APPLICATION OF THE ROD-INSERTION METHOD FOR CONTROL ROD WORTH MEASUREMENTS IN RESEARCH REACTORS

Details of the rod-insertion method as applied for control rod worth m easurements in research reactors are presented. Sources of errors and corrections are discussed, particularly the effects of detector positi on, control rod interference, and flux redistribution. The analysis is supported by calculations to explain the physical phenomena involved. The method is applied to two TRIGA reactors, which differ significant ly in the characteristics of their control rods. The results show that the rod-insertion method is very quick and simple to apply, and suffi ciently accurate for practical purposes. The conclusions related to co ntrol rod interference and flux redistribution effects are also applic able to other methods for control rod worth measurements and to the ca libration of the nuclear detectors.