Well, a couple things: Energy Solutions is a direct wholly-owned subsidiary. So there's some layers of separation. It's also a waste site and not a sensitive DOE site. So it won't be new territory for a foreign company (say BNFL) being teamed in cleanup projects.
In theory, these subsidiaries are just trade names or recognizable brand names like EG&G, URS, Westinghouse, but there's nothing left of the original company.