Combined nuclear and steam propulsion system (CONAS) is used on the Kirov-class guided missile cruisers.
Complementary to the nuclear component there are two conventional boilers, installed as a backup in case of reactor failure. Both components are capable of driving two geared steam turbines, generating 120,000 hp (89 MW) at two prop shafts.
References
Combined nuclear and steam propulsion Wikipedia(Text) CC BY-SA