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For an overview of Nuclear Option faction quests, see The Nuclear Option.
Press that button and you not only defeat our enemy, you restore order and decency to the Commonwealth. It's time, Paladin. The Institute and their synth abominations must be eradicated.Arthur Maxson

The Nuclear Option is the final Brotherhood of Steel main quest and an achievement/trophy in Fallout 4.

Quick walkthroughEdit

Brotherhood of Steel main quest: The Nuclear Option
Speak with Elder Maxson.
Go to Father's quarters.
(Optional) Speak to Father.
(Optional) Issue evacuation order.
(Optional) Activate synth deactivation code.
Use terminal to override Institute lockdown.
Reach the reactor.
Plant fusion pulse charge inside reactor.
Talk to Elder Maxson.
Get to the Relay.
Talk to Proctor Ingram.
Take Shaun with you.
Leave Shaun behind.
Step into the Relay.
Activate the detonator.
Talk to Elder Maxson.
Reward: 1500+ XP
Leads to: A New Dawn

Detailed walkthroughEdit

The Sole Survivor must talk to Ingram, and she will say to start up Liberty Prime. Once it is started up, the Sole Survivor must follow it through Boston, to C.I.T. ruins. The Sole Survivor will encounter multiple enemies, and many obstacles. When at the ruins, Arthur Maxson will give an order to destroy the synths attempting to interrupt Liberty Prime. Once Liberty Prime is finished, the Sole Survivor will have to jump into the ruins with Ingram, Maxson, and several soldiers, including Paladin Brandis if he was convinced to rejoin the Brotherhood.

The Sole Survivor must go through a ruined section of the Institute, through Bioscience (if the Sole Survivor has not gotten Virgil's Cure, they can do so now).

Once in the main section of the Institute, they must clear it of enemies. Once done, they must go to speak to Father. Once finished, they can do as they wish with Father, and issue the evacuation order if they wish to. Afterwards, they must enter Advanced Systems, then clear the section of enemies, and get to the reactor. After doing so, they must activate the terminal, and activate the radiation sweep, then disable the reactor's shielding. Then, they must plant the explosive. They will then be teleported out of the reactor section. Ingram will explain that Shaun showed up. The Sole Survivor must decide what to do with Shaun, and then must step into the Molecular Relay. Afterwards, Maxson will tell them that the honor should be theirs to activate the explosive. After doing so, Maxson will tell them to return to The Prydwen and the quest will be completed.

Quest stagesEdit

StageStatusDescriptionLog Entry
300 Talk to Elder Maxson
400 Reach Institute ReactorWe've entered the Institute. I need to reach the reactor and place a Fusion Pulse Charge on it so we can destroy the entire facility remotely.
430 Use Terminal to Override Institute LockdownThe only way to reach the Institute's reactor is through a terminal in the Director's quarters.
450 (Optional) Issue Evacuation Order
475 Reach the Reactor
500 Plant Fusion Pulse Charge Inside ReactorWe've arrived at the Institute reactor. Once the Fusion Pulse Charge has been planted, we can finally destroy the Institute once and for all.
600 Talk to Elder MaxsonThe charge is in place; we need to get out of the Institute and reach a safe distance before it can be detonated.
700 Talk to Proctor Ingram
710 Talk to Shaun
740 Step into the relay
800 Activate detonatorWe've successfully made it out of the Institute. All that's left to do now is push the button that will destroy them completely.
900 Talk to Elder MaxsonIt's over. The Institute has been destroyed, and the Brotherhood of Steel is victorious.
1000Quest finishedIcon checkQuest complete


  • If Paladin Brandis was convinced to rejoin the Brotherhood ranks after the Lost Patrol, he will be part of the forces entering the Institute. Be warned, he can die during this mission.
  • With 10 Intelligence and Idiot Savant rank 2 triggering, this quest can yield a staggering 9750 XP upon completion.
  • After this quest has been completed several synth soldiers (along with a suit of power armor) will occasionally appear floating above the now cratered remains of the C.I.T. ruins. They are not hostile unless shot and even then don't pose much of a threat since they are swimming. The power armor is unfortunately stuck floating forever.
    • The armor can be retrieved, without the use of console commands, by exploiting the physics glitch related to engine blocks. Though difficult, one can position themselves over the armor, let go of the block, and get in, thus depositing the player and power armor in the water below. Due to the rarity of engine block models in the world, and the considerable distance they must be carried to the Institute crater, this method is a considerable undertaking.
  • Shortly after the explosion, the ending cutscene will start.


  • pcIcon pc After blowing up the Institute one may find themselves unable to talk to Elder Maxson to continue the quest, or he may be absent. For the PC, open the console and use commands prid 1cc18, recycleactor and then moveto player to teleport Elder Maxson to the player's location. [verified]
    • One may not need to use recycleactor, just prid & moveto.
  • ps4Icon ps4 Entering and exiting the FEV lab may cause several synths to become allied to the Brotherhood and attack other synths. [verification overdue]
  • The player can sometimes be unable to fast travel after killing themselves and reloading on the Mass Fusion building before detonating the bomb.[platforms tag needed] [verification overdue]
  • After completing Ad Victoriam and entering the Institute, Elder Maxson and the rest of the team may not show up. It will not be possible to receive this quest from Elder Maxson but one can enter the Institute, but they will attack once the player steps out of the elevator. [platforms tag needed] [verification overdue]
  • pcIcon pc Quest may become stuck on "Speak with Shaun" with no way to move forward without using the console. [verified]
    • SetStage MQ302BOS 720 (taking Shaun) or SetStage MQ302BOS 730 (leaving Shaun) will fix this issue.
  • If Father was killed before confronting him during the quest, his body will spawn sideways in mid air. [verification overdue]

See alsoEdit