NOVELTY - The source has two deformable repositories (S148) compressed about compressed metal hydride powder (242), thermally connected to the compressed metal hydride powder and encapsulating the compressed metal hydride powder. An open end of one of the deformable repositories is nested over an open end of the other deformable repository to define volume filled by the compressed metal hydride powder. A tortuous fluid flow path is defined by the deformable repositories, and fluidly connects the volume to an exterior of the former deformable repository.    USE - High energy density metal hydride fuel source for reducing expansion of hydride e.g. aluminum hydride such as alpha-Alane polymorph hydride, beta-Alane polymorph hydride and gamma-Alane polymorph hydride, sodium borohydride and lithium borohydride, during hydrogen release in a fuel cell field.    ADVANTAGE - The source reduces the hydride expansion during fuel release in an effective manner. The source facilitates encapsulation of the metal hydride pellet to reduce metal hydride powder loss during metal hydride manufacture when the encapsulation functions as a carrier during metal hydride pellet production. The open end of the repository prevents metal hydride egress from the repository.    DETAILED DESCRIPTION - The deformable repositories comprise malleable material, thermally conductive material and aluminum foil. An INDEPENDENT CLAIM is also included for a method for manufacturing a metal hydride fuel source for reducing fuel source expansion during fuel release.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view illustrating a method for blocking and compressing an encapsulated metal hydride pellet by blocking an open end of a repository with a pellet cap and another repository, sealing the open end of the latter repository and compressing the sealed open end and closed end of the former repository.    Deformable repositories (S148)    Receptacles (220A, 220B)    Compressed metal hydride powder (242)