A study on the burn-up characteristics of inert matrix fuels

• Conduct the research on the characteristics of Inert Matrix Fuel(IMF).
• Systematic comparison study of Pu and MA burn-up accumulation of IMF, UO2, MOX.
• The yields of 237Np and Np of IMF is two order smaller than that of UO2 and MOX.
• IMF fuels has high efficiency on Pu incineration and capability to reduce the amount of TRU.

Proper disposal of minor actinides (MA), long-lived fission products (LLFPs), and transuranium element (TRU) plays a key role in the sustainable development of fission nuclear power. Adoption of inert matrix fuels (IMFs) can effectively reduce the amount of 237Np and Np element in the spent fuel of present-day commercial power reactors. In order to study the burn-up characteristics of IMFs caused by the unique composition, burn-up calculations and MA accumulation of two typical IMFs, PuO2 + ZrO2 + MgO and PuO2 + ThO2, are performed in this paper. Results indicate that kinf at beginning of life (BOL) and reactivity drop with burn-up for PuO2 + ZrO2 + MgO are much larger than those of PuO2 + ThO2 IMF. The yields of 237Np and Np element in IMFs are two orders smaller than those of UO2 and mixed oxide (MOX) fuels. For the same PuO2 volume fraction and a certain burn-up, the masses of 237Np, Np element, and 241Am for PuO2 + ZrO2 + MgO are smaller than those of PuO2 + ThO2; however, the mass of total MA is larger. IMF has high destruction efficiencies of TRU and plutonium (Pu). The results and conclusion provide basic data for the ongoing IMF design and application study.