gwd

GWd stands for gigawatt-day, a unit of energy equal to one gigawatt of power sustained for one day. It is equal to 24 gigawatt-hours (GWh) or 86.4 terajoules (TJ). This unit is commonly used in power-generation and nuclear engineering to express cumulative energy production or fuel burnup.

In nuclear contexts, burnup of fuel is frequently expressed as MWd/MTU (megawatt-days per metric ton of uranium) or GWd/MTU, indicating the amount of energy produced per unit mass of fissile material. GWd provides a convenient scale for high-output systems and long fuel cycles. For example, a reactor that has produced 100 GWd of energy per MTU has yielded 100 gigawatt-days of energy from each metric ton of uranium present in the fuel.

Notes: The GWd unit is not an SI unit; energy is also expressed in joules, watt-hours, or megawatt-days (MWd). Conversions are straightforward: 1 GWd = 24 GWh = 86.4 TJ.

Context: Used primarily in electricity generation and spent-fuel analysis; in academic literature and industry reports you may encounter MWd or GWd per MTU. The prefix indicates the scale of the energy quantity being described. See also burnup, MWd/MTU, and related energy units.