Originally Posted by
rickair7777
My guess is dynamics of flight would cause small leaks to pop up over time, hence needing a vented containment. Maybe somebody will come up with a leak-proof system which will last 30+ years and 100,000+ airframe cycles.
The containment doesn't need to be high tech, or metal. With sufficient flow, it doesn't need to be perfect either, just prevent more than trace H2 concentrations in the shroud. Old engineering refrain: Dilution is the Solution.
We are just going to disagree on that. Remember, a gas is contained by a pressure vessel, not a tank. Pressure vessels are much thicker. As a result, they are more robust and less prone to impacts of flight dynamics. Metal fatigue is tested for periodically, just like structural integrity metal fatigue of the plane.