control rod

English Thesaurus

1. a steel or aluminum rod that can be moved up or down to control the rate of the nuclear reaction (noun.artifact)

hypernym	:	rod,
definition	:	a long thin implement made of metal or wood (noun.artifact)

part meronym	:	nuclear reactor, reactor,
definition	:	(physics) any of several kinds of apparatus that maintain and control a nuclear reaction for the production of energy or artificial elements (noun.artifact)