According to Lucy, the procratemod (proc rate modifier) is 0 which means it procs as much as a "normal" weapon. This is in comparison to the Ethereal Destroyer which has the same proc on it, but is "crippled" by only procing at 85% of the "normal" rate.
The base normal rate as shown by parsing on the war page comes out over time to be 2 procs per minute.