THE PRELIMINARY PERFORMANCE ANALYSIS OF THE TRANSMUTATION FUEL FOR HYPER
A U-TRU-(40-60)Zr metallic fuel is being considered as the transmutation fuel for HYPER in Korea. U-TRU-15Zr is also considered as the reference fuel for a critical system. The MACSIS-H for an metallic fuel is being developed as a steady-state performance computer code. The fuel temperature calculation schemes were developed and implemented into the MACSIS-H code to analyze the fuel rod performance. A constituent migration subroutine has been made and installed into the MACSIS-H code to simulate the constituent redistribution. The He production rates calculated by other code were inserted into the swelling/FGR routine of the code. The burnup limits and CDF (cumulative damage fraction) were analyzed by the MACSIS-H code. There are lots of uncertainties in the modelling, so some experimental tests are needed for clarifying the uncertainties of the fuel modeling.
Analysis of constituent redistribution in the γ (bcc) U–Pu–Zr alloys under gradients of temperature and concentrations
Abstract Rods of a ternary alloy (71U–19Pu–10Zr by weight percent) were annealed under a temperature gradient of 220°C/cm for 41 days and examined for micro-structural development and compositional redistribution. An enrichment of Zr with concurrent depletion of U was observed within the γ (bcc) phase region on the hot-end side (T≅740°C). The experimental redistribution of the elements in the γ (bcc) phase was analyzed in the framework of multicomponent mass transport with due consideration of thermotransport and ternary diffusional interactions. Based on a new analysis involving an integration of interdiffusion fluxes in the diffusion zone, kinetic parameters related to the thermotransport and ternary interdiffusion were calculated for each component i over selected ranges of composition. The thermotransport coefficients of U, Pu, and Zr were in the approximate ratio of 1:2:−4.5 in the hot-end region. In addition, the interdiffusion flux contributions arising from the gradients of temperature and concentrations of U and Zr were estimated.
An analysis of concentration profiles for fluxes, diffusion depths, and zero-flux planes in multicomponent diffusion
Concentration profiles developed during isothermal, multicomponent diffusion for a single-phase, solid-solid diffusion couple are expressed on the basis of a relative concentration variable for each component and analyzed for the determination of interdiffusion fluxes. The individual concentration profiles intersect at a common cross-over composition where the relative concentrations of all components are identical. New relations are developed for describing internal consistency among the concentration profiles of the various components. A link is made between the cross-over composition and the depths of the diffusion zone on either side of the Matano plane for a diffusion couple. The cross-over composition is interpreted as the average relative concentration of each component over the diffusion zone. The identification of a zero-flux plane from concentration profiles is also described. The analysis offers several advantages in presenting as well as checking the self-consistency of results as illustrated with a single phase Cu-Ni-Zn diffusion couple annealed at 775 °C.