Speaker
Description
In 2022 both helium circulators in the target primary cooling system had a critical failure during a test. The helium circulators, called Turbo-Circulators (TC), are state-of-the-art, that was designed for a flow rate of 3 kg/s of helium at 10 bar to remove 3 MW of heat power deposited to the ESS Tungsten Target.
Since December 2021, three testing periods have been conducted by the He-circulator team to perform preliminary calibration and operations on the two Turbo-Circulators. The failures happened in August 3rd at 11:50 with the failure of Turbo-Circulator A, while it was rotating at the full speed (38kRPM). Later in the afternoon at 15:28 it was decided to resume testing with the Turbo-Circulator B, where it failed at (~30kRPM). While looking closer at the turbo-circulators it was clear that both had received critical damage.
Following the accident an independent investigation team looked at causes leading to the failure of the two given helium circulators. This poster gives a summary of the findings in the independent investigation.