Not in the conventional sense. But the "ammunition" it does require would be power. It's either going to suck the base dry of power whilst operating or require it's own dedicated power source. Which will weight something and require refuelling and maintainence.
Instead of 10 mags, you're asking for 10 kW or 10 jerries.
Surely that would be a bad idea for an anti-mortar solution? Agreed, the Phalanx on a ship is great, but can you imagine that in the centre of Basrah, great, you might knock a few mortars out, but those rounds it fires have to land somewhere.......and there's more than just a couple!