The improvised explosive devices were left in two duffle-type bags placed near the fence of the facility in a residential area in Rockport Park.
The PSNI said an examination of CCTV footage indicated that the bombs "partially initiated" at about 11.35pm last night but "failed to fully explode".
No bomb warning was made.
The finger of suspicion will again fall on dissident republicans opposed to the Norths peace process. Foyle MLA Raymond McCartney has condemned the incident: