Scram

A scram or SCRAM is an emergency shutdown of a nuclear reactor – though the term has been extended to cover shutdowns of other complex operations, such as server farms and even large model railroads (see Tech Model Railroad Club). In commercial reactor operations, this emergency shutdown is often referred to as a "SCRAM" at boiling water reactors (BWR), and as a "reactor trip" at pressurized water reactors (PWR). In many cases, a SCRAM is part of the routine shutdown procedure as well.