Reactor Theory (Nuclear Parameters)DOE-HDBK-1019/2-93CONTROL RODSIntegraland DifferentialControlRodWorthThe exact effect of control rods on reactivity can be determined experimentally. For example,a control rod can be withdrawn in small increments, such as 0.5 inch, and the change inreactivity can be determined following each increment of withdrawal. By plotting the resultingreactivity versus the rod position, a graph similar to Figure 9 is obtained. The graph depictsintegral control rod worth over the full range of withdrawal. The integral control rod worth isthe total reactivity worth of the rod at that particular degree of withdrawal and is usually definedto be the greatest when the rod is fully withdrawn.Figure 9 Integral Control Rod WorthRev. 0NP-03Page 51