Simple past tense and past participle of scram.(verb)
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Use "scrammed" in a sentence
"Vermont Yankee "scrammed" - automatically shut down Thursday, Aug 30th in the afternoon."
""scrammed" -- or went into automatic shutdown -- when a problem developed with equipment in the switchyard where it connects to the power grid."
"After the reactors "scrammed"—meaning the nuclear reaction was stopped—they still had to cool down before inspectors could get inside the reactor-containment buildings."