In PWRs - a different LWR system - control rods are withdrawn from the core, and the control is acheived with soluble B-10 in the coolant (which is buffered with LiOH) to maintain a pH above 6.9 or perhaps closer to 7.1 - 7.4 for purposes of minimizing the accumulation of crud (metal corrosion products) on the fuel.
Rhetorical patterns have an additional function of helping writers to organize information in ways their readers can understand easily (425). Another term for these patterns is topoi (commonplaces). Many of these topoi are useful in numerous situations.
A figure of speech or rhetorical figure is figurative language in the form of a single word or phrase. It can be a special repetition, arrangement or omission of words with literal meaning, or a phrase with a specialized meaning not based on the literal meaning of the words. There are five main figures of speech: simile, metaphor, hyperbole, personification and synecdoche.