Sealing braids undergoing unprecedented tests


Developing high efficiency & reliability machines


Nuclear equipment qualification


Customer requirement:

Evaluation of the performance, behaviour and sealing properties of PTFE braids under normal conditions of use and after exposure to ionising radiation.

Benefits for the customer:

Cetim’s expertise in the design of instrumented test benches equipped with a hydraulic system operating at 200 bars and 300°C. Performance of the test campaign and analysis of the results. Interface with the external laboratory in charge of the irradiation operations.

Cetim’s solution:

Manufacturing of a modular cycling test bench complying with EDF’s requirements and equipped with a removable mechanical device, representative of the valve head, which allows the ionisation of the braid to be carried out in an external laboratory without any change being made to the tightening force.


The performance of the Teflon braids were evaluated several times before and after ionisation with a gradual increase in the radiation dose. Teflon braids are now qualified for deployment on all gates and valves in nuclear plants.