Adjuster Rod Aging in Darlington's CANDU Reactors: Behaviour, Measurement and Implications for Operation

Abstract

Presented are the simulation methodology and the results of reactivity worth measurements performed on adjuster rods in an equilibrium Darlington (large CANDU) core. Simulation had predicted the effect of neutron irradiation on device properties for adjuster rods of different construction and in-core residence times. The expected difference in the rate of irradiation-induced reactivity worth loss in rods containing titanium versus all stainless steel has been confirmed by comparing measured reactivity values for adjuster rods that differ in material construction and in-core service times. Also discussed are the method for conducting the measurements, and the accuracy of pre-simulation results.