VNX5500 can't delete storage pool

Hi I have two VNX5500,

I have created a storage pool "pool 0" and expanded it to 10TB. 

There is no data on it but it has 3TB used by 18 Virtual Disks which I can see under private luns.

I want to delete the pool but cannot delete it directly or delete the 18 virtual disks.

Any idea how I can do this?

I have checked and I cannot see and mirrors, san copies or snapshots associated with it.