A hydrogen fuel cartridge comprising: a fuel chamber; an outlet; a first valve assembly disposed between the fuel chamber and the outlet, the first valve assembly comprising: a valve stem having a resilient proximal seal member disposed around the stem and a distal seal member disposed around the stem, the proximal and distal seal members being axially separated from one another along the valve stem; a housing defining a valve chamber in which the valve stem is confined so as to be axially displaceable within the valve chamber, the housing defining a first portion of the valve chamber in which the proximal seal member resides and a second portion of the valve chamber in which the distal seal member resides and further defining a cross-bore chamber which opens into the valve chamber in a third portion between the first and second portions; wherein the third portion has a minimum cross-sectional diameter greater than the cross-sectional diameter of the first portion; a second valve assembly including a valve stem for actuation, and disposed between the fuel chamber and the outlet; a cross-bore chamber extending between the first valve assembly and the second valve assembly, the valve assemblies together configured to enable release of fluid from the fuel chamber to the outlet via the first and second valve assemblies and the cross-bore chamber upon actuation of the valve stems of both the first and second valve assemblies. a fuel chamber; an outlet; a first valve assembly disposed between the fuel chamber and the outlet, the first valve assembly comprising: a valve stem having a resilient proximal seal member disposed around the stem and a distal seal member disposed around the stem, the proximal and distal seal members being axially separated from one another along the valve stem; a housing defining a valve chamber in which the valve stem is confined so as to be axially displaceable within the valve chamber, the housing defining a first portion of the valve chamber in which the proximal seal member resides and a second portion of the valve chamber in which the distal seal member resides and further defining a cross-bore chamber which opens into the valve chamber in a third portion between the first and second portions; wherein the third portion has a minimum cross-sectional diameter greater than the cross-sectional diameter of the first portion; a valve stem having a resilient proximal seal member disposed around the stem and a distal seal member disposed around the stem, the proximal and distal seal members being axially separated from one another along the valve stem; a housing defining a valve chamber in which the valve stem is confined so as to be axially displaceable within the valve chamber, the housing defining a first portion of the valve chamber in which the proximal seal member resides and a second portion of the valve chamber in which the distal seal member resides and further defining a cross-bore chamber which opens into the valve chamber in a third portion between the first and second portions; wherein the third portion has a minimum cross-sectional diameter greater than the cross-sectional diameter of the first portion; a second valve assembly including a valve stem for actuation, and disposed between the fuel chamber and the outlet; a cross-bore chamber extending between the first valve assembly and the second valve assembly, the valve assemblies together configured to enable release of fluid from the fuel chamber to the outlet via the first and second valve assemblies and the cross-bore chamber upon actuation of the valve stems of both the first and second valve assemblies.