In PWRs - a different LWR system - control rods are withdrawn from the core, and the control is acheived with soluble B-10 in the coolant (which is buffered with LiOH) to maintain a pH above 6.9 or perhaps closer to 7.1 -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.
Thought patterns (or patterns of organization) are signaled using transitions to show the logical relationship between the ideas in a paragraph, passage, or textbook chapter. The time order thought pattern generally shows a chain of events. The actions or events are listed in the order in which they occur.