.683
Springfields
(Springfields Fuels Ltd)
NIL NIL -2.179 +22.222 +3.033
URENCO
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

Site contacts