A device for sealed attachment of an oval or circular interchangeable member in an oval or circular chamber ring including a mechanical system for secure immobilization of the interchangeable element through the retaining ring mounted on a wall of a containment cell. The attachment device includes an oval or circular retaining ring supporting the interchangeable member. The integral retaining ring includes at least three recesses and the chamber ring includes at least three bolts able to penetrate into the recesses in order to lock the retaining ring on the chamber ring. The retaining ring receives a set of keys supporting the interchangeable element.