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 published, 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 means that the figures for 2006/7 onwards are published, as a matter of routine, on the HSE website.
| Site | Plutonium kg 1 | HEU kg U-235 2 | LEU t U 3 | Natural U t U 3 | Depleted U t U 3 |
|---|---|---|---|---|---|
| Dounreay | -0.076 | +2.434 | +0.003 | NIL | -0.026 |
| Harwell | +0.004 | +0.003 | <+0.001 | NIL | <+0.001 |
| Windscale 4 | NIL | NIL | NIL | NIL | NIL |
| Winfrith | <+0.001 | <+0.001 | <+0.001 | <+0.001 | <+0.001 |
| Sellafield | -2.557 | <-0.001 | -0.593 | <-0.001 | +0.161 |
| Capenhurst (Sellafield Ltd) 5 | NIL | NIL | +0.075 | <+0.001 | -0.015 |
| Springfields | NIL | NIL | -1.262 | +9.212 | -1.167 |
| Urenco Capenhurst 6 | N/A | NIL | |<------------ (+0.390) ------------>| | ||
+ 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 0% 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 of material for the sake of completeness.
4 for which Sellafield Ltd became the site licensee on 1 April 2008
5 operated by Sellafield Ltd for the year concerned
6 the figure for Urenco Capenhurst is a consolidated figure for Urenco UK Ltd and Enrichment Technology UK Ltd