In Generation V OU, Kyurem does not run Dragon Pulse. This is for a few reasons:
- Dragon is a poor offensive type
- Dragon Pulse has relatively low BP
- Kyurem has other moves it needs to perform effectively
Helpfully, Kyurem also learns Earth Power, which provides excellent coverage in conjunction with Ice Beam, thus rendering Dragon Pulse irrelevant.
This isn't to say Kyurem can't use its Dragon STAB effectively — indeed, it frequently runs Draco Meteor to muscle past bulkier threats. But this is even more damning for Dragon Pulse: why use a mediocre STAB move when you can use a nuke instead?
If you're asking about Kyurem-Black, the answer is much the same, plus the obvious caveat of having to forgo an impressive base 170 Attack.