Study of the Self-Controllability for the Fast Reactor Core with High-Thermal-Conductivity Fuel

Abstract

The tolerance capability against ATWS for the FBR core with metallic fuel can be improved by employing a fuel with high thermal conductivity (HTC fuel) instead of the conventional metallic fuel, U-Pu-Zr. To investigate the self-controllability for the HTC-fueled core with U-Pu-Al alloy fuel, having one order of magnitude higher thermal conductivity than that of the U-Pu-Zr, the core employing the U-Pu-Al fuel was evaluated against ULOF and UTOP. Based on the systematic calculation, it was found that the larger temperature margin between the steady state and ULOF/UTOP conditions caused the excellent tolerance capability against ULOF and UTOP for the HTC-fueled core compared with that for the Zralloy-fueled core. Also, the conditions of the core reactivity coefficients required for neither fuel melting nor coolant boiling were investigated by using a ''self-controllability map'' consisting of effective fuel and coolant reactivities. As a result, the self-controllable region was found to be expanded especially for UTOP in the case of the HTC-fueled core.

Helium interactions with alumina formed by atomic layer deposition show potential for mitigating problems with excess helium in spent nuclear fuel

“…Also, aluminum's low neutron cross section [23] precludes significant neutron interactions during nuclear fuel operation and storage. In fact, fuels directly incorporating aluminum for, among other advantages, improved thermal conductivity have been previously investigated [24,25]. Helium transport properties in alumina can be understood with complementary data such has been previously obtained by van Veen [19] and Hurst [26].…”