The amount of energy that has been generated from a unit of nuclear fuel; usually measured in megawatt-days per metric ton of initial heavy metal.

1. To be consumed in flames; to cause to be consumed in flames.
2. When something is completely destroyed by heat or fire, it burns up.

1. When people or things destroy something with heat or fire, they burn it up.
2. When something makes you very angry, it burns you up.