PFR/TREAT CO1 and LO1 experiments

The CO1 and LO1 TREAT experiments were the first two in a series of international fast reactor safety experiments to be conducted as part of the PFR/TREAT program being performed by the US and the UK. Conditions for these two experiments simulated a large fast reactor hypothetical (150 ms period) transient overpower (TOP) accident. The CO1 configuration was a single fuel pin in a NaK filled capsule while LO1 used a seven-pin bundle in a flowing sodium loop. The fuel pins in both experiments had no prior irradiation and represented the PFR driver fuel. The CO1 and LO1 experiments were performed on November 5 and November 24, 1980, respectively. This paper describes the objectives, test articles, experimental approach, and the major observations. Post-transient examination results and fuel failure modeling studies are also presented