Import Google Reader subscriptions into Flipboard
Yes there is and it is described in an article on the Flipboard web page: "We’ve Got Your RSS Covered! Save Your Google Reader Feeds Now". 

Basically you just have to choose Google Reader in the Accounts tab. Once imported, Flipboard will fetch the feeds on its own. So it will also stay when Google has shut down Reader.

Just one more hint:
If you want to save your feeds in a stand-alone file (e.g. for backing up) you could use Google Takeout.