The main issue, Equation, was not so much their maintenance. They US Navy understood these costs and had factored them into the life cycle when the vessels were built.
The main issue was as I stated...they would have been too costly, and this was an extra major cost...to upgrade to make them as effective as the AEGIS vessels the US Navy began building in the 1980s.
First the Ticonderoga Cruisers and then the Burke AEGIS Destroyers. The AEGIS system and then the VLS capabilitie made those AEGIS vessels much more capable and effective in defense of the Carrier Group than these nuclear powered cruisers. In order to get these nuclear vessels up to that standard, when they had not been designed for those types of provisions, it would have virtually cost as mcuh to change these vessels as it did to build a new vessel.
So, they were retired early due to their defense systems (in the twin armed launchers and the missiles they could carry) and sensors being made obsolete from the US perspective by the AEGIS VLS.
I created a seperate thread for this:
HERE
...so members can continue to discuss the nuclear powered surface combatant issue without going off topic on threads like this.
Cheers!