When Yankee powers down, it will have to be “decommissioned”. However, that process only applies to those structures and appurtenances that were actually involved in nuclear production or otherwise affected. There are numerous other buildings that can remain. They should be put to useful service.
The spent fuel, of course, must be dealt with in an urgent manner. In reality, nothing useful can be developed there while the fuel remains.
One of the biggest assets at the site is the 345,000 volt transmission line network extending North, South and East. Although not owned by Yankee, it is located there and has been significantly upgraded recently. Any new development needs to take this into consideration.