ATOMIC ARCHIVESFO76…

MISSION: COUNTDOWN

Quest

Mission: Countdown Alpha, Mission: Countdown Bravo, and Mission: Countdown Charlie are repeatable main quests in Fallout 76 which trigger a nuke launch upon a map location selected by the player, creating a Blast Zone.

From “Mission: Countdown” on The Fallout Wiki, CC BY-SA 4.0, adapted (formatting).

WHERE

No map location in the game files (it may happen anywhere, or in an instanced area).

From the quest's location aliases; a quest that travels may list where it starts.

REWARDS (113)

ITEMCHANCE
MissileAlways
Stimpak: Diluted50%
Purified Water25%
RadAway: Diluted17%
.449%
10mm9%
Hunting Rifle9%
Rad-X: Diluted8%
Baton3%
Bowie Knife3%
Fire Axe3%
Meat Hook3%
Revolutionary Sword3%
Recipe: Healing Salve (Forest)3%
Recipe: Psycho3%
Recipe: Bloatfly Loaf<1%
Recipe: Dog Meat Steak<1%
Recipe: Firecap Souffle<1%
Recipe: Fried Deerskins<1%
Recipe: Fried Radtoad Legs<1%
Recipe: Glowing Fungus Puree<1%
Recipe: Ground Molerat<1%
Recipe: Iguana Soup<1%
Recipe: Pumpkin Pie<1%
Recipe: Squirrel On A Stick<1%
Recipe: Steeped Carrot Flower Tea<1%
Recipe: Steeped Melon Blossom Chai<1%
Recipe: Steeped Tato Flower Tea<1%
Recipe: Sweet Mutfruit Tea<1%
Recipe: Sweet Tato Stew<1%
> Show 83 more rewards

Gameplay Reward records, leveled lists at max level; chances are estimates. Rewards a script hands out aren't listed.