The Nuclear Option Main Story, The Railroad Quest
This quest will be triggered or can be aquired when you complete Rockets' Red Glare quest.
Related points of interest
Stages of "The Nuclear Option" quest
1. Talk to Desdemona
After defeating the Brotherhood of Steel, I need to check in with Desdemona to find out how we're going to deal with the Institute.
2. Talk to Z1-14
It's time to finally put the Railroad's plan into action. I need to find Z1-14 in the Institute and let him know we're ready.
3. Kill everyone in the Relay Control Room
5. Reach the Reactor
Z1-14 has brought Railroad members into the Institute. I need to reach the reactor and place a Fusion Pulse Charge on it so we can destroy the entire facility remotely.
First, you need to proceed through the old part of the Institute. There is a fusion core generator here.
When you get to the central part of the Insitute, the next stage will begin.
6. Use Terminal to Override Institute Lockdown
The only way to reach the Institute's reactor is through a terminal in the Director's quarters.
Terminal is in Father's quarters. Use the main elevator to get there. Unlock it and select Master Security Lockdown Override.
You can also talk to dying Father and you can try to convince him to help you. If you succeed, he will give you an access code to turn off some of the synths. To do it, use his terminal and select Director Access: Synth Shutdown.
7. Reach the Reactor
The path to the Institute reactor is now unlocked; I need to pass through the Advanced Systems lab to reach it.
8. Plant Fusion Pulse Charge Inside Reactor
We've arrived at the Institute reactor. Once the Fusion Pulse Charge has been planted, we can finally destroy the Institute once and for all.
9. Talk to Desdemona
The charge is in place; we need to get out of the Institute and reach a safe distance before it can be detonated.
12. Step Into the Relay
13. Use the Detonator
We've successfully made it out of the Institute. All that's left to do now is push the button that will destroy them completely.
14. Talk to Desdemona
It's over. The Institute has been destroyed, and the Railroad stands victorious.