Tor Browser runs Tor and then opens browser (Firefox), so all security risks associated with Tor are also applicable to Tor Browser.
But as far as you don't reveal your IP while browsing anon network (for example, by catching a remote exploit), the only thing that could potentially be discovered is the fact, that some IP, who seeds a torrent, is also running a copy of Tor - not sure what exactly.
So in general, the answer for your question is yes, it is safe.
Running UTorrent on the same computer with Tor adds no more security risks to Tor & Tor Browser except they already have.
But for really safe security setup I would recommend you to separate all Tor's related stuff inside a virtual machine, and have all it's traffic routed transparently through middlebox Tor Gateway. Read this for more details.
Here is some theory about this solution: Isolating Proxy Concept
and why it is considered much stronger than usual one. In a few words: the operating system doesn't know your real IP at all, it never appears there in any way.