while true do
  local reactor = peripheral.wrap("BigReactors-Reactor_5")
  local low = 100000
  local high = 200000

  if reactor.getEnergyStored() <= low then
    reactor.setAllControlRodLevels(0)
  end

  if reactor.getEnergyStored() >= high then
    reactor.setAllControlRodLevels(90)
  end

  sleep(5)
end