Physical Properties and Irradiation Behavior Analysis of Np- and Am-Bearing MOX Fuels

Abstract

The physical properties and irradiation behavior of Np-and Am-bearing MOX were evaluated for the development of advanced fast reactor fuels. The physical properties, lattice parameter, melting temperature, thermal conductivity, and oxygen potential of the fuels were described as functions of Np content, Am content, and oxygen-to-metal (O=M) ratio, and the effect of a few percent Np and Am addition into MOX on those properties was found to be negligibly small. The irradiation tests of fuel pellets having O=M ratios of 1.98 or 1.96 were carried out at a high linear heat rate of about 430 W/cm for 24 h. The redistributions of actinide element and oxygen were analyzed by using the physical properties for Np-and Am-bearing MOX, and the maximum temperatures of the pellets were estimated. The maximum temperatures of the pellets of O=M ¼ 1:96 and 1.98 were estimated to be 2,701 and 2,510 K, respectively. The analysis result showed that the higher maximum temperature in the low-O=M pellet was caused by the low thermal conductivity in the outer region of the pellets, and the maximum temperatures of the pellets did not exceed their melting temperatures. In the results of postirradiation examination, no trace of melting was observed.

Melting temperature of MOX fuel for FBR applications: TRANSURANUS modelling and experimental findings

“…The fair agreement of the Adamson's model predictions with the results of the Konno's model confirms an ideal solution behaviour at high burn-up with an irradiation effect close to the calculations presented in (Adamson et al, 1985). In agreement with the results published in literature, the comparison confirms a negligible effect (Adamson et al, 1985;Hirosawa and Sato, 2011;Kato et al, 2011;Kato et al, 2008b;Konno and Hirosawa, 1998). of the O/M ratio (Konno and Hirosawa, 2002). These models showed a good agreement with the experimental data.…”

“…According to their results, the solidus temperature decreases with increasing O/M ratio, a conclusion confirmed in the MOX measurements performed for comparison (Morimoto et al, 2005). The solidus temperature of MOX fuel containing 1.6 wt.% of americium and 1.6 wt.% of neptunium was measured and compared to the results of MOX specimens with the same concentration of plutonium (30 wt.%) (Kato et al, 2011). The solidus temperature, measured by using a rhenium capsule, decreased with increasing plutonium content and increased with decreasing O/M ratio (Kato et al, 2011).…”

“…The solidus temperature, measured by using a rhenium capsule, decreased with increasing plutonium content and increased with decreasing O/M ratio (Kato et al, 2011). The authors evaluated the effect due to the presence of MA in the range 2-4 K per wt.% (Kato et al, 2011). The melting temperature of MOX fuel bearing 3 wt.% of americium and loaded with fission products to simulate an irradiation to 150 GWd/t was presented in (Tanaka et al, 2012).…”

“…The solidus temperature of MOX fuel containing 1.6 wt.% of americium and 1.6 wt.% of neptunium was measured and compared to the results of MOX specimens with the same concentration of plutonium (30 wt.%) (Kato et al, 2011). The solidus temperature, measured by using a rhenium capsule, decreased with increasing plutonium content and increased with decreasing O/M ratio (Kato et al, 2011). The authors evaluated the effect due to the presence of MA in the range 2-4 K per wt.% (Kato et al, 2011).…”

Report on Evaluation, Verification, and Assessment of Porosity Migration Model in Fast Reactor MOX Fuel

“…A thermal conductivity model for MOX fuel was used in this simulation from Kato et al [7]. In the calculations shown here, the magnitude of thermal conductivity was decreased as the porosity increased in a fashion similar to that described in the following equation, which is consistent with other modeling e↵orts.…”