Neutronic Analysis of an In-Core co-60 Production in CANDU6 Reactor

Abstract

In this study, an innovative way of producing Co-60 in CANDU6 reactors is introduced and the neutronic analysis is performed. Unlike the conventional Co-60 production method, the central fuel element in the standard fuel bundle is replaced by a Co-59 target and Co-60 is obtained after the fuel bundle is discharged. Various lattice based studies are performed to determine the possible amount of Co-59 loading and to derive an optimal Co target configuration. Through the lattice depletion analysis, the

achievable fuel discharge burnup as well as the possible Co-60 production capacity have been calculated with several neutronic assumptions. Major safety parameters including fuel temperature coefficient, void reactivity, and coolant temperature coefficient are also evaluated and compared with those of the standard

CANDU6 core. For a more reliable investigation, the Serpent2-COREDAX-2 code system is applied to simulate the 3-D equilibrium core for a Co-loaded CANDU6 core. To compensate for the negative reactivity caused by the Co loading, some of the adjuster rods are removed to achieve the typical fuel burnup. Derived equilibrium core performances are evaluated in terms of fuel burnup and power profile. The power coefficient of reactivity is also evaluated for the 3-D equilibrium core. Also, in this work, Co-60 production in the 3-D time-average core is evaluated and compared with those obtained with simple lattice-based analyses.