VMS Help DCE_SECURITY, Admin Intro, DCE$IMPORT, IMPORT, Data Qualifiers, /LIFETIME=hours  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /LIFETIME=hours

    Specifies the maximum amount of time, in hours, that a
    ticket can be valid.

    If not specified the Maximum Certificate Lifetime defined
    as registry authorization policy is used.