I do not find any crash reports under your email address with which you've registered on this forum. Do you submit the reports under a different email perhaps? Is the crash dialog you receive an Apple dialog or an Adobe dialog?
Macro, before running LR, start the Activity Monitor and click on the Memory tab. Arrange your windows so you can see both the Activity Monitor and Lightroom. As you edit keywords, what is the memory usage of LR right before it crashes?