Treat Meltdown of Irradiated Metallic Fast-Reactor Fuel in an Inert Atmosphere

Behavior of two types of irradiated metallic fast-reactor fuel pins under transient heating in an inert-gas atmosphere in the TREAT reactor was studied under conditions ranging up to complete meltdown. Irradiation-induced changes in failure thresholds, modes of failure, and post-failure fuel motion were significant but not enough to make gross changes in the course of an accident. The amount of swelling observed in the post-experimental fuel residue was large enough to have played a significant role in determining the course of a meltdown accident.