Optimization Study on LLFPs Transmutation in PWRs

A systematic study on the Long-lived fission products (LLFPs) transmutation in a PWR has been performed, aiming to devise optimal transmutation strategy in present nuclear power plants. The LLFPs selected in the analysis include ⁹⁹Tc and ¹²⁹I discharged from LWRs. The isotope, ¹²⁷I is also considered to avoid the difficulties in isotopes separation. To minimize the negative impacts of LLFPs on the core performance and safety parameters, technetium or MgI₂ targets mixed with zirconium hydride are designed and investigated. The equilibrium cycles are investigated. The transmuted amounts of ⁹⁹Tc and ¹²⁹I are equals to the yields from 1.94 and 4.22 1000 MWe PWRs, respectively. Numerical results indicate that both the ⁹⁹Tc and ¹²⁹I can be transmuted conveniently in present PWRs in the form of target pins.