United States Nuclear Regulatory Commission - Protecting People and the Environment

Excursion

A sudden, very rapid rise in the power level of a reactor caused by supercriticality. Excursions are usually quickly suppressed by the moderator temperature coefficient, the fuel temperature coefficient, or the void coefficient of reactivity (depending upon reactor design), or by rapid insertion of control rods.

Page Last Reviewed/Updated Thursday, November 20, 2014