Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
interval [ˈɪntəvl] n (also MUS) интерва́л; (BRIT) (SPORT) переры́в; (:THEAT) антра́кт
bright intervals (in weather) проясне́ния ntpl
at intervals вре́мя от вре́мени
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.