How do I make a nuke explode in a building and make the building destroyed?

I am trying to make a script where a nuke explodes and then the building changes to a destroyed version but neither scripts are working for me. Here's the script:

game.Workspace.Nuke.Transparency = 0
game.Workspace.Nuke.CanCollide = true

local originPart = game.Workspace.Nuke
local radius = 1000

function killFromOrigin()
    for i,v in pairs (game.Workspace:GetChildren()) do
        local humanoid = v:FindFirstChild("Humanoid")
        local head = v:FindFirstChild("Head")
        if head ~= nil and humanoid ~= nil then
            if (originPart.Position - head.Position).Magnitude <= radius then
                humanoid.Health = 0
game.Workspace.ReactorCore1:Destroy()
local map = game.ServerStorage.ReactorCore2
map:Clone().Parent = game.Workspace

            end
        end
    end
end