reactor = peripheral.wrap("BigReactors-Reactor_1")
mon = peripheral.wrap("monitor_0")

while true do
  -- reset everything
  mon.clear()
  mon.setBackgroundColor(colors.black)
  mon.setTextColor(colors.white)


  -- active state:
  local activeColor = if reactor.getActive() then colors.green else colors.red end
  local activeText = if reactor.getActive() then "active" else "inactive" end

  mon.setCursorPos(1, 1)
  mon.write("reactor: ")
  mon.setTextColor(activeColor)
  mon.write(activeText)

  sleep(5)
end