Just as a note to a 'not a DBA', switching to simple recovery is not typically something you'd do to an important DB as that breaks the log chain and prevents point-in-time restores after the switch (as covered in the first article I referenced)
ReportServerTempDB should be in simple recovery anyway unless someone switched it into full recovery for some reason
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability