> 1) Is gas in the envelope at the start the only source of Hydrogen,
Yes, the reactor may be subject to vacuum to remove air before the start of operation. If the envelope is initialized with hydrogen from a tank, the hydride will take the pressure up too high upon heating. The initialization/shutdown cycle is controlled through heating and cooling only. No hydrogen manipulation is required. > > or replaced from a bottle during the course of the experiment? > No replacement. This is to keep the init/shutdown process systemic in terms of pressure. 2) Is there any hydride of another metal present (e.g. Lanthanum)? > Yes > 3) Was the Ni powder saturated with H during the initial pressurization? > No. Pressurization occurs as the hydride heats and releases hydrogen to the envelope. I speculate that the envelope is subject to a vacuum before operations. > 4) Was any Hydrogen left in the envelope after the experiment? > The hydrogen is reabsorbed by the hydride upon cooling of the reactor. How hydrogen is handled throughout the test will be of great interest when the test procedure is released. But it is safe to say, to make the reactor idiot proof, and failsafe, no hydrogen manipulation is permitted in commercial operations. As a design objective, the reactor must be a sealed unit to protect its intellectual content.
