Nuclear keycard is a miscellaneous item in Fallout 76.
A crucial part of the automated nuclear missile silo network in Appalachia, nuclear keycards are required to unlock access to the launch console so that the launch code could be input. The receptacle in the missile control rooms would destroy the keycard regardless of whether the correct code was entered or not. This limitation was intended to limit the amount of nuclear weapons any single officer had at their disposal and the supply of keycard in case of escalation would be delivered by automated couriers of the Strategic Air Command.
Convoys were set by the SAC to occur should the automated system monitoring Appalachia deem it necessary, based on the aggregate DEFCON rating. The Enclave under President Thomas Eckhart deliberately released various horrors upon Appalachia to trick the system into raising the DEFCON rating, starting with Chinese Liberators and ending with Scorchbeasts.
- Transported by Strategic Air Command cargobots through Appalachia. Locations can be found through the repeatable Hide and Seek and Destroy quest obtained at The Whitespring Bunker.
- The Whitespring Bunker nuclear training: "Greeting, general. Welcome to your nuclear launch training session. Over the course of the next four posters, you'll be taught everything you need to know about utilizing the Appalachian Automated Launch system. During your briefing, you should've been issued a Nuclear Keycard. During an actual launch, you will need to insert the card into the designated slot before entering your launch code, at which point the keycard will be consumed. Additional card drops will be brought in by automated convoy should the DEFCON rating continue to worsen. You may speak to your logistics officer as to the location of the pick-up for your additional cards, should the circumstances arise."
- The Whitespring Bunker terminals: "Tricking DEFCON [...]"