In PWRs - a different LWR system - control rods are withdrawn from the core, and the control is acheived with soluble B-10 in the coolant (which is buffered with LiOH) to maintain a pH above 6.9 or perhaps closer to 7.1 -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.
the repeated use of the same word or word pattern as a rhetorical device. the reversal of the normal order of words. the use of a word in a sense opposite to its normal sense (especially in irony) the juxtaposition of contrasting words or ideas to give a feeling of balance.