NOTE: Rod Withdrawl Sequence A Group to Base Load Operation Position of 25.5 inches E Group to 50 inches, if required, then D Group to 58 inches, if required, then C Group to 58 inches, if required, then B Group to 50 inches, if required, then X Rod to 58 inches, if required.
A tolerable SUR will be dependent on the prevailing "noise spikes" indicated by the SUR meters. For information purposes, the following three points are listed from the graph of average SUR versus reactivity:
Reactivity Average SUR 8 cents 0.21 16 cents 0.55 24 cents 1.05
Approximately uniform reactivity increments of either <=8 cents or <= 16 cents for startup rod withdrawal are defined by the sequence of rod positions below.
Group A Group E Group D Group C, B 8c 16c 8c 16c 8c 16c 8c 16c 0.0 * 0.0 * 0.0 * 0.0 * 2.5 2.0 4.0 2.0 5.0 * 4.0 * 6.0 * 4.0 * 6.0 5.5 7.5 5.5 7.0 * 7.0 * 9.0 * 7.0 * 8.0 8.0 10.0 8.0 9.0 * 9.0 * 11.0 * 9.0 * 9.5 1" 2" 1" 2" 9.5 10.0 * pulls pulls pulls pulls 10.0 * 1/2" 1" | | | | 1/2" 1" pulls pulls | | | | pulls pulls | | | | | | | | | | | | | | | | | | \|/ \|/ \|/ \|/ \|/ \|/ | | 27.0 * 30.0 * 34.0 * | | 28.5 31.5 35.5 \|/ \|/ 30.0 * 33.0 * 37.0 * To Base 31.5 34.5 38.5 Load 33.0 * 36.0 * 40.0 * Position 35.0 38.0 43.0 37.0 * 40.0 * 46.0 * 40.0 42.0 50.0 43.0 * 45.0 * 58.0 * 48.0 50.0 58.0 * 58.0 *