Alert

The NRC is shutdown due to the lapse in appropriations. Exempted activities to maintain critical health and safety activities and progress on critical activities, including activities outlined in Executive Order 14300, as described in the OMB Approved NRC Lapse Plan will continue.

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 Tuesday, March 09, 2021