There is a difference between the recordings made by CVR in the cockpit and recordings made at ATC ON THE GROUND.
ICAO Document describing it and giving recommendations.
CVR records sound of what is happening in the cockpit as well as voice communication with ATC. It can not record ATC communication with other aircraft on other frequency, nor radar feed in ATC.
ICAO requeres that ATC recordings are kept for at least two weeks if there is no crash and as long as needed if there is a crash. KIEV ATC recordings were not given to the international investigative team. It has nothing do do with intact Black boxes (orange box on the picture) given to Investigators in U.K.