As you have noted elsewhere, molten lithium would interfere with magnetic containment. Lithium hydride melts at a rather higher temperature. I don't know how re

As you have noted elsewhere, molten lithium would interfere with magnetic containment. Lithium hydride melts at a rather higher temperature. I don't know how reactive molten LiH would be with pipes. I know letting any air into contact with molten LiH would be, as we say, bad.