抄録
Long-term reactivity control consists of the compensation of fuel reactivity loss due to the fission products build up in the nuclear fuel. This reactivity loss is balanced by the reactivity gain caused by the burnable absorber (BA) depletion. Introduction of burnable absorber leads to flattening of reactivity during fuel depletion and consequently allow long fuel cycles with higher fuel enrichments. Research of fuel depletion aims at development of advanced types of BAs in nuclear fuel. The paper describes the neutronic calculation comparison of rare earth oxides that can be used as burnable absorbers. VVER nuclear fuel with 5.0 wt% enrichment was selected for the study. Content of rare earth oxides in the fuel was selected to have the same compensation of initial reactivity excess for all studied cases. Multiplication factor during depletion, pin power peaking and residual poisoning was evaluated. Comparison calculations were performed with state-of-art statistical and deterministic depletion codes SERPENT and SCALE/TRITON and with fast depletion code U_WB_1 that are currently under development. Accuracy and calculation speed of calculational tools is commented.
