Units for nuclear fuel burnup

The most common units for nuclear fuel burnup are $MW_{th}d/tonne$. A burnup of $5 MW_{th}d/tonne$ would describe a fuel that has operated at some power level over a period of time. For example,

  • $1 MW_{th}/tonne$ for 5 days,
  • $5 MW_{th}/tonne$ for 1 day, or
  • $25 MW_{th}/tonne$ for 0.2 days.

Since specific power may be measured in other units, these could also be written as:

  • $1 W_{th}/g$ for 5 days,
  • $5 W_{th}/g$ for 1 day, or
  • $25 W_{th}/g$ for 0.2 days.