Access device for transferring toxic or radioactive substances between a flanged flask and a containment

This invention concerns the transfer of toxic or radioactive substances between a containment and a flask in which such substances are transported. When toxic or radioactive substances are being transferred, it is important to ensure that such substances cannot excape into the surrounding atmosphere and, preferably, the appliance utilized has to be capable of making a misuse impossible, whether accidental or calculated. The flask to which this invention applies is of the type comprising lugs, near its open ends, which act in combination with a groove made around an access opening to hold and maintain the flask in position against the wall of the containment, so that its open end is aligned with an access opening provided in the containment wall