Why do wav.ReaPeaks files get created

When you record/import audio, Reaper scans it to get all of the information it needs for drawing the waveform in the item - that data is stored in the ReaPeak file, so it doesn't have to re-scan every file every time. You don't need to keep them, and I think there's a setting somewhere to disable storing them; it'll just mean waiting for that "building peaks" window every time.

If it bothers you the .reapeaks files appear in the same directory as the original file, you can set up a global alternative location for the .reapeaks files in the Reaper preferences.

Thanks... 

Appreciate the info. Darn things just get into the way and have caused a lot of irritation. I also took the advice and rerouted them to a junk folder. Thanks...Mark.

I have my reapeaks set to be written onto a 512MB RAM-drive. Works very well, Reaper generates them in the background nicely, so it doesn't even interfere with working on the project. And when I turn off the computer all of then are gone.