in 1976. Both are rated for 40 years. Since almost all NPPs in the US were "over built", the actual life of these plants is probably at least 60 years which is why the NRC has generally allowed the 20 year increase in life.

Newer III and III+ generation plants that they are planning on building in the US all have 60 year lifespans with expectation they may go to 80 or 100 years of actual operation.

David Walters

They were actually built in the early 70's to last longer than 40 years (the original license length) and certain practices were instituted in the 80's to allow the plants to last at least an additional 20 years.  Most plants of the IP2 and 3 type have had their licenses extended another 20 years.  IP has held off this process for awhile (probably) because of the anti-nuke climate in NY.