Tout dépend de ta définition d'orphelin.
Sinon tu as yum-utils (package-cleanup) qui pourrait peut-être t'aller.
Voici les switchs avec une breve description tu pourras savoir si ça correspond a ce que tu veux faire:
[root@rainbow SPECS]# package-cleanup
usage: package-cleanup [options]
options:
-h, --help show this help message and exit
--problems List dependency problems in the local RPM database
--leaves List leaf nodes in the local RPM database
--all When listing leaf nodes also list leaf nodes that are
not libraries
--orphans List installed packages which are not available from
currenly configured repositories.
-q, --quiet Print out nothing unecessary
-y Agree to anything asked
--oldkernels Remove old kernel and kernel-devel packages
--count=KERNELCOUNT Number of kernel packages to keep on the system
(default 2)
--keepdevel Do not remove kernel-devel packages when removing
kernels
Please specify either --problems, --leaves, --orphans or --oldkernels
