When they were in the design phase for the first reactor systems, negotiating contracts, the potential vendors for main coolant pumps asked for a specification on allowed leakage.
"There must be zero leakage," said Rickover. The vendors responded, "Every pump made has some leakage! You have to give us some maximum allowable amount to shoot for."
"Alright," he responded, "the maximum allowable leakage must be less than one thimble-full per century."
One of the great honors of my life was being publicly lauded (along with another reactor operator) for excellent performance by Hymie over the 1MC, when he gave his end-of-drills critique during sea trials on the Seahorse. That was after I had gotten into a (very brief!) argument with him, when my watch's drills were over, about who could relieve me. LOL!